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  • 1.
    Ahlgren, Sara
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences.
    Orlova, Anna
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science.
    Wållberg, Helena
    Affibody AB, Stockholm, Sweden.
    Hansson, Monika
    Affibody AB, Stockholm, Sweden.
    Sandström, Mattias
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Oncology.
    Lewsley, Richard
    Department of Metabolism, Covance Laboratories Ltd, Harrogate, UK.
    Wennborg, Anders
    Affibody AB, Stockholm, Sweden.
    Abrahmsén, Lars
    Affibody AB, Stockholm, Sweden.
    Tolmachev, Vladimir
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science.
    Feldwisch, Joachim
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science.
    Targeting of HER2-Expressing Tumors Using 111In-ABY-025, a Second-Generation Affibody Molecule with a Fundamentally Reengineered Scaffold2010In: Journal of Nuclear Medicine, ISSN 0161-5505, E-ISSN 1535-5667, Vol. 51, no 7, p. 1131-1138Article in journal (Refereed)
    Abstract [en]

    Overexpression of HER2 in breast carcinomas predicts response to trastuzumab therapy. Affibody molecules based on a non-immunoglobulin scaffold have demon-strated high potential for in vivo molecular imaging of HER2-expressing tumors. Re-engineering of the molecular scaffold has led to a second generation of optimized Affibody molecules, having a surface distinctly different from the parental protein domain from staphylococcal protein A. The new tracer showed further increased melting point, stability and overall hydrophilicity compared to the parental molecule, and was shown to be more amenable for chemical peptide synthesis. The goal of this study was to assess potential effects of this extensive re-engineering on HER2 targeting, using ABY-025, a DOTA conjugated variant of the novel tracer.

    Methods: 111In-ABY-025 was compared with previously evaluated parent HER2-binding Affibody tracers in vitro and in vivo. The in vivo behavior was further evaluated in mice bearing SKOV-3 xenografts, in rats and in cynomolgus macaques.

    Results: 111In-ABY-025 bound specifically to HER2 in vitro and in vivo. Direct comparison with the previous generation of HER2-binding tracers showed that ABY-025 retained excellent targeting properties. Rapid blood clearance was shown in mice, rats and macaques. A highly specific tumor uptake of 16.7 ± 2.5 %IA/g was seen at 4 h after injection. The tumor-to-blood ratio was 6.3 at 0.5 h, 88 at 4 h, and increased up to 3 days after injection. Gamma camera imaging of tumors was already possible 0.5 h after injection. Furthermore, repeated i.v. administration of ABY-025 did not induce antibody formation in rats.

    Conclusions: The biodistribution of 111In-ABY-025 was in remarkably good agreement with the parent tracers, despite profound re-engineering of the non-binding surface. The molecule displayed rapid blood clearance in all species investigated and excellent targeting capacity in tumor bearing mice, leading to high tumor-to-organ-ratios and high contrast imaging shortly after injection.

  • 2.
    Ahlgren, Sara
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences.
    Wållberg, Helena
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology, Biomedical Radiation Sciences.
    Tran, Thuy A.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology, Biomedical Radiation Sciences.
    Widström, Charles
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology, Section of Medical Physics.
    Hjertman, Magnus
    Affibody AB, Stockholm, Sweden.
    Abrahmsén, Lars
    Affibody AB, Stockholm, Sweden.
    Berndorff, Dietmar
    Global Drug Discovery, Bayer Schering Pharma AG, Berlin, Germany.
    Dinkelborg, Ludger M.
    Global Drug Discovery, Bayer Schering Pharma AG, Berlin, Germany.
    Cyr, John E.
    Global Drug Discovery, Bayer Schering Pharma AG, Berlin, Germany.
    Feldwisch, Joachim
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology, Biomedical Radiation Sciences.
    Orlova, Anna
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology, Biomedical Radiation Sciences.
    Tolmachev, Vladimir
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology, Biomedical Radiation Sciences.
    Targeting of HER2-expressing tumors with a site-specifically 99mTc-labeled recombinant affibody molecule, ZHER2:2395, with C-terminally engineered cysteine2009In: Journal of Nuclear Medicine, ISSN 0161-5505, E-ISSN 1535-5667, Vol. 50, no 5, p. 781-789Article in journal (Refereed)
    Abstract [en]

    The detection of human epidermal growth factor receptor type 2 (HER2) expression in malignant tumors provides important information influencing patient management. Radionuclide in vivo imaging of HER2 may permit the detection of HER2 in both primary tumors and metastases by a single noninvasive procedure. Small (7 kDa) high-affinity anti-HER2 Affibody molecules may be suitable tracers for SPECT visualization of HER2-expressing tumors. The use of generator-produced (99m)Tc as a label would facilitate the prompt translation of anti-HER2 Affibody molecules into use in clinics. METHODS: A C-terminal cysteine was introduced into the Affibody molecule Z(HER2:342) to enable site-specific labeling with (99m)Tc. Two recombinant variants, His(6)-Z(HER2:342)-Cys (dissociation constant [K(D)], 29 pM) and Z(HER2:2395)-Cys, lacking a His tag (K(D), 27 pM), were labeled with (99m)Tc in yields exceeding 90%. The binding specificity and the cellular processing of Affibody molecules were studied in vitro. Biodistribution and gamma-camera imaging studies were performed in mice bearing HER2-expressing xenografts. RESULTS: (99m)Tc-His(6)-Z(HER2:342)-Cys was capable of targeting HER2-expressing SKOV-3 xenografts in SCID mice, but the liver radioactivity uptake was high. A series of comparative biodistribution experiments indicated that the presence of the His tag caused elevated accumulation in the liver. (99m)Tc-Z(HER2:2395)-Cys, not containing a His tag, showed low uptake in the liver and high and specific uptake in HER2-expressing xenografts. Four hours after injection, the radioactivity uptake values (percentage of injected activity per gram of tissue [%IA/g]) were 6.9 +/- 2.5 (mean +/- SD) %IA/g in LS174T xenografts (moderate level of HER2 expression) and 15 +/- 3 %IA/g in SKOV-3 xenografts (high level of HER2 expression). The corresponding tumor-to-blood ratios were 88 +/- 24 and 121 +/- 24, respectively. Both LS174T and SKOV-3 xenografts were clearly visualized with a clinical gamma-camera 1 h after injection of (99m)Tc-Z(HER2:2395)-Cys. CONCLUSION: The Affibody molecule (99m)Tc-Z(HER2:2395)-Cys is a promising tracer for SPECT visualization of HER2-expressing tumors.

  • 3.
    Altai, Mohamed
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Medical Radiation Science.
    Membreno, Rosemery
    CUNY Hunter Coll, Dept Chem, New York, NY 10021 USA.;CUNY, Grad Ctr, PhD Program Chem, New York, NY USA.;Mem Sloan Kettering Canc Ctr, Dept Radiol, 1275 York Ave, New York, NY 10021 USA..
    Cook, Brendon
    CUNY Hunter Coll, Dept Chem, New York, NY 10021 USA.;CUNY, Grad Ctr, PhD Program Chem, New York, NY USA.;Mem Sloan Kettering Canc Ctr, Dept Radiol, 1275 York Ave, New York, NY 10021 USA..
    Tolmachev, Vladimir
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Medical Radiation Science.
    Zeglis, Brian M.
    CUNY Hunter Coll, Dept Chem, New York, NY 10021 USA.;CUNY, Grad Ctr, PhD Program Chem, New York, NY USA.;Mem Sloan Kettering Canc Ctr, Dept Radiol, 1275 York Ave, New York, NY 10021 USA..
    Pretargeted Imaging and Therapy2017In: Journal of Nuclear Medicine, ISSN 0161-5505, E-ISSN 1535-5667, Vol. 58, no 10, p. 1553-1559Article in journal (Refereed)
    Abstract [en]

    In vivo pretargeting stands as a promising approach to harnessing the exquisite tumor-targeting properties of antibodies for nuclear imaging and therapy while simultaneously skirting their pharmacokinetic limitations. The core premise of pretargeting lies in administering the targeting vector and radioisotope separately and having the 2 components combine within the body. In this manner, pretargeting strategies decrease the circulation time of the radioactivity, reduce the uptake of the radionuclide in healthy nontarget tissues, and facilitate the use of short-lived radionuclides that would otherwise be incompatible with antibody-based vectors. In this short review, we seek to provide a brief yet informative survey of the 4 preeminent mechanistic approaches to pretargeting, strategies predicated on streptavidin and biotin, bispecific antibodies, complementary oligonucleotides, and bioorthogonal click chemistry.

  • 4.
    Altai, Mohamed
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Medical Radiation Science.
    Perols, Anna
    Tsourma, Maria
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Medical Radiation Science.
    Mitran, Bogdan
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Preclinical PET Platform.
    Honarvar, Hadis
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Medical Radiation Science.
    Robillard, Marc
    Rossin, Raffaella
    Ten Hoeve, Wolter
    Lubberink, Mark
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology.
    Orlova, Anna
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Preclinical PET Platform.
    Eriksson Karlström, Amelie
    Tolmachev, Vladimir
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Medical Radiation Science.
    Feasibility of affibody-based bioorthogonal chemistry-mediated radionuclide pretargeting2016In: Journal of Nuclear Medicine, ISSN 0161-5505, E-ISSN 1535-5667, Vol. 57, no 3, p. 431-436Article in journal (Refereed)
    Abstract [en]

    Affibody molecules constitute a new class of probes for radionuclide tumor targeting. The small size of affibody molecules is favorable for rapid localization in tumors and clearance from circulation. However, high renal re-absorption of affibody molecules prevents the use of residualizing radiometals, including a number of promising low energy beta- and alpha-emitters, for radionuclide therapy. We tested a hypothesis that affibody-based pretargeting mediated by a bioorthogonal interaction between trans-cyclooctene (TCO) and tetrazine would provide higher accumulation of radiometals in tumor xenografts than in the kidneys.

    Methods:

    TCO was conjugated to the anti-HER2 affibody molecule Z2395. DOTA-tetrazine was labeled with indium-111 and lutetium-177. In vitro pretargeting was studied in HER2-expressing SKOV-3 and BT474 cell lines. In vivo studies were performed on BALB/C nu/nu mice bearing SKOV-3 xenografts.

    Results:

    125I-Z2395-TCO bound specifically to HER2-expressing cells in vitro with an affinity of 45±16 pM. 111In-tetrazine bound specifically and selectively to Z2395-TCO pre-treated cells. In vivo studies demonstrated HER2-specific 125I-Z2395-TCO accumulation in xenografts. TCO-mediated 111In-tetrazine localization was shown in tumors, when the radiolabeled tracer was injected 4 h after an injection of Z2395-TCO. At 1 h post injection, the tumor uptake of 111In-tetrazine and 177Lu-tetrazine was ca. 2-fold higher than the renal uptake. Pretargeting provided more than a 56-fold reduction of renal uptake of 111In in comparison with direct targeting.

    Conclusion:

    The feasibility of affibody-based bioorthogonal chemistry-mediated pretargeting was demonstrated. The use of pretargeting provides a substantial reduction of radiometal accumulation in kidneys, creating preconditions for palliative radionuclide therapy.

  • 5.
    Altai, Mohamed
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Biomedical Radiation Sciences.
    Wållberg, Helena
    Honarvar, Hadis
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Biomedical Radiation Sciences.
    Strand, Joanna
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Biomedical Radiation Sciences.
    Orlova, Anna
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Preclinical PET Platform.
    Varasteh, Zohreh
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Preclinical PET Platform.
    Sandström, Mattias
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Medical Radiation Sciences. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Section of Nuclear Medicine and PET.
    Löfblom, John
    Larsson, Erik
    Strand, Sven-Erik
    Lubberink, Mark
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Section of Nuclear Medicine and PET. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Section of Medical Physics.
    Ståhl, Stefan
    Tolmachev, Vladimir
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Biomedical Radiation Sciences.
    188Re-ZHER2:V2, a promising affibody-based targeting agent against HER2-expressing tumors: preclinical assessment2014In: Journal of Nuclear Medicine, ISSN 0161-5505, E-ISSN 1535-5667, Vol. 55, no 11, p. 1842-1848Article in journal (Refereed)
    Abstract [en]

    Affibody molecules are small (7 kDa) nonimmunoglobulin scaffold proteins with favorable tumor-targeting properties. Studies concerning the influence of chelators on biodistribution of 99mTc-labeled Affibody molecules demonstrated that the variant with a C-terminal glycyl-glycyl-glycyl-cysteine peptide–based chelator (designated ZHER2:V2) has the best biodistribution profile in vivo and the lowest renal retention of radioactivity. The aim of this study was to evaluate 188Re-ZHER2:V2 as a potential candidate for radionuclide therapy of human epidermal growth factor receptor type 2 (HER2)–expressing tumors.

    Methods:

    ZHER2:V2 was labeled with 188Re using a gluconate-containing kit. Targeting of HER2-overexpressing SKOV-3 ovarian carcinoma xenografts in nude mice was studied for a dosimetry assessment.

    Results:

    Binding of 188Re-ZHER2:V2 to living SKOV-3 cells was demonstrated to be specific, with an affinity of 6.4 ± 0.4 pM. The biodistribution study showed a rapid blood clearance (1.4 ± 0.1 percentage injected activity per gram [%ID/g] at 1 h after injection). The tumor uptake was 14 ± 2, 12 ± 2, 5 ± 2, and 1.8 ± 0.5 %IA/g at 1, 4, 24, and 48 h after injection, respectively. The in vivo targeting of HER2-expressing xenografts was specific. Already at 4 h after injection, tumor uptake exceeded kidney uptake (2.1 ± 0.2 %IA/g). Scintillation-camera imaging showed that tumor xenografts were the only sites with prominent accumulation of radioactivity at 4 h after injection. Based on the biokinetics, a dosimetry evaluation for humans suggests that 188Re-ZHER2:V2 would provide an absorbed dose to tumor of 79 Gy without exceeding absorbed doses of 23 Gy to kidneys and 2 Gy to bone marrow. This indicates that future human radiotherapy studies may be feasible.

    Conclusion:

    188Re-ZHER2:V2 can deliver high absorbed doses to tumors without exceeding kidney and bone marrow toxicity limits.

  • 6. Andersson, Jesper L
    et al.
    Sundin, Anders
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Radiology. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Section of Nuclear Medicine and PET.
    Valind, Sven
    A method for coregistration of PET and MR brain images1995In: Journal of Nuclear Medicine, ISSN 0161-5505, E-ISSN 1535-5667, Vol. 36, no 7, p. 1307-1315Article in journal (Refereed)
    Abstract [en]

    Combining MRI morphological data with functional PET data offers significant advantages in research as well as in many clinical situations. Automatic methods are needed, however, to coregister the data from the two modalities.

    METHODS:

    Simulated PET images were created by simple and automatic segmentation of MR images followed by the assignment of different uptake values to various tissue types. The simulated PET images were registered to actual PET images using a pixel-by-pixel, PET-PET registration method. The transformation matrix was then applied to the MR images. The method was used to register MRI data to PET transmission scans and emission scans obtained with FDG, nomifensine and raclopride. Validation was performed by comparing the results to those obtained by matching internal points manually defined in both volumes.

    RESULTS:

    Emission and transmission PET images were successfully registered to MR data. Comparison to the manual method indicated a registration accuracy on the order of 1-2 mm in each direction. No difference in accuracy between the different tracers was found. The error sensitivity for the method's assumptions seemed to be sufficiently low to allow complete automation of the method.

    CONCLUSION:

    We present a rapid, robust and fully automated method to register PET and MR brain images with sufficient accuracy for most clinical applications.

  • 7.
    Antoni, Gunnar
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Preclinical PET Platform.
    Lubberink, Mark
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Section of Nuclear Medicine and PET.
    Estrada, Sergio
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Preclinical PET Platform.
    Axelsson, Jan
    Carlson, Kristina
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Haematology.
    Lindsjö, Lars
    Kero, Tanja
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Section of Nuclear Medicine and PET.
    Långström, Bengt
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Granstam, Sven-Olof
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Clinical Physiology.
    Rosengren, Sara
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Haematology.
    Vedin, Ola
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, UCR-Uppsala Clinical Research Center.
    Wassberg, Cecilia
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Section of Nuclear Medicine and PET.
    Wikström, Gerhard
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Cardiology.
    Westermark, Per
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Molecular and Morphological Pathology.
    Sörensen, Jens
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Section of Nuclear Medicine and PET.
    In Vivo Visualization of Amyloid Deposits in the Heart with 11C-PIB and PET2013In: Journal of Nuclear Medicine, ISSN 0161-5505, E-ISSN 1535-5667, Vol. 54, no 2, p. 213-220Article in journal (Refereed)
    Abstract [en]

    Cardiac amyloidosis is a differential diagnosis in heart failure and is associated with high mortality. There is currently no noninvasive imaging test available for specific diagnosis. N-[methyl-11C]2-(4′-methylamino-phenyl)-6-hydroxybenzothiazole (11C-PIB) PET is used in the evaluation of brain amyloidosis. We evaluated the potential use of 11C-PIB PET in systemic amyloidosis affecting the heart.

    Methods:

    Patients (n = 10) diagnosed with systemic amyloidosis—including heart involvement of either monoclonal immunoglobulin light-chain (AL) or transthyretin (ATTR) type—and healthy volunteers (n = 5) were investigated with PET/CT using 11C-PIB to study cardiac amyloid deposits and with 11C-acetate to measure myocardial blood flow to study the impact of global and regional perfusion on PIB retention.

    Results:

    Myocardial 11C-PIB uptake was visually evident in all patients 15–25 min after injection and was not seen in any volunteer. A significant difference in 11C-PIB retention in the heart between patients and healthy controls was found. The data indicate that myocardial amyloid deposits in patients diagnosed with systemic amyloidosis could be visualized with 11C-PIB. No correlation between 11C-PIB retention index and myocardial blood flow as measured with 11C-acetate was found on the global level, whereas a positive correlation on the segmental level was seen in a single patient.

    Conclusion:

    11C-PIB and PET could be a method to study systemic amyloidosis of type AL and ATTR affecting the heart and should be investigated further both as a diagnostic tool and as a noninvasive method for treatment follow-up.

  • 8.
    Appel, Lieuwe
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Section of Nuclear Medicine and PET. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology.
    Jonasson, My
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Section of Nuclear Medicine and PET. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology.
    Danfors, Torsten
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Section of Nuclear Medicine and PET. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology.
    Nyholm, Dag
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurology.
    Askmark, Håkan
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurology.
    Lubberink, Mark
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Section of Nuclear Medicine and PET. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology.
    Sörensen, Jens
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Section of Nuclear Medicine and PET. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology.
    Use of C-11-PE2I PET in Differential Diagnosis of Parkinsonian Disorders2015In: Journal of Nuclear Medicine, ISSN 0161-5505, E-ISSN 1535-5667, Vol. 56, no 2, p. 234-242Article in journal (Refereed)
    Abstract [en]

    In idiopathic Parkinson disease and atypical parkinsonian disorders, central dopaminergic and overall brain functional activity are altered to different degrees, causing difficulties in achieving an unambiguous clinical diagnosis. A dual examination using I-123-FP-CIT (I-123-N-omega-fluoropropyl- 2 beta-carbomethoxy-3 beta-(4-iodophenyl) nortropane, or I-123-ioflupane) SPECT and F-18-FDG PET provides complementary information on dopamine transporter (DAT) availability and overall brain functional activity, respectively. Parametric images based on a single, dynamic C-11-PE2I (N-(3-iodoprop-2E-enyl)-2 beta-carbomethoxy-3 beta-(4-methyl-phenyl) nortropane) scan potentially supply both DAT availability (nondisplaceable binding potential [BPND]) and relative cerebral blood flow (relative delivery [R-1]) at voxel level. This study aimed to evaluate the validity of C-11-PE2I PET against the dual-modality approach using I-123-FP-CIT SPECT and F-18-FDG PET.

    Methods: Sixteen patients with parkinsonian disorders had a dual examination with F-18-FDG PET and I-123-FP-CIT SPECT following clinical routines and additionally an experimental C-11-PE2I PET scan. Parametric BPND and R-1 images were generated using receptor parametric mapping with the cerebellum as a reference. T1-weighted MR imaging was used for automated definition of volumes of interest (VOI). The DAT VOIs included the basal ganglia, whereas the overall brain functional activity was examined using VOIs across the brain. BPND and R-1 values were compared with normalized I-123-FP-CIT and F-18-FDG uptake values, respectively, using Pearson correlations and regression analyses. In addition, 2 masked interpreters evaluated the images visually, in both the routine and the experimental datasets, for comparison of patient diagnoses.

    Results: Parametric C-11-PE2I BPND and R-1 images showed high consistency with I-123-FP-CIT SPECT and F-18-FDG PET images. Correlations between C-11-PE2I BPND and I-123-FP-CIT uptake ratios were 0.97 and 0.76 in the putamen and caudate nucleus, respectively. Regional C-11-PE2I R-1 values were moderately to highly correlated with normalized F-18-FDG values (range, 0.61-0.94). Visual assessment of DAT availability showed a high consistency between C-11-PE2I BPND and I-123-FP-CIT images, whereas the consistency was somewhat lower for appraisal of overall brain functional activity using I-123-FP-CIT and F-18-FDG images. Substantial differences were found between clinical diagnosis and both neuro-imaging diagnoses.

    Conclusion: A single, dynamic C-11-PE2I PET investigation is a powerful alternative to a dual examination with I-123-FP-CIT SPECT and F-18-FDG PET for differential diagnosis of parkinsonian disorders. A large-scale patient study is, however, needed to further investigate distinct pathologic patterns in overall brain functional activity for various parkinsonian disorders.

  • 9. Baum, Richard P
    et al.
    Prasad, Vikas
    Müller, Dirk
    Schuchardt, Christiane
    Orlova, Anna
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology.
    Wennborg, Anders
    Tolmachev, Vladimir
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology.
    Feldwisch, Joachim
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology.
    Molecular imaging of HER2-expressing malignant tumors in breast cancer patients using synthetic 111In- or 68Ga-labeled affibody molecules2010In: Journal of Nuclear Medicine, ISSN 0161-5505, E-ISSN 1535-5667, Vol. 51, no 6, p. 892-897Article in journal (Refereed)
    Abstract [en]

    The clinical utility of a human epidermal growth factor receptor 2 (HER2)-targeting Affibody molecule for detection and characterization of HER2-positive lesions was investigated in patients with recurrent metastatic breast cancer. METHODS: Three patients received (111)In- or (68)Ga-labeled DOTA(0)-Z(HER2:342-pep2) (ABY-002). gamma-Camera, SPECT, or PET/CT images were compared with earlier (18)F-FDG PET/CT results. RESULTS: Administration of radiolabeled ABY-002 was well tolerated. Blood kinetics of radiolabeled ABY-002 showed a first half-life of 4-14 min, second half-life of 1-4 h, and third half-life of 12-18 h. Radiolabeled ABY-002 detected 9 of 11 (18)F-FDG-positive metastases as early as 2-3 h after injection. CONCLUSION: Molecular imaging using (111)In- or (68)Ga-labeled ABY-002 has the potential to localize metastatic lesions in vivo, adds qualitative information not available today by conventional imaging techniques, and may allow the HER2 status to be determined for metastases not amenable to biopsy. To our knowledge, this is the first report on clinical imaging data obtained with a non-immunoglobulin-based scaffold protein.

  • 10.
    Bergström, Mats
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Pharmacy. Uppsala Univ, PET Ctr, Uppsala, Sweden..
    The Use of Microdosing in the Development of Small Organic and Protein Therapeutics2017In: Journal of Nuclear Medicine, ISSN 0161-5505, E-ISSN 1535-5667, Vol. 58, no 8, p. 1188-1195Article in journal (Refereed)
    Abstract [en]

    Microdosing as a regulatory concept was introduced to facilitate exploratory studies in humans. The concept involves the use of very low doses of a radionuclide-labeled compound for imaging studies or for assessing plasma pharmacokinetics using equipment that has a highly sensitive readout. The supporting principle is that use of these low doses for a limited time in well-controlled, small populations will limit exposure and have a low risk of adverse effects. Microdosing regulations specify a reduced preclinical toxicology-assessment package in order to shorten the route to human studies and reduce its cost. However, for extrapolation to therapeutically relevant doses and plasma concentrations, there are specific aspects of the use of these low doses and low plasma concentrations that require special attention. These specific aspects are reviewed in this article, with separate attention being paid to small organic molecules and protein therapeutics. The indications for microdosing in drug development are discussed in terms of the 3 pillars of survival in drug development, the first of which is characterization of tissue distribution and access to the site of action; the second, engagement of the target; and the third, induction of tissue responses relevant to a therapeutic response.

  • 11. Bergström, Mats
    et al.
    Eriksson, Barbro
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences.
    Öberg, Kjell
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences.
    Sundin, Anders
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Radiology.
    Ahlström, Håkan
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Radiology.
    Lindner, K J
    Bjurling, Pernilla
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology.
    Långström, Bengt
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    In vivo demonstration of enzyme activity in endocrine pancreatic tumors: decarboxylation of carbon-11-DOPA to carbon-11-dopamine1996In: Journal of Nuclear Medicine, ISSN 0161-5505, E-ISSN 1535-5667, Vol. 37, no 1, p. 32-37Article in journal (Refereed)
    Abstract [en]

    METHODS:

    We used PET to characterize the uptake and decarboxylation of 11C-L-DOPA in vivo in two patients with endocrine pancreatic tumors: one glucagonoma and one gastrinoma.

    RESULTS:

    With L-DOPA labeled with 11C in the beta position, in which the radioactive label follows the molecule through decarboxylation to dopamine, significant uptake was observed in the tumors. With L-DOPA labeled in the carboxyl group, in which the label is rapidly eliminated from the tissue as 11CO2 if decarboxylation takes place, an almost complete lack of uptake is noted.

    CONCLUSION:

    This study shows that, using selective position labeling, an in vivo action of enzymatic activity can be observed with PET and that significant decarboxylation occurs in the tested endocrine pancreatic tumors. Also, marked retention of radioactivity occurs after treatment with somatostatin analogs. It is hypothesized that this is a reflection of a reduction of exocytosis which is induced by this treatment.

  • 12. Bergström, Mats
    et al.
    Juhlin, Claes
    Bonasera, Tomas A
    Sundin, Anders
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Radiology. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Section of Nuclear Medicine and PET.
    Rastad, Jonas
    Åkerström, Göran
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Endocrine Surgery.
    Långström, Bengt
    PET imaging of adrenal cortical tumors with the 11beta-hydroxylase tracer 11C-metomidate2000In: Journal of Nuclear Medicine, ISSN 0161-5505, E-ISSN 1535-5667, Vol. 41, no 2, p. 275-282Article in journal (Refereed)
    Abstract [en]

    The purpose of the study was to evaluate PET with the tracer 11C-metomidate as a method to identify adrenal cortical lesions.

    METHODS:

    PET with 11C-metomidate was performed in 15 patients with unilateral adrenal mass confirmed by CT. All patients subsequently underwent surgery, except 2 who underwent biopsy only. The lesions were histopathologically examined and diagnosed as adrenal cortical adenoma (n = 6; 3 nonfunctioning), adrenocortical carcinoma (n = 2), and nodular hyperplasia (n = 1). The remaining were noncortical lesions, including 1 pheochromocytoma, 1 myelolipoma, 2 adrenal cysts, and 2 metastases.

    RESULTS:

    All cortical lesions were easily identified because of exceedingly high uptake of 11C-metomidate, whereas the noncortical lesions showed very low uptake. High uptake was also seen in normal adrenal glands and in the stomach. The uptake was intermediate in the liver and low in other abdominal organs. Images obtained immediately after tracer injection displayed high uptake in the renal cortex and spleen. The tracer uptake in the cortical lesions increased throughout the examination. For quantitative evaluation of tracer binding in individual lesions, a model with the splenic radioactivity concentration assigned to represent nonspecific uptake was applied. Values derived with this method, however, did show the same specificity as the simpler standardized uptake value concept, with similar difference observed for cortical versus noncortical lesions.

    CONCLUSION:

    PET with 11C-metomidate has the potential to be an attractive method for the characterization of adrenal masses with the ability to discriminate lesions of adrenal cortical origin from noncortical lesions.

  • 13. Bergström, Mats
    et al.
    Lu, Li
    Fasth, Karl-Johan
    Wu, Feng
    Bergström-Pettermann, Erzebet
    Tolmachev, Vladimir
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology.
    Hedberg, Elisabeth
    Cheng, Aiping
    Långström, Bengt
    In vitro and animal validation of bromine-76-bromodeoxyuridine as a proliferation marker1998In: Journal of Nuclear Medicine, ISSN 0161-5505, E-ISSN 1535-5667, Vol. 39, no 7, p. 1273-9Article in journal (Refereed)
    Abstract [en]

    The potential of 76Br-bromodeoxyuridine as a PET tracer for characterizing proliferation potential was investigated in multicellular tumor aggregates and in healthy rats and pigs. METHODS: Bromine-76-bromide was produced by proton irradiation of a 76Se-enriched target using a 17-MeV cyclotron and recovered by thermal diffusion. Bromine-76-BrdU was prepared from the corresponding trimethylstannate by an oxidative bromination. Multicellular aggregates from a carcinoid cell line and two bladder cancer cell lines were co-incubated with 76Br-BrdU and 3H-thymidine and the uptake and DNA incorporation analyzed. About 0.5 MBq 76Br-BrdU were injected in the tail vein of unanaesthetised Sprague-Dawley rats. Two to 36 hr later they were decapitated and the radioactivity concentration and fraction of radioactivity incorporated into DNA determined in five different organs and the blood. Parallel studies were performed in animals pretreated with hydroxyurea. In separate experiments, rats were given an injection of 76Br-bromide and organ uptake was evaluated after 20 hr. PET studies were performed in two pigs and the uptake in different organs was investigated after injection of 76Br-BrdU. In these studies, diuresis was induced by furosemide and mannitol and radioactivity in blood and organs was followed during 10 hr. RESULTS: In the cell aggregates, 30%-90% of the radioactivity was extracted in the DNA fraction. A good correlation was found between 76Br-BrdU and 3H-thymidine with respect to total uptake and DNA fraction. The DNA fraction increased from 2-10 hr after incubation. With in vivo injection in the rat, relatively high uptake of radioactivity was found in all organs, unrelated to the degree of DNA synthesis. However, inhibition by hydroxyurea occurred only in the spleen and intestines, organs which also showed a high degree of incorporation of 76Br-BrdU into DNA. In the pig, the highest in vivo uptake was observed in the red bone marrow and the intestines. In these organs, 70%-80% of the radioactivity was recovered in the DNA fraction. The concentration of radioactivity in the heart, liver and kidney was 3-10 times lower, and here the DNA fraction accounted for 10%-20% of the radioactivity. The decay-corrected radioactivity in blood and nonproliferating organs decreased with diuresis with a half-life of 13 and 16 hr, respectively. CONCLUSION: It is suggested that the radioactivity uptake as seen after the administration of 76Br-BrdU, is constituted by two parts: one relating to incorporation into DNA and one existing as free 76Br- or metabolites of 76Br-BrdU. If sufficient time has passed, 76Br- dominates other metabolites. A correct assessment of DNA-incorporated radioactivity using PET with 76Br-BrdU is not trivial and can only be made with due correction for 76Br-, using either a complementary investigation after hydroxyurea pretreatment (in animal studies) or a separate 76Br-bromide investigation. Alternatively, the free bromide can be eliminated partially through forced diuresis.

  • 14.
    Bergström, Mats
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Pharmaceutical Biosciences.
    Monazzam, Azita
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology, Oncology. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Endocrine Tumor Biology.
    Razifar, Pasha
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis.
    Ide, Susan
    Josephsson, Raymond
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences.
    Långström, Bengt
    Modeling spheroid growth, PET tracer uptake, and treatment effects of the Hsp90 inhibitor NVP-AUY9222008In: Journal of Nuclear Medicine, ISSN 0161-5505, E-ISSN 1535-5667, Vol. 49, no 7, p. 1204-1210Article in journal (Refereed)
    Abstract [en]

    For a PET agent to be successful as a biomarker in early clinical trials of new anticancer agents, some conditions need to be fulfilled: the selected tracer should show a response that is related to the antitumoral effects, the quantitative value of this response should be interpretable to the antitumoral action, and the timing of the PET scan should be optimized to action of the drug. These conditions are not necessarily known at the start of a drug-development program and need to be explored. We proposed a translational imaging activity in which experiments in spheroids and later in xenografts are coupled to modeling of growth inhibition and to the related changes in the kinetics of PET tracers and other biomarkers. In addition, we demonstrated how this information can be used for planning clinical trials. Methods: The first part of this concept is illustrated in a spheroid model with BT474 breast cancer cells treated with the heat shock protein 90 (Hsp90) inhibitor NVP-AUY922. The growth-inhibitory effect after a pulse treatment with the drug was measured with digital image analysis to determine effects on volume with high accuracy. The growth-inhibitory effect was described mathematically by a combined E-max and time course model fitted to the data. The model was then used to simulate a once-per-week treatment, in these experiments the uptake of the PET tracers F-18-FDG and 3'-deoxy-3'-F-18-fluorothymidine (F-18-FLT) was determined at different doses and different time points. Results: A drug exposure of 2 h followed by washout of the drug from the culture medium generated growth inhibition that was maximal at the earliest time point of 1 d and decreased exponentially with time during 10-12 d. The uptake of F-18-FDG per viable tumor volume was minimally affected by the treatment, whereas the F-18-FLT uptake decreased in correlation with the growth inhibition. Conclusion: The study suggests a prolonged action of the Hsp90 inhibitor that supports a once-per-week schedule. F-18-FLT is a suitable tracer for the monitoring of effect, and the F-18-FLT PET study might be performed within 3 d after dosing.

  • 15.
    Borges, João Batista
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Clinical Physiology.
    Hedenstierna, Göran
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Clinical Physiology.
    The Rediscovery of Galligas REPLY2011In: Journal of Nuclear Medicine, ISSN 0161-5505, E-ISSN 1535-5667, Vol. 52, no 6, p. 1004-1004Article in journal (Refereed)
  • 16.
    Borges, João Batista
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Clinical Physiology. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Anaesthesiology and Intensive Care.
    Velikyan, Irina
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Biomedical Radiation Sciences.
    Långström, Bengt
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Sörensen, Jens
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Clinical Physiology. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Section of Nuclear Medicine and PET.
    Ulin, Johan
    Maripuu, Enn
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Section of Medical Physics.
    Sandström, Mattias
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Oncology.
    Widström, Charles
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Section of Medical Physics.
    Hedenstierna, Göran
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Clinical Physiology.
    Ventilation Distribution Studies Comparing Technegas and "Gallgas" Using (GaCl3)-Ga-68 as the Label2011In: Journal of Nuclear Medicine, ISSN 0161-5505, E-ISSN 1535-5667, Vol. 52, no 2, p. 206-209Article in journal (Refereed)
    Abstract [en]

    Ventilation distribution can be assessed by SPECT with Technegas. This study was undertaken in piglets with different degrees of ventilation inhomogeneity to compare PET using Ga-68-labeled pseudogas or "Gallgas" with Technegas. Methods: Twelve piglets were studied in 3 groups: control, lobar obstruction, and diffuse airway obstruction. Two more piglets were assessed for lung volume (functional residual capacity). Results: In controls, SPECT and PET images showed an even distribution of radioactivity. With lobar obstruction, the absence of ventilation of the obstructed lobe was visible with both techniques. In diffuse airway obstruction, SPECT images showed an even distribution of radioactivity, and PET images showed more varied radioactivity over the lung. Conclusion: PET provides detailed ventilation distribution images and a better appreciation of ventilation heterogeneity. Gallgas with PET is a promising new diagnostic tool for the assessment of ventilation distribution.

  • 17. Carter, Stephen F.
    et al.
    Scholl, Michael
    Almkvist, Ove
    Wall, Anders
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science.
    Engler, Henry
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Clinical Physiology.
    Långström, Bengt
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Physical Organic Chemistry.
    Nordberg, Agneta
    Evidence for Astrocytosis in Prodromal Alzheimer Disease Provided by (11)C-Deuterium-L-Deprenyl: A Multitracer PET Paradigm Combining (11)C-Pittsburgh Compound B and (18)F-FDG2012In: Journal of Nuclear Medicine, ISSN 0161-5505, E-ISSN 1535-5667, Vol. 53, no 1, p. 37-46Article in journal (Refereed)
    Abstract [en]

    Astrocytes colocalize with fibrillar amyloid-beta (A beta) plaques in postmortem Alzheimer disease (AD) brain tissue. It is therefore of great interest to develop a PET tracer for visualizing astrocytes in vivo, enabling the study of the regional distribution of both astrocytes and fibrillar A beta. A multitracer PET investigation was conducted for patients with mild cognitive impairment (MCI), patients with mild AD, and healthy controls using (11)C-deuterium-L-deprenyl ((11)C-DED) to measure monoamine oxidase B located in astrocytes. Along with (11)C-DED PET, (11)C-Pittsburgh compound B ((11)C-PIB; fibrillar A beta deposition), (18)F-FDG (glucose metabolism), T1 MRI, cerebrospinal fluid, and neuropsychologic data were acquired from the patients. Methods: (11)C-DED PET was performed in MCI patients (n = 8; mean age 6 SD, 62.6 +/- 7.5 y; mean Mini Mental State Examination, 27.5 +/- 2.1), AD patients (n = 7; mean age, 65.1 +/- 6.3 y; mean Mini Mental State Examination, 24.4 +/- 5.7), and healthy age-matched controls (n = 14; mean age, 64.7 +/- 3.6 y). A modified reference Patlak model, with cerebellar gray matter as a reference, was chosen for kinetic analysis of the (11)C-DED data. (11)C-DED data from 20 to 60 min were analyzed using a digital brain atlas. Mean regional (18)F-FDG uptake and (11)C-PIB retention were calculated for each patient, with cerebellar gray matter as a reference. Results: ANOVA analysis of the regional (11)C-DED binding data revealed a significant group effect in the bilateral frontal and bilateral parietal cortices related to increased binding in the MCI patients. All patients, except 3 with MCI, showed high (11)C-PIB retention. Increased (11)C-DED binding in most cortical and subcortical regions was observed in MCI (11)C-PIB+ patients relative to controls, MCI (11)C-PIB (negative) patients, and AD patients. No regional correlations were found between the 3 PET tracers. Conclusion: Increased (11)C-DED binding throughout the brain of the MCI (11)C-PIB+ patients potentially suggests that astrocytosis is an early phenomenon in AD development.

  • 18. Danad, I.
    et al.
    Raijmakers, P. G.
    Appelman, Y. E.
    Harms, H. J.
    De Haan, S.
    Van Den Oever, M. L. P.
    Heymans, M. W.
    Tulevski, I. I.
    Van Kuijk, C.
    Hoekstra, O. S.
    Lammertsma, A. A.
    Lubberink, Mark
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Section of Nuclear Medicine and PET.
    Van Rossum, A. C.
    Knaapen, P.
    Hybrid imaging using quantitative H2 15O PET and CT-based coronary angiography for the detection of coronary artery disease2013In: Journal of Nuclear Medicine, ISSN 0161-5505, E-ISSN 1535-5667, Vol. 54, no 1, p. 55-63Article in journal (Refereed)
    Abstract [en]

    Hybrid imaging using PET in conjunction with CT-based coronary angiography (PET/CTCA) enables near-simultaneous quantification of myocardial blood flow (MBF) and anatomical evaluation of coronary arteries. CTCA is an excellent imaging modality to rule out obstructive coronary artery disease (CAD), but functional assessment is warranted in the presence of a CTCA-observed stenosis because the specificity of CTCA is relatively low. Quantitative H 2 15O PET/CTCA may yield complementary information and enhance diagnostic accuracy. The purpose of this study was to evaluate the diagnostic accuracy of quantitative H2 15O PET/CTCA in a clinical cohort of patients with suspected CAD who underwent both cardiac H 2 15O PET/CTCA and invasive coronary angiography (ICA). In addition, this study aimed to evaluate and compare the accuracy of hyperemic MBF versus coronary flow reserve (CFR). Methods: Patients (n = 120; mean age ± SD, 61 ± 10 y; 77 men and 43 women) with a predominantly intermediate pretest likelihood for CAD underwent both quantitative H 2 15O PET/CTCA and ICA. A ≥50% stenosis at ICA or a fractional flow reserve ≤ 0.80 was considered significant. Results: Obstructive CAD was diagnosed in 49 of 120 patients (41%). The diagnostic accuracy of hyperemic MBF was significantly higher than CFR (80% vs. 68%, respectively, P = 0.02), with optimal cutoff values of 1.86 mL/min/g and 2.30, respectively. On a per-patient basis, the sensitivity, specificity, negative predictive value, and positive predictive value of CTCA were 100%, 34%, 100%, and 51%, respectively, as compared with 76%, 83%, 83%, and 76%, respectively, for quantitative hyperemic MBF PET. Quantitative H2 15O PET/CTCA reduced the number of false-positive CTCA studies from 47 to 6, although 12 of 49 true-positive CTCAs were incorrectly reclassified as false-negative hybrid scans on the basis of (presumably) sufficient hyperemic MBF. Compared with CTCA (61%) or H2 15O PET (80%) alone (both P < 0.05), the hybrid approach significantly improved diagnostic accuracy (85%). Conclusion: The diagnostic accuracy of quantitative H 2 15O PET/CTCA is superior to either H2 15O PET or CTCA alone for the detection of clinically significant CAD. Hyperemic MBF was more accurate than CFR, implying that a single measurement of MBF in diagnostic protocols may suffice.

  • 19. de Langen, Adrianus J
    et al.
    van den Boogaart, Vivian
    Lubberink, Mark
    Department of Nuclear Medicine and PET Research, VU University Medical Center, Amsterdam, The Netherlands .
    Backes, Walter H
    Marcus, Johannes T
    van Tinteren, Harm
    Pruim, Jan
    Brans, Boudewijn
    Leffers, Pieter
    Dingemans, Anne-Marie C
    Smit, Egbert F
    Groen, Harry J M
    Hoekstra, Otto S
    Monitoring response to antiangiogenic therapy in non-small cell lung cancer using imaging markers derived from PET and dynamic contrast-enhanced MRI2011In: Journal of Nuclear Medicine, ISSN 0161-5505, E-ISSN 1535-5667, Vol. 52, no 1, p. 48-55Article in journal (Refereed)
    Abstract [en]

    With antiangiogenic agents, tumor shrinkage may be absent, despite survival benefit. The present study assessed the predictive value of molecular imaging for the identification of survival benefit during antiangiogenic treatment with bevacizumab and erlotinib in patients with advanced non–small cell lung cancer.

    Methods:

    Patients were evaluated using an imaging protocol including CT, 18F-FDG PET, H215O PET, and dynamic contrast-enhanced MRI to derive measurements on tumor size, glucose metabolism, perfusion, and microvascular permeability. The percentage change in imaging parameters after 3 wk of treatment as compared with baseline was calculated and correlated with progression-free survival (PFS).

    Results:

    Forty-four patients were included, and 40 underwent CT and 18F-FDG PET at both time points. Complete datasets, containing all imaging modalities, were available for 14 patients. Bevacizumab and erlotinib treatment resulted in decreased metabolism, perfusion, and tumor size. A decrease in standardized uptake value or tumor perfusion of more than 20% at week 3 was associated with longer PFS (9.7 vs. 2.8 mo, P = 0.01, and 12.5 vs. 2.9 mo, P = 0.009, respectively). Whole-tumor Ktrans (the endothelial transfer constant) was not associated with PFS, but patients with an increase of more than 15% in the SD of tumor Ktrans values—that is, an increase in regions with low or high Ktrans values—after 3 wk had shorter PFS (2.3 vs. 7.0 mo, P = 0.008). A partial response, according to the response evaluation criteria in solid tumors (RECIST), at week 3 was also associated with prolonged PFS (4.6 vs. 2.9 mo, P = 0.017). However, 40% of patients with a partial response as their best RECIST response still had stable disease at week 3. In these cases tumor perfusion was already decreased and Ktrans heterogeneity showed no increase, indicating that the latter parameters seem to be more discriminative than RECIST at the 3-wk time point.

    Conclusion:

    PET and dynamic contrast-enhanced MRI were able to identify patients who benefit from bevacizumab and erlotinib treatment. Molecular imaging seems to allow earlier response evaluation than CT.

  • 20.
    Eriksson, Olof
    et al.
    Univ Turku, Turku PET Ctr, FI-20521 Turku, Finland.;Abo Akad Univ, Dept Biosci, Turku, Finland..
    Mikkola, Kirsi
    Univ Turku, Turku PET Ctr, FI-20521 Turku, Finland..
    Espes, Daniel
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Cell Biology.
    Tuominen, Lauri
    Univ Turku, Turku PET Ctr, FI-20521 Turku, Finland.;Univ Turku, Dept Psychiat, FI-20521 Turku, Finland..
    Virtanen, Kirsi
    Univ Turku, Turku PET Ctr, FI-20521 Turku, Finland..
    Forsbaeck, Sarita
    Univ Turku, Turku PET Ctr, FI-20521 Turku, Finland..
    Haaparanta-Solin, Merja
    Univ Turku, Turku PET Ctr, FI-20521 Turku, Finland..
    Hietala, Jarmo
    Univ Turku, Turku PET Ctr, FI-20521 Turku, Finland.;Univ Turku, Dept Psychiat, FI-20521 Turku, Finland..
    Solin, Olof
    Univ Turku, Turku PET Ctr, FI-20521 Turku, Finland.;Abo Akad Univ, Accelerator Lab, Turku, Finland..
    Nuutila, Pirjo
    Univ Turku, Turku PET Ctr, FI-20521 Turku, Finland.;Turku Univ Hosp, Dept Endocrinol, FIN-20520 Turku, Finland..
    The Cannabinoid Receptor-1 Is an Imaging Biomarker of Brown Adipose Tissue2015In: Journal of Nuclear Medicine, ISSN 0161-5505, E-ISSN 1535-5667, Vol. 56, no 12, p. 1937-1941Article in journal (Refereed)
    Abstract [en]

    Recently, the existence of significant deposits of brown adipose tissue (BAT) in human adults was confirmed. Its role in the human metabolism is unknown but could be substantial. Inhibition of the cannabinoid receptor-1 (CB1) by the antagonist rimonabant (SR141716) has been associated with activation of BAT thermogenesis and weight loss in mice and rats. The role of peripheral and central CB1 in the activation of BAT merits further investigation. Here we developed a technique for quantifying CB1 in BAT by PET. Methods: Sections of rat BAT and subcutaneous white adipose tissue (WAT) were stained for CB1 and uncoupling protein-1 by immunofluorescent staining. Binding of the radiolabeled CB1 antagonist (3R,5R)-5-(3-(18F-fluoromethoxy)phenyl)-3-(((R)-1-phenylethyl)amino)-1-(4-(trifluoromethyl)-phenyl)pyrrolidin-2-one (F-18-FMPEP-d(2)) to BAT in vivo and in vitro was assessed in rats by PET. Results: We found that CB1 was colocalized with uncoupling protein-1 in BAT, but neither protein was found in WAT. Binding of the radiotracer to BAT sections (but not WAT) in vitro was high and displaceable by pretreatment with rimonabant. Deposits of BAT in rats had significant binding of F-18-FMPEP-d(2) in vivo, indicating high CB1 density. WAT deposits were negative for F-18-FMPEP-d(2), consistent with the immunofluorescent staining and in vitro results. Conclusion: F-18-FMPEP-d(2) PET can quantify CB1 density noninvasively in vivo in rats. CB1 is therefore a promising surrogate imaging biomarker for assessing the presence of BAT deposits as well as for elucidating the mechanism of CB1 antagonist-mediated weight loss.

  • 21.
    Eriksson, Olof
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Preclinical PET Platform.
    Selvaraju, Ram K
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Preclinical PET Platform.
    Johansson, Lars
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Radiology.
    Eriksson, Jan W
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Clinical diabetology and metabolism.
    Sundin, Anders
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Radiology.
    Antoni, Gunnar
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Oncology.
    Sörensen, Jens
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Section of Nuclear Medicine and PET.
    Eriksson, Barbro
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Endocrine Tumor Biology.
    Korsgren, Olle
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Clinical Immunology.
    Quantitative Imaging of Serotonergic Biosynthesis and Degradation in the Endocrine Pancreas2014In: Journal of Nuclear Medicine, ISSN 0161-5505, E-ISSN 1535-5667, Vol. 55, no 3, p. 460-465Article in journal (Refereed)
    Abstract [en]

    Serotonergic biosynthesis in the endocrine pancreas, of which the islets of Langerhans is the major constituent, has been implicated in insulin release and β cell proliferation. In this study, we investigated the feasibility of quantitative noninvasive imaging of the serotonergic metabolism in the pancreas using the PET tracer (11)C-5-hydroxy-l-tryptophan ((11)C-5-HTP).

    METHODS: Uptake of (11)C-5-HTP, and its specificity for key enzymes in the serotonergic metabolic pathway, was assessed in vitro (INS-1 and PANC1 cells and human islet and exocrine preparations) and in vivo (nonhuman primates and healthy and diabetic rats).

    RESULTS: In vitro tracer uptake in endocrine cells (INS-1 and human islets), but not PANC1 and exocrine cells, was mediated specifically by intracellular conversion into serotonin. Pancreatic uptake of (11)C-5-HTP in nonhuman primates was markedly decreased by inhibition of the enzyme dopa decarboxylase, which converts (11)C-5-HTP to (11)C-serotonin and increased after inhibition of monoamine oxidase-A, the main enzyme responsible for serotonin degradation. Uptake in the rat pancreas was similarly modulated by inhibition of monoamine oxidase-A and was reduced in animals with induced diabetes.

    CONCLUSION: The PET tracer (11)C-5-HTP can be used for quantitative imaging of the serotonergic system in the endocrine pancreas.

  • 22.
    Fahlström, Markus
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology.
    Lindskog, Karolina
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology.
    Appel, Lieuwe
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology.
    Engström, Mathias
    GE Healthcare, Stockholm, Sweden..
    Antoni, Gunnar
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Division of Molecular Imaging.
    Kumlien, Eva
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurology.
    Larsson, Elna-Marie
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology.
    Lubberink, Mark
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology.
    Correlation between regional cerebral blood flow based on simultaneously acquired arterial spin labelling MRI and 15O-water-PET using zero-echo-time-based attenuation correction2017In: Journal of Nuclear Medicine, ISSN 0161-5505, E-ISSN 1535-5667, Vol. 58, no S1, article id 362Article in journal (Other academic)
    Abstract [en]

    Objectives: Arterial spin labelling (ASL) MRI promises clinical value in several common neurological disorders. Its quantitative accuracy and reproducibility, however, need to be further validated, ideally using simultaneously acquired measurements with 15O-water-PET on an integrated PET-MR scanner. However, so far, few studies have attempted this and the inclusion of bone in MR-based attenuation correction for PET has thus far been a challenge, compromising the quantitative accuracy of PET-MR based 15O-water PET data. The aim of the present work was to assess the correlation of ASL- and 15O-water-PET based regional cerebral blood flow (rCBF) values based on simultaneously acquired data, using zero-echo-time (ZTE)-based attenuation correction, as well as to assess the reproducibility of ASL-based rCBF.

    Methods: Six subjects underwent 10 min PET scans after automated bolus injection of 400 MBq 15O-water (1 mL/s during 5 s followed by 35 mL saline at 2 mL/s) on a time-of-flight integrated PET-MR scanner (Signa PET-MR, GE Healthcare). Arterial blood radioactivity concentrations were monitored using continuous sampling from the radial artery (Swisstrace Twilite Two). Simultaneously, a 3D FSE pseudo-continuous ASL (3D pCASL) with a spiral read-out as supplied by the scanner manufacturer in the commercial software were acquired using an 8 channel head coil (Invivo Hi-Res Head Coil). In addition, 3D T1-w, ZTE and Dixon fat-water MRI were acquired. The ASL procedure was repeated after 2 h (patients remained in the scanner). Quantifiable ASL-based CBF maps were generated. PET images were reconstructed into 26 frames of increasing durations using time-of-flight OSEM (2 iterations, 28 subsets) and a 5 mm post-filter, with ZTE-based attenuation correction. Blood sampler data were corrected for delay and dispersion and 15O-water-based CBF maps were calculated using a basis function implementation of the single tissue compartment model including a fitted blood volume parameter. CBF maps were co-registered to each patient's T1-w image. 3D T1-w images were segmented and normalised to MNI space using SPM12, and anterior, middle and posterior flow territory volumes of interest (VOIs) were created from a standard template in MNI space and inversely transformed for each patient. In addition, a 45-VOI probabilistic template was applied using PVElab software. Correlations between PET- and ASL-based rCBF values were assessed using regression analysis, and reproducibility of ASL using a paired t-test.

    Results: Mean (CI) total brain grey matter CBF values were 67.2 (48.0-86.5) mL/min/100 g for 15O-water-PET and 65.5 (55.7-75.5) mL/min/100 g for ASL. Although correlation and agreement between 15O-water and ASL-based rCBF for individual VOIs in the 45-VOI template were generally poor, significant correlations were found on a grey matter flow territory basis, with R2 ranging from 0.70 in the anterior flow territory to 0.86 in the middle flow territory. rCBF values were significantly reduced between second and first ASL for all flow territories (p<0.01), with a mean decrease of 10%.

    Conclusion: A good correlation between regional flow territory CBF values based on ASL and 15O-water-PET was found, using ZTE-based attenuation correction for PET data which takes bone tissue into account. ASL values for regional flow territories may have potential applications in patients with dementia or cerebrovascular diseases affecting blood flow such as moya moya. The decrease of ASL-based rCBF values in the reproducibility study needs to be investigated further to assess whether this is a methodological issue or reflects a true decrease in rCBF. Research Support: Uppsala County Council

  • 23.
    Gedda, Lars
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Biomedical Radiation Sciences.
    Fondell, Amelie
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Biomedical Radiation Sciences.
    Lundqvist, Hans
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Biomedical Radiation Sciences.
    Park, John
    Department of medicine, Division of Haematology-Oncology, Cancer research institute, University of California San Fransisco, USA.
    Edwards, Katarina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Analytical Chemistry.
    Experimental radionuclide therapy of HER2-expressing xenografts using two-step targeting Nuclisome-particles2012In: Journal of Nuclear Medicine, ISSN 0161-5505, E-ISSN 1535-5667, Vol. 53, no 3, p. 480-487Article in journal (Refereed)
    Abstract [en]

    The therapeutic potential of Auger-electron emitting radionuclides is strongly dependent on their close vicinity to DNA, since the energy deposition is mainly localized within a few cubic nanometers around the site of decay. Thus, apart from specificity, successful tumor therapy relies on a nuclear delivery strategy. We recently presented a two-step targeting strategy to transport Auger-electron-emitting radionuclides into the cell nucleus by means of nuclide-filled liposomes (Nuclisome particles), that is, polyethylene glycol-stabilized, tumor-cell-targeting liposomes loaded with (125)I-labeled anthracyclines. In the present study, the survival of mice intraperitoneally inoculated with human HER2-expressing SKOV-3 tumor cells and treated with HER2-targeting Nuclisome particles was studied.

    METHODS:

    BALB/c nu/nu mice were inoculated with 10(7) SKOV-3 cells intraperitoneally and thereafter directly injected with Nuclisome particles with increasing specific radioactivity. Groups of 10-12 mice were treated with 0.01 MBq/mouse up to 2 MBq/mouse, and survival was monitored and compared with that in control groups (n = 33). Organs were analyzed for HER2 expression and radiotoxic effects histologically. Absorbed doses were estimated using dose factors from the online Radiation Dose Assessment Resource model.

    RESULTS:

    The results showed a clear correlation between administered radioactive dose and survival. No such dose-dependent survival was observed for mice treated with Nuclisome particles lacking HER2-targeting ability. With HER2-targeting Nuclisome particles, a significant increase in survival, compared with that of untreated control mice, could already be seen at an administered activity of 0.1 MBq/mouse (P = 0.0301). At the highest activity administered, 2 MBq/mouse (P < 0.0001), 70% of the mice survived the study and most were tumor-free. Neither macroscopic nor microscopic radiotoxic side effects were observed. Dosimetric calculations, assuming nonreceptor targeting, revealed that the radioactive doses to normal tissues were low.

    CONCLUSION:

    Taken together the results show that with successful targeting to the tumor-cell nucleus it is possible to obtain a therapeutic effect from Auger-electron-emitting radionuclides administered at radioactive doses low enough to spare normal tissue from radiotoxic side effects.

  • 24. Golla, Sandeep S V
    et al.
    Boellaard, Ronald
    Oikonen, Vesa
    Hoffmann, Anja
    van Berckel, Bart N M
    Windhorst, Albert D
    Virta, Jere
    Te Beek, Erik T
    Groeneveld, Geert Jan
    Haaparanta-Solin, Merja
    Luoto, Pauliina
    Savisto, Nina
    Solin, Olof
    Valencia, Ray
    Thiele, Andrea
    Eriksson, Jonas
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Division of Molecular Imaging.
    Schuit, Robert C
    Lammertsma, Adriaan A
    Rinne, Juha O
    Parametric Binding Images of the TSPO Ligand 18F-DPA-714.2016In: Journal of Nuclear Medicine, ISSN 0161-5505, E-ISSN 1535-5667, Vol. 57, no 10, p. 1543-1547Article in journal (Refereed)
    Abstract [en]

    (18)F-labeled N,N-diethyl-2-(2-[4-(2-fluoroethoxy)phenyl]-5,7-dimethylpyrazolo[1,5-α]pyrimidine-3-yl)acetamide (DPA-714) is a radioligand for the 18-kDa translocator protein. The purpose of the present study was to identify the best method for generating quantitative parametric images of (18)F-DPA-714 binding.

    METHODS: Ninety-minute dynamic (18)F-DPA-714 PET scans with full arterial sampling from 6 healthy subjects and 9 Alzheimer disease (AD) patients were used. Plasma-input-based Logan graphical analysis and spectral analysis were used to generate parametric volume of distribution (VT) images. Five versions of Ichise, reference Logan, and 2 basis function implementations (receptor parametric mapping and simplified reference tissue model 2 [SRTM2]) of SRTM, all using gray matter cerebellum as the reference region, were applied to generate nondisplaceable binding potential (BPND) images.

    RESULTS: Plasma-input Logan analysis (r(2) = 0.99; slope, 0.88) and spectral analysis (r(2) = 0.99, slope, 0.93) generated estimates of VT that correlated well with values obtained using nonlinear regression. BPND values generated using SRTM2 (r(2) = 0.83; slope, 0.95) and reference Logan analysis (r(2) = 0.88; slope, 1.01) correlated well with nonlinear regression-based estimates.

    CONCLUSION: Both Logan analysis and spectral analysis can be used to obtain quantitatively accurate VT images of (18)F-DPA-714. In addition, SRTM2 and reference Logan analysis can provide accurate BPND images. These parametric images could be used for voxel-based comparisons.

  • 25. Harms, Hendrik J
    et al.
    de Haan, Stefan
    Knaapen, Paul
    Allaart, Cornelis P
    Lammertsma, Adriaan A
    Lubberink, Mark
    Department of Nuclear Medicine and PET Research, VU University Medical Center, Amsterdam, The Netherlands.
    Parametric Images of Myocardial Viability Using a Single 15O-H2O PET/CT Scan2011In: Journal of Nuclear Medicine, ISSN 0161-5505, E-ISSN 1535-5667, Vol. 52, no 5, p. 745-749Article in journal (Refereed)
    Abstract [en]

    Perfusable tissue index (PTI) is a marker of myocardial viability and requires acquisition of transmission, 15O-CO, and 15O-H2O scans. The aim of this study was to generate parametric PTI images from a 15O-H2O PET/CT scan without an additional 15O-CO scan.

    Methods:

    Data from 20 patients undergoing both 15O-H2O and 15O-CO scans were used, assessing correlation between PTI based on 15O-CO (PTICO) and on fitted blood volume fractions (PTIVb). In addition, parametric PTIVb images of 10 patients undergoing 15O-H2O PET/CT scans were generated using basis-function methods and compared with PTIVb obtained using nonlinear regression. Simulations were performed to study the effects of noise on PTIVb.

    Results:

    Correlation between PTICO and PTIVb was high (r2 = 0.73). Parametric PTIVb correlated well with PTIVb obtained using nonlinear regression (r2 = 0.91). Simulations showed low sensitivity to noise (coefficient of variation < 10% at 20% noise).

    Conclusion:

    Parametric PTI images can be generated from a single 15O-H2O PET/CT scan.

  • 26.
    Harms, Hendrik J.
    et al.
    Vrije Univ Amsterdam, Med Ctr, Dept Radiol & Nucl Med, POB 7057, NL-1007 MB Amsterdam, Netherlands..
    Huisman, Marc C.
    Vrije Univ Amsterdam, Med Ctr, Dept Radiol & Nucl Med, POB 7057, NL-1007 MB Amsterdam, Netherlands..
    Rijnierse, Mischa T.
    Vrije Univ Amsterdam, Med Ctr, Dept Cardiol, Amsterdam, Netherlands..
    Greuter, Henri
    Vrije Univ Amsterdam, Med Ctr, Dept Radiol & Nucl Med, POB 7057, NL-1007 MB Amsterdam, Netherlands..
    Hsieh, Yu-Lung
    Philips Healthcare, Cleveland, OH USA..
    de Haan, Stefan
    Vrije Univ Amsterdam, Med Ctr, Dept Cardiol, Amsterdam, Netherlands..
    Schuit, Robert C.
    Vrije Univ Amsterdam, Med Ctr, Dept Radiol & Nucl Med, POB 7057, NL-1007 MB Amsterdam, Netherlands..
    Knaapen, Paul
    Vrije Univ Amsterdam, Med Ctr, Dept Cardiol, Amsterdam, Netherlands..
    Lubberink, Mark
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology. Vrije Univ Amsterdam, Med Ctr, Dept Radiol & Nucl Med, POB 7057, NL-1007 MB Amsterdam, Netherlands..
    Lammertsma, Adriaan A.
    Vrije Univ Amsterdam, Med Ctr, Dept Radiol & Nucl Med, POB 7057, NL-1007 MB Amsterdam, Netherlands..
    Noninvasive Quantification of Myocardial C-11-Meta-Hydroxyephedrine Kinetics2016In: Journal of Nuclear Medicine, ISSN 0161-5505, E-ISSN 1535-5667, Vol. 57, no 9, p. 1376-1381Article in journal (Refereed)
    Abstract [en]

    C-11-meta-hydroxyephedrine (C-11-HED) kinetics in the myocardium can be quantified using a single-tissue-compartment model together with a metabolite-corrected arterial blood sampler input function (BSIF). The need for arterial blood sampling, however, limits clinical applicability. The purpose of this study was to investigate the feasibility of replacing arterial sampling with imaging-derived input function (IDIF) and venous blood samples. Methods: Twenty patients underwent 60-min dynamic C-11-HED PET/CT scans with online arterial blood sampling. Thirteen of these patients also underwent venous blood sampling. Data were reconstructed using both 3 dimensional row-action maximum-likelihood algorithm (3DR) and a time-of-flight (TF) list-mode reconstruction algorithm. For each reconstruction, IDIF results were compared with BSIF results. In addition, IDIF results obtained with venous blood samples and with a transformed venous-to-arterial metabolite correction were compared with results obtained with arterial metabolite corrections. Results: Correlations between IDIF- and BSIF-derived K-1 and V-T were high (r(2) > =0.89 for 3DR and TF). Slopes of the linear fits were significantly different from 1 for K-1, for both 3DR (slope = 0.94) and TF (slope = 1.06). For V-T, the slope of the linear fit was different from 1 for TF (slope = 0.93) but not for 3DR (slope = 0.98). Use of venous blood data introduced a large bias in V-T (r(2) = 0.96, slope = 0.84) and a small bias in K-1 (r(2) = 0.99, slope = 0.98). Use of a second-order polynomial venous-to-arterial transformation was robust and greatly reduced bias in V-T (r(2) = 0.97, slope = 0.99) with no effect on K-1. Conclusion: IDIF yielded precise results for both 3DR and TF. Venous blood samples can be used for absolute quantification of C-11-HED studies, provided a venous-to-arterial transformation is applied. A venous-to-arterial transformation enables noninvasive, absolute quantification of C-11-HED studies.

  • 27. Harms, Hendrik J
    et al.
    Lubberink, Mark
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology.
    de Haan, Stefan
    Knaapen, Paul
    Huisman, Marc C
    Schuit, Robert C
    Windhorst, Albert D
    Allaart, Cornelis P
    Lammertsma, Adriaan A
    Use of a Single 11C-Meta-Hydroxyephedrine Scan for Assessing Flow-Innervation Mismatches in Patients with Ischemic Cardiomyopathy2015In: Journal of Nuclear Medicine, ISSN 0161-5505, E-ISSN 1535-5667, Vol. 56, no 11, p. 1706-1711Article in journal (Refereed)
    Abstract [en]

    UNLABELLED: Mismatch between areas of reduced myocardial blood flow (MBF) and reduced myocardial innervation (defect areas) may be used to estimate the risk for ventricular arrhythmias. The presence of a mismatch zone can be derived using a combined protocol consisting of both an MBF scan and an (11)C-meta-hydroxyephedrine ((11)C-HED) scan. The rate of influx from blood to myocardium (K1) of (11)C-HED is proportional to MBF and can potentially be used as an index for defining MBF defects. The aim of this study was to assess whether K1 derived from an (11)C-HED scan can be used as an index of MBF, potentially allowing for an assessment of MBF-innervation mismatch areas from a single (11)C-HED scan.

    METHODS: Seventeen patients with known ischemic cardiomyopathy underwent dynamic (15)O-water and (11)C-HED scans. Discrete arterial blood samples were taken during (11)C-HED scans for metabolite correction of the image-derived input function. (11)C-HED influx rate was obtained using a single-tissue-compartment model and compared with transmural MBF (MBFT), defined as MBF as measured with (15)O-water multiplied by perfusable tissue fraction. Defect sizes were obtained from parametric K1 and MBFT images, using 50% of a remote control segment as the cutoff value.

    RESULTS: There was a significant correlation between MBFT and K1 (y = 0.40x + 0.05 mL·g(-1)·min(-1), r = 0.80, P < 0.001), although K1 was significantly lower than MBFT (slope of the regression line significantly different from 1, P < 0.001). Correlation between MBFT and K1 defect sizes was high (y = 0.89x + 1.38%, r = 0.95, P < 0.001), with no significant difference in mean defect size based on K1 or MBFT (20.9% ± 11.3% and 20.1% ± 10.7% for MBFT and K1, respectively, P = 0.41).

    CONCLUSION: (11)C-HED influx rate K1 can be used as an alternative to a separate MBF scan for assessing mismatch areas between MBF and myocardial innervation.

  • 28.
    Harms, Hendrik Johannes
    et al.
    Aarhus Univ Hosp, Dept Nucl Med, Palle Juul Jensens Blvd 99, DK-8200 Aarhus N, Denmark.;Aarhus Univ Hosp, PET Ctr, Palle Juul Jensens Blvd 99, DK-8200 Aarhus N, Denmark..
    Hansson, Nils Henrik Stubkjaer
    Aarhus Univ Hosp, Dept Cardiol, Aarhus, Denmark..
    Tolbod, Lars Poulsen
    Aarhus Univ Hosp, Dept Nucl Med, Palle Juul Jensens Blvd 99, DK-8200 Aarhus N, Denmark.;Aarhus Univ Hosp, PET Ctr, Palle Juul Jensens Blvd 99, DK-8200 Aarhus N, Denmark..
    Kim, Won Yong
    Aarhus Univ Hosp, Dept Cardiol, Aarhus, Denmark..
    Jakobsen, Steen
    Aarhus Univ Hosp, Dept Nucl Med, Palle Juul Jensens Blvd 99, DK-8200 Aarhus N, Denmark.;Aarhus Univ Hosp, PET Ctr, Palle Juul Jensens Blvd 99, DK-8200 Aarhus N, Denmark..
    Bouchelouche, Kirsten
    Aarhus Univ Hosp, Dept Nucl Med, Palle Juul Jensens Blvd 99, DK-8200 Aarhus N, Denmark.;Aarhus Univ Hosp, PET Ctr, Palle Juul Jensens Blvd 99, DK-8200 Aarhus N, Denmark..
    Wiggers, Henrik
    Aarhus Univ Hosp, Dept Cardiol, Aarhus, Denmark..
    Frokiaer, Jorgen
    Aarhus Univ Hosp, Dept Nucl Med, Palle Juul Jensens Blvd 99, DK-8200 Aarhus N, Denmark.;Aarhus Univ Hosp, PET Ctr, Palle Juul Jensens Blvd 99, DK-8200 Aarhus N, Denmark..
    Sörensen, Jens
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology. Aarhus Univ Hosp, Dept Nucl Med, Palle Juul Jensens Blvd 99, DK-8200 Aarhus N, Denmark.;Aarhus Univ Hosp, PET Ctr, Palle Juul Jensens Blvd 99, DK-8200 Aarhus N, Denmark..
    Automatic Extraction of Myocardial Mass and Volume Using Parametric Images from Dynamic Nongated PET2016In: Journal of Nuclear Medicine, ISSN 0161-5505, E-ISSN 1535-5667, Vol. 57, no 9, p. 1382-1387Article in journal (Refereed)
    Abstract [en]

    Dynamic cardiac PET is used to quantify molecular processes in vivo. However, measurements of left ventricular (LV) mass and volume require electrocardiogram-gated PET data. The aim of this study was to explore the feasibility of measuring LV geometry using nongated dynamic cardiac PET. Methods: Thirty-five patients with aortic-valve stenosis and 10 healthy controls underwent a 27-min C-11-acetate PET/CT scan and cardiac MRI (CMR). The controls were scanned twice to assess repeatability. Parametric images of uptake rate K-1 and the blood pool were generated from nongated dynamic data. Using software-based structure recognition, the LV wall was automatically segmented from K-1 images to derive functional assessments of LV mass (m(LV)) and wall thickness. End systolic and end-diastolic volumes were calculated using blood pool images and applied to obtain stroke volume and LV ejection fraction (LVEF). PET measurements were compared with CMR. Results: High, linear correlations were found for LV mass (r = 0.95), end-systolic volume (r = 0.93), and end-diastolic volume (r = 0.90), and slightly lower correlations were found for stroke volume (r = 0.74), LVEF (r = 0.81), and thickness (r = 0.78). Bland Altman analyses showed significant differences for m(LV) and thickness only and an overestimation for LVEF at lower values. Intra- and interobserver correlations were greater than 0.95 for all PET measurements. PET repeatability accuracy in the controls was comparable to CMR. Conclusion: LV mass and volume are accurately and automatically generated from dynamic C-11-acetate PET without electrocardiogram gating. This method can be incorporated in a standard routine without any additional workload and can, in theory, be extended to other PET tracers.

  • 29. Heskamp, Sandra
    et al.
    Laverman, Peter
    Rosik, Daniel
    Boschetti, Frederic
    van der Graaf, Winette T A
    Oyen, Wim J G
    van Laarhoven, Hanneke W M
    Tolmachev, Vladimir
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Biomedical Radiation Sciences.
    Boerman, Otto C
    Imaging of Human Epidermal Growth Factor Receptor Type 2 Expression with 18F-Labeled Affibody Molecule ZHER2:2395 in a Mouse Model for Ovarian Cancer2012In: Journal of Nuclear Medicine, ISSN 0161-5505, E-ISSN 1535-5667, Vol. 53, no 1, p. 146-153Article in journal (Refereed)
    Abstract [en]

    Affibody molecules are small (7 kDa) proteins with subnanomolar targeting affinity. Previous SPECT studies in xenografts have shown that the Affibody molecule 111In-DOTA-ZHER2:2395 can discriminate between high and low human epidermal growth factor receptor type 2 (HER2)–expressing tumors, indicating that radiolabeled Affibody molecules have potential for patient selection for HER2-targeted therapy. Compared with SPECT, PET with positron-emitting radionuclides, such as 18F, may improve imaging of HER2 expression because of higher sensitivity and improved quantification of PET. The aim of the present study was to determine whether the 18F-labeled NOTA-conjugated Affibody molecule ZHER2:2395 is a suitable agent for imaging of HER2 expression. The tumor-targeting properties of 18F-labeled ZHER2:2395 were compared with 111In- and 68Ga-labeled ZHER2:2395 in mice with HER2-expressing SK-OV-3 xenografts.

    Methods:

    ZHER2:2395 was conjugated with NOTA and radiolabeled with 18F, 68Ga, and 111In. Radiolabeling with 18F was based on the complexation of Al18F by NOTA. The 50% inhibitory concentration values for NOTA-ZHER2:2395 labeled with 19F, 69Ga, and 115In were determined in a competitive cell-binding assay using SK-OV-3 cells. Mice bearing subcutaneous SK-OV-3 xenografts were injected intravenously with radiolabeled NOTA-ZHER2:2395. One and 4 h after injection, PET/CT or SPECT/CT images were acquired, and the biodistribution was determined by ex vivo measurement.

    Results:

    The 50% inhibitory concentration values for 19F-, 69Ga-, and 115In-NOTA-ZHER2:2395 were 5.0, 6.3, and 5.3 nM, respectively. One hour after injection, tumor uptake was 4.4 ± 0.8 percentage injected dose per gram (%ID/g), 5.6 ± 1.6 %ID/g, and 7.1 ± 1.4 %ID/g for 18F-, 68Ga-, and 111In-NOTA-ZHER2:2395, respectively, and the respective tumor-to-blood ratios were 7.4 ± 1.8, 8.0 ± 1.3, and 4.8 ± 1.3. Tumor uptake was specific, because uptake could be blocked efficiently by coinjection of an excess of unlabeled ZHER2:2395. PET/CT and SPECT/CT images clearly visualized HER2-expressing SK-OV-3 xenografts.

    Conclusion:

    This study showed that 18F-NOTA-ZHER2:2395 is a promising new imaging agent for HER2 expression in tumors. Affibody molecules were successfully labeled with 18F within 30 min, based on the complexation of Al18F by NOTA. Further research is needed to determine whether this technique can be used for patient selection for HER2-targeted therapy.

  • 30. Hsu, David Fc
    et al.
    Ilan, Ezgi
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology.
    Peterson, William T
    Uribe, Jorge
    Lubberink, Mark
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology.
    Levin, Craig S
    Studies of a Next Generation Silicon-Photomultiplier-Based Time-of-Flight PET/CT System2017In: Journal of Nuclear Medicine, ISSN 0161-5505, E-ISSN 1535-5667, Vol. 58, no 9, p. 1511-1518Article in journal (Refereed)
    Abstract [en]

    This article presents system performance studies of the Discovery MI PET/CT system, a new time-of-flight (TOF) system based on silicon photomultipliers. System performance and clinical imaging comparisons were made between this next-generation system and other commercially available PET/CT and PET/MR systems, as well as between different reconstruction algorithms. Methods: Spatial resolution, sensitivity, NECR, scatter fraction, count rate accuracy, and image quality were characterized with the NEMA NU-2 2012 standards. Energy and coincidence time resolution were measured. Tests were conducted independently and results were averaged on two Discovery MI scanners installed at Stanford and Uppsala University Hospitals. Back-to-back patient scans were also performed between the Discovery MI PET/CT, Discovery 690 PET/CT, and SIGNA PET/MR systems. Clinical images were reconstructed with both ordered-subset expectation maximization (OSEM) and the "Q.Clear" reconstruction algorithms, and examined qualitatively. Results: The averaged full-width half max (FWHM) of the radial/tangential/axial spatial resolution reconstructed with FBP at 1, 10, and 20 cm from the system center are, respectively, 4.10/4.19/4.48 mm, 5.47/4.49/6.01 mm, and 7.53/4.90/6.10 mm. The averaged sensitivity is 13.7 cps/kBq at the center of the FOV. Averaged peak noise equivalent count rate is 193.4 kcps at 21.9 kBq/mL with a scatter fraction of 40.6%. The averaged contrast recovery coefficients for the image quality phantom are 53.7/64.0/73.1/82.7/86.8/90.7 for the 10/13/17/22/28/37 mm diameter spheres. The average photopeak energy resolution is 9.40% FWHM and the average coincidence time resolution is 375.4 ps FWHM. Clinical image comparisons between the PET/CT systems demonstrate the high quality of the Discovery MI system. Comparisons between the Discovery MI and SIGNA systems show similar spatial resolution and overall imaging performance. Lastly, results indicate significant image quality and contrast-to-noise performance enhancement for the "Q.Clear" reconstruction algorithm when compared to OSEM. Conclusion: Excellent performance was achieved with the new Discovery MI system, including 375 ps FWHM coincidence time resolution and sensitivity of 14 cps/kBq. Comparisons between different image reconstruction algorithms and other multimodal SiPM and non-SiPM-based PET detector system designs indicate substantial performance enhancements are possible with this next-generation system.

  • 31.
    Hsu, David
    et al.
    Stanford Univ, Radiol, Elect Engn, Stanford, CA 94305 USA..
    Ilan, Ezgi
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology.
    Peterson, William
    GE Healthcare, Waukesha, WI USA..
    Uribe, Jorge
    GE Healthcare, Waukesha, WI USA..
    Lubberink, Mark
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology.
    Levin, Craig
    Stanford Univ, Radiol, Elect Engn, Bioengn, Stanford, CA 94305 USA..
    Studies of a Next Generation Silicon-Photomultiplier-Based Time-of-Flight PET/CT System2017In: Journal of Nuclear Medicine, ISSN 0161-5505, E-ISSN 1535-5667, Vol. 58, no S1, article id 89Article in journal (Other academic)
    Abstract [en]

    Objectives: This article presents studies performed with the Discovery MI PET/CT system, a new time-of-flight (TOF) system based on silicon photomultipliers. System performance was characterized according to the NEMA NU-2 2012 standards. Comparisons of performance and clinical images were also made between this next-generation system and other commercially available PET/CT and PET/MR systems, as well as between different image reconstruction algorithms.

    Methods: Spatial resolution, sensitivity, NECR, scatter fraction, count rate accuracy, and image quality were characterized according to the NEMA NU-2 2012 standards. In addition, energy and coincidence time resolution were measured using a line source at the center of the field-of-view (CFOV). Tests were conducted independently on two Discovery MI scanners installed at Stanford University Hospital and Uppsala University Hospital, and results were averaged between the two systems. In addition, back-to-back patient scans were performed between the Discovery MI PET/CT, Discovery 690 PET/CT, and SIGNA PET/MR systems. Clinical images were reconstructed with both ordered-subset expectation maximization (OSEM) reconstruction algorithms and the block-sequential regularized expectation maximization (BSREM) "Q.Clear" reconstruction algorithm, and examined qualitatively.

    Results: The averaged FWHM of the radial, tangential, and axial spatial resolution reconstructed with filtered backprojection (FBP) at 1/10/20 cm from the system center are, respectively, 4.10/4.19/4.48 mm, 5.47/4.49/6.01 mm, and 7.53/4.90/6.10 mm. The averaged sensitivity is 13.7 cps/kBq at the center and 13.4 cps/kBq at 10 cm radial offset from the center. Averaged peak noise equivalent count rate (NECR) is 193.4 kcps at 21.9 kBq/mL with a scatter fraction (SF) of 40.6%. The averaged contrast recovery (CR) coefficients for the image quality (IQ) phantom are 53.7/64.0/73.1/82.7/86.8/90.7 for the 10/13/17/22/28/37 mm diameter spheres over 3 separate acquisitions. The average photopeak energy resolution is 9.40% FWHM and the average coincidence time resolution is 375.4 ps FWHM. Clinical image comparisons between the PET/CT systems demonstrate the very high quality of the Discovery MI system. Comparisons between the Discovery MI PET/CT and SIGNA PET/MR systems, which contain identical detector architectures but with different detector diameters, show similar spatial resolution and overall imaging performance. Lastly, results indicate significant image quality and contrast-to-noise performance enhancement for the "Q.Clear" reconstruction algorithm when compared to OSEM.

    Conclusion: Excellent performance was achieved with the new Discovery MI system, including 375 ps FWHM coincidence time resolution and sensitivity of 14 cps/kBq. Comparisons between different image reconstruction algorithms and other multimodal SiPM and non-SiPM-based PET detector system designs indicate substantial performance enhancements are possible with this next-generation system. Research Support: None

  • 32. Höglund, Johanna
    et al.
    Shirvan, Anat
    Antoni, Gunnar
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Oncology.
    Gustavsson, Sven-Åke
    Uppsala University.
    Långström, Bengt
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Ringheim, Anna
    Sörensen, Jens
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science.
    Ben-Ami, Miri
    Ziv, Ilan
    F-18-ML-10, a PET Tracer for Apoptosis: First Human Study2011In: Journal of Nuclear Medicine, ISSN 0161-5505, E-ISSN 1535-5667, Vol. 52, no 5, p. 720-725Article in journal (Refereed)
    Abstract [en]

    Clinical PET of apoptosis may have substantial value in advancing patient care. We report here the first-in-humans study with F-18-labeled 2-(5-fluoropentyl)-2-methyl malonic acid (F-18-ML-10), a small-molecule PET tracer for apoptosis. Presented are the dosimetry, biodistribution, stability, and safety profiles of this PET tracer in healthy human volunteers. Also reported is tracer binding to targeted apoptotic cells in testicular tissue, where a relative abundance of apoptotic cells is normally observed. Methods: F-18-ML-10 (233 +/- 90 MBq) was intravenously administered to 8 healthy subjects, followed by whole-body PET/CT for 220 min. Serial blood and urine samples were collected for radioactivity measurement, and plasma tracer stability was assessed by high-performance liquid chromatography. Dosimetry calculations were performed using OLINDA/EXM software. Results: F-18-ML-10 manifested high stability in vivo and rapid distribution followed by fast clearance, with an elimination half-life of 1.3 +/- 0.1 and 1.1 +/- 0.2 h from the blood and from all other organs, respectively, and excretion through the urine. Dosimetry showed an average effective whole-body dose of 15.4 +/- 3.7 mu Sv/MBq, with the urinary bladder being the dose-limiting organ. Selective accumulation and retention of the tracer in the testes was observed in all male subjects, a finding also demonstrated in mice using both small-animal PET and histopathology, confirming binding to apoptotic cells. Administration of F-18-ML-10 was safe, without adverse effects. Conclusion: F-18-ML-10 administered to healthy humans demonstrated a favorable dosimetry, biodistribution, stability, and safety profile. Binding to apoptotic sites was also demonstrated. These data support further development of this small-molecule probe for clinical PET of apoptosis.

  • 33.
    Ilan, Ezgi
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology.
    Deller, Timothy
    Gen Elect, Elm Grove, WI USA..
    Kjellberg, Fredric
    GE Healthcare, Stockholm, Sweden..
    Peterson, William
    GE Healthcare, Waukesha, WI USA..
    Lubberink, Mark
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology.
    Performance comparison of three commercially available PET systems: SIGNA PET/MR, Discovery IQ and Discovery MI2017In: Journal of Nuclear Medicine, ISSN 0161-5505, E-ISSN 1535-5667, Vol. 58, no S1, article id 1353Article in journal (Other academic)
    Abstract [en]

    Objectives: The NEMA performance measurement standard (NEMA NU 2-2012) for PET scanners provides guidelines on how to assess the performance of Positron Emission Tomography (PET). Three different state of the art PET systems were installed at Uppsala University Hospital between years 2014-2016 and independent NEMA standard tests were performed. The aim of this study was to compare system performance of the three scanners.

    Methods: Three commercially available scanners from GE-healthcare (SIGNA PET/MR; Discovery IQ PET/CT; Discovery MI PET/CT) were evaluated. The SIGNA and MI systems are based on LYSO crystals and digital SiPMs, whereas the IQ uses BGO crystals and regular PMTs. Spatial resolution, sensitivity, count rate statistics, count rate accuracy and image quality were assessed according to the NEMA NU 2-2012 standards. In addition to the NEMA standard test, recovery was assessed for different reconstructions using the NEMA image quality phantom at a contrast of 4:1 in all spheres, and a triple line insert phantom. These tests were performed on all three scanners in a single session, avoiding differences due to variability in phantom preparation.

    Results: Full width of half maximum (FWHM) of the spatial resolution (radial/tangential/axial) reconstructed with filtered back projection (FBP) at 1,10 and 20 cm from the centre of FOV is illustrated in figure 1A for each system. The average sensitivity, Peak NECR, scatter fraction and count rate accuracy of each system is presented in table 1. The average image contrast recovery coefficients of SIGNA, IQ and MI varied between 45, 40 and 56 % (10 mm sphere) to 74, 72 and 84 % (22 mm sphere) respectively. The average image contrast recovery coefficients is presented in figure 1B. The lung error for SIGNA, IQ and MI were 2.7, 18 and 5.2 % respectively. Using reconstruction settings recommended for clinical use (Signa: TOF-OSEM, 2 iterations/28 subsets, 5 mm post-filter; IQ: OSEM, 4/12, 4 mm; MI: TOF-OSEM, 3/16, 5 mm, all with resolution recovery) recovery based on a volume of interest over whole spheres varied between 50, 38 and 51 % (10 mm sphere) to 86, 83 and 87 % (22 mm sphere), respectively. In addition to the recommended settings for clinical use, Q.Clear (Block-sequential regularized expectation maximization (BSREM) with PSF modeling) reconstructions with beta values ranging from 100 to 500 with step of 200 were reconstructed. The volume recovery of each system for varying reconstructions is presented in Figure 1C. The mean radial/tangential/central spatial resolution of SIGNA, IQ and MI using the triple line insert phantom when using the recommended standard reconstructions and Q.Clear reconstruction is presented in Figure 1D.

    Conclusion: As expected, the two ToF systems based on LYSO crystals coupled to digital SiPMs (SIGNA and MI), resulted in an overall better resolution, image quality, NECR and volume recovery than the non-TOF BGO coupled to non-digital detector system (IQ). The image quality and spatial resolution improved when Q.Clear reconstruction was used. The sensitivity was higher in SIGNA than in MI and IQ due to a 25 cm axial FOV in SIGNA, compared to 20 cm for MI and IQ. In conclusion, the new SiPM-based PET detector systems provide a considerable enhancement in system performance.

  • 34.
    Ilan, Ezgi
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology.
    Sandström, Mattias
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology.
    Velikyan, Irina
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology.
    Sundin, Anders
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology.
    Eriksson, Barbro
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences.
    Lubberink, Mark
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology.
    Parametric Net Influx Rate Images of Ga-68-DOTATOC and Ga-68-DOTATATE: Quantitative Accuracy and Improved Image Contrast2017In: Journal of Nuclear Medicine, ISSN 0161-5505, E-ISSN 1535-5667, Vol. 58, no 5, p. 744-749Article in journal (Refereed)
    Abstract [en]

    (68)Ga-DOTATOC and (68)Ga-DOTATATE are radiolabelled somatostatin analogs used for diagnosis of somatostatin receptor expressing neuroendocrine tumors (NETs) and SUV -measurements are suggested for treatment monitoring. However, changes in net-influx rate (Ki) may better reflect treatment effects than those of the SUV, and accordingly there is a need to compute parametric images showing Ki at the voxel level. The aim of this study was to evaluate parametric methods for computation of parametric Ki images by comparison to volume of interest based methods and to assess image contrast in terms of tumor-to-liver ratio.

    METHODS: Ten patients with metastatic NETs underwent a 45-min dynamic PET examination followed by whole-body PET/CT at 1 h post injection of (68)Ga-DOTATOC and (68)Ga-DOTATATE on consecutive days. Parametric Ki images were computed using a basis function method (BFM) implementation of the two tissue irreversible compartment model and the Patlak method using a descending aorta image-derived input function, and mean tumor Ki values were determined for 50% isocontour VOIs and compared to Ki values based on non-linear regression (NLR) of the whole-VOI time-activity curve. A subsample of healthy liver was delineated in the whole-body and Ki images and tumor-to-liver ratios were calculated in order to evaluate image contrast. Correlation and agreement between VOI-based and parametric Ki values were assessed using regression and Bland-Altman analysis.

    RESULTS: Correlation (R2) between NLR-based and parametric image-based (BFM) tumor Ki values was 0.98 (slope 0.81) and 0.97 (slope 0.88) for (68)Ga-DOTATOC and (68)Ga DOTATATE, respectively. For Patlak analysis, correlation between NLR-based and parametric based (Patlak) tumor Ki were 0.95 (slope 0.71) and 0.92 (slope 0.74) for (68)Ga-DOTATOC and (68)Ga-DOTATATE, respectively. There was no bias between NLR and parametric based Ki-values. Tumor-to-liver contrast was 1.6 and 2.0 times higher in the parametric BFM-Ki images, and 2.3 and 3.0 times in the Patlak images, than in the whole-body images for (68)Ga-DOTATOC and (68)Ga-DOTATATE, respectively.

    CONCLUSION: A high correlation and agreement between NLR- and parametric based Ki values was found, showing that parametric net influx rate images are quantitatively accurate. In addition, tumor-to-liver contrast was superior in the parametric Ki images compared to whole-body images both for (68)Ga-DOTATOC and (68)Ga DOTATATE.

  • 35.
    Ilan, Ezgi
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Section of Nuclear Medicine and PET. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology.
    Sandström, Mattias
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Section of Nuclear Medicine and PET. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology.
    Wassberg, Cecilia
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Radiology.
    Sundin, Anders
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Radiology.
    Garske-Román, Ulrike
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Radiology.
    Eriksson, Barbro
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Endocrine Tumor Biology.
    Granberg, Dan
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences.
    Lubberink, Mark
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Radiology.
    Dose Response of Pancreatic Neuroendocrine Tumors Treated with Peptide Receptor Radionuclide Therapy Using 177Lu-DOTATATE2015In: Journal of Nuclear Medicine, ISSN 0161-5505, E-ISSN 1535-5667, Vol. 56, no 2, p. 177-182Article in journal (Refereed)
    Abstract [en]

    UNLABELLED: Peptide receptor radionuclide therapy (PRRT) is a promising treatment for patients with neuroendocrine tumors, giving rise to improved survival. Dosimetric calculations in relation to PRRT have been concentrated to normal organ dosimetry in order to limit side effects. However, the relation between the absorbed dose to the tumor and treatment response has so far not been established. Better knowledge in this respect may improve the understanding of treatment effects, allow for improved selection of those patients who are expected to benefit from PRRT, and avoid unnecessary treatments. The aim of the present work was to evaluate the dose-response relationship for pancreatic neuroendocrine tumors treated with PRRT using (177)Lu-DOTATATE.

    METHODS: Tumor-absorbed dose calculations were performed for 24 lesions in 24 patients with metastasized pancreatic neuroendocrine tumors treated with repeated cycles of (177)Lu-DOTATATE at 8-wk intervals. The absorbed dose calculations relied on sequential SPECT/CT imaging at 24, 96, and 168 h after infusion of (177)Lu-DOTATATE. The unit density sphere model from OLINDA was used for absorbed dose calculations. The absorbed doses were corrected for partial-volume effect based on phantom measurements. On the basis of these results, only tumors larger than 2.2 cm in diameter at any time during the treatment were included for analysis. To further decrease the effect of partial-volume effect, a subgroup of tumors (>4.0 cm) was analyzed separately. Tumor response was evaluated by CT using Response Evaluation Criteria In Solid Tumors.

    RESULTS: Tumor-absorbed doses until best response ranged approximately from 10 to 340 Gy. A 2-parameter sigmoid fit was fitted to the data, and a significant correlation between the absorbed dose and tumor reduction was found, with a Pearson correlation coefficient (R(2)) of 0.64 for tumors larger than 2.2 cm and 0.91 for the subgroup of tumors larger than 4.0 cm. The largest tumor reduction was 57% after a total absorbed dose of 170 Gy.

    CONCLUSION: The results imply a significant correlation between absorbed dose and tumor reduction. However, further studies are necessary to address the large variations in response for similar absorbed doses.

  • 36.
    Jonasson, My
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology. Univ Uppsala Hosp, Med Phys, Uppsala, Sweden.
    Wall, Anders
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology. Univ Uppsala Hosp, PET Ctr, Uppsala, Sweden.
    Chiotis, Konstantinos
    Karolinska Inst, Dept Neurobiol Care Sci & Soc, Ctr Alzheimer Res, Translat Alzheimer Neurobiol, S-14157 Huddinge, Sweden.
    Saint-Aubert, Laure
    Karolinska Inst, Dept Neurobiol Care Sci & Soc, Ctr Alzheimer Res, Translat Alzheimer Neurobiol, S-14157 Huddinge, Sweden.
    Wilking, Helena
    Univ Uppsala Hosp, PET Ctr, Uppsala, Sweden.
    Sprycha, Margareta
    Univ Uppsala Hosp, PET Ctr, Uppsala, Sweden.
    Borg, Beatrice
    Univ Uppsala Hosp, PET Ctr, Uppsala, Sweden.
    Thibblin, Alf
    Univ Uppsala Hosp, PET Ctr, Uppsala, Sweden.
    Eriksson, Jonas
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Division of Molecular Imaging. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Preclinical PET-MRI Platform. Univ Uppsala Hosp, PET Ctr, Uppsala, Sweden.
    Sörensen, Jens
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology. Univ Uppsala Hosp, PET Ctr, Uppsala, Sweden.
    Antoni, Gunnar
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Preclinical PET-MRI Platform. Univ Uppsala Hosp, PET Ctr, Uppsala, Sweden.
    Nordberg, Agneta
    Karolinska Inst, Dept Neurobiol Care Sci & Soc, Ctr Alzheimer Res, Translat Alzheimer Neurobiol, S-14157 Huddinge, Sweden.; Karolinska Univ, Huddinge Hosp, Dept Geriatr Med, Stockholm, Sweden.
    Lubberink, Mark
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology. Univ Uppsala Hosp, Med Phys, Uppsala, Sweden.
    Tracer kinetic analysis of (S)-18F-THK5117 as a PET tracer for assessing tau pathology.2016In: Journal of Nuclear Medicine, ISSN 0161-5505, E-ISSN 1535-5667, Vol. 57, no 4, p. 574-581Article in journal (Refereed)
    Abstract [en]

    Because a correlation between tau pathology and the clinical symptoms of Alzheimer's disease (AD) has been hypothesized, there is increasing interest in developing PET tracers that bind specifically to tau protein. The aim of this study was to evaluate tracer kinetic models for quantitative analysis and generation of parametric images for the novel tau ligand (S)-(18)F-THK5117.

    METHODS: 9 subjects (5 with AD, 4 with mild cognitive impairment) received a 90 min dynamic (S)-(18)F-THK5117 PET scan. Arterial blood was sampled for measurement of blood radioactivity and metabolite analysis. VOI-based analysis was performed using plasma-input models; single-tissue and two-tissue (2TCM) compartment models and plasma-input Logan, and reference tissue models; simplified reference tissue model (SRTM), reference Logan and standardised uptake value ratio (SUVr). Cerebellum grey matter was used as reference region. Voxel-level analysis was performed using basis function implementations of SRTM, reference Logan and SUVr. Regionally averaged voxel values were compared to VOI-based values from the optimal reference tissue model and simulations were made to assess accuracy and precision. In addition to 90 min, initial 40 and 60 min data were analysed.

    RESULTS: Plasma-input Logan distribution volume ratio (DVR)-1 values agreed well with 2TCM DVR-1 values (R2=0.99, slope=0.96). SRTM binding potential (BPND) and reference Logan DVR-1 values were highly correlated with plasma-input Logan DVR-1 (R2=1.00, slope≈1.00) while SUVr70-90-1 values correlated less well and overestimated binding. Agreement between parametric methods and SRTM was best for reference Logan (R2=0.99, slope=1.03). SUVr70-90-1 values were almost 3 times higher than BPND values in white matter and 1.5 times higher in grey matter. Simulations showed poorer accuracy and precision for SUVr70-90-1 values than for the other reference methods. SRTM BPND and reference Logan DVR-1 values were not affected by a shorter scan duration of 60 min.

    CONCLUSION: SRTM BPND and reference Logan DVR-1 values were highly correlated with plasma-input Logan DVR-1 values. VOI-based data analyses indicated robust results for scan durations of 60 min. Reference Logan generated quantitative (S)-(18)F-THK5117 DVR-1 parametric images with the greatest accuracy and precision, and with a much lower white matter signal than seen with SUVr-1 images.

  • 37. Kehler, Jan
    et al.
    Kilburn, John Paul
    Estrada, Sergio
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Preclinical PET Platform.
    Christensen, Soren Rahn
    Wall, Anders
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Section of Nuclear Medicine and PET.
    Thibblin, Alf
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Preclinical PET Platform.
    Lubberink, Mark
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Section of Nuclear Medicine and PET.
    Bundgaard, Christoffer
    Brennum, Lise Tottrup
    Steiniger-Brach, Bjoern
    Christoffersen, Claus Tornby
    Timmermann, Stine
    Kreilgaard, Mads
    Antoni, Gunnar
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Preclinical PET Platform.
    Bang-Andersen, Benny
    Nielsen, Jacob
    Discovery and Development of C-11-Lu AE92686 as a Radioligand for PET Imaging of Phosphodiesterase10A in the Brain2014In: Journal of Nuclear Medicine, ISSN 0161-5505, E-ISSN 1535-5667, Vol. 55, no 9, p. 1513-1518Article in journal (Refereed)
    Abstract [en]

    Phosphodiesterase 10A (PDE10A) plays a key role in the regulation of brain striatal signaling, and several pharmaceutical companies currently investigate PDE10A inhibitors in clinical trials for various central nervous system diseases. A PDE10A PET ligand may provide evidence that a clinical drug candidate reaches and binds to the target. Here we describe the successful discovery and initial validation of the novel radiolabeled PDE10A ligand 5,8-dimethyl-2-[2-((1-C-11-methyl)-4-phenyl-1H-imidazol-2-yl)-ethyl]-[1,2,4]triazolo[1,5-a]pyridine (C-11-Lu AE92686) and its tritiated analog H-3-Lu AE92686. Methods: Initial in vitro experiments suggested Lu AE92686 as a promising radioligand, and the corresponding tritiated and C-11-labeled compounds were synthesized. 3H-Lu AE92686 was evaluated as a ligand for in vivo occupancy studies in mice and rats, and C-11-Lu AE92686 was evaluated as a PET tracer candidate in cynomolgus monkeys and in humans. Results: C-11-Lu AE92686 displayed high specificity and selectivity for PDE10A-expressing regions in the brain of cynomolgus monkeys and humans. Similar results were found in rodents using 3H-Lu AE92686. The binding of C-11-Lu AE92686 and 3H-Lu AE92686 to striatum was completely and dose-dependently blocked by the structurally different PDE10A inhibitor 2-[4-(1-methyl-4-pyridin-4-yl-1H-pyrazol-3-yl)-phenoxymethyl]-quinoline (MP-10) in rodents and in monkeys. In all species, specific binding of the radioligand was seen in the striatum but not in the cerebellum, supporting the use of the cerebellum as a reference region. The binding potentials (BPND) of C-11-Lu AE92686 in the striatum of both cynomolgus monkeys and humans were evaluated by the simplified reference tissue model with the cerebellum as the reference tissue, and BPND was found to be high and reproducible-that is, BP(ND)s were 6.5 +/- 0.3 (n = 3) and 7.5 +/- 1.0 (n = 12) in monkeys and humans, respectively. Conclusion: Rodent, monkey, and human tests of labeled Lu AE92686 suggest that C-11-Lu AE92686 has great potential as a human PET tracer for the PDE10A enzyme.

  • 38.
    Kero, Tanja
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology.
    Sörensen, Jens
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Clinical Physiology. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology.
    Ahlström, Håkan
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology.
    Lubberink, Mark
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology.
    Quantitative myocardial blood flow imaging with integrated time-of-flight PET-MR2015In: Journal of Nuclear Medicine, ISSN 0161-5505, E-ISSN 1535-5667, Vol. 56, no 3Article in journal (Other academic)
  • 39.
    Khalighi, Mohammad Mehdi
    et al.
    GE Healthcare, San Jose, CA USA..
    Engström, Mathias
    GE Healthcare, Stockholm, Sweden..
    Fan, Audrey
    Stanford Univ, Stanford, CA 94305 USA..
    Gulaka, Praveen
    Stanford Univ, Stanford, CA 94305 USA..
    Appel, Lieuwe
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology.
    Lubberink, Mark
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology.
    Zaharchuk, Greg
    Stanford Univ, Stanford, CA 94305 USA..
    Validation of an image derived input function estimation method on PET/MR2017In: Journal of Nuclear Medicine, ISSN 0161-5505, E-ISSN 1535-5667, Vol. 58, no S1, article id 661Article in journal (Other academic)
    Abstract [en]

    Objectives: The study objective was to validate a recently introduced non-invasive image derived input function (IDIF) estimation method with the gold standard arterial blood sampling.

    Methods: Six subjects (31-50 years old) were injected with 408±62 MBq of 15O-water simultaneously with the start of a 10 min PET scan on the SIGNA PET-MR (GE Healthcare, WI, Waukesha). During PET scanning, a sagittal vascular (inhance 3D velocity) MR series was used with the following parameters: TR=8.7 ms, TE=4.1 ms, FOV=24×21.6 cm, slice thickness=3 mm, 32 slices, velocity encoding=40, phase acceleration=2.0, and scan time=1:21 min. The PET list file was unlisted for every second and total true and scatter coincident events were plotted to identify tracer arrival into the brain arteries. Then, a short time frame over the arrival of the tracer to the cervical region was reconstructed to obtain a PET angiogram. The cervical arteries were then segmented using the MR vascular images and PETA images. Spill-over and spill- in artifacts were estimated using PETA images and the actual arterial volume was measured from the MR vascular images. The PET list file was unlisted and images were reconstructed for every 1 s for the first 30 s, every 3 s for the next 30 s, every 5 s for the 2nd minute, every 10 s for the 3rd and 4th minute and every 30 s for 5th to 10th minutes. The AIF was estimated by dividing total counts from the cervical arteries of each frame by the MR-based arterial volume. For each patient, blood samples were continuously drawn from the radial artery at the wrist using a peristaltic pump, and the tracer concentration in the arterial blood was measured using a Twilite two detector (Swisstrace) to estimate the AIF. In order to calculate the AIF at the brain arteries from these blood samples, the delay and dispersion of the arterial input function was corrected using standard PET-based methods. The CBF and distribution volume were calculated using both the IDIF method and the blood samples by minimizing the mean square of the error between the PET observations and model fit using the Nelder-Mead simplex algorithm in MATLAB (Mathworks, Wilmington, MA).

    Results: Figure 1 shows the (a) PETA and (b) MR vascular images for one of the patients. The PETA images clearly show the arteries and the extent of the spill-over. Figure 2 compares the AIF curve estimated by the proposed IDIF method and the AIF curve measured by the blood samples. The comparison shows excellent correspondence between the IDIF method and the gold standard blood sampling method with 9% and 11% difference for the 1st pass and the entire AIF, respectively. The IDIF captures the AIF peak correctly and has increased signal-to-noise ratio compared to the blood sampling method. The delay and the dispersion of the AIF curve is nearly identical between the two methods. The CBF over the whole brain was measured 29.5±8.7 and 27.0±14 ml/s/100g with the AIF measured by IDIF method and blood samples, respectively with a mean difference of 14% between the two methods. The volume distribution over the whole brain was measured 0.5±0.1 for both methods with a mean difference of 15% between them.

    Conclusion: As the results show, the proposed method is capable of determining a high fidelity IDIF from simultaneous PET/MRI data. Having a “blood-free” method that obviates the need for direct arterial sampling is of benefit to both investigators and their subjects, because of the high costs, inconvenience, and potential risks associated with arterial cannulation. It has applications beyond 15O-water PET, enabling pharmacokinetic modeling to be performed that is required for quantitative PET tracer studies. Research Support: GE Healthcare, Stanford University Lucas Center, Uppsala University.

  • 40. Krasniqi, Ahmet
    et al.
    D'Huyvetter, Matthias
    Devoogdt, Nick
    Frejd, Fredrik Y
    Sorensen, Jens
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology.
    Orlova, Anna
    Keyaerts, Marleen
    Tolmachev, Vladimir
    Same-day imaging using small proteins: Clinical experience and translational prospects in oncology.2018In: Journal of Nuclear Medicine, ISSN 0161-5505, E-ISSN 1535-5667, Vol. 59, no 6, p. 885-891, article id jnumed.117.199901Article in journal (Refereed)
    Abstract [en]

    Imaging of expression of therapeutic targets may enable patients' stratification for targeted treatments. The use of small radiolabeled probes based on the heavy-chain variable region of heavy-chain-only immunoglobulins or non-immunoglobulin scaffolds permits rapid localization of radiotracers in tumors and rapid clearance from normal tissues. This makes high-contrast imaging possible on the day of injection. This mini-review focuses on small proteins for radionuclide-based imaging that would allow same-day imaging, with the emphasis on clinical applications and promising preclinical developments within the field of oncology.

  • 41.
    Lilja, Johan
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology. Hermes Med Solut, Stockholm, Sweden.
    Leuzy, Antoine
    Karolinska Inst, Stockholm, Sweden..
    Chiotis, Konstantinos
    Karolinska Inst, Dept Neurobiol, Ctr Alzheimer Res, Stockholm, Sweden..
    Savitcheva, Irina
    Karolinsk Univ Hosp Huddinge, Dept Nucl Med, Stockholm, Sweden..
    Sörensen, Jens
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Clinical Physiology. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology.
    Nordberg, Agneta
    Karolinska Univ Hosp Huddinge, Dept Geriatr Med, Stockholm, Sweden..
    Spatial normalization of [18F] flutemetamol PET images utilizing an adaptive principal components template2017In: Journal of Nuclear Medicine, ISSN 0161-5505, E-ISSN 1535-5667, Vol. 58, no S1, article id 294Article in journal (Other academic)
  • 42.
    Lilja, Johan
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology. GE Healthcare, Uppsala, Sweden..
    Thurfjell, Lennart
    GE Healthcare, Uppsala, Sweden.;Univ Gothenburg, Sahlgrenska Acad, Inst Neurosci & Physiol, Gothenburg, Sweden..
    Sörensen, Jens
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Clinical Physiology. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology.
    Visualization and Quantification of 3-Dimensional Stereotactic Surface Projections for F-18-Flutemetamol PET Using Variable Depth2016In: Journal of Nuclear Medicine, ISSN 0161-5505, E-ISSN 1535-5667, Vol. 57, no 7, p. 1078-1083Article in journal (Refereed)
    Abstract [en]

    Three-dimensional stereotactic surface projection (3D-SSP) is a widely used method for the analysis of clinical F-18-FDG brain studies. However, for PET amyloid scans the use of 3D-SSP is challenging because of nonspecific uptake in white matter. Our objective was to implement a method for 3D-SSP quantification and visualization of F-18-flutemetamol images that avoids extraction of white matter signal. METHODS: Triangulated brain surface models were extracted from a T1-weighted MR template image. Using an F-18-flutemetamol-negative template, a maximum depth for each vertex on the surface models was calculated to avoid extraction of white matter. The method was evaluated using F-18-flutemetamol images from 2 cohorts. Cohort 1 consisted of 105 healthy volunteers and was used to create a normal database for each reference region. Cohort 2 consisted of 171 subjects including patients with Alzheimer disease and mild cognitive impairment and healthy volunteers. Images were spatially normalized using an adaptive template registration method, and SUV ratio 3D-SSP values were computed using the pons and cerebellar cortex as reference regions. Images from cohort 2 were then compared with the normal database and classified into negatives and positives, based on a calculated z score threshold. The results were compared with consensus visual interpretation results from 5 trained interpreters blinded to clinical data. RESULTS: With the pons as the reference region, the optimal z score threshold was 1.97, resulting in an overall agreement with visual interpretation results in 170 of 171 images (99.42%). With the cerebellar cortex as the reference region, the optimal z score threshold was 2.41, with an overall agreement with visual interpretation in 168 of 171 images (98.25%). CONCLUSION: Variable-depth 3D-SSP allows computation and visualization of F-18-flutemetamol 3D-SSP maps, with minimized contribution from white matter signal while retaining sensitivity in detecting gray matter signal.

  • 43.
    Lindbo, Sarah
    et al.
    KTH Royal Inst Technol, Dept Prot Technol, SE-10691 Stockholm, Sweden.
    Garousi, Javad
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Medical Radiation Science.
    Mitran, Bogdan
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Division of Molecular Imaging.
    Buijs, Jos
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Medical Radiation Science.
    Altai, Mohamed
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Medical Radiation Science.
    Orlova, Anna
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Division of Molecular Imaging.
    Hober, Sofia
    KTH Royal Inst Technol, Dept Prot Technol, SE-10691 Stockholm, Sweden.
    Tolmachev, Vladimir
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Medical Radiation Science.
    Radionuclide tumor targeting using ADAPT scaffold proteins: aspects of label positioning and residualizing properties of the label2018In: Journal of Nuclear Medicine, ISSN 0161-5505, E-ISSN 1535-5667, Vol. 59, no 1, p. 93-99Article in journal (Refereed)
    Abstract [en]

    Visualization of cancer-associated alterations of molecular phenotype using radionuclide imaging is a noninvasive approach to stratifying patients for targeted therapies. The engineered albumin-binding domain-derived affinity protein (ADAPT) is a promising tracer for radionuclide molecular imaging because of its small size (6.5 kDa), which satisfies the precondition for efficient tumor penetration and rapid clearance. Previous studies demonstrated that the human epidermal growth factor receptor type 2 (HER2)-targeting ADAPT6 labeled with radiometals at the N terminus is able to image HER2 expression in xenografts a few hours after injection. The aim of this study was to evaluate whether the use of a non-residualizing label or placement of the labels at the C terminus would further improve the targeting properties of ADAPT6. Methods: Two constructs, Cys(2)-ADAPT6 and Cys(59)-ADAPT6, having the (HE)(3)DANS sequence at the N terminus were produced and site-specifically labeled using In-111-DOTA or I-125-iodo-((4-hydroxyphenyl) ethyl) maleimide (HPEM). The conjugates were compared in vitro and in vivo. HER2-targeting properties and biodistribution were evaluated in BALB/C nu/nu mice bearing ovarian carcinoma cell (SKOV-3) xenografts. Results: Specific HER2 binding and high affinity were preserved after labeling. Both Cys(2)-ADAPT6 and Cys59-ADAPT6 were internalized slowly by HER2-expressing cancer cells. Depending on the label position, uptake at 4 h after injection varied from 10% to 22% of the injected dose per gram of tumor tissue. Regardless of terminus position, the I-125-HPEM label provided more than 140-fold lower renal uptake than the In-111-DOTA label at 4 after injection. The tumor-to-organ ratios were, in contrast, higher for both of the (111)InDOTA- labeled ADAPT variants in other organs. Tumor-to-blood ratios for In-111-labeled Cys(2)-ADAPT6 and Cys(59)-ADAPT6 did not differ significantly (250-280), but In-111-DOTA-Cys(59)-ADAPT6 provided significantly higher tumor-to-lung, tumor-to-liver, tumor-to-spleen, and tumor-to-muscle ratios. Radioiodinated variants had similar tumor-to-organ ratios, but I-125-HPEM-Cys(59)-ADAPT6 had significantly higher tumor uptake and a higher tumor-to-kidney ratio. Conclusion: Residualizing properties of the label strongly influence the targeting properties of ADAPT6. The position of the radiolabel influences targeting as well, although to a lesser extent. Placement of a label at the C terminus yields the best biodistribution features for both radiometal and radiohalogen labels. Low renal retention of the radioiodine label creates a precondition for radionuclide therapy using I-131-labeled HPEM-Cys(59)-ADAPT6.

  • 44.
    Lindström, Elin
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology. Uppsala Univ Hosp, Med Phys, Uppsala, Sweden..
    Lindsjö, Lars
    Uppsala Univ Hosp, PET Ctr, Uppsala, Sweden..
    Ilan, Ezgi
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology. Uppsala Univ Hosp, Med Phys, Uppsala, Sweden..
    Sundin, Anders
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology. Uppsala Univ Hosp, PET Ctr, Uppsala, Sweden..
    Sörensen, Jens
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Clinical Physiology. Uppsala Univ Hosp, PET Ctr, Uppsala, Sweden..
    Danfors, Torsten
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology. Uppsala Univ Hosp, PET Ctr, Uppsala, Sweden..
    Antoni, Gunnar
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Division of Molecular Imaging. Uppsala Univ Hosp, PET Ctr, Uppsala, Sweden..
    Lubberink, Mark
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology. Uppsala Univ Hosp, Med Phys, Uppsala, Sweden..
    Optimisation of penalized likelihood estimation reconstruction (Q.Clear) on a digital time-of-flight PET-CT scanner for four different PET tracers2017In: Journal of Nuclear Medicine, ISSN 0161-5505, E-ISSN 1535-5667, Vol. 58, no S1, article id 1355Article in journal (Other academic)
    Abstract [en]

    Objectives: The penalized likelihood estimation reconstruction algorithm Q.Clear (GE Healthcare) allows for full convergence and edge preservation through a block sequential regularized expectation maximization technique. In this study the performance of Q.Clear was investigated for different penalization factors (β) with the aim to optimize its clinical use for four different tracers.

    Methods: Q.Clear reconstructions with β values of 200, 400, 600 and 800 were compared to time-of-flight ordered subset expectation maximization (TF-OSEM) (3 iterations, 16 subsets and 5 mm Gaussian filter) with point spread function recovery. Clinical whole-body PET/CT (Discovery MI, GE Healthcare) scans with 68Ga-DOTATOC, 18F-FDG, 11C-acetate or 18F-fluoride were analyzed for level of noise in healthy liver tissue, signal to noise ratio (SNR), signal to background ratio (SBR) and maximum standardized uptake value (SUVmax). In addition, acquisition times per bed position and transaxial field of view (FOV) of the reconstructed images were varied. For each tracer, images from 10 patients were included, with a mean of 30 lesions per tracer. A spherical reference volume of interest (VOI) was placed in the liver and lesions were delineated employing a 41% threshold of the maximum voxel.

    Results: The lowest levels of noise were reached with the highest beta factor resulting in the highest SNR, but this in turn gave the lowest SBR. Noise equivalence to OSEM was found with β 600 for 68Ga-DOTATOC, 18F-FDG and 18F-fluoride, and β 400 for 11C-acetate with a resulting significant increase of SUVmax (19.4%, 9.7%, 22.5% and 19.0% respectively) (P < 0.0001, paired t-test), SNR (22.1%, 22.6%, 9.5% and 33.6%) and SBR (19.5%, 11.7%, 21.3% and 18.5%) compared to OSEM. SNR decreased while SBR increased for all tracers when extending FOV from 500 to 700 mm, but only significantly for 18F-fluoride. Decreasing image acquisition time gave no statistical difference of SUVmax for 68Ga-DOTATOC, 18F-fluoride (2 to 1.5 min) for any reconstruction method nor for 11C-acetate (3 to 2 min) with β 蠅 400. Decreasing time for 18F-FDG (3 to 2 min) resulted in a change of optimal beta to β 800 in order to reach noise equivalence to OSEM along with maintaining a higher SNR than OSEM.

    Conclusion: Images reconstructed by Q.Clear result in a tracer-dependent increase in tumour SUVmax values compared to OSEM at matched levels of noise, and an improved SNR. The optimal penalization factor, both in terms of noise-equivalence to OSEM and in terms of absolute SNR, is tracer dependent.

  • 45.
    Lindström, Elin
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology.
    Sundin, Anders
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology.
    Trampal, Carlos
    Lindsjö, Lars
    Ilan, Ezgi
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology.
    Danfors, Torsten
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology.
    Antoni, Gunnar
    Sörensen, Jens
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology.
    Lubberink, Mark
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology.
    Evaluation of penalized likelihood estimation reconstruction on a digital time-of-flight PET/CT scanner for 18F-FDG whole-body examinations.2018In: Journal of Nuclear Medicine, ISSN 0161-5505, E-ISSN 1535-5667, article id jnumed.117.200790Article in journal (Refereed)
    Abstract [en]

    as well as improved SNR and SBR at a matched level of noise. BSREM reconstruction allowed for a shorter image acquisition time compared to TOF-OSEM with a resulting equal image quality outcome.

  • 46.
    Lubberink, Mark
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology.
    Appel, Lieuwe
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology.
    Gaging, Johannes
    Uppsala Univ, Uppsala, Sweden..
    Lindskog, Karolina
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology.
    Danfors, Torsten
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology.
    Larsson, Elna-Marie
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology.
    Kumlien, Eva
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurology.
    Antoni, Gunnar
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Division of Molecular Imaging.
    Tracer kinetic analysis of the SV2A ligand 11C-UCBA as a PET marker for synaptic density in humans2017In: Journal of Nuclear Medicine, ISSN 0161-5505, E-ISSN 1535-5667, Vol. 58, no S1, article id 631Article in journal (Other academic)
    Abstract [en]

    Objectives: Quantitative imaging of the synaptic vesicle glycoprotein 2A (SV2A) with PET can be used as a measure of synaptic density in the human brain (Finnema et al, Science Tr Med 2016), changes of which occur in many neurodegenerative diseases. 11C-UCBA has previously been validated as an SV2A tracer in pigs (Estrada et al, Nucl Med Biol 2016), showing dose-dependent blocking and reversible binding. The aim of the present work was to evaluate tracer kinetic models and simplified methods for quantification of synaptic density using 11C-UCBA in humans.

    Methods: Eight subjects (6 epilepsy patients, 2 controls) underwent 90 min PET scans starting with injection of 5 MBq/kg 11C-UCBA on a time-of-flight integrated PET-MR scanner (Signa PET-MR, GE Healthcare). Arterial blood was withdrawn for measurements of whole blood and plasma concentrations and metabolite analysis. Images were reconstructed using zero-echo-time MR-based attenuation correction, accounting for bone attenuation. A probabilistic VOI template was defined on a T1-MRI image, acquired during the PET scan, and transferred to the dynamic PET images. A centrum semiovale VOI was drawn as potential reference tissue. Data were analysed using single-tissue (1T2k), two-tissue irreversible (2T3k) and reversible (2T4k) models, as well as the simplified reference tissue model (SRTM) and plasma- and reference-Logan methods, resulting in total distribution volume (VT) and binding potential (BPND) values, with binding potential both estimated directly and as distribution volume ratio to centrum semiovale (DVR). The optimal compartment model was determined using the Akaike information criterion (AIC). Standardized uptake value ratios (SUVR) at various time points were compared to modelling outcomes using regression analysis.

    Results: Plasma and brain kinetics of 11C-UCBA were slow, with peak activity in brain at 70-80 min. Parent fraction was approximately 50% at 90 min. Plasma-input data were best described using the 2T4k model, but this could often not provide robust VT or BPND values. Mean plasma-Logan VT was 24±17. Plasma-Logan DVR using centrum semiovale as reference tissue correlated well with 2T4k DVR (R2 0.94) for those regions where robust DVR values could be determined. Reference-Logan DVR showed good correlation with plasma-Logan DVR (R2 0.72). Plasma-Logan DVR-1 and SUVR-1 images are shown in Figure 1. SUVR for the 40-60 and 70-90 min intervals correlated well with reference-Logan DVR (R2 0.92 and 0.98).

    Conclusion: Slow kinetics of 11C-UCBA resulted in poor robustness of outcome parameters of reversible compartment models. However, reference-Logan DVR correlated well with plasma-Logan DVR. SUVR at 70-90 min p.i. correlated well with DVR and may be used as a simplified measure of synaptic density using 11C-UCBA. Research Support: Uppsala County Council

  • 47.
    Lubberink, Mark
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology.
    Golla, Sanjeep S. V.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology.
    Jonasson, My
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology.
    Rubin, Kristofer
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology.
    Glimelius, Bengt
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Experimental and Clinical Oncology.
    Sörensen, Jens
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology.
    Nygren, Peter
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Experimental and Clinical Oncology.
    O-15-Water PET Study of the Effect of Imatinib, a Selective Platelet-Derived Growth Factor Receptor Inhibitor, Versus Anakinra, an IL-1R Antagonist, on Water-Perfusable Tissue Fraction in Colorectal Cancer Metastases2015In: Journal of Nuclear Medicine, ISSN 0161-5505, E-ISSN 1535-5667, Vol. 56, no 8, p. 1144-1149Article in journal (Refereed)
    Abstract [en]

    High interstitial fluid pressure (IFP) in colorectal cancer metastases may decrease the uptake and, thus, the effects of antitumor drugs. Imatinib, a selective inhibitor of platelet-derived growth factor receptors, and anakinra, an interleukin-1 receptor antagonist, respectively, increase drug uptake or decrease IFP in preclinical models of carcinoma. Drug-induced decrease in IFP in human metastases has not been objectively shown but should be reflected by an increase in water-perfusable tissue fraction (PTF) or tumor blood flow (TBF) using O-15-water PET/CT and kinetic modeling. Hence, the aim of this study was to assess the effects of imatinib and anakinra on PTF and TBF in colorectal cancer metastases in patients. Methods: Nine patients with documented progressive disease despite all established therapy underwent O-15-water PET/CT at baseline and at 2 d and 6-7 d after the start of oral administration of imatinib (400 mg/d). After a washout period of 1 wk, the protocol was repeated with anakinra (100 mg/d) subcutaneously. Six patients underwent a second baseline scan on the same day to assess reproducibility of PTF and TBF measurements. Volumes of interest were drawn over liver metastases and aorta. PTF and TBF were calculated using the standard single-tissue-compartment model. Results: Imatinib administration during 6-7 d increased PTF from 0.62 +/- 0.12 to 0.69 +/- 0.13, compared with baseline and day 2 (P = 0.02, Wilcoxon test). No significant changes were found in TBF. PTF values were no longer significantly different from baseline 1 wk after the last imatinib dosage. Anakinra induced no significant change in PTF or TBF. The repeatability coefficients of PTF and TBF in liver lesions were 22% and 28%, respectively. Conclusion: Imatinib increases PTF of colorectal cancer metastases in patients and hence may increase the delivery of antitumor drugs. O-15-water PET/CT and kinetic modeling provide insights into the microenvironment of human cancers.

  • 48.
    Lubberink, Mark
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology.
    Tolmachev, Vladimir
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology.
    Widström, Charles
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology.
    Bruskin, Alexander
    Lundqvist, Hans
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology.
    Westlin, Jan-Erik
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology.
    110mIn-DTPA-D-Phe1-octreotide for imaging of neuroendocrine tumors with PET2002In: Journal of Nuclear Medicine, ISSN 0161-5505, E-ISSN 1535-5667, Vol. 43, no 10, p. 1391-7Article in journal (Refereed)
    Abstract [en]

    The somatostatin analog diethylenetriaminepentaacetic acid (DTPA)-D-Phe1-octreotide labeled with 111In has been applied extensively for diagnosis of neuroendocrine tumors using SPECT or planar scintigraphy. However, the spatial resolution of planar scintigraphy and SPECT prohibits imaging of small tumors, and the quantification accuracy of both methods is limited. METHODS: We developed a method to prepare the positron-emitting radiopharmaceutical 110mIn-DTPA-D-Phe1-octreotide based on a commercially available kit. Phantom studies were done to investigate and compare the performance of 110mIn PET and 111In SPECT. A clinical imaging study using 110mIn-DTPA-D-Phe1-octreotide and PET was done to investigate the application of this radiopharmaceutical. RESULTS: An almost 3-fold better resolution and much better quantitative capabilities were found for 110mIn PET than for 111In SPECT. The clinical imaging study demonstrated the potential use of 110mIn-octreotide in PET to image tumors and quantify radioactivity uptake in humans using (110m)In-DTPA-D-Phe1-octreotide. CONCLUSION: PET with 110mIn-DTPA-D-Phe1-octreotide greatly improved detection of small tumors and offers a possibility of more accurate quantification of tumor uptake than can be obtained with 111In-DTPA-D-Phe1-octreotide and SPECT.

  • 49.
    Lubberink, Mark
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Avdelningen för sjukhusfysik.
    Wong, Yeun Ying
    Raijmakers, Pieter G. H. M.
    Schuit, Robert C.
    Luurtsema, Gert
    Boellaard, Ronald
    Knaapen, Paul
    Vonk-Noordegraaf, Anton
    Lammertsma, Adriaan A.
    Myocardial Oxygen Extraction Fraction Measured Using Bolus Inhalation of O-15-Oxygen Gas and Dynamic PET2011In: Journal of Nuclear Medicine, ISSN 0161-5505, E-ISSN 1535-5667, Vol. 52, no 1, p. 60-66Article in journal (Refereed)
    Abstract [en]

    The aim of this study was to determine the accuracy of oxygen extraction fraction (OEF) measurements using a dynamic scan protocol after bolus inhalation of O-15(2). The method of analysis was optimized by investigating potential reuse of myocardial blood flow (MBF), perfusable tissue fraction, and blood and lung spillover factors derived from separate O-15-water and (CO)-O-15 scans. Methods: Simulations were performed to assess the accuracy and precision of OEF for a variety of models in which different parameters from O-15-water and (CO)-O-15 scans were reused. Reproducibility was assessed in 8 patients who underwent one 10-min dynamic scan after bolus injection of 1.1 GBq of O-15-water, two 10-min dynamic scans after bolus inhalation of 1.4 GBq of O-15(2), and a 6-min static scan after bolus inhalation of 0.8 GBq of (CO)-O-15 for region-of-interest definition. Results: Simulations showed that accuracy and precision were lowest when all parameters were determined from the O-15(2) scan. The optimal accuracy and precision of OEF were obtained when fixing MBF, perfusable tissue fraction, and blood spillover to values derived from a O-15-water scan and estimating spillover from the pulmonary gas volume using an attenuation map. Optimal accuracy and precision were confirmed in the patient study, showing an OEF test-retest variability of 13% for the whole myocardium. Correction of spillover from pulmonary gas volume requires correction of the lung time-activity curve for pulmonary blood volume, which could equally well be obtained from a O-15-water rather than (CO)-O-15 scan. Conclusion: Measurement of OEF is possible using bolus inhalation of O-15(2) and a dynamic scan protocol, with optimal accuracy and precision when other relevant parameters, such as MBF, are derived from an additional O-15-water scan.

  • 50. Lundqvist, Roger
    et al.
    Lilja, Johan
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Radiology.
    Thomas, Benjamin A
    Lötjönen, Jyrki
    Villemagne, Victor L
    Rowe, Christopher C
    Thurfjell, Lennart
    Implementation and validation of an adaptive template registration method for 18F-flutemetamol imaging data.2013In: Journal of Nuclear Medicine, ISSN 0161-5505, E-ISSN 1535-5667, Vol. 54, no 8, p. 1472-8Article in journal (Refereed)
    Abstract [en]

    UNLABELLED: The spatial normalization of PET amyloid imaging data is challenging because different white and gray matter patterns of negative (Aβ-) and positive (Aβ+) uptake could lead to systematic bias if a standard method is used. In this study, we propose the use of an adaptive template registration method to overcome this problem.

    METHODS: Data from a phase II study (n = 72) were used to model amyloid deposition with the investigational PET imaging agent (18)F-flutemetamol. Linear regression of voxel intensities on the standardized uptake value ratio (SUVR) in a neocortical composite region for all scans gave an intercept image and a slope image. We devised a method where an adaptive template image spanning the uptake range (the most Aβ- to the most Aβ+ image) can be generated through a linear combination of these 2 images and where the optimal template is selected as part of the registration process. We applied the method to the (18)F-flutemetamol phase II data using a fixed volume of interest atlas to compute SUVRs. Validation was performed in several steps. The PET-only adaptive template registration method and the MR imaging-based method used in statistical parametric mapping were applied to spatially normalize PET and MR scans, respectively. Resulting transformations were applied to coregistered gray matter probability maps, and the quality of the registrations was assessed visually and quantitatively. For comparison of quantification results with an independent patient-space method, FreeSurfer was used to segment each subject's MR scan and the parcellations were applied to the coregistered PET scans. We then correlated SUVRs for a composite neocortical region obtained with both methods. Furthermore, to investigate whether the (18)F-flutemetamol model could be generalized to (11)C-Pittsburgh compound B ((11)C-PIB), we applied the method to Australian Imaging, Biomarkers and Lifestyle (AIBL) (11)C-PIB scans (n = 285) and compared the PET-only neocortical composite score with the corresponding score obtained with a semimanual method that made use of the subject's MR images for the positioning of regions.

    RESULTS: Spatial normalization was successful on all scans. Visual and quantitative comparison of the new PET-only method with the MR imaging-based method of statistical parametric mapping indicated that performance was similar in the cortical regions although the new PET-only method showed better registration in the cerebellum and pons reference region area. For the (18)F-flutemetamol quantification, there was a strong correlation between the PET-only and FreeSurfer SUVRs (Pearson r = 0.96). We obtained a similar correlation for the AIBL (11)C-PIB data (Pearson r = 0.94).

    CONCLUSION: The derived adaptive template registration method allows for robust, accurate, and fully automated quantification of uptake for (18)F-flutemetamol and (11)C-PIB scans without the use of MR imaging data.

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