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  • 1.
    Ahnesjö, Anders
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Medical Radiation Science.
    Patient Dose Computation2014In: Comprehensive Biomedical Physics: Volume 9: Radiation Therapy Physics and Treatment Optimization / [ed] Anders Brahme, Amsterdam: Elsevier, 2014, p. 235-247Chapter in book (Refereed)
    Abstract [en]

    Various dose calculation methods have been proposed to serve the needs in treatment planning of radiotherapy. Common to these are that they need a patient model to describe the interaction properties of the irradiated tissues, and a sufficiently accurate description of the incident radiation. This chapter starts with a brief review of the contexts in which patient dose calculations may serve, followed by a description of common methods for patient modelling and beam characterization. The focus is on external beam photon, but also partly covers particle beams like electrons and protons. The last section describes common approaches of varying complexity for dose calculations ranging from simple factor based models, more elaborate pencil and point kernel models, and finally summarizes some aspects of Monte Carlo and grid based methods.

  • 2.
    Ajaxon, Ingrid
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Holmberg, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Öhman Mägi, Caroline
    Persson, Cecilia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Fatigue life of a brushite cement under cyclic compressive loading2017Conference paper (Refereed)
  • 3.
    Ajaxon, Ingrid
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Holmberg, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Öhman Mägi, Caroline
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Persson, Cecilia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Long-term degradation of brushite cements in three different liquids2016Conference paper (Other academic)
  • 4. Augustine, Robin
    Near-field dosimetry for the millimeter-wave exposure of human cells in vitro2012In: Bioelectromagnetics, ISSN 0197-8462, E-ISSN 1521-186X, p. 55-64Article in journal (Refereed)
    Abstract [en]

    Due to the expected mass deployment of millimeter-wave wireless technologies, thresholds of potential millimeter-wave-induced biological and health effects should be carefully assessed. The main purpose of this study is to propose, optimize, and characterize a near-field exposure configuration allowing illumination of cells in vitro at 60 GHz with power densities up to several tens of mW/cm(2) . Positioning of a tissue culture plate containing cells has been optimized in the near-field of a standard horn antenna operating at 60 GHz. The optimal position corresponds to the maximal mean-to-peak specific absorption rate (SAR) ratio over the cell monolayer, allowing the achievement of power densities up to 50 mW/cm(2) at least. Three complementary parameters have been determined and analyzed for the exposed cells, namely the power density, SAR, and temperature dynamics. The incident power density and SAR have been computed using the finite-difference time-domain (FDTD) method. The temperature dynamics at different locations inside the culture medium are measured and analyzed for various power densities. Local SAR, determined based on the initial rate of temperature rise, is in a good agreement with the computed SAR (maximal difference of 5%). For the optimized exposure setup configuration, 73% of cells are located within the ±3 dB region with respect to the average SAR. It is shown that under the considered exposure conditions, the maximal power density, local SAR, and temperature increments equal 57 mW/cm(2) , 1.4 kW/kg, and 6 °C, respectively, for the radiated power of 425 mW.

  • 5.
    Bläckberg, Lisa
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Massachusetts General Hospital & Harvard Medical School.
    El Fakhri, Georges
    Massachusetts General Hospital & Harvard Medical School.
    Sabet, Hamid
    Massachusetts General Hospital & Harvard Medical School.
    Simulation study of light transport in laser-processed LYSO:Ce detectors with single-side readout2017In: Physics in Medicine and Biology, ISSN 0031-9155, E-ISSN 1361-6560, Vol. 62, no 21, p. 8419-8440Article in journal (Refereed)
    Abstract [en]

    A tightly focused pulsed laser beam can locally modify the crystal structure inside the bulk of a scintillator. The result is incorporation of so-called optical barriers with a refractive index different from that of the crystal bulk, that can be used to redirect the scintillation light and control the light spread in the detector. We here systematically study the scintillation light transport in detectors fabricated using the laser induced optical barrier technique, and objectively compare their potential performance characteristics with those of the two mainstream detector types: monolithic and mechanically pixelated arrays. Among countless optical barrier patterns, we explore barriers arranged in a pixel-like pattern extending all-the-way or half-way through a 20 mm thick LYSO:Ce crystal. We analyze the performance of the detectors coupled to MPPC arrays, in terms of light response functions, flood maps, line profiles, and light collection efficiency. Our results show that laser-processed detectors with both barrier patterns constitute a new detector category with a behavior between that of the two standard detector types. Results show that when the barrier-crystal interface is smooth, no DOI information can be obtained regardless of barrier refractive index (RI). However, with a rough barrier-crystal interface we can extract multiple levels of DOI. Lower barrier RI results in larger light confinement, leading to better transverse resolution. Furthermore we see that the laser-processed crystals have the potential to increase the light collection efficiency, which could lead to improved energy resolution and potentially better timing resolution due to higher signals. For a laser-processed detector with smooth barrier-crystal interfaces the light collection efficiency is simulated to  >42%, and for rough interfaces  >73%. The corresponding numbers for a monolithic crystal is 39% with polished surfaces, and 71% with rough surfaces, and for a mechanically pixelated array 35% with polished pixel surfaces and 59% with rough surfaces.

  • 6.
    Cantoni, Federico
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Hilborn, Jöns
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Polymer Chemistry.
    Johansson, Sofia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Pohlit, Hannah
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Polymer Chemistry.
    Porras, Ana Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Samanta, Ayan
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Polymer Chemistry.
    Tenje, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    2D and 3D patterning of biological hydrogels for organ-on-chip applications2018Conference paper (Other academic)
  • 7.
    Chu, Jiangtao
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Koudriavtsev, Vitali
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Dahlin, Andreas P
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Flourescence imaging of molecule transport in high molecular weight cut-off microdialysis2014Conference paper (Refereed)
  • 8.
    Chu, Jiangtao
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Koudriavtsev, Vitali
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Dahlin, Andreas P
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Flourescence imaging of molecule transport in high molecular weight cut-off microdialysis2014Conference paper (Refereed)
  • 9.
    Chu, Jiangtao
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Koudriavtsev, Vitali
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Dahlin, Andreas P
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Fluorescence imaging of macromolecule transport in high molecular weight cut-off microdialysis2014In: Analytical and Bioanalytical Chemistry, ISSN 1618-2642, E-ISSN 1618-2650, Vol. 406, no 29, p. 7601-7609Article in journal (Refereed)
    Abstract [en]

    When microdialysis (MD) membrane exceeds molecular weight cut-off (MWCO) of 100 kDa, the fluid mechanics are in the ultrafiltration regime. Consequently, fluidic mass transport of macromolecules in the perfusate over the membrane may reduce the biological relevance of the sampling and cause an inflammatory response in the test subject. Therefore, a method to investigate the molecular transport of high MWCO MD is presented. An in vitro test chamber was fabricated to facilitate the fluorescent imaging of the MD sampling process, using fluoresceinylisothiocyanate (FITC) dextran and fluorescence microscopy. Qualitative studies on dextran behavior inside and outside the membrane were performed. Semiquantitative results showed clear dextran leakage from both 40 and 250 kDa dextran when 100 kDa MWCO membranes were used. Dextran 40 kDa leaked out with an order of magnitude higher concentration and the leakage pattern resembled more of a convective flow pattern compared with dextran 250 kDa, where the leakage pattern was more diffusion based. No leakage was observed when dextran 500 kDa was used as a colloid osmotic agent. The results in this study suggest that fluorescence imaging could be used as a method for qualitative and semiquantitative molecular transport and fluid dynamics studies of MD membranes and other hollow fiber catheter membranes.

  • 10.
    Cubo, Rubén
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Automatic control. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Systems and Control.
    Fahlström, Markus
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology. Uppsala Univ Hosp, Dept Biomed Technol Med Phys & IT, Uppsala, Sweden.
    Jiltsova, Elena
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurology.
    Andersson, Helena
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Systems and Control. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Automatic control.
    Medvedev, Alexander
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Systems and Control. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Automatic control.
    Semi-Individualized electrical models in deep brain stimulation: A variability analysis2017In: 2017 IEEE Conference on Control Technology and Applications (CCTA), IEEE, 2017, p. 517-522Conference paper (Refereed)
    Abstract [en]

    Deep Brain Stimulation (DBS) is a well-established treatment in neurodegenerative diseases, e.g. Parkinson's Disease. It consists of delivering electrical stimuli to a target in the brain via a chronically implanted lead. To expedite the tuning of DBS stimuli to best therapeutical effect, mathematical models have been developed during recent years. The electric field produced by the stimuli in the brain for a given lead position is evaluated by numerically solving a Partial Differential Equation with the medium conductivity as a parameter. The latter is patient- and target-specific but difficult to measure in vivo. Estimating brain tissue conductivity through medical imaging is feasible but time consuming due to registration, segmentation and post-processing. On the other hand, brain atlases are readily available and processed. This study analyzes how alternations in the conductivity due to inter-patient variability or lead position uncertainties affect both the stimulation shape and the activation of a given target. Results suggest that stimulation shapes are similar, with a Dice's Coefficient between 93.2 and 98.8%, with a higher similarity at lower depths. On the other hand, activation shows a significant variation of 17 percentage points, with most of it being at deeper positions as well. It is concluded that, as long as the lead is not too deep, atlases can be used for conductivity maps with acceptable accuracy instead of fully individualized though medical imaging models.

  • 11.
    Engstrand, Johanna
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Persson, Cecilia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Influence of polymer addition on the mechanical properties of a premixed calcium phosphate cement2013In: Biomatter, ISSN 2159-2535, Vol. 3, no 4, p. e27249-Article in journal (Refereed)
    Abstract [en]

    Premixed calcium phosphate cements can reduce handling complications that are associated with the mixing of cements in the operating room. However, to extend the clinical indication of ceramic cements their mechanical properties need to be further improved. The incorporation of a polymeric material with intrinsically high tensile properties could possibly assist in increasing the mechanical properties of calcium phosphate cement. In this study polymer microparticles made from poly(lactid-co-glycolide) plasticised with poly(ethylene glycol) 400 (PLGA/PEG microparticles) were added in amounts of up to 5 wt% to a premixed acidic calcium phosphate cement. The PLGA/PEG microparticles added undergo a shape transformation at 37°C, which could give a better integration between polymer microparticles and ceramic cement compared to polymer microparticles lacking this property. The results showed that the incorporation of 1.25 wt% PLGA/PEG microparticles increased the compressive strength by approximately 20% up to 15.1 MPa while the diametral tensile strength was kept constant. The incorporation of PLGA/PEG microparticles increased the brushite to monetite ratio after setting compared to pure ceramic cements. In conclusion, small amounts of PLGA/PEG microparticles can be incorporated into premixed acidic calcium phosphate cement and increase their mechanical properties, which could lead to increased future applications.

  • 12.
    Fjärstedt, Jenny
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Catheter Related Problems in Pediatric Oncology Treatment: A Technical Investigation Performed at Uppsala Akademsika Sjukhus2016Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In this project, problems related to loss of free flow in central venous catheter and implanted subcutaneous ports have been investigated. The catheters investigated in this project are intended for children with cancer diseases. The initial hypothesis was that the length, radius and curvature of the catheter would affect the flow. Two other things that can have a negative impact on the flow are if the catheter is squashed or kinked. Experiments and simulations have been performed in order to test the hypothesis and investigate how a deformation of the catheter affects the flow.

    The results from the experiments and simulations show that the length and radius of the catheter have major impact on the pressure drop, and hence the flow. The curvature of the catheter has less impact on the flow as long as the catheter is not kinked. Experiments with squashed catheters show a decrease in outlet pressure with a decrease of the catheter lumen.

  • 13.
    Fornell, Anna
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Johannesson, Carl
    Lund University.
    Searle, Sean
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Uppsala University, Science for Life Laboratory, SciLifeLab. National University of Singapore.
    Happstadius, Axel
    Lund University.
    Nilsson, Johan
    Lund University.
    Tenje, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Acoustic trapping: a non-contact method to handle cell-laden hydrogel droplets in a microchannel2019Conference paper (Other academic)
  • 14.
    Fornstedt, Helena
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Industrial Engineering & Management.
    Persson-Fischier, Ulrika
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Industrial Engineering & Management.
    Askfors, Ylva
    KTH Royal Institute of Technology.
    Sheep on a slide: About a culture of scepticism among healthcare professionals2016In: Sheep on a slide: About a culture of scepticism among healthcare professionals / [ed] Thomas Lennerfors, David Sköld, 2016Conference paper (Refereed)
  • 15.
    Fransson, Christine
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Adersteg, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Industrial Engineering & Management. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Mathematics.
    Wester, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Att skapa stabila intäktströmmar från mobilhälsolösningar: En studie av möjligheterna för ett oetablerat företag på den svenska hälso- och sjukvårdsmarknaden att för mobilhälsolösningar skapa hållbara affärsmodeller2015Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This master thesis aims to investigate the possibilities for an unestablished company within the Swedish healthcare industry to generate a reliable revenue stream from mobile health solutions. The theoretical bases for part 1 are value theory and business model theory. The empirical material were collected through interviews with representatives from health technology companies and stakeholders within the Swedish healthcare system. The study shows that the Swedish healthcare system does not encourage the use of mobile health solutions. The main problem for commercialization of mobile health solutions is the fact that the reimbursement models used by the county councils are not suitable for mobile health solutions. The reimbursement models are however likely to change within the near future and the actors prepared and wellpositioned for the change have an increased possibility to succeed. A general description of Health Impact Bonds, a new innovative reimbursement model, is given in part 2. A potential approach for pricing Health Impact Bonds is then described and evaluated in detail. 

  • 16.
    Gallinetti, Sara
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Öhman Mägi, Caroline
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Long-term degradation of novel multiphasic calcium phosphate cements2017Conference paper (Refereed)
  • 17. Gatica Gustavsson, Yonatan
    Development and verification of an automated amplification module for next generation in vitro molecular diagnostics2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Today’s healthcare system is in dire need for diagnostic tools capable of not only rapidly diagnosis of infectious diseases but also the detection of markers for compatible treatment methods, such as antibiotic resistance markers. The emerging field of nucleic acid based Point-of-care-testing shows great promise in providing this. This master thesis investigates the possibility of a fully automated rolling circle amplification based module for incorporation in such a test. The thesis was conducted within the EU project “Development of rapid point-of-care test platforms for infectious diseases”.

  • 18.
    Hemmingsson, Helena
    et al.
    Stockholm Univ, Dept Special Educ, S-11418 Stockholm, Sweden.;Linkoping Univ, Dept Social & Welf Studies, S-58183 Norrkoping, Sweden..
    Ahlsten, Gunnar
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Women's and Children's Health, Research group (Dept. of women´s and children´s health), Neuropediatrics/Paediatric oncology.
    Wandin, Helena
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Public Health and Caring Sciences, Research in Disability and Habilitation. Swedish Natl Ctr Rett Syndrome & Related Disorder, S-83223 Froson, Sweden.
    Rytterström, Patrik
    Linkoping Univ, Dept Social & Welf Studies, S-58183 Norrkoping, Sweden..
    Borgestig, Maria
    Linkoping Univ, Dept Social & Welf Studies, S-58183 Norrkoping, Sweden.;Orebro Univ, Fac Med & Hlth, Sch Hlth Sci, S-70281 Orebro, Sweden..
    Eye-Gaze Control Technology as Early Intervention for a Non-Verbal Young Child with High Spinal Cord Injury: A Case Report2018In: TECHNOLOGIES, ISSN 2227-7080, Vol. 6, no 1, article id 12Article in journal (Refereed)
    Abstract [en]

    Assistive technology (AT) can be used as early intervention in order to reduce activity limitations in play and communication. This longitudinal case study examines eye-gaze control technology as early intervention for a young child with high spinal cord injury without the ability to make sounds. The young child was followed by repeated measures concerning performance and communication from baseline at 9 months to 26 months, and finalized at 36 months by field observations in the home setting. The results showed eye-gaze performance and frequency of use of eye-gaze control technology increased over time. Goals set at 15 months concerning learning and using the AT; naming objects and interactions with family was successfully completed at 26 months. Communicative functions regarding obtaining objects and social interaction increased from unintentional actions to purposeful choices and interactions. At 36 months, the toddler was partly independent in eye gazing, used all activities provided, and made independent choices. In conclusion, the results show that a 9-month-old child with profound motor disabilities can benefit from eye-gaze control technology in order to gradually perform activities, socially interact with family members, and make choices.

  • 19.
    Hjort, Klas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Rask-Andersen, Helge
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Otolaryngology and Head and Neck Surgery.
    Li, Hao
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Otolaryngology and Head and Neck Surgery.
    Softer, thinner and more compliant implants2018Conference paper (Refereed)
    Abstract [en]

    Tissue irritation is caused by two main reasons – chemical and mechanical. In recent years, material chemical biocompatibility has been much improved but most implants used in soft tissue still have low compliance. This is especially severe in the brain, where the tissue often has a compliance of a soft hydrogel and ordinary silicone materials like PDMS have an elastic modulus up to 1,000 times higher, i.e. like a wooden stick irritating your skin. Starting from the remaining challenges of the highly successful Cochlear Implants and recent work on stretchable electronics this review conclude on the merits with soft stretchable printed circuitboards, with components of fluids, gels, and sprinkled with a smart dust of small chips.

  • 20.
    Hollmark, M
    et al.
    Division of Medical Radiation Physics, Department of Oncology-Pathology, Karolinska Institutet and Stockholm University.
    Uhrdin, J
    Dz, Belkić
    Gudowska, I
    Brahme, A
    Influence of multiple scattering and energy loss straggling on the absorbed dose distributions of therapeutic light ion beams: I. Analytical pencil beam model.2004In: Physics in Medicine and Biology, ISSN 0031-9155, E-ISSN 1361-6560, Vol. 49, no 14, p. 3247-65Article in journal (Refereed)
    Abstract [en]

    The lateral and longitudinal distributions of absorbed dose of broad and narrow light ion beams in water are investigated. An analytical algorithm based on the generalized Fermi-Eyges theory is developed and used to calculate the effects of multiple scattering and range straggling on the dose distribution of light ion beams in water. A first-order Gaussian multiple scattering and energy loss straggling approach is generally sufficiently accurate for describing the lateral and longitudinal spread of the Bragg peak and the associated energy deposition distribution of therapeutic light ion beams at ranges of clinical interest. Nuclear reactions are not taken into account in this study. The analytical algorithm given in the present study allows an accurate description of the radial spread and the range straggling of light ions traversing matter. A verification of this approach by comparing with experimental data, Monte Carlo methods and other analytical techniques will be presented in a forthcoming paper.

  • 21.
    Holm, Malin
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Visual Information and Interaction.
    Simulating Dialysis: Concept Evaluation of a PC Training Simulator for Nurses2013Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Nurses at a haemodialysis clinic are required to handle complex technological equipment in a stressful environment, with the patients’ lives at risk. A training needs analysis (TNA) that was made at Karolinska University Hospital Huddinge in 2010 identifies the nurses’ need to practice alarm situations in the safe environment of a computer-based training simulator. This project builds on the conclusions of the TNA and the aim is to evaluate the concept of a training simulator by developing and evaluating a prototype program.

    The simulation model used is the prototype is based on a problem solving approach with virtual patient scenarios. During the entire development process continuous input has been gathered from nurses who work with dialysis. The project was completed by structured user test focusing on evaluating the usability and realism of the prototype.

    The conclusion of the project is that nurses working with dialysis need to practice alarm situations and that a training simulator could meet this need.

    The report is written in English.

  • 22.
    Johansson, Dongni
    et al.
    Univ Gothenburg, Sahlgrenska Acad, Inst Neurosci & Physiol, Dept Clin Neurosci, Gothenburg, Sweden.
    Thomas, Ilias
    Dalarna Univ, Dept Microdata Anal, Falun, Sweden.
    Ericsson, Anders
    RISE Acreo, Gothenburg, Sweden;Karolinska Inst, Dept Clin Neurosci, Neurol, Stockholm, Sweden.
    Johansson, Anders
    Medvedev, Alexander
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Automatic control. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Systems and Control.
    Memedi, Mevludin
    Orebro Univ, Sch Business, Informat, Orebro, Sweden.
    Nyholm, Dag
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Landtblom: Neurology.
    Ohlsson, Fredrik
    RISE Acreo, Gothenburg, Sweden.
    Senek, Marina
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience.
    Spira, Jack
    Sensidose AB, Sollentuna, Sweden.
    Westin, Jerker
    Dalarna Univ, Dept Microdata Anal, Falun, Sweden.
    Bergquist, Filip
    Univ Gothenburg, Sahlgrenska Acad, Inst Neurosci & Physiol, Dept Clin Neurosci, Gothenburg, Sweden;Univ Gothenburg, Sahlgrenska Acad, Inst Neurosci & Physiol, Dept Pharmacol, Gothenburg, Sweden.
    Evaluation of a sensor algorithm for motor state rating in Parkinson's disease2019In: Parkinsonism & Related Disorders, ISSN 1353-8020, E-ISSN 1873-5126, Vol. 64, p. 112-117Article in journal (Refereed)
    Abstract [en]

    Introduction: A treatment response objective index (TRIS) was previously developed based on sensor data from pronation-supination tests. This study aimed to examine the performance of TRIS for medication effects in a new population sample with Parkinson's disease (PD) and its usefulness for constructing individual dose-response models.

    Methods: Twenty-five patients with PD performed a series of tasks throughout a levodopa challenge while wearing sensors. TRIS was used to determine motor changes in pronation-supination tests following a single levodopa dose, and was compared to clinical ratings including the Treatment Response Scale (TRS) and six sub-items of the UPDRS part III.

    Results: As expected, correlations between TRIS and clinical ratings were lower in the new population than in the initial study. TRIS was still significantly correlated to TRS (r(s) = 0.23, P < 0.001) with a root mean square error (RMSE) of 1.33. For the patients (n = 17) with a good levodopa response and clear motor fluctuations, a stronger correlation was found (r(s) = 0.38, RMSE = 1.29, P < 0.001). The mean TRIS increased significantly when patients went from the practically defined off to their best on state (P = 0.024). Individual dose-response models could be fitted for more participants when TRIS was used for modelling than when TRS ratings were used.

    Conclusion: The objective sensor index shows promise for constructing individual dose-response models, but further evaluations and retraining of the TRIS algorithm are desirable to improve its performance and to ensure its clinical effectiveness.

  • 23.
    Nilsson, Linus
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Scientific Computing.
    Real-time simulation of diaphragm displacement during physiological and mechanical ventilation2013Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis presents a tunable 3D real-time interactive simulator of the geometrical displacement of the thoracic diaphragm during physiological and mechanical ventilation. Particular attention is placed on capturing the heterogeneous tissue composition while maintaining computational efficiency and accuracy. The long term goal is to establish an accurate theoretical model to complement the experimental and clinical studies of the side effects associated with mechanical ventilation and to overcome the ethical difficulties of performing time resolved studies on human patients. The deformations are modelled using a commercial 3D model and a mass-spring model together with distance constraints and Verlet integration. The simulator is easily adjusted in real-time to many different cases of ventilation and validated through inspection and comparison with existing models. More research is needed to validate the model using patient specific data, as well as extending the model to include additional physiological and pathophysiological components. Long term goals includes considering the microscopic aspects of cellular mechanics to capture the underlying causes of ventilator-induced diaphragmatic dysfunction.

  • 24.
    Orvehed Hiltunen, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Computing Science.
    Robust optimization of radiotherapy treatment plans considering time structures of the delivery2018Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Cancer is the second largest mortal disease in Sweden, and high efforts are made to develop the treatment of cancer. One of the main treatment methods is radiotherapy, which uses ionizing radiation to damage the cancerous cells. This has the chance of stopping the cell reproduction, and the goal is to reduce the tumor and stop the tumor growth.

    The most common forms of radiotherapy uses external beams to irradiate the tumor. In intensity modulated radiotherapy, IMRT, the beam fluences are optimized to give a highly conformal dose, i.e. a dose distribution which is restricted to the tumor and has low dose values outside of the tumor. A conformal dose is necessary to spare healthy tissue and sensitive organs, and thus keep the side-effects of the treatment at an acceptable level. The optimized beam shapes are created using a multileaf collimator, MLC. Finding the leaf positions and dose levels is formulated as a problem in the framework of mathematical optimization.

    Currently, one of the limitations in delivering conformal dose is due to patient movement during the treatment. In IMRT, the beams are delivered by consecutive segments, and the exact pairing of the segments with the patient position will have an impact on the delivered dose. This is called the interplay effect, and can cause both underdosage of the tumor and overdosage of the surrounding tissue.

    There are methods of mitigating the interplay effect. For example, the beam could be restricted to a single phase of the motion by repeatedly turning it on and off. This is known as gating. However, gating and many other interplay mitigation techniques lead to prolonged treatment times, which decreases the clinical throughput, causes higher patient discomfort and gives higher uncertainties in the delivered dose. This makes it desirable to find methods which avoid prolonged treatment times, while still giving highly conformal doses. Ideally, the best method would be to have a beam which follows any target movement. This idea is known as target tracking.

    In this thesis, an optimization method is suggested which includes the interplay effect in the treatment optimization. Two main treatment strategies are proposed. The method which is simplest to implement clinically is to create plans which are robust against uncertainties in the times for the patient motion. The resulting doses are found to give acceptable target covering where similar, conventional plans give a significant target underdose. To further increase the conformality of the doses, a non-robust method paired with gating technology is suggested. This method can effectively be seen as a target tracking method, and has the possibility to give highly conformal doses under acceptable treatment times.   

  • 25.
    Porras, Ana Maria
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Shi, Liyang
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Polymer Chemistry.
    Ossipov, Dmitri A.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Polymer Chemistry.
    Tenje, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Chemical micropatterning of hyaluronic acid hydrogels for controlled cell adhesion2018Conference paper (Other academic)
    Abstract [en]

    The blood brain barrier is constituted by endothelial cells, astrocytes and pericytes; and are organized into well structured units [1]. Standard cell culture techniques cannot recapitulate this organized structure. Hydrogels are an attractive scaffold due to their mechanical and chemical properties similar to those in body tissue[2] We propose the use of a photo-crosslinkable hyaluronic acid hydrogel as cell culture scaffold. Furthermore, chemical cues can be added into the hydrogel matrix to promote and control cell adhesion using UV lithography.

  • 26.
    Redzwan, Syaiful
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Velander, Jacob
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Perez, Mauricio D.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Asan, Noor Badariah
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Rajabi, Mina
    KTH Royal Inst Technol, Sch Elect Engn, Dept Micro & Nanosyt, Stockholm, Sweden.
    Niklaus, Frank
    KTH Royal Inst Technol, Sch Elect Engn, Dept Micro & Nanosyt, Stockholm, Sweden.
    Nowinski, Daniel
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Plastic Surgery.
    Lewén, Anders
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Enblad: Neurosurgery.
    Enblad, Per
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Enblad: Neurosurgery.
    Augustine, Robin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Initial In-Vitro Trial for Intra-Cranial Pressure Monitoring Using Subdermal Proximity-Coupled Split-Ring Resonator2018In: Proceedings of the 2018 IEEE/MTT-S International Microwave Biomedical Conference (IMBioC), IEEE, 2018, p. 73-75Conference paper (Refereed)
    Abstract [en]

    Intra cranial pressure (ICP) monitoring is used in treating severe traumatic brain injury (TBI) patients. All current clinical available measurement methods are invasive presenting considerable social costs. This paper presents a preliminary investigation of the feasibility of ICP monitoring using an innovative microwave-based non-invasive approach. A phantom mimicking the dielectric characteristics of human tissues of the upper part of the head at low microwave frequencies is employed together to a proof-of-concept prototype based on the proposed approach consisting in a readout system and a sub-dermally implanted passive device, both based in split ring resonator techniques. This study shows the potential of our approach to detect two opposite pressure variation stages inside the skull. The employed phantom model needs to be improved to support finer variations in the pressure and better phantom parts, principally for the skull mimic and the loss tangent of all mimics.

  • 27.
    Sladkova, Martina
    et al.
    The New York Stem Cell Foundation Research Institute.
    Pujari-Palmer, Michael
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Öhman, Caroline
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Cheng, Jiayi
    The New York Stem Cell Foundation Research Institute.
    Al-Ansari, Shoug
    The New York Stem Cell Foundation Research Institute.
    Saad, Munerah
    The New York Stem Cell Foundation Research Institute.
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    de Peppo, Giuseppe Maria
    The New York Stem Cell Foundation Research Institute.
    Engineering human bone grafts with new macroporous calcium phosphate cement scaffolds2018In: Journal of Tissue Engineering and Regenerative Medicine, ISSN 1932-6254, E-ISSN 1932-7005, Vol. 12, no 3, p. 715-726Article in journal (Refereed)
    Abstract [en]

    Bone engineering opens the possibility to grow large amounts of tissue products by combining patient-specific cells with compliant biomaterials. Decellularized tissue matrices represent suitable biomaterials, but availability, long processing time, excessive cost, and concerns on pathogen transmission have led to the development of biomimetic synthetic alternatives. We recently fabricated calcium phosphate cement (CPC) scaffolds with variable macroporosity using a facile synthesis method with minimal manufacturing steps and demonstrated long-term biocompatibility in vitro. However, there is no knowledge on the potential use of these scaffolds for bone engineering and whether the porosity of the scaffolds affects osteogenic differentiation and tissue formation in vitro. In this study, we explored the bone engineering potential of CPC scaffolds with two different macroporosities using human mesenchymal progenitors derived from induced pluripotent stem cells (iPSC-MP) or isolated from bone marrow (BMSC). Biomimetic decellularized bone scaffolds were used as reference material in all experiments. The results demonstrate that, irrespective of their macroporosity, the CPC scaffolds tested in this study support attachment, viability, and growth of iPSC-MP and BMSC cells similarly to decellularized bone. Importantly, the tested materials sustained differentiation of the cells as evidenced by increased expression of osteogenic markers and formation of a mineralized tissue. In conclusion, the results of this study suggest that the CPC scaffolds fabricated using our method are suitable to engineer bone grafts from different cell sources and could lead to the development of safe and more affordable tissue grafts for reconstructive dentistry and orthopaedics and in vitro models for basic and applied research.

  • 28.
    Thomas, Ilias
    et al.
    Dalarna Univ, S-79131 Falun, Sweden.
    Westin, Jerker
    Dalarna Univ, S-79131 Falun, Sweden.
    Alam, Moudud
    Dalarna Univ, S-79131 Falun, Sweden.
    Bergquist, Filip
    Gothenburg Univ, S-40530 Gothenburg, Sweden.
    Nyholm, Dag
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurology.
    Senek, Marina
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurology.
    Memedi, Mevludin
    Orebro Univ, S-70281 Orebro, Sweden;Dalarna Univ, S-79131 Falun, Sweden.
    A Treatment-Response Index From Wearable Sensors for Quantifying Parkinson's Disease Motor States2018In: IEEE journal of biomedical and health informatics, ISSN 2168-2194, E-ISSN 2168-2208, Vol. 22, no 5, p. 1341-1349Article in journal (Refereed)
    Abstract [en]

    The goal of this study was to develop an algorithm that automatically quantifies motor states (off, on, dyskinesia) in Parkinson's disease (PD), based on accelerometry during a hand pronation-supination test. Clinician's ratings using the Treatment Response Scale (TRS), ranging from -3 (veryOff) to 0 (On) to +3 (very dyskinetic), were used as target. For that purpose, 19 participants with advanced PD and 22 healthy persons were recruited in a single center open label clinical trial in Uppsala, Sweden. The trial consisted of single levodopa dose experiments for the people with PD (PwP), where participants were asked to perform standardized wrist rotation tests, using each hand, before and at prespecified time points after the dose. The participants used wrist sensors containing a three-dimensional accelerometer and gyroscope. Features to quantify the level, variation, and asymmetry of the sensor signals, three-level discrete wavelet transform features, and approximate entropy measures were extracted from the sensors data. At the time of the tests, the PwP were video recorded. Three movement disorder specialists rated the participants' state on the TRS. A Treatment Response Index from Sensors (TRIS) was constructed to quantify the motor states based on the wrist rotation tests. Different machine learning algorithms were evaluated to map the features derived from the sensor data to the ratings provided by the three specialists. Results from cross validation, both in tenfold and a leave-one-individual out setting, showed good predictive power of a support vector machine model and high correlation to the TRS. Values at the end tails of the TRS were under and over predicted due to the lack of observations at those values but the model managed to accurately capture the dose-effect profiles of the patients. In addition, the TRIS had good test-retest reliability on the baseline levels of the PD participants (Intraclass correlation coefficient of 0.83) and reasonable sensitivity to levodopa treatment (0.33 for the TRIS). For a series of test occasions, the proposed algorithms provided dose-effect time profiles for participants with PD, which could be useful during therapy individualization of people suffering from advanced PD.

  • 29.
    Tilly, David
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Section of Medical Physics.
    Tilly, Nina
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Section of Medical Physics.
    Ahnesjö, Anders
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Section of Medical Physics.
    Dose mapping sensitivity to deformable registration uncertainties in fractionated radiotherapy – applied to prostate proton treatments2013In: BMC Medical Physics, ISSN 1756-6649, E-ISSN 1756-6649, Vol. 13, no 2Article in journal (Refereed)
    Abstract [en]

    Background

    Calculation of accumulated dose in fractionated radiotherapy based on spatial mapping of the dose points generally requires deformable image registration (DIR). The accuracy of the accumulated dose thus depends heavily on the DIR quality. This motivates investigations of how the registration uncertainty influences dose planning objectives and treatment outcome predictions.

    A framework was developed where the dose mapping can be associated with a variable known uncertainty to simulate the DIR uncertainties in a clinical workflow. The framework enabled us to study the dependence of dose planning metrics, and the predicted treatment outcome, on the DIR uncertainty. The additional planning margin needed to compensate for the dose mapping uncertainties can also be determined. We applied the simulation framework to a hypofractionated proton treatment of the prostate using two different scanning beam spot sizes to also study the dose mapping sensitivity to penumbra widths.

    Results

    The planning parameter most sensitive to the DIR uncertainty was found to be the targetD95. We found that the registration mean absolute error needs to be ≤0.20 cm to obtain an uncertainty better than 3% of the calculated D95 for intermediate sized penumbras. Use of larger margins in constructing PTV from CTV relaxed the registration uncertainty requirements to the cost of increased dose burdens to the surrounding organs at risk.

    Conclusions

    The DIR uncertainty requirements should be considered in an adaptive radiotherapy workflow since this uncertainty can have significant impact on the accumulated dose. The simulation framework enabled quantification of the accuracy requirement for DIR algorithms to provide satisfactory clinical accuracy in the accumulated dose.

  • 30.
    Tilly, David
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Medical Radiation Science. Elekta Instruments AB, Stockholm, Sweden.
    van de Schoot, Agustinus J A J
    Academic Medical Center, Univesity of Amsterdam, Amsterdam, The Netherlands.
    Grusell, Erik
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Medical Radiation Science.
    Bel, Arjan
    Academic Medical Center, Univesity of Amsterdam, Amsterdam, The Netherlands.
    Ahnesjö, Anders
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Medical Radiation Science.
    Dose coverage calculation using a statistical shape model: applied to cervical cancer radiotherapy2017In: Physics in Medicine and Biology, ISSN 0031-9155, E-ISSN 1361-6560, Vol. 62, no 10, p. 4140-4159Article in journal (Refereed)
    Abstract [en]

    A comprehensive methodology for treatment simulation and evaluation of dose coverage probabilities is presented where a population based statistical shape model (SSM) provide samples of fraction specific patient geometry deformations.The learning data consists of vector fields from deformable image registration of repeated imaging giving intra-patient deformations which are mapped to an average patient serving as a common frame of reference. The SSM is created by extracting the most dominating eigenmodes through principal component analysis of the deformations from all patients. The sampling of a deformation is thus reduced to sampling weights for enough of the most dominating eigenmodes that describe the deformations.For the cervical cancer patient datasets in this work, we found seven eigenmodes to be sufficient to capture 90% of the variance in the deformations of the, and only three eigenmodes for stability in the simulated dose coverage probabilities. The normality assumption of the eigenmode weights was tested and found relevant for the 20 most dominating eigenmodes except for the first. Individualization of the SSM is demonstrated to be improved using two deformation samples from a new patient. The probabilistic evaluation provided additional information about the trade-offs compared to the conventional single dataset treatment planning.

  • 31. Waligórski, M P R
    et al.
    Hollmark, M
    Lesiak, J
    A simple track structure model of ion beam radiotherapy.2006In: Radiation Protection Dosimetry, ISSN 0144-8420, E-ISSN 1742-3406, Vol. 122, no 1-4, p. 471-4Article in journal (Refereed)
    Abstract [en]

    A simple radiotherapy ion beam calculation based on the cellular track structure model, using in vitro cell survival parameters fitted from recent experimental data, is presented. The calculation represents a single-fraction ion exposure (roughly corresponding to a 2 Gy fraction of megavolt X rays) and exploits concepts used in clinical radiotherapy, such as entrance, or 'skin' ion dose. The depth distribution of cells surviving their irradiation by a beam of 385 MeV amu(-1) carbon ions is calculated over the range of the stopping ions, as a sequence of track-segments, in the continuous slowing-down approximation. An interpretation of the 'clinical relative biological effectiveness' concept is suggested.

  • 32.
    Waligórski, M P R
    et al.
    nstitute of Nuclear Physics, Polish Academy of Sciences, Kraków, Poland.
    Hollmark, M
    Division of Medical Radiation Physics, Department of Oncology-Pathology, Karolinska Institutet and Stockholm University.
    Lind, B
    Gudowska, I
    Cellular parameters for track structure modeling of radiation hazard in space.2004In: Advances in Space Research, ISSN 0273-1177, E-ISSN 1879-1948, Vol. 34, no 6, p. 1378-82Article in journal (Refereed)
    Abstract [en]

    Based on irradiation with 45 MeV/u N and B ions and with Co-60 gamma rays, cellular parameters of Katz's track structure model have been fitted for the survival of V79-379A Chinese hamster lung fibroblasts. Cellular parameters representing neoplastic transformations in C3H10T/1/2 cells after their irradiation with heavy ion beams, taken from earlier work, were also used to model the radiation hazard in deep space, following the system for evaluating, summing and reporting occupational exposures proposed in 1967 by a subcommittee of NCRP. We have performed model calculations of the number of transformations in surviving cells, after a given fluence of heavy charged particles of initial energy 500 MeV/u, penetrating thick layers of cells. We take the product of cell transformation and survival probabilities, calculated along the path lengths of charged particles using cellular survival and transformation parameters, to represent a quantity proportional to the "radiation risk factor" discussed in the NCRP document. The "synergistic" effect of simultaneous charged particle transfers is accounted for by the "track overlap" mode inherent in the model of Katz.

  • 33. Waligórski, Michael P R
    et al.
    Hollmark, Malin
    Gudowska, Irena
    Lesia, Jan
    Cellular parameters and RBE-LET dependences for modelling heavy-ion radiotherapy.2004In: Radiotherapy and Oncology, ISSN 0167-8140, E-ISSN 1879-0887, Vol. 73 Suppl 2, p. S173-5Article in journal (Refereed)
    Abstract [en]

    Sets of four parameters (m, E0, sigma0 and kappa) of the cellular track structure model of Katz have been fitted to recently published data concerning human melanoma (AA) and mammalian (V79) cells exposed to a variety of lighter ions and to mixed ion-Co60 and ion-ion irradiation. Using these parameters, model predictions of V79 survival were verified against experimental data. RBE-LET dependences were calculated and compared with experimental data obtained for V79 cells after exposure to 3He, 12C and 20Ne ion beams. The presented track-segment approach used in track structure calculations, while satisfactory for heavier ions, may be of limited value for predicting the RBE-LET dependence of proton and helium radiotherapy beams in regions close to the distal range of these particles. We discuss the predictive capability of this model and propose standards in reporting cellular radiobiology data for application in modelling heavy ion beam radiotherapy.

  • 34.
    Öhman, Caroline
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Espino, Daniel M.
    School of Mechanical Engineering, University of Birmingham, Birmingham, UK.
    Baleani, Massimiliano
    Laboratorio di Tecnologia Medica, Istituto Ortopedico Rizzoli, Italy.
    Erani, Paolo
    Laboratorio di Tecnologia Medica, Istituto Ortopedico Rizzoli, Italy.
    Juszczyk, Mateusz
    Laboratorio di Tecnologia Medica, Istituto Ortopedico Rizzoli, Italy.
    Maccarrone, Pierro G.
    Laboratorio di Tecnologia Medica, Istituto Ortopedico Rizzoli, Italy.
    Falco, Luigi
    Laboratorio di Tecnologia Medica, Istituto Ortopedico Rizzoli, Italy.
    Toni, Aldo
    Laboratorio di Tecnologia Medica, Istituto Ortopedico Rizzoli, Italy.
    AN EXPERIMENTAL METHOD TO CHARACTERISE KNEE STABILITY: PRELIMINARY TESTS WITH A PORCINE MODEL2012Conference paper (Refereed)
  • 35.
    Öhman Mägi, Caroline
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Holub, Ondrej
    School of Mechanical Engineering, University of Leeds, UK.
    Hall, Richard M
    School of Mechanical Engineering, University of Leeds, UK.
    Persson, Cecilia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Predicting the mechanical properties of vertebral trabecular bone - a review2017Conference paper (Refereed)
1 - 35 of 35
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