uu.seUppsala University Publications
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Optimisation of penalized likelihood estimation reconstruction (Q.Clear) on a digital time-of-flight PET-CT scanner for four different PET tracers
Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology. Uppsala Univ Hosp, Med Phys, Uppsala, Sweden..
Uppsala Univ Hosp, PET Ctr, Uppsala, Sweden..
Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology. Uppsala Univ Hosp, Med Phys, Uppsala, Sweden..
Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology. Uppsala Univ Hosp, PET Ctr, Uppsala, Sweden..
Show others and affiliations
2017 (English)In: Journal of Nuclear Medicine, ISSN 0161-5505, E-ISSN 1535-5667, Vol. 58, no S1, 1355Article in journal, Meeting abstract (Other academic) Published
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.

Place, publisher, year, edition, pages
2017. Vol. 58, no S1, 1355
National Category
Radiology, Nuclear Medicine and Medical Imaging
Identifiers
URN: urn:nbn:se:uu:diva-333337ISI: 000404949906146OAI: oai:DiVA.org:uu-333337DiVA: diva2:1157077
Conference
Annual Meeting of the Society-of-Nuclear-Medicine-and-Molecular-Imaging (SNMMI), JUN 10-14, 2017, Denver, CO
Available from: 2017-11-15 Created: 2017-11-15 Last updated: 2017-11-15Bibliographically approved

Open Access in DiVA

No full text

Other links

http://jnm.snmjournals.org/content/58/supplement_1/1355.abstract?sid=09c4410f-1904-4433-9a47-069a4256a8df

Authority records BETA

Lindström, ElinIlan, EzgiSundin, AndersSörensen, JensDanfors, TorstenAntoni, GunnarLubberink, Mark

Search in DiVA

By author/editor
Lindström, ElinIlan, EzgiSundin, AndersSörensen, JensDanfors, TorstenAntoni, GunnarLubberink, Mark
By organisation
RadiologyClinical PhysiologyDivision of Molecular Imaging
In the same journal
Journal of Nuclear Medicine
Radiology, Nuclear Medicine and Medical Imaging

Search outside of DiVA

GoogleGoogle Scholar

urn-nbn

Altmetric score

urn-nbn
Total: 62 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf