A Monte Carlo Study of the dependence of early frame sampling on uncertainty and bias in pharmacokinetic parameters from dynamic PET Journal Article


Authors: Häggström, I.; Axelsson, J.; Schmidtlein, C. R.; Karlsson, M.; Garpebring, A.; Johansson, L.; Sörensen, J.; Larsson, A.
Article Title: A Monte Carlo Study of the dependence of early frame sampling on uncertainty and bias in pharmacokinetic parameters from dynamic PET
Abstract: Compartmental modeling of dynamic PET data enables quantification of tracer kinetics in vivo, through the calculated model parameters. In this study, we aimed to investigate the effect of early frame sampling and reconstruction method on pharmacokinetic parameters obtained from a 2-tissue model, in terms of bias and uncertainty (SD). Methods: The GATE Monte Carlo software was used to simulate 2 × 15 dynamic 3'-deoxy-3'-18F-fluorothymidine (18F-FLT) brain PET studies, typical in terms of noise level and kinetic parameters. The data were reconstructed by both 3-dimensional (3D) filtered backprojection with reprojection (3DRP) and 3D ordered-subset expectation maximization (OSEM) into 6 dynamic image sets with different early frame durations of 1, 2, 4, 6, 10, and 15 s. Bias and SD were evaluated for fitted parameter estimates, calculated from regions of interest. Results: The 2-tissue-model parameter estimates K<inf>1</inf>, K<inf>2</inf>, and fraction of arterial blood in tissue depended on early frame sampling, and a sampling of 6-15 s generally minimized bias and SD. The shortest sampling of 1 s yielded a 25% and 42%larger bias than the other schemes, for 3DRP and OSEM, respectively, and a parameter uncertainty that was 10%-70% higher. The schemes from 4 to 15 s were generally not significantly different in regards to bias and SD. Typically, the reconstruction method 3DRP yielded less framesampling dependence and less uncertain results, compared with OSEM, but was on average more biased. Conclusion: Of the 6 sampling schemes investigated in this study, an early frame duration of 6-15 s generally kept both bias and uncertainty to a minimum, for both 3DRP and OSEM reconstructions. Veryshort frames of 1 s should be avoided because they typically resulted in the largest parameter bias and uncertainty. Furthermore, 3DRP may be preferred over OSEM for short frames with poor statistics. © 2015 by the Society of Nuclear Medicine and Molecular Imaging, Inc.
Keywords: neuroimaging; positron emission tomography; simulation; artifact; half life time; fluorine 18; amplitude modulation; image reconstruction; gate; monte carlo; pet scanner; monte carlo method; dynamic pet; kinetic parameters; compartment model; arterial blood; uncertainty; clearance; article; compartment modeling; frame sampling; dynamic positron emission tomography; sampling bias
Journal Title: Journal of Nuclear Medicine Technology
Volume: 43
Issue: 1
ISSN: 0091-4916
Publisher: Society of Nuclear Medicine and Molecular Imaging  
Date Published: 2015-04-01
Start Page: 53
End Page: 60
Language: English
DOI: 10.2967/jnmt.114.141754
PROVIDER: scopus
PUBMED: 25613339
DOI/URL:
Notes: Export Date: 2 July 2015 -- Source: Scopus
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