Abstract
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Objectives To develop a population of realistic digital phantoms and corresponding Tc-99m and Tl-201 projections for use in myocardial perfusion SPECT research.
Methods The population is based on the XCAT phantom with organ parameters sampled from the Emory PET Torso Model Database. Phantoms included 3 variations each in body size, heart size, and subcutaneous adipose tissue level, for a total of 27 phantoms of each gender. Uptake parameters were obtained from 30 clinical studies. For each phantom, the heart, liver, lungs, kidneys, blood pool, gall bladder and remaining organs were separately simulated, allowing use of post-simulation summing to efficiently model uptake variations. The SimSET Monte Carlo code and angular response functions were used to model interactions in the body and the collimator-detector system, respectively. A criterion, based on maximizing the effective count level for a given total number of simulated photons, for the optimal number of simulations for each organ was derived and used. This technique provided a quantitative estimate of the true noise in the simulated projection data, including residual MC simulation noise. Projections were generated in 1 keV wide windows from 48-184 keV to permit study of the effects of window width, energy resolution, and crosstalk.
Results The simulation approach, database structure, and number of simulations have been optimized, and the database is being populated. The production of projection data for each complete phantom realization requires ~104 CPU hours and 5 GB of disk space.
Conclusions We have developed and applied an efficient method for the generation of a realistic digital phantom population. The population will be useful to evaluate acquisition and compensation methods, optimize energy windows, and investigate the effects of energy resolution and crosstalk on image quality in myocardial perfusion SPECT.
Research Support This work is supported by Public Health Service grant R01-EB00288