RT Journal Article
SR Electronic
T1 NCINM: a computational phantom-based dosimetry tool for patients undergoing nuclear medicine procedures
JF Journal of Nuclear Medicine
JO J Nucl Med
FD Society of Nuclear Medicine
SP 1634
OP 1634
VO 60
IS supplement 1
A1 VILLOING, Daphnee
A1 Lee, Choonsik
YR 2019
UL http://jnm.snmjournals.org/content/60/supplement_1/1634.abstract
AB 1634Background: Nuclear medicine techniques used for diagnostic and therapeutic purposes make up about 25% of the per capita medical effective dosein the United States1. To make informed decisions for potential risk and benefit, a better understanding of the magnitude of radiation dose and health risk resulting from nuclear medicine procedures is crucial. However, existing organ dose estimation tools are limited to simplified human anatomy models or commercial programs. To fill the research gaps, we developed a new dose calculation tool using advanced anatomy models. Methods: We used the twelve National Cancer Institute pediatric and adult phantoms2 developed from patient images. Specific Absorbed Fractions (SAFs) were calculated for photon and electron on these phantoms for 68 source and 55 target regions using the MCNPX Monte Carlo radiation transport code3. S values were then derived from the SAFs for 299 radionuclides commonly used in nuclear medicine4. A graphical user interface-based computer program, named National Cancer Institute dosimetry system for Nuclear Medicine (NCINM) was finally developed to facilitate data input/output. We conducted a comprehensive comparison of our S values with those previously published for iodine-131 (Lamart et al.5 based on the ICRP reference adult phantoms6 and OLINDA/EXM 1.07 based on the ORNL stylized phantoms). Results: The ratios of our iodine-131 S values to those from Lamart et al. were on average 0.99±0.04σ and 0.98±0.03σ, respectively, for adult male and female phantoms in case of self-absorption within 8 major organs (adrenals, brain, kidneys, liver, lungs, pancreas, spleen, and thyroid), and 0.79±0.46σ and 0.93±0.51σ, respectively, for adult male and female phantoms in case of cross-irradiation between these same organs. The ratios of our S values for iodine-131, technetium-99m and gallium-68 to those from OLINDA/EXM 1.0 were on average 0.91±0.15σ, 0.87±0.14σ, and 0.88±0.15σ over eight adult and pediatric phantoms, in case of self-absorption, and 1.34± 0.62σ, 1.48±0.82σ, and 1.36±0.62σ in case of cross-irradiation between the same organs, respectively. Conclusions: A good agreement was observed between iodine-131 S values calculated on realistic phantoms: the NCI phantom series vs. the ICRP 110 reference phantoms. Greater differences were, however, revealed in S values between the NCI phantoms (NCINM) and the stylized phantoms (OLINDA), especially for cross-irradiation, which emphasizes the impact of realistic human anatomy models on S values. The program will be useful for epidemiologic studies of risk and patient dose monitoring in nuclear medicine procedures. We are incorporating the S values based on the ICRP reference pediatric and adult phantoms into NCINM and plan to release the program free of charge for research purpose.