Purpose: To implement two major updates into the previously-published organ dose calculation program, NCI dosimetry system for Nuclear Medicine (NCINM): (1) a library of S values calculated using the International Commission on Radiological Protection (ICRP) reference pediatric and adult voxel phantoms and (2) the ICRP biokinetic models for selected radiopharmaceuticals.
Methods: We calculated a library of photon and electron SAFs for a total of 68 source organs and 55 target organs by using the ICRP reference newborn, 1-, 5-, 10-, 15-year-old, and adult male and female voxel phantoms. We then derived S values from the SAFs for a total of 299 radionuclides frequently used in nuclear medicine procedures using the energy spectra from ICRP Publication 107. We also extracted the biokinetic models for twelve radiopharmaceuticals from ICRP Publication 80 and 106. The S values and biokinetic models were implemented into the NCINM program. We compared our organ doses for 18F-FDG with those from ICRP Publication 106.
Results: We found that the organ doses from ICRP Publication 106 are overall smaller than those from NCINM. The breast dose from the ICRP 106 is about 20% of that of NCINM for the 1-year-old child phantoms. As an exception, the urinary bladder wall dose of ICRP is up to 2.5-fold greater than that of NCINM.
Conclusion: We implemented a new library of S values based on the ICRP reference pediatric and adult phantoms and the biokinetic models of twelve radiopharmaceuticals into NCINM. The upgraded NCINM should be useful for nuclear medicine physicists to readily estimate organ doses in major nuclear medicine procedures based on the international reference anatomical and biokinetic models.
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