Dose conversion factors for marrow and bone by skeletal regions
- Oak Ridge National Lab., TN (United States)
- Oak Ridge Institute for Science and Education, TN (United States)
Radiation dose estimates for the active bone marrow are of primary importance in radioimmunotherapy. The dose coefficients of MIRD 11 (S values) and ICRP 30 (values of specific effective energy, SEE) reflect unnecessary simplifying assumptions regarding anatomical and radiological parameters that may limit the ability of these coefficients to predict clinical symptoms associated with irradiation of the marrow at the multi-gray level. The results of new calculations of electron transport in the skeleton, based on the microstructure have been applied to the skeletal regions of the Cristy-Eckerman phantom series to produce dose coefficients (absorbed dose per disintegration) for active marrow and bone surface cells as targets from electron sources in the marrow, on the surfaces of bone, or in bone volume. The coefficients are determined for fifteen skeletal regions, thus allowing estimation of the absorbed dose to these different skeletal regions. The development of these new coefficients will be described, and the coefficients will be compared with similar coefficients from the MIRD and ICRP dosimetry systems. For I-131, the region-specific dose coefficients for marrow irradiating marrow in the adult range from 2.1 x 10{sup -5} mGy/MBq-s (pelvis) to 5.6 x 10{sup -4} mGy/MBq-s (clavicles). A weighted average coefficient for the whole skeleton (marrow irradiating marrow, I-131) is 9.5 x 10{sup -6} mGy/MBq-s, in comparison with 1.7 x 10{sup -5} mGy/MBq-s from MIRD-11 and 2.9 x 10{sup -5} mGy/MBq-s from ICRP-30. Weighted average coefficients for newborns through 15-year-olds (marrow irradiating marrow, I-131) vary from 3.2 x 10{sup -4} to 1.05 x 10{sup -5} mGy/MBq-s. Sample dose estimates for several nuclear medicine radiopharmaceuticals, with an emphasis on radioimmunotherapy, will be presented.
- OSTI ID:
- 197983
- Report Number(s):
- CONF-940605-; ISSN 0161-5505; TRN: 95:007029-0123
- Journal Information:
- Journal of Nuclear Medicine, Vol. 35, Issue Suppl.5; Conference: 41. annual meeting of the Society of Nuclear Medicine, Orlando, FL (United States), 5-8 Jun 1994; Other Information: PBD: May 1994
- Country of Publication:
- United States
- Language:
- English
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