COMS eye plaque brachytherapy dosimetry simulations for {sup 103}Pd, {sup 125}I, and {sup 131}Cs
- Department of Radiation Oncology, Tufts University School of Medicine, Boston, Massachusetts 02111 (United States)
Monte Carlo (MC) simulations were performed to estimate brachytherapy dose distributions for Collaborative Ocular Melanoma Study (COMS) eye plaques. Brachytherapy seed models 200, 6711, and CS-1 Rev2 carrying {sup 103}Pd, {sup 125}I, and {sup 131}Cs radionuclides, respectively, were modeled and benchmarked against previously published values. Calculated dose rate constants {sub MC}{lambda} were 0.684, 0.924, and 1.052 cGy h{sup -1} U{sup -1} ({+-}2.6%, k=1 uncertainty) for models 200, 6711, and CS-1 Rev2, respectively. The seeds were distributed into 10, 12, 14, 16, 18, 20, and 22 mm-diameter COMS eye plaques. Simulations were performed in both heterogeneous and homogeneous environments, where the latter were in-water and the former included the silastic seed carrier insert and gold-alloy plaque. MC-based homogenous central axis dose distributions agreed within 2%{+-}1% ({+-}1 s.d.) to hand-calculated values. For heterogeneous simulations, notable photon attenuation was observed, with dose reduction at 5 mm of 19%, 11%, and 9% for {sup 103}Pd, {sup 125}I, and {sup 131}Cs, respectively. A depth-dependent correction factor was derived to correct homogenous central-axis dose distributions for plaque component heterogeneities, which were found to be significant at short radial distances.
- OSTI ID:
- 21120858
- Journal Information:
- Medical Physics, Vol. 35, Issue 7; Other Information: DOI: 10.1118/1.2940604; (c) 2008 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-2405
- Country of Publication:
- United States
- Language:
- English
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