Palladium-103 versus iodine-125 for ophthalmic plaque radiotherapy
- Cornell Univ. Medical College, New York, NY (United States) New York Eye and Ear Infirmary, New York, NY (United States)
- Cornell Univ. Medical College, New York, NY (United States)
A dosimetry study compared the use of I-125 vs. Pd-103 radioactive seeds for ophthalmic plaque brachytherapy. Pd-103 seeds in ophthalmic plaques were used to treat 15 patients with intraocular malignant melanoma. Computer-aided simulations were performed to evaluate the intraocular dose distribution of I-125 versus Pd-103 ophthalmic plaques (delivering equivalent apex doses). Seven target points were selected. Starting at the outer scleral surface, four were located along the central axis of the plaque: the 1 mm point (the inner sclera), the 6 mm point, the tumors apex, and the opposite eye wall. They also evaluated the fovea, optic nerve, and the lens because they were considered to be critical structures. These studies demonstrated that the lower energy photons generated by Pd-103 seeds (average 21 KeV) in ophthalmic plaques were more rapidly absorbed in tissue than photons generated by I-125 (average 28 KeV). Therefore, during ophthalmic plaque radiotherapy, Pd-103 photons were found to be more rapidly absorbed within the tumor and less likely to reach most normal ocular structures. On average, the use of Pd-103 decreased the dose to the fovea by 5.7%, to the optic nerve by 8.4%, to the lens by 26%, and to the opposite eye wall by 38.4%. Pd-103 ophthalmic plaque brachytherapy resulted in slightly more irradiation of the tumor and less radiation to most normal ocular structures. 36 refs., 1 fig., 3 tabs.
- OSTI ID:
- 7066135
- Journal Information:
- International Journal of Radiation Oncology, Biology and Physics; (United States), Vol. 27:4; ISSN 0360-3016
- Country of Publication:
- United States
- Language:
- English
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61 RADIATION PROTECTION AND DOSIMETRY
EYES
MELANOMAS
IODINE 125
SPATIAL DOSE DISTRIBUTIONS
RADIOTHERAPY
PALLADIUM 103
BETA DECAY RADIOISOTOPES
BODY
BODY AREAS
CARCINOMAS
DAYS LIVING RADIOISOTOPES
DISEASES
ELECTRON CAPTURE RADIOISOTOPES
EPITHELIOMAS
EVEN-ODD NUCLEI
FACE
HEAD
INTERMEDIATE MASS NUCLEI
INTERNAL CONVERSION RADIOISOTOPES
IODINE ISOTOPES
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NEOPLASMS
NUCLEAR MEDICINE
NUCLEI
ODD-EVEN NUCLEI
ORGANS
PALLADIUM ISOTOPES
RADIATION DOSE DISTRIBUTIONS
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RADIOLOGY
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560151* - Radiation Effects on Animals- Man
560101 - Biomedical Sciences
Applied Studies- Radiation Effects- Dosimetry & Monitoring- (1992-)