Radiotherapy of choroidal melanoma with iodine-125.

The low-energy radioactive source iodine-125 is ideal for the irradiation of an intraocular tumor tumor such as a choroidal melanoma. The energy (28 kev) of iodine-125 should be sufficient to allow sterilization of tumors as high as 10 mm. However, shielding of 18-kev photons can be achieved with thin metal (eg, gold) plaques. Thse eye plaques can be individually designed for each eye tumor, depending on its size, shape, and location. This paper deals with the basic considerations and preliminary observations that have lead us to the adoption of iodine-125 as the sole source for the radiation treatment of all intraocular tumors.