[Development and dosimetry of a 125 iodine applicator for brachytherapy of intraocular tumors].

Due to the low gamma energy (27-35 ke V), iodine 125 is especially suitable for brachytherapy of intraocular tumors. 125I is available as encapsulated seeds. Applicators can be individually loaded with these seeds to accommodate the shape of the tumor as much as possible. To measure the depth-dose distribution LiF thermoluminence detectors (TLDs, 1 mm3) are embedded in an RW-1 eye phantom at various distances and directions from the high active plaque positioned at the top of the phantom. To obtain the three-dimensional dose distribution, the TLDs are read after exposure for the appropriate time period. Based on experimental measurements of the 125I plaque, a computer program is developed to calculate the dose distribution within the eye and the radiation time for intraocular tumors. These results are very similar to those obtained when using mathematical equations published in the literature. In summary, three-dimensional dose distribution at various distances from an 125I eye plaque has been experimentally determined using a new method. This is an important prerequisite for introducing 125I plaques into the treatment of intraocular tumors.