Dosimetric investigation of beta-emitting ophthalmic plaques for treatment of ocular tumors

Understanding the dose distribution of beta-emitting eye plaques respect to the location of tumor is of importance. In this study, the geometry of CCB, COB and CIB plaques (BEBIG manufacturer) for specific eye tumors were simulated and the effects of different coated radionuclides and plaque materials were investigated, by Geant4 simulation toolkit. For validation, a dosimetric investigation was performed for Ru-106 eye plaques, using radiochromic EBT3 films and Plaque Simulator software. Ru-106 plaques can be replaced by Sr-90 or Pr-142 plaques for the tumor apex up to 3 mm. Ho-166 and Re-188 plaques only can be utilized for superficial lesions due to their intense dose fall-off. Gold plaques show more attenuation and can be made thinner. They may be used in COB and CIB models, due to their vicinity of optic nerve and iris, respectively.