In this study, the dose distribution has been calculated for the Collaborative Ocular Melanoma Study (COMS) eye plaques at various diameters 10–22 mm, loaded with the 103-Pd brachytherapy seeds (Model IR06-103Pd). Several Monte Carlo (MC) simulations have been employed to carry out the gold backing and Silastic insert effect on dose distribution around the eye plaque. Version 5 of the Monte Carlo N-particle (MCNP) code has been used to carry out the simulations. The new palladium seed was modelled in three geometric orientations (ideal, vertical and diagonal). Results are compared with the calculated data for COMS eye plaque loaded with Theragenics model 200 and Best model 2335 palladium-103 seeds and model 6711 iodine-125 seeds. The calculated dose rate constant of the IR06-103Pd seed was found to be 0.692 ± 0.020 cGy h−1 U−1. The air kerma strength to deliver 85 Gy to tumour apex in a water medium was found to be 4.10 U/seed. The dosimetric parameters calculated in this work for the new palladium seed indicate the IR06-103Pd seed is suitable for use in brachytherapy. In COMS plaques, the dose distribution to points of interest was compared for three 103-Pd seed models. With the exception of sclera dose and for a given prescription dose, the IR06 seed delivers lower dose ocular points of interest.
This study will briefly explain the production of 103Pd via cyclotron for brachytherapy use. The excitation functions of 103Rh(p,n)103Pd and 103Rh(d,2n)103Pd reactions were calculated using ALICE/91, ALICE/ASH, and TALYS-1.2 codes and compared with published data. Production of 103Pd was done via 103Rh(p,n)103Pd nuclear reaction. The target was bombarded with 18 MeV protons at 200 μA beam current for 15 h. After irradiation and radiochemical separation of the electroplated rhodium target, at the optimum condition, 103Pd was absorbed into Amberlite®IR-93 resin. The preparation of the brachytherapy seed, which is loaded by the resin beads, has also been presented. At least, the method to determine the dosimetric parameters for the seed by experimental measurement has been presented.
Part of the book: Recent Techniques and Applications in Ionizing Radiation Research