[Show abstract][Hide abstract] ABSTRACT: Background: The formalism recommended by Task Group 60 (TG-60) of the American Association of Physicists in Medicine (AAPM) is applicable for β sources. Radioactive biocompatible and biodegradable 153Sm glass seed without encapsulation is a β- emitter with a short half life and delivers a high dose rate to the tumor in the millimeter range. In this work the dosimetry parameters of the seed for brachytherapy were evaluated. Materials and Methods: Using MCNP4C code data, the Dosimetric parameters of AAPM TG-60 recommendations including the reference dose rate, the radial dose function and the anisotropy function were obtained. Two dimensional dose distributions were also calculated. Results: The dose rate at reference point was estimated to be 9.41 cGy.h-1.μCi-1 for 153Sm. 153Sm with its relatively low energy beta component falls off the most rapidly of the other beta emitters. The calculated data was compared with that of several beta and photon emitting seeds. Conclusion: The results showed the advantage of the beta emitting 153Sm source in comparison with the other beta emitting sources, Because of its rapid dose fall-off of beta-ray and high dose rate at the short distances of the seed. The results would be helpful in development of the radioactive implants using 153Sm seeds for the brachytherapy treatment.
Full-text · Article · Sep 2011 · Iranian journal of radiation research (IJRR)
[Show abstract][Hide abstract] ABSTRACT: For the treatment of some cancerous tumors using brachytherapy, an American Association of Physicists in Medicine (AAPM) Task Group No. 43U1 report recommends that the dosimetric parameters of a new brachytherapy source must be determined in two experimental and Monte Carlo theoretical methods before using each new source clinically. This study presents the results of Monte Carlo calculations of the dosimetric parameters for a Ir2.A85-2 brachytherapy source design.
Version 5 of the (MCNP) Monte Carlo radiation transport code was used to calculate the dosimetry parameters around the source.
The Monte Carlo calculated dose rate constant, Λ, of the Ir2.A85-2 source was found to be 1.113 ± 0.033 cGyU(-1)h(-1). Also in this study, the line-source radial dose function, g ( l )(r) and the anisotropy function, F(r,θ), have been calculated at distances from 0.5 to 10 cm. The results of these calculations have been compared with the published data for the same source.
All the results are in good concordance with previously published data, with a few exceptions in small angles and short distances. The dosimetric parameters calculated in this work can be used as input data in a treatment planning system (TPS) for exact brachytherapy treatment planning or to verify the calculations of the TPS used in brachytherapy.
No preview · Article · Jun 2011 · Japanese journal of radiology