Evaluation of a Proposed Biodegradable ¹⁸⁸Re Source for Brachytherapy Application : A Review of Dosimetric Parameters

Abstract

This study aimed to evaluate dosimetric characteristics based on Monte Carlo (MC) simulations for a proposed beta emitter bioglass ¹⁸⁸Re seed for internal radiotherapy applications.

The bioactive glass seed has been developed using the sol-gel technique. The simulations were performed for the seed using MC radiation transport code to investigate the dosimetric factors recommended by the AAPM Task Group 60 (TG-60).

Dose distributions due to the beta and photon radiation were predicted at different radial distances surrounding the source. The dose rate in water at the reference point was calculated to be 7.43 ± 0.5 cGy/h/μCi. The dosimetric factors consisting of the reference point dose rate, D( r ₀, θ ₀), the radial dose function, g( r), the 2-dimensional anisotropy function, F( r, θ), the 1-dimensional anisotropy function, φ _an ^(r), and the R90 quantity were estimated and compared with several available beta-emitting sources.

The element ¹⁸⁸Re incorporated in bioactive glasses produced by the sol-gel technique provides a suitable solution for producing new materials for seed implants applied to brachytherapy applications in prostate and liver cancers treatment. Dose distribution of ¹⁸⁸Re seed was greater isotropic than other commercially attainable encapsulated seeds, since it has no end weld to attenuate radiation.

The beta radiation-emitting ¹⁸⁸Re source provides high doses of local radiation to the tumor tissue and the short range of the beta particles limit damage to the adjacent normal tissue.