Borosilicate glass slide as thermoluminescence dosimeter for ⁶⁰Co Hdr brachytherapy

Brachytherapy is commonly used in treatment of cervical, prostate, breast and skin cancers, typically via the application of sealed radioactive sources that are inserted within or alongside the area to be treated. A particular aim of the various brachytherapy techniques is to accurately transfer to the targeted tumour the largest possible dose, at the same time minimizing dose to the surrounding normal tissue, including organs at risk. The fall-off of dose with distance from the sources is steep, the dose gradient representing a factor limiting the dose distribution, also representing a challenge to the conduct of measurements around sources. Amorphous borosilicate glass (B₂O₃) in the form of microscope cover slips are recognized to offer a practicable system for thermoluminescence dosimetry (TLD), providing for high-spatial resolution (down to < 1 mm), wide dynamic dose range, good reproducibility and reusability, minimal fading, resistance to water and low cost. Herein, investigation is made of the proposed dosimeter using a 1.25 MeV High Dose Rate (Hdr) ⁶⁰Co brachytherapy source, characterizing dose response, sensitivity, linearity index and fading. Analysis of the Tl glow curves were obtained using the T_max-T_stop method and first-order kinetics using Glow Fit software, detailing the frequency factors and activation energy. (author)