Preliminary investigation of performance of thermoluminescent dosimeters for dose verification in brachytherapy

Brachytherapy represents the treatment of choice for many cancerous lesions, including skin tumours. Purpose of the study was to investigate the performance of thermoluminescent dosimeters of type 100, (TLD-100), for dose verification in high dose-rate treatment with a radioactive source of iridium-192. A set of TLDs-100 was calibrated with a 250 kVp X-ray beam in the dose range 0-5 Gy. Through a head and neck phantom, TLDs were fixed on districts corresponding to volumes of interest, including the target volume and some critical structures, then a single fraction of brachytherapy treatment was delivered. The dose measurements provided by TLDs were compared with the planned ones and the results were discussed in the light of limitations affecting the current treatment planning systems and critical aspects relating to brachytherapy implementation that still occurred in clinical settings. The findings of the study allow us to conclude that TLDs-100 show a good performance in the radiation field investigated and the use of so small, cheap and practical dosimetry system is potentially an optimal strategy of improving and standardizing the quality assurance protocol in brachytherapy.