Thermoluminescent dosimeters (TLDs-100) calibration for dose verification in photon and proton radiation therapy

Thermoluminescent dosimeters (TLDs) are practical, accurate, and precise tools for point dosimetry in medical physics applications. TLDs are nowadays extensively used to measure dose in conformal radiation therapy in order to guarantee the safety of the treatment. Several national and international organizations recommend checking the effective dose delivered to an individual patient by means of in vivo dosimetry. Modern radiotherapy techniques employing both photon and ion beams exhibit excellent target conformation throught high steep-dose gradients between tumour and adjacent organs and tissues. In this context, catching potential dose errors and uncertainties in treatment delivering is the first step to ensure the optimization of the treatment plan. This study shows the results of the characterization of TLDs-100 at two Italian facilities devoted to advanced radiation treatments with photon and proton therapy. The individual sensitivity factor was determined, and the calibration curves were carried out in the dose range 0-20 Gy. By the analysis of the dose response curves, the linear region was identified under the dose level of 10 Gy. Characterization of the TLDs-100 has enabled their use for in vivo dosimetry especially in the dose range corresponding to the linear region of the dose response curves.