Thermoluminescent dosimeters (TLD-100 and GR-200) calibration for dose verification in radiotherapy: Different photon and electron energies

Abstract

Radiotherapy is a local treatment, so it is necessary to know the dose delivered and absorbed in the organs at risk and the target volumes. There are several types of radiation dosimetry measurements. Thermoluminescent Dosimeters (TLDs) are suitable for performing measurements on patients or phantoms due to their small size. TLD-100 and GR-200 are the most important types of TLD used in radiation dosimetry. This study aimed to determine the dependence of the TLD-100 and GR-200 doses on the energy and type of radiation. To investigate the effect of energy on the response of TLD-100 and GR-200, calibration was performed with electron beams of 6, 8, 10, and 15 MeV and photon beams of 6, 10, and 18 MV, delivering doses of 30, 50, 70, and 100 cGy. Energy-dependence curves were then plotted for different TLD doses. TLDs calibrated with electron and photon were significantly different at various doses and energies, then the regression values (R²) and the ratio of the standard deviation to the average values were calculated by drawing the calibration curve for TLD-100 and GR-200. The obtained results showed that the calibration curves in the dose range of 0–100 cGy for TLD-100 were more linear than those for GR-200, making TLD-100 better suited for dosimetry applications.