Calibration of gamma rays with LiF thermoluminescence dosimeters

OBJECTIVES: We aimed in this study to calibrate lithium fluoride thermoluminescence dosimeters (TLDs), alloyed with magnesium and titanium, by using gamma rays. METHODS: 168 application-na ve TLDs were annealed and then calibrated in a TLD-reader system at a sensitivity level of ±1% after achieving a saturation level by gamma irradiation. Five selected TLDs were placed in the center of the reference area, formed by using Rando phantom, and irradiated at the dose of 180 cGy with 6 MV to measure the accuracy of a given dose. RESULTS: The doses exposed by the TLD were determined with a reader system as follows: 182.1, 181.0, 180.3, 180.3, and 180.0 cGy. CONCLUSION: The exposed doses were in the range of ±1% in all TLDs except TLD#1. The error in the dose measured for TLD#1 was found as +0.6%. This could be attributed to incomplete release of energy traps due to the complicated annealing process, temperature and humidity of ambient and lack of sterilization.