Thermoluminescent dosimetry of high energy photons produced in a medical uses Linac

An effective Radiotherapy Quality Assurance procedure requires a dosimetric system that allows estimating the dose delivered to the patient. The comprehensive results of the measurements provide the necessary information to evaluate the accuracy and precision in the planning and administration of the dose in a specific treatment site. During the last 50 years the variety of thermoluminescent materials and their different physical forms have made possible the determination of different amounts of radiation in a wide range of absorbed doses. This makes TLDs very useful in radiotherapy where doses are up to several Gy. Results of measurements in solid water phantoms performed to compare the measured entry dose with the dose calculated by the treatment planning system using LiF: Mg, Ti TLDs are presented. The characterization of the system was performed for energies of 6, 10 and 18 MeV s in an Elekta linear accelerator. A linear response was observed in the dose range from 0.5 to 4.5 Gy. (Author)