The Study Of TLD Dose Audit For The Linear Accelerator Based On The International Atomic Energy Agency (IAEA)

The objective of the project is to increase the rate of dose audit by the International Atomic Energy Agency through a rigorous process in the radiation therapy center.The accuracy of the linear accelerator radiation dose is the basis of all clinical radiation therapy. Both radical therapeutic or palliative treatment, the ultimate goal of tumor radiation therapy is given to tumor enough dose, at the same time, the surrounding normal tissues and organs by the least amount of radiation dose. Trying to improve the local control rate of the tumor and reduce the radiation side effect of normal tissues. So the accuracy of the radiation dose is an important part of quality control.The research project was based on TRS-398 report as the standard. We cheked the linear accelerator of high energy photons for calibration, in order to improve the accuracy of the output dose of linear accelerator, at the same time, according to the TLD IAEA dose audit requirements, reduce the deviation, improve the pass rate of the audit results. The subject provides a reference in the dose audit of IAEA.In the project, the mechanical properties of the linear accelerator were tested before the measurement, including the coincidence between light field and radiation field, the accuracy of the machine position. While scanning the PDD data to obtain the x ray quality parameters. After all the parameters were determined, the temperature and pressure was corrected, and the output dose of the linear accelerator was calibrated, and the output dose was 1MU=1cGy at the maximum dose depth. In the calibration, the correction factors are considered. After calibration of the dose output of the linear accelerator, the measuring bracket is set up, and the radiation dose of the 200 cGy radiation dose is delivered, and the radiation dose of the capsule is sent to the International Atomic Energy Agency.Through the above results, the theoretical value of the two TLD capsules is 2.0Gy,the results are 2.03 Gy and 1.99 Gy, the average value is 2.01 Gy, the calibration error is0.6%, and the deviation range of the 5% is completely in acceptance of the International Atomic Energy Agency.