Evaluation of the performance of an ionization chamber cylindrical (PTW) by the ELEKTA linear accelerator: Case of pulsed radiation

Abstract

The performance evaluation of cavity cylindrical ionization chamber dosimeters is the basis for the evolution of radiotherapy treatment processes. Studies focused on the statistical and physical performances of the ionization chamber dosimeter used in the radiotherapy department at the hospital oncology CHU-Fez-Morocco. This allowed having a qualitative and quantitative critical view, which is based on previous studies and works. The diagnostic of the dispersion results was calculated between measurements that were taken by the same dosimeter under different test conditions. These tests were then rechecked against two different operators. The general purpose of our study is to optimize measurement and treatment processes, with the desired level of quality according to international standards and protocols. The evaluation of this dosimeter is made by a source of pulsed radiation. This evaluation is carried out using an ELEKTA linear accelerator, using photon beams (6, 10 and 18 Mev). Experimental Results confirmed that the response of the cylindrical ionization chamber depends on several parameters, which influence the performance of the device/machine. The study reveals a total dosimeter uncertainty of the order 3.25 %, which is in the international standards. Even, this can cause an effect on the performance of the ionization chamber detector.