The dose rate response characterization of four kinds of dosimeters for linear accelerator

Objective: To explore the dose rate response characterization of four kinds of dosimeters for clinical application. Methods: Within the range of 100-600 cGy/min, the dose rate responses of the PTW 0.6 cm³ ion chamber, 0.015 cm³ ion chamber, Matrixx Evolution 2D diode array and MapCHECK 2D diode array under the same measuring conditions were measured. The dose rate response of the PTW 0.6 cm³ ion chamber under different energy and working voltage were analyzed. Results: All ionization chamber types of measured equipment showed certain dose rate dependence for 6 MV X-rays. All the differences were below 1%. The dose rate dependence disappeared for 15 MV X-rays. The 2D diode array had strong dose rate dependence and the response difference was about 2%. Conclusions: It is necessary to test and analyze the dose rate response of the measured equipment in treatment technology with dose rate varying, in order to ensure the precision of daily calibration and dose verification. (authors)