探討FWT-70系列輻射色染劑量計對能量3.2~12.6 MeV電子射束的敏度反應

Abstract

Objective: The sensitivity response of radiochromic dye film (RDF) dosimeter with high energy electron beams was studied in this paper. The feasibility of RDF as a dosimeter for measuring the electron beams of a medical accelerator was studied. Materials and Methods: Type FWT-70 series were used as the RDF dosimeter, and the electron beams with 6-20 MeV were from a medical linear accelerator. Various types of RDF dosimeter were placed at the maximum dose position in a solid water phantom, that exposed by various electron beam conditions with different energies, doses, and dose rates. Results: In the two different RDF dosimeters of the FWT-70 series: (1) the sensitivity and threshold dose of type FWT-70-40 (M) are 0.0099 OD/Gy and 8 Gy respectively and that of FWT-70-83 (M) RDF are 0.0015 OD/Gy and 20 Gy respectively. (2) FWT-70-40 (M) RDF has higher sensitivity of electron beam energy than Type FWT-70-83 (M). (3) the dose rate dependence of Types FWT-70-40 (M) and FWT-70-83 (M) RDF dosimeters are about 200% and 60%. Conclusion: In conventional RDF dosimeters of Type FWT-70 series was using for measuring high dose in a gamma radiation field from 60Co. In this paper, we show that it also can be applied in the electron radiation field with high energy, dose and dose rate. However, the type of dosimeter should be well selected and calibrated according to the sensitivity dependence on electron beam energy and dose rate.