Evaluation of attenuation rate error for optimisation of skin dosimeter in electron beam therapy

Abstract

In the field of radiation therapy, the need for a flexible dosimeter that can be applied on the flexor surface for precise measurement of the surface dose is increasing. In particular, electron beam therapy has a shorter treatment depth than photon beam therapy; therefore, the surface dose must be measured accurately. This study investigates attenuation errors in a dosimeter. We demonstrated that the attenuation error depends on the thickness of the flexible functional materials, and it can serve as fundamental research for creating a flexible dosimeter that can be applied on the human body. The results indicated that the maximum attenuation error of a polyethylene terephthalate film with a thickness of 75 μm was 0.40% and 0.027% at 6 MeV and 9 MeV, respectively. Moreover, when using HgI2 and PbI2 as photoconductor materials, the maximum attenuation errors at 6 MeV were 1.35% and 1.67%, respectively. This study provides fundamental insights into dose errors by using a surface dosimeter and error variables to produce a surface dosimeter. Further, because the study investigates flexible materials, the findings can be extended to various applications in the field of radiation therapy.