Feasibility study of a photochromic diarylethene film as a clinical dosimeter for kV X-rays

Abstract

Radiochromic film (RCF) is commonly used as a measurement tool in radiation therapy and diagnostic X-ray imaging. However, the results are not immediately available. This study establishes the workflow of a new diarylethene (DAE) film dosimetry and investigates the film response versus dose against kV X-rays, with the results immediately available for analysis. The DAE film includes a phosphor layer (BaFCl:Eu), a DAE layer, and a UV cut filter. The workflow of the DAE film dosimetry is as follows: (1) irradiation, where the absorbed doses were between 0.1 and 5.0 Gy at 150 kVp X-ray; (2) scanning with blue excitation light (λ = 465 nm) within 1 h of irradiation to obtain a fluorescence intensity map; and (3) analysis of the relationship between the fluorescence intensity and the absorbed dose, and then comparison between such relationship and that between the optical density and absorbed dose of the RCF. Results show that the fluorescence intensity of the DAE film increased with increasing dose. Moreover, the DAE film had a roughly linear response, while the response of RCF was logarithmic (Pearson's correlation coefficients are 0.979 and 0.843, respectively). The DAE film is feasible as a clinical dosimeter of choice.