Linear energy transfer characterization of five gel dosimeter formulations for electron and proton therapeutic beams

• Published in: Applied radiation and isotopes 2021-12, Vol.178, p.109972-109972, Article 109972
• Main Authors: Valente, M., Chacón, D., Mattea, F., Meilij, R., Pérez, P., Romero, M., Scarinci, I., Vedelago, J., Vitullo, F., Wolfel, A.
• Format: Article
• Language: English
• Subjects: Electrons; Energy Transfer; Gel dosimetry; Gels; Linear energy transfer; Monte Carlo Method; Monte Carlo simulation; Protons; Radiometry - methods
• ISSN: 0969-8043; 1872-9800
• DOI: 10.1016/j.apradiso.2021.109972

Gel dosimeters, including radiochromic types like Fricke, as well as polymer formulations, are considered to be the only reliable option for accurate 3D dosimetry. Nevertheless, their implementation in daily clinical quality assurance still remains strongly limited for a few high specialized radiotherapy centres. Although gel dosimeters present very good water-equivalence due to their inherent chemical and isotopic compositions, addressing the corresponding dosimetry outputs is highly challenging, needing careful assessment in terms of the different radiation qualities involved in the mixed field. Accurate estimations of the linear energy transfer for each gel dosimeter formulation stands as a baseline for further accurate dose deconvolution in mixed radiation fields. The present study reports on the linear energy transfer characterization of five different gel dosimeter formulations, Fricke, Itabis, Magic, Nipam, and Pagat, for electron and proton therapeutic beams as obtained by Monte Carlo approaches, along with experimental results for validation purposes. The linear energy transfer, as a function of beam quality and penetration depth, is obtained for electron and proton therapeutic beams remarking the presence of non-negligible variations, which need to be accounted for a further accurate implementation of gel dosimetry as well as for precise dose deconvolution in mixed radiation fields. •Electron and proton linear energy transfer is reported for five gel dosimeter formulations.•In-depth LET distributions relative to liquid water are assessed by theoretical and Monte Carlo means.•The proposed analytic approach attains in-depth LET distributions due to primary beam component.•The obtained results may be used as input data to assess gel dosimeters' LET correction factors.