Triple channel analysis of Gafchromic EBT3 irradiated with clinical carbon-ion beams

• Verfasst von: Holm, Kim Marina [VerfasserIn]
• Verfasst von: Yukihara, Eduardo G. [VerfasserIn]
• Verfasst von: Ahmed, Md Foiez [VerfasserIn]
• Verfasst von: Greilich, Steffen [VerfasserIn]
• Verfasst von: Jäkel, Oliver [VerfasserIn]
• Titel: Triple channel analysis of Gafchromic EBT3 irradiated with clinical carbon-ion beams
• Verf.angabe: Kim Marina Holm, Eduardo G. Yukihara, Md Foiez Ahmed, Steffen Greilich, Oliver Jäkel
• E-Jahr: 2021
• Jahr: July 2021
• Umfang: 8 S.
• Fussnoten: Available online 16 June 2021, version of record 16 June 2021
• Titel Quelle: Enthalten in: Physica medica
• Ort Quelle: Amsterdam : Elsevier, 1996
• Jahr Quelle: 2021
• Band/Heft Quelle: 87(2021), Seite 123-130
• ISSN Quelle: 1724-191X
• DOI: doi:10.1016/j.ejmp.2021.06.009
• Datenträger: Online-Ressource
• Sprache: eng
• Sach-SW: Carbon-ion beams
• Sach-SW: Gafchromic EBT3
• Sach-SW: Triple channel analysis
• K10plus-PPN: 1790050278

Abstract

Self-developing radiochromic film is widely used in radiotherapy QA procedures. To compensate for typical film inhomogeneities, the triple channel analysis method is commonly used for photon-irradiated film. We investigated the applicability of this method for GafchromicTMEBT3 (Ashland) film irradiated with a clinically used carbon-ion beam. Calibration curves were taken from EBT3 film specimens irradiated with monoenergetic carbon-ion beams of different doses. Measurements of the lateral field shape and homogeneity were performed in the middle of a passively modulated spread-out Bragg peak and compared to simultaneous characterization by means of a 2D ionization chamber array. Additional measurements to investigate the applicability of EBT3 for quality assurance (QA) measurement in carbon-ion beams were performed. The triple-channel analysis reduced the relative standard deviation of the doses in a uniform carbon ion field by 30% (from 1.9% to 1.3%) and reduced the maximum deviation by almost a factor of 3 (from 28.6% to 9.8%), demonstrating the elimination of film artifacts. The corrected film signal showed considerably improved image quality and quantitative agreement with the ionization chamber data, thus providing a clear rationale for the usage of the triple channel analysis in carbon-beam QA.