Comprehensive Evaluation and New Recommendations in the Use of Gafchromic EBT3 Film

Authors

Kevin Liu
Patrik Gonçalves Jorge
Ramesh Tailor
Raphaël Moeckli
Emil Schüler

Publication Date

11-1-2023

Journal

Medical Physics

Abstract

BACKGROUND: Gafchromic film's unique properties of tissue-equivalence, dose-rate independence, and high spatial resolution make it an attractive choice for many dosimetric applications. However, complicated calibration processes and film handling limits its routine use.

PURPOSE: We evaluated the performance of Gafchromic EBT3 film after irradiation under a variety of measurement conditions to identify aspects of film handling and analysis for simplified but robust film dosimetry.

METHODS: The short- (from 5 min to 100 h) and long-term (months) film response was evaluated for clinically relevant doses of up to 50 Gy for accuracy in dose determination and relative dose distributions. The dependence of film response on film-read delay, film batch, scanner type, and beam energy was determined.

RESULTS: Scanning the film within a 4-h window and using a standard 24-h calibration curve introduced a maximum error of 2% over a dose range of 1-40 Gy, with lower doses showing higher uncertainty in dose determination. Relative dose measurements demonstrated50% of the maximum dose value (R

CONCLUSIONS: This is the first comprehensive evaluation of the temporal and batch dependence of Gafchromic EBT3 film evaluated on consolidated data over 8 years. The relative dosimetric measurements were insensitive to the type of calibration applied (batch- or time-specific) and in-depth time-dependent dosimetric signal behaviors can be established for film scanned outside of the recommended 16-24 h post-irradiation window. We generated guidelines based on our findings to simplify film handling and analysis and provide tabulated dose- and time-dependent correction factors to achieve this without reducing the accuracy of dose determination.

Keywords

Film Dosimetry, Calibration, Uncertainty, EBT3, radiochromic film, temporal dependence, film dosimetry

Comments

Associated Data

PMID: 37403570