A comparative study of uncertainty in dose calibration on EBT4 and EBT3 films
10.3760/cma.j.cn113030-20250116-00030
- VernacularTitle:EBT4与EBT3胶片在剂量标定中的不确定度对比研究
- Author:
Xiaotong WANG
1
;
Yanchen YING
;
Lyu HUANG
;
Yangkang JIANG
;
Long SUN
;
Wenjie WU
;
Binbing WANG
Author Information
1. 浙江省肿瘤医院放射物理科，中国科学院杭州医学研究所，杭州 310022
- Publication Type:Journal Article
- Keywords:
Radiotherapy;
EBT4 film;
EBT3 film;
Dose calibration;
Uncertainty
- From:
Chinese Journal of Radiation Oncology
2025;34(9):937-943
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To compare the uncertainty of dose calibration systems between EBT4 and EBT3 films, and to evaluate the effectiveness and accuracy of EBT4 films in radiotherapy dose measurements.Methods:EBT4 and EBT3 films were irradiated with clinical 6 MV photon beams at doses ranging from 0 to 1,600 MU. Films were scanned after resting for 0 and 24 h to establish dose calibration functions based on net optical density. The dose uncertainties introduced by function fitting, dose resolution, film non-uniformity, scan repeatability, and scanner non-uniformity during calibration of the two films were obtained through experimental tests and mathematical calculations. Independent-sample t-tests were used to compare differences in fitting uncertainty and dose resolution between the two films, while homogeneity of variance tests were used to compare differences in film non-uniformity and scan repeatability. The combined total uncertainty was then calculated and compared. Finally, the total combined uncertainty was calculated by integrating all individual sources of uncertainty and compared between the two films. Results:Within the absorbed dose range of 1-12 Gy, EBT4 films exhibited significantly lower dose uncertainties from function fitting and dose resolution than EBT3 films at the same standing time ( P<0.01). No significant differences were observed between the two films in terms of non-uniformity and scan repeatability ( P>0.05). The total dose uncertainties of EBT4 and EBT3 films at 0 h standing were 5.65% and 7.87%, respectively, while the total uncertainties at 24 h standing were 4.73% and 6.33%, respectively. Overall, the dose calibration system of EBT4 films demonstrated consistently lower total uncertainty. Conclusion:Under identical conditions, EBT4 films demonstrate superior and more stable dose uncertainty compared with EBT3 films, thereby meeting the clinical requirements for radiation dose measurements with higher precision.
