Research on calculation method of Gamma pass rate based on cubic spline interpolation
10.3969/j.issn.1672-8270.2025.09.029
- VernacularTitle:基于三次样条插值伽玛通过率计算方法的研究
- Author:
Funan TANG
1
;
Ying WANG
1
;
Hui ZHANG
1
Author Information
1. 南京医科大学第一附属医院(江苏省人民医院)临床医学工程处 南京 210029
- Publication Type:Journal Article
- Keywords:
Radiotherapy;
Medical linear accelerator;
Treatment planning system(TPS);
Gamma pass rate(GPR);
Cubic spline interpolation;
Runge phenomenon
- From:
China Medical Equipment
2025;22(9):150-154
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To propose a calculation method of Gamma pass rate(GPR)based on cubic spline interpolation,so as to improve accuracy of calculating GPR for dose of radiation field of radiotherapy plan.Methods:First,a calculation method based on cubic spline interpolation for calculating GPR was established.Secondly,a virtual dose distribution with uncertainties and errors,which was simulated by using a treatment planning system(TPS)system,was used to replace the distribution of exposure dose that was actually measured.Finally,the GPR calculation method based on cubic spline interpolation was adopted to conduct Gamma analysis for the calculation value of planning dose and the virtually measured value,so as to verify the effectiveness of GPR calculation method based on cubic spline interpolation for improving the precision of the calculation.Results:Under a simulated positional shift of 0.5 mm,the average Gamma Passing Rate(GPR)for 10 treatment plans calculated using cubic spline interpolation was 99.49%,which is essentially equivalent to that obtained with conventional polynomial interpolation(99.52%)and significantly higher than that without interpolation(97.94%).At 1 mm shift,the mean GPR derived from cubic spline interpolation was 98.59%,virtually identical to the polynomial approach(98.58%)and markedly superior to the non-interpolated value(96.31%).When the shift increased to 2 mm,cubic spline interpolation yielded an average GPR of 90.22%,outperforming both polynomial interpolation(90.0%)and the non-interpolated method(85.44%).Overall,the cubic-spline-based GPR algorithm produced results consistent with conventional methods.Detailed comparison of two-dimensional GPR maps revealed that the cubic spline approach notably improves accuracy in high-dose-gradient regions.Conclusion:Using cubic spline interpolation for calculating the gamma pass rate in radiotherapy planning can effectively improve the accuracy of gamma analysis,which has a positive effect on using gamma analysis to improve the evaluation of radiotherapy plans.
