Impact of tumor treating fields transducer arrays on concurrent radiotherapy dosimetry
10.3760/cma.j.cn113030-20230518-00118
- VernacularTitle:电场治疗联合放疗中贴片阵列对放疗剂量学的影响
- Author:
Keqiang WANG
1
;
Jie CHEN
;
Jianbo JIAN
;
Peng WANG
;
Xinshan ZHANG
;
Hongyang ZHANG
;
Wenxue ZHANG
Author Information
1. 天津医科大学总医院放射治疗科，天津 300052
- Keywords:
Radiotherapy;
Tumor treating fields;
Tumor treating fields arrays;
Automatic delineation;
Relative electron density;
Beam energy
- From:
Chinese Journal of Radiation Oncology
2024;33(5):438-445
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To investigate the dosimetric impact of tumor treating fields (TTF) transducer arrays on concurrent radiotherapy for patients with glioblastoma (GBM).Methods:A strategy was developed to accurately simulate the dosimetric impact of TTF arrays on radiotherapy, including the establishment of accurate auto-segmentation technique for TTF arrays, determination of the relative electron density (RED) of the transducer arrays and validation of the dose calculation accuracy in the treatment planning system (TPS) for TTF arrays. Based on this strategy, the dosimetric impact of TTF arrays on clinical treatment plans of 10 patients with GBM was evaluated. Furthermore, the dosimetric comparison between the clinical plans with different beam energies were investigated when TTF arrays were used. The methods of analysis of variance were paired t-test or Wilcoxon signed-rank test based on whether the differences followed a normal distribution. Results:The auto-segmentation technique for TTF arrays was established by designing a workflow in Mim software and achieved a Dice coefficient of 0.93 and a Jaccard index of 0.87 compared to the standard contours. The RED of TTF arrays was 3.3 which was derived from the comparison between the measured and simulated percentage depth dose (PDD) with and without TTF arrays on phantom. Measured and calculated dose distributions were compared using the 2D gamma analysis. The gamma passing rates on the coronal plane of 4 mm and 5.1 cm depth were 96.64% and 94.55% at the criteria of 3% /3 mm, indicating that the calculation accuracy of algorithm in TPS for TTF arrays could meet clinical requirements. In the clinical treatment plans of patients with GBM, the presence of TTF arrays caused a mean reduction of planning target volume (PTV) dose of approximately 1%, and an increase in scalp dose of approximately 5%, with minimal impact on other organs at risk (OAR). The 10 MV plans resulted in a higher dose of PTV by 0.3% and lower dose of scalp by approximately 3% compared to the 6 MV plans, when considering TTF arrays.Conclusions:The accurate simulation strategy for the dosimetric impact of TTF arrays on radiotherapy established in this study ensures the accuracy and precision of the calculations. In TTF therapy combined with concurrent radiotherapy for GBM, TTF arrays have slight effect on PTV dose, but significantly increase scalp dose. High-energy beam can reduce the impact of TTF arrays.
