Verification of doses to PTV and OAR and 2D dose distribution in IMRT for 8 accelerators in Henan province
10.3760/cma.j.issn.0254-5098.2020.02.012
- VernacularTitle: 河南省8台加速器调强放疗靶体积和危及器官剂量及二维剂量分布验证方法研究
- Author:
Chuanpeng HU
1
;
Chenzhi JIA
1
;
Kunjie WEI
1
;
Xian XUE
2
;
Zhijian HE
2
;
Suming LUO
2
Author Information
1. Department of Radiological Health, Henan Institute for Occupational Medicine, Zhengzhou 450052, China
2. Key Laboratory of Radiological Protection and Nuclear Emergency, China CDC, National Institute for Radiological Protection, Chinese Center for Disease Control and Prevention, Beijing 100088, China
- Publication Type:Journal Article
- Keywords:
Intensity modulated radiation therapy;
Radiochromic film;
Planned target volume;
Organ at risk;
Two-dimensional dose distribution
- From:
Chinese Journal of Radiological Medicine and Protection
2020;40(2):140-144
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To use TLDs and radiochromic films to verify the prescribed doses to both planned target volume (PTV) and organ at risk (OAR) and the 2D dose distribution in IMRT.
Methods:Eight accelerators of different models were selected in Henan province. The polystyrene phantom provided by IAEA was scanned using CT scanners and then the scanned images were transmitted to treatment planning system (TPS) for prescribing respectively the doses to PTV and OAR. IMRT was performed with phantom exposed to a 6 MV X-rays. The irradiated TLDs and films were delivered for measurement and estimation at Secondary Standard Dosimetry Laboratory at National Institute for Radiological Protection, Chinese Center for Disease Control and Prevention.
Results:According to IAEA requirements, the relative deviations of the TLD-measured and TPS-planned values were within ±7.0% for the prescribed doses to PTV and OAR. The measured results for PTV have shown that the relative deviation of TLD-measured and TPS-planned values were within -0.3% to 6.9% for 8 accelerators, all consistent with the IAEA requirements. For OAR, the relative deviations of TLD-measured and TPS-planned were within -7.0% to 0.3% for 6 accelerators, consistent with the requirements, whereas those for other 2 accelerators were within -10.8% to -8.4%, not up to the requirements. IAEA required that, for 2D dose distribution, the pass rate of 3 mm/3% be ≥90%. The measured values for 7 accelerators were from 90.2% to 99.9%, consistent with the requirements, whereas that for another one was 70.0%, not meeting the requirement.
Conclusions:The method to verify, using radiochromic film and TLD, the prescribed doses to PTV and OAR and the pass rate of 2D dose distribution is simple and reliable. It is an important step to implement quality control for IMRT and can provide effective support for medical or third-party service institution to verify clinically prescribed dose.
