Development of methodology for quality audit of doses in target area and organ at risk and two dimensional dose distribution in intensity modulated radiotherapy
10.3760/cma.j.issn.0254-5098.2020.02.009
- VernacularTitle: 调强放射治疗靶区和危及器官剂量及二维剂量分布质量核查方法研究
- Author:
Suming LUO
1
;
Hao WU
2
;
Zhijian HE
1
;
Xian XUE
1
;
Jilong YUAN
1
Author Information
1. 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
2. Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Department of Radiation Oncology, Peking University Cancer Hospital & nstitute, Beijing 100036, 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):122-128
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To develop the methodology for using TLD and radiochromic film to measure the planned target volume (PTV) and organ at risk (OAR) doses and 2D dose distribution in IMRT, in order to provide technical guidance on the dose quality audit in IMRT at home.
Methods:China has participated in the research project launched by the international multi-radiotherapy centre (IMRC). IMRT polystyrene phantom provided by IAEA was scanned by CT scanner and then the scanned images were transmitted to TPS to outline prescribed dose to PTV and to OAR. The former was limited to 400 cGy while the latter limited to 200 cGy. IMRT was implemented with the phantom irradiated using 6 MV X-ray. The irradiated TLDs and films were sent to IAEA dosimerty laboratory for measurement and calculation. Jiangsu, Sichuan, Hubei and Henan provinces were selected to engage with this study for their variety of accelerators and highly skilled physicists. The procedures used were the same as in the IMRC and the irradiated TLDs and films were required to send to external audit group for measurement and calculation.
Results:According to IAEA requirement, the relative deviations of the TLD-measured and TPS planned doses are within ±7.0% for PTV and OAR. The China′s research results at the IMRC have shown that the relative deviation of TLD-measured and TPS-planned values for the upper and lower PTV were -0.2% and 0.8%, respectively, consistent with the IAEA requirement, and the values for upper and lower OAR were -0.6% and -1.0%, respectively, consistent with the requirement. As the results have shown in four provinces, the relative deviations of the TLD-measured and TPS-planned were within 0 to 10.6% for upper and lower PTV and -0.6% to 20.9% for upper and lower OAR. According to IAEA requirement, the passing rate should be greater than 90% for 3 mm /3% for 2D dose distribution. China′s result at the IMRC is 100%, being excellent. The four provinces′ results have shown that 2D dose distribution pass rate of 3 mm/3% was in the range of 45.0%-100.0%.
Conclusions:The uses of TLD in quality audit for PTV and OAR doses and the radiochromic film in 2D dose distribution pass rate in IMRT are characterized by scientific feasibility, strong operability, easy-to-mail and data realibility. They are can be applied to quality assurance and audit in medical institutions in the country to on a large scale.
