Verification of doses to PTV and OAR and 2D dose distribution in IMRT for 7 accelerators in Sichuan province
10.3760/cma.j.issn.0254-5098.2020.02.013
- VernacularTitle: 四川省7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:
Ran LIU
1
;
Qiao MA
1
;
Deming LIU
1
;
Changhong LI
1
;
Xian XUE
2
;
Suming LUO
2
Author Information
1. Institute of Occupational Health and Radiological Health, Sichuan Center for Disease Control and Prevention, Chengdu 610041, 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):145-149
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To study a method for verifying the doses to PTV and OAR as well as the 2D dose distribution arising from IMRT through using radiochromic films and TLDs.
Methods:Totally 7 medical electronic linear accelerators from Varian, Siemens and Elekta were selected. The polystyrene phantom provided by IAEA was conducted with CT scan. After irradiation with 6 MV X-rays, the TLDs and films were returned to the secondary standard dosimetry laboratory of China CDC for measurement and estimation.
Results:According to the IAEA requirements, the relative deviations between TLD-measured and TPS-planned values for PTV and OAR doses were both within ±7.0%. For PTV, the measured relative deviations for 5 accelerators were in the range of -4.0% to 3.4%, consistent with the IAEA requirements, whereas the values for the other 2 accelerators were in the range of -7.0% to 10.6%, not consistent with the requirements. For OAR, the values for 4 accelerators were in the range of -5.6% to 3.3%, consistent with the IAEA requirements, whereas the values for the other 3 accelerators were in the range of -20.8% to 11.5%, not meeting the requirements. As required by the IAEA, the 2D dose distribution 3 mm/3% pass rate should be higher than 90%. The measured values for 5 accelerators were in the range of 91.8% to 98.5%, consistent with the requirements, whereas the values measured for the other 2 were 45.0% and 77.0% respectively, not meeting the requirements.
Conclusions:It is feasible for using TLDs and radiochromic films to verify the doses to PTV and OAR and the 2D dose distribution in IMRT. This method should be applied to not only quality verification but also hospital internal audit to the extent possible.
