Verification of doses to PTV and OAR and 2D dose distribution in IMRT for 7 accelerators in Hubei province
10.3760/cma.j.issn.0254-5098.2020.02.011
- VernacularTitle: 湖北省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:
Gangtao SUN
1
;
Wenshan ZHOU
1
;
Song YE
1
;
Xian XUE
2
;
Suming LUO
2
Author Information
1. Department of Radiological Health Monitoring and Evaluation, Hubei Provincial Center for Disease Control and Prevention, Wuhan 430079, 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):134-139
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To study a method to measure the doses to planned target volume (PTV) and organ at risk (OAR) and 2D dose distribution in IMRT by using TLD and radiochromic film for a verification purpose.
Methods:Totally 7 different types of medical linear accelerators were selected from seven hospitals in Hubei province. A polystyrene phantom provided by IAEA was CT scanned and then the scanned images were returned to the Treatment Planning System (TPS) for determining the prescribed doses to PTS and OAR and the corresponding MU. After the phantom was irradiated with 6 MV X-ray, the TLDs and films were transmitted to the secondary standard dosimetry laboratory of China CDC for measurement and estimation.
Results:The IAEA required the relative deviations between TLD-measured and TPS-planned doses to OAR and PTV be within ±7.0%. For PTV, the measured-to-planned deviation values for 7 accelerator were within -5.4% to 6.5%, all consistent with the IAEA requirements. For OAR, the values for 5 accelerators were within -2.2% to 6.7%, not consistent the requirements, whereas the values for the other 2 were -8.6% and 8.2% respectively, beyond the required values. The IAEA required that the 2D dose distribution 3 mm/3% pass rate be higher than 90%. The measured values for 7 accelerators were in the range of 90.3%-98.9%, all consistent with the requirements.
Conclusions:It is feasible scientifically and easy to operate in practice for using TLD and film to carry out dose verification in IMRT. It would be advisable to apply this method to quality verification in IMRT in medical institutions to the extent possible.
