| Yu Yanjun,Deng Minmin,Gao Yanxiang,Wang Qin,Cheng Jinsheng,Zhang Fuli.Feasibility of a domestically developed two-dimensional water tank for quality control of beam of a helical TomoTherapy system[J].Chinese Journal of Radiological Medicine and Protection,2024,44(4):272-277 |
| Feasibility of a domestically developed two-dimensional water tank for quality control of beam of a helical TomoTherapy system |
| Received:May 30, 2023 |
| DOI：10.3760/cma.j.cn112271-20230530-00167 |
| KeyWords:Domestic 2D water tank Helix Tomotherapy Gamma analysis |
| FundProject:北京市科技计划(Z181100001718011) |
| Author Name | Affiliation | E-mail | | Yu Yanjun | Radiotherapy Department, No.7 Medical Center of the PLA General Hospital, Beijing 100700, China | | | Deng Minmin | Radiotherapy Department, No.7 Medical Center of the PLA General Hospital, Beijing 100700, China | | | Gao Yanxiang | Radiotherapy Department, No.7 Medical Center of the PLA General Hospital, Beijing 100700, China | | | Wang Qin | Radiotherapy Department, Beijing Shijitan Hospital Affiliated to Capital Medical University, Beijing 100038, China | | | Cheng Jinsheng | Key Laboratory of Radiological Protection and Nuclear Emergency, China CDC, WHO Collaborating Centre for Radiation and Health, National Institute for Radiological Protection, Chinese Center for Disease Control and Prevention, Beijijng 100088, China | | | Zhang Fuli | Radiotherapy Department, No.7 Medical Center of the PLA General Hospital, Beijing 100700, China | radiozfli@163.com |
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| Abstract:: |
| Objective To measure percentage depth dose (PDD) and the off-axis dose profiles of radiation fields using a domestically developed two-dimensional (2D) water tank on a helical TomoTherapy (TOMO) system and to explore the feasibility of the 2D water tank in the application to the beam quality control of the TOMO system. Method The beam data of the TOMO system were collected using the domestically developed 2D water tank. Three radiation fields, 40.0 cm ×1.0 cm, 40.0 cm × 2.5 cm, and 40.0 cm×5.0 cm, were selected to measure the transverse off-axis dose profiles at depths of 1.5, 5.0, 10.0, 15.0 and 20.0 cm. Other three radiation fields, 25.0 cm × 1.0 cm, 25.0 cm ×2.5 cm, and 25.0 cm × 5.0 cm, were employed to determine the PDD curves and longitudinal off-axis dose profiles at depths of 1.5, 5.0, 10.0, 15.0 and 20.0 cm. The gamma analysis of all data was performed using the TomoTherapy ElectroMeter Measurement System (TEMS). Results Compared to the manufacturer's gold standard data, the PDD curves of the domestically developed 2D water tank agreed well under three radiation fields but differed greatly in the build-up regions, with the relative deviation of the PDD20/PDD10 ratio greater than 1%. Under three different radiation fields, the transverse off-axis dose profiles displayed full width at quarter maximum (FWQM) less than 1% measured at four depths except for 20.0 cm. The data measured under three different radiation fields and depths had gamma values greater than 1 based on a gamma criterion of 2%/1 mm. Under different depths and the three radiation fields except for 25.0 cm × 1.0 cm, the longitudinal off-axis dose profiles displayed FWHM less than 1%. Except for radiation field 25.0 cm × 5.0 cm and depths 15.0 and 20.0 cm, the data measured under other different radiation fields and depths had gamma values larger than 1 based on a gamma criterion of 2%/(1% of radiation field width). Conclusions The domestic 2D water tank partially meets the demand for the daily quality control of a TOMO system. Nevertheless, further optimization and improvement are still required to fully meet the requirements of the clinical acceptance of a TOMO system. |
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