Implementation and evaluation of WS531- 2017 "specification for testing of quality control in
helical tomotherapy unit"(PDF)
《中国医学物理学杂志》[ISSN:1005-202X/CN:44-1351/R]
- Issue:
- 2018年第9期
- Page:
- 1012-1016
- Research Field:
- 医学放射物理
- Publishing date:
Info
- Title:
- Implementation and evaluation of WS531- 2017 "specification for testing of quality control in
helical tomotherapy unit"
- Author(s):
- CHENG Xiaolong; LIU Jiping; YANG Shuangyan; SHI Jianfang
- Department of Radiation Physics, Zhejiang Cancer Hospital, Hangzhou 310022, China
- Keywords:
- helical tomotherapy unit; quality control; radiotherapy dose; deviation
- PACS:
- R318.6
- DOI:
- DOI:10.3969/j.issn.1005-202X.2018.09.004
- Abstract:
- Objective To perform an annual test on the system stability of the first helical tomotherapy unit (Tomotherapy, TOMO)
in Zhejiang province according toWS531-2017 "specification for testing of quality control in helical tomotherapy unit", and to
further standardize the quality control operation, understand the properties of the system and ensure the accurate implementation
of clinical radiotherapy. Methods According to the requirements of WS531-2017, 8-channel measurement instrument
(TomoElectrometer), ionization chamber A1SL (Standing Imaging, USA) and A17 (Standing Imaging, USA), cylindrical phantom
(Cheese Phantom), equivalent rectangular solid water, two-dimensional water tank, EBT3 film, and Vidar film analyzer were
used to detect 10 key indicators of TOMO. Results The static output dose deviation was -0.6%, and the rotational output dose
deviation was 1.4%. The difference between beam quality and planned value was 0.8%. The symmetry of the horizontal dose
curve of the radiation field was -1.2%; and the full width at half-maximum deviation of the longitudinal dose curve of the radiation
field was 0.7 mm. The horizontal offset of multi-leaf collimator was -0.6 mm. The green laser offset in axial plane, sagittal plane
and coronal plane were 0.08, 0.2 and 0.2 mm to the virtual isocenter. The red laser offset was -0.4 mm. The movement deviation
of the treatment couch was 0.3 mm; and the synchronous deviation of the rotation of the treatment couch and gantry was -0.6
mm. Conclusion All 10 key indicators of TOMO meet the requirements of WS531-2017. Some necessary testing items, such
as MVCT image quality verification, should be added to the annual TOMO quality control in order to ensure the good stability
and normal working of system.
Last Update: 2018-09-28