Imaging doses and positioning accuracy under different scanning modes of Tomotherapy MVCT for pediatric patients(PDF)
《中国医学物理学杂志》[ISSN:1005-202X/CN:44-1351/R]
- Issue:
- 2020年第1期
- Page:
- 7-10
- Research Field:
- 医学放射物理
- Publishing date:
Info
- Title:
- Imaging doses and positioning accuracy under different scanning modes of Tomotherapy MVCT for pediatric patients
- Author(s):
- WANG Haiyang1; MAO Kai2; WU Jian’an2; DAI Tiantian2; HAN Yuanyuan2; WU Hao1; DU Yixiao1; ZHANG Yibao1; CAO Wentian3
- 1. Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Department of Radiation Oncology, Peking University Cancer Hospital & Institute, Beijing 100142, China; 2. Department of Radiation Oncology/Center of Respiratory Medicine, China-Japan Friendship Hospital; National Clinical Research Center for Respiratory Disease, Beijing 100029, China; 3. Beijing Key Laboratory of Medical Physics and Engineering, Peking University, Beijing 100871
- Keywords:
- Keywords: pediatric patient; imaging; megavoltage computed tomography; helical tomotherapy; image-guided radiotherapy
- PACS:
- R811.1
- DOI:
- DOI:10.3969/j.issn.1005-202X.2020.01.002
- Abstract:
- Abstract: Objective To investigate the imaging doses needed for helical tomotherapy (TOMO) megavoltage computed tomography (MVCT) using 3 scanning modes for pediatric patients and study the effects of different scanning modes on positioning accuracy. Methods Under 3 scanning modes, the imaging dose to the identical sample points in a virtual water phantom (Cheese phantom) were measured using an Exradin A1SL chamber. CIRS 1-year-old infant and 5-year-old pediatric anthropomorphic phantoms were used for stimulating the MVCT-guided positioning. The registration accuracies of "normal" and "coarse" modes were compared with that of "fine" mode. Results The imaging doses of "fine" mode were about 2 (2.003±0.048) and 3 (3.056±0.099) times higher than those-of "normal" and "coarse" modes, which were consistent with the pitch ratio. The deviations of "normal" mode were within clinical tolerance (±1 mm) and the results were better than those of "coarse" mode. The isocenter deviations of "normal" mode versus "coarse" mode were 0.53 mm vs 0.59 mm (head and neck), 0.25 mm vs 0.99 mm (pelvis) for 1-year-old infant phantom, and 0.36 mm vs 1.11 mm (head and neck), 0.12 mm vs 1.11 mm (pelvis) for 5-year-old pediatric phantom. Conclusion The imaging dose and positioning accuracy of TOMO MVCT were negatively correlated with the pitch ratio. The accuracy of "coarse" mode was relatively lower especially in longitudinal direction, which requires special attention and manual intervention if necessary.
Last Update: 2020-01-14