Development of T-shaped oral fixator and its effects on setup errors and dosimetric change in nasopharyngeal carcinoma radiotherapy(PDF)
《中国医学物理学杂志》[ISSN:1005-202X/CN:44-1351/R]
- Issue:
- 2020年第11期
- Page:
- 1367-1372
- Research Field:
- 医学放射物理
- Publishing date:
Info
- Title:
- Development of T-shaped oral fixator and its effects on setup errors and dosimetric change in nasopharyngeal carcinoma radiotherapy
- Author(s):
- QIU Minmin1; XU Yuan1; ZHONG Jiajian2; DENG Yongjin2; ZHOU Linghong1
- 1. College of Biomedical Engineering, Southern Medical University, Guangzhou 510515, China 2. Department of Radiotherapy, First Affiliated Hospital of Sun Yat-sen University, Guangzhou 510080, China
- Keywords:
- Keywords: nasopharyngeal carcinoma self-made T-shaped oral fixator setup errors dosimetric change
- PACS:
- R811.1
- DOI:
- DOI:10.3969/j.issn.1005-202X.2020.11.005
- Abstract:
- Abstract: Objective To explore the effects of the self-made T-shaped oral fixator on the setup errors and the PTV and organ-at-risk (OAR) dose in radiotherapy for nasopharyngeal carcinoma. Methods 40 cases of nasopharyngeal carcinoma were randomly divided into two groups, with 20 patients in each group. Group A was immobilized by conventional thermoplastic mask, and group B was immobilized by thermoplastic maskplus self-made T-shaped oral fixator. Cone beam CT was used to compare the linear errors and rotation errors in the head and neck between those two groups. The PTV and organ-at-risk (OAR) dose were recalculated based on the above setup errors in planning system, and were compared with the original plan. Results The linear errors of two groups were very close, but the rotation errors were reducedin the group B, among which, the rotation errors in neck reduced to within 2°. In group A, the errors ratesin Cor, Sag and Tra axis were 88.7%, 83.4% and 80.5% respectively, while that of group B were 98.4%, 95.3% and 96.9%, which has a statistically significant difference (P<0.01, P<0.01, P<0.01). As for the percentage of gross target volume dose in PTV, Group As GTVnx-D98%, GTVnd-D98%, CTV1-D95% and CTV2-D95% within ±3% occupied 87.5%, 88.3%, 98.5% and 98.5% respectively, but that of group B were 100%, 96.8%, 100% and 100% respectively, which also have their statistical differences （P<0.01, P<0.01, P<0.01, P<0.01）. Conclusions Thermoplastic mask plus self-made T-shaped oral fixator can effectively reduce the setup errors, enhance therepeatability of setup, improve the accuracy of dosage in PTV, especially on neck. It can be popularized in clinical practice.
Last Update: 2020-12-02