Y-axis accuracy based on the center point of radiotherapy for nasopharyngeal carcinoma(PDF)
《中国医学物理学杂志》[ISSN:1005-202X/CN:44-1351/R]
- Issue:
- 2020年第8期
- Page:
- 955-957
- Research Field:
- 医学放射物理
- Publishing date:
Info
- Title:
- Y-axis accuracy based on the center point of radiotherapy for nasopharyngeal carcinoma
- Author(s):
- LIU Yuanyuan1; CAI Yonglin2
- 1. the First Radiotherapy District, Wuzhou Red Cross Hospital, Wuzhou 543002, China 2. Department of Laboratory, Wuzhou Red Cross Hospital, Wuzhou 543002, China
- Keywords:
- Keywords: nasopharyngeal carcinoma intensity-modulated radiotherapy treatment center Y-axis accuracy
- PACS:
- R739.6；R811.1
- DOI:
- DOI:10.3969/j.issn.1005-202X.2020.08.003
- Abstract:
- Abstract: Objective To analyze the Y-axis precision based on the center point of radiotherapy for nasopharyngeal carcinoma (NPC). Methods A total of 200 NPC patients were enrolled and randomly divided into groups A and B, with 100 cases in each group. Double-arc volumetric modulated arc therapy (VMAT) reverse optimization was adopted in group A, while traditional intensity-modulated radiotherapy reverse optimization was adopted in group B. Eclipse13.5 planning system was used for optimization design in two groups. Y-axis accuracy was analyzed based on the center point of optimized radiotherapy and that in reconstruction images. Results The incidence of Y-axis movement in group A was 43.00%, lower than 58.00% in group B (P<0.05). The direction of Y-axis movement in group A was downward, accounting for 53.49%, while the Y-axis in group B was moved upward, accounting for 68.97%. The positioning errors (moving upward) were (1.07±1.01) mm and (2.15±1.38) mm in group A and group B, and the positioning errors (moving downward) were (1.12±1.13) mm and (2.07±1.24) mm in group A and group B (P<0.05). The proportions of treatment center located at layer 1 were 38.00% and 44.00% in group A and group B, respectively, without statistical differences (P>0.05) and the proportions of treatment center located at layer 2 were 62.00% and 56.00%, respectively, without statistical differences (P>0.05). The center point movement in group A mainly occurred at layer 2, with an incidence of 69.35%. The incidence of the center point movement in group B was 36.36% at layer 1 and 75.00% at layer 2. The center point located at layer 1 in group B was mainly moved upward. The incidences of upward movement and downward movement of center point located at layer 2 were 46.51% and 53.49% in group A, and the movement of center point located at the layer 2 in group B was mainly moved upward, with an incidence of 51.72%. Conclusion During the radiotherapy for NPC, VMAT reverse optimization has more advantages and can improve the accuracy of Y-axis of the treatment center during radiotherapy, which is worthy of application and promotion.
Last Update: 2020-08-27