中国医疗设备2024，Vol.39Issue(3)：68-72,79,6.DOI:10.3969/j.issn.1674-1633.2024.03.012
MLC运动误差对不同射野面积的鼻咽癌容积调强计划的影响
Impacts of MLCerror on the Different Beam Area of Volumetric Arc Therapy for Nasopharyngeal Carcinoma
摘要
Abstract
Objective To analyze the influence between the mean aperture area(MAA)and the multi-leaf collimator error(MLCerror)for nasopharyngeal carcinoma volumetric modulated arc therapy.Methods 30 patients diagnosed with postoperative nasopharyngeal carcinoma were selected as the study objects.Every original plan for each patient was exported and compiled using Python.Six modified plans were generated by different MLCerror(±0.2 mm,±0.5 mm,±1.0 mm).The dosimetry parameters and passing rate of the original and modified plan were compared and the relationship among MLCerror,and MAA was analyzed.Among them,the planned target volume(PTV)of nasopharyngeal tumor and the target area of cervical metastatic lymph node tumor were integrated into PTV69 by Boolean operation.Results The corresponding variation of PTV69,planning clinical target volume 1 and planning clinical target volume 2 due to MLCerror(-1-1 mm)were 6.1%/mm,6.0%/mm and 6.3%/mm(P<0.05).The dose gradient of the organs at risk(OAR)was higher than that of the target area.The dose fall-off were 10.6%/mm,10.5%/mm,12.3%/mm,12.0%/mm,8.1%/mm and 11.2%/mm in spinal-cord,brainstem,parotid-L,parotid-R,oral and larynx(P<0.05).With the increase of MLCerror,the passing rate difference of different MAA plan showed an increasing trend.When the MLCerror reached±1.0 mm,the discrepancy of different MAA plan was largest(51.7%-90.2%).Conclusion It is more beneficial for limiting MLCerror value to protect OAR than target.For the complicated nasopharyngeal carcinoma,less than 0.5 mm MLCerror is suggested to be the operation tolerance and decreasing the the small segment is recommended to protect OAR and ensure the dose accuracy.关键词
鼻咽癌/多叶准直器运动误差/容积调强放疗/子野平均面积/验证通过率Key words
nasopharyngeal cancer/multi-leaf collimator error/volumetric modulated arc therapy/mean aperture area/passing rate分类
医药卫生引用本文复制引用
贾晓斌,岳堃..MLC运动误差对不同射野面积的鼻咽癌容积调强计划的影响[J].中国医疗设备,2024,39(3):68-72,79,6.基金项目
九院基础研究助推计划资助,上海交通大学医学院附属第九人民医院种子基金(JJZZ192). （JJZZ192）
