改良二维矩阵探测器MatriXX测量方法在立体定向放射治疗计划验证中的应用
The Application of Improved Two-Dimensional Matrix Detector MatriXX Measurement Method in Validation of Stereotactic Body Radiation Therapy Plan
庞金猛 1周京凤 1姚伟1
作者信息
- 1. 湖南省肿瘤医院 (湖南长沙 410000)
- 折叠
摘要
目的 探讨改良二维矩阵探测器MatriXX测量方法在立体定向放射治疗(SBRT)计划验证中的应用价值.方法 随机选取2020年1月至2022年12月于医院行SBRT的40例患者的治疗计划,重新设计以二维矩阵探测器MatriXX为模体的验证计划.设置机架和准直器为 0°,源皮距(SSD)为 140 cm,MatriXX上增加厚度 5 cm的固体水,按照验证计划要求摆位(摆位前确认医用直线加速器十字线精度).首先,完成 1 次传统等中心摆位测量,然后,采用改良方法进行多次测量,即通过移动MatriXX位置提高分辨率:将治疗床沿正x方向分别移动 2.5、5.0 mm并出束测量,沿正y方向分别移动 2.5、5.0 mm并出束测量,再将治疗床沿正x方向和正y方向分别移动 2.5、5.0 mm进行组合测量,共得到 9 组测量数据.将改良方法测量得到的 9 组数据整合为 1 组数据,得到分辨率为 2.5 mm(SSD=140 cm时分辨率为 2.5 mm,相对于SSD=100 cm时分辨率约 1.8 mm)的SBRT计划数据,然后将该数据与治疗计划系统计算数据比较,得出改良方法的γ通过率,再与传统单次测量的γ通过率进行比较.结果 改良方法和传统单次测量的γ通过率(3%/2 mm)分别为(98.2±1.0)%、(95.2±1.8)%,差异有统计学意义(P<0.05).结论 改良二维矩阵探测器MatriXX测量方法可提高MatriXX的分辨率,进而提高SBRT计划验证的γ通过率,可用于小靶区、高剂量梯度的计划验证,也可进行医用直线加速器平坦度和对称性等精细测量.
Abstract
Objective To explore the application value of the improved two-dimensional matrix detector MatriXX measurement method in the validation of stereotactic body radiation therapy(SBRT)plans.Methods With the random selection of the treatment plans of 40 patients underwent SBRT in hospitals from January 2020 to December 2022,the validation plan with the two-dimensional matrix detector MatriXX as model was redesigned.With the setting of the frame and collimator to 0° and the source skin distance(SSD)to 140 cm,addition of solid water with a thickness of 5 cm on the MatriXX,and setting of the position according to the requirements of the verification plan(the accuracy of the medical linear accelerator crossline was confirmed before positioning),firstly,one traditional isocenter positioning measurement was completed,and then an improved method was adopted for multiple measurements,which improved the resolution by moving the MatriXX position:The treatment bed was moved along the positive x direction by 2.5 and 5.0 mm respectively for beam measurement,along the positive y direction by 2.5 and 5.0 mm respectively for beam measurement.In addition,the treatment bed was moved 2.5 mm and 5.0 mm along the positive x and y directions for combined measurement,resulting in a total of 9 sets of measurement data.With the integration of the 9 sets of data measured by the improved method into 1 set of data,the SBRT plan data with a resolution of 2.5 mm(The resolution for SSD=140 cm was 2.5 mm,which was relative to the resolution of about 1.8 mm for SSD=100 cm)was obtained.Then,by comparing the data with the calculated data from the treatment planning system,the γ pass rate for the improved method was obtained,and compared with γ pass rate for the traditional single measurement.Results The γ pass rates(3%/2 mm)of the improved method and traditional single measurement were(98.2±1.0)%and(95.2±1.8)%,respectively,with statistically significant differences(P<0.05).Conclusions Improved the measurement method of two-dimensional matrix detector MatriXX can improve the resolution of MatriXX,thereby increasing the γ pass rate of SBRT program verification.It can be used for small target area and high dose gradient program verification,as well as for fine measurement of flatness and symmetry of medical linear accelerators.
关键词
MatriXX/计划验证/立体定向放射治疗/分辨率Key words
MatriXX/Plan validation/Stereotactic body radiation therapy/Resolving power引用本文复制引用
出版年
2024
NETL
NSTL
万方数据