红外定位系统OPS技术在直肠癌放疗中的临床应用

目的:通过比较常规改进型腹板加热塑膜固定方式（A）与改进型腹板加热塑膜配合红外定位系统（optical positioning system,OPS）使用的固定技术（B）在直肠癌放疗中对摆位误差的影响，探讨在直肠癌放疗中的临床应用价值。方法:回顾分析本院行A、B方法的直肠癌患者各16例，其中A为对照组，B为实验组。两组患者在每周首次放疗前均行CBCT扫描，每组均采集160组数据，其中对照组采用常规激光灯对齐方式进行摆位再行CBCT扫描，实验组采用对准激光线后调整患者体位使OPS监控显示治疗中心在X(左右方向)、Y（头脚方向）、Z（腹背方向）方向误差在3 mm以内再行CBCT扫描。结果:对照组和实验组患者在X、Y、Z轴方向上的摆位线性误差分别为（2.20±1.04）mm、（2.63±1.24）mm、（2.10±1.17）mm和（1.87±0.95）mm、（2.09±1.01）mm、（1.89±0.89）mm。两种固定方式在Z（腹背方向)方向摆位误差无统计学差异（P＞0.05）；在X(左右方向)及Y(头脚方向)方向摆位误差具有显著性差异（P＜0.05）。结论:直肠癌患者使用改进型腹板加热塑膜配合OPS技术可以有效的提高患者放疗中左右及头脚方向的摆位误差，对于提高直肠癌腹板摆位的精度具有临床应用价值。

Clinical application of optical positioning system (OPS) in radiotherapy of rectal cancer

Objective:By comparing the effect of conventional modified Belly board heating plastic film fixation (A) and improved Belly board heating plastic film fixation (B) combined with optical positioning system (OPS) on the positioning error in radiotherapy of rectal cancer,the clinical application value of B in radiotherapy of rectal cancer was discussed.Methods:Sixteen patients with rectal cancer treated by A and B methods were retrospectively analyzed.Among them,A was the control group and B was the experimental group.Two groups of patients were scanned by CBCT before the first radiotherapy every week.160 groups of data were collected in each group.The control group was placed by conventional laser lamp alignment and then scanned by CBCT.The experimental group used alignment laser line to adjust the patient's position so that OPS monitoring and displaying treatment center in X (left and right direction),Y (head and foot direction),Z (abdomen and back direction) axis error within 3 mm and then scanned by CBCT.Sketch.Results:The linear errors of X,Y and Z axis in the control group and the experimental group were (2.20±1.04)mm,(2.63±1.24)mm,(2.10±1.17)mm and (1.87±0.95)mm,(2.09±1.01)mm,(1.89±0.89)mm,respectively.There was no significant difference in the placement error between the two fixation methods in the abdominodorsal direction (Z) (P＞0.05),while there was significant difference in the placement error between the left and right (X) and the head and foot direction (Y) (P＜0.05).Conclusion:The improved belly board heating plastic film combined with OPS technology can effectively improve the positioning errors of left and right sides and head and foot directions in patients with rectal cancer during radiotherapy.It has clinical application value for improving the accuracy of belly board positioning of rectal cancer.