模拟机对宫颈癌放射治疗摆位不确定度的研究

目的：探讨盆腔源皮距照射的宫颈癌患者在治疗过程中的不确定度。方法：选择首次放疗的宫颈癌患15例,仰卧体位,照射野两侧缘在股骨头内1/3附近,根据肿瘤的范围下缘在耻骨联合下缘,上缘在髂棘（腰椎4,5）水平。根据视野灯在盆腔皮肤上的投影用皮肤墨水勾画出方框,并在模拟机上采集照射野的定位图像,然后实施治疗。在治疗的1至5周,每周在模拟机进行重复摆位,对好病人照射野的方框后在模拟机下重复采集校野图像。将验证体位重复性的校野图像与初次计划时的定位图像进行比较。结果：通过30例患者的100次重复校野图像和初次定位图像相比对,得出同一解剖骨性标志点在x,z轴方向上的移值分别为（10.20±2.50）mm,（5.80±1.00）mm。结论：利用模拟定位多次重复摆位采集校野图像来研究宫颈癌治疗过程中的摆位不确定度是简便,可行的。

Study on the uncertainty of cervical cancer patients＇ positioning used by aralog machine

Objective：To investigate the uncertainty of patients with cervical cancer ,who accepted cavitas pelvis ource - skin Distance exposed during the process of treatment. Methods： Fifteen patients with cervical cancer received radiotherapy first time. Supine body position, bilateralis lateral margin close to anterior superior iliac spine （ 1/3 inside caput femoris） , according to the extent of tumor which inferior was in the border of articulation of pubis and superior border was near spina iliace （abdominal vertebra 4,5 ） . According to aerial image made by campus visualis lamp in the skin of cavitas pelvis, square frame was drawed by dermat - ink, collect locating mapping of exposure field in the analog machine, then went on therapy. During the 1 - 5 weeks in treatment, patients must positioning reduplicative in the analog machine every week , then according to the square frame of exposure field , we can collect correct campus visualis mapping in the analog machine, and compare corrected campus visualis mapping about verification body position with the first planning locating mapping. Results： According to 100 times about the compare of corrected campus visualis mapping and locating mapping in the 30 patients, we can conclude that the same anatomical osseous signal may move （ 10.20 ±2.50） mm in the direct of X axis and （5.80± 1.00） mm in the direct of Z axis. Conclusion： It is convenient and feasible to investigate the uncertainty of positioning during the therapy processs of cervical carcinoma, which used by simulation and positioning reduplicativly to collect corrected campus visualis mapping.