宫颈癌放射治疗中宫颈偏移的测试结果与影响

目的探讨宫颈偏移对中央挡铅野及盆腔两侧剂量分布和均匀性的影响。方法随机测量252例放射治疗后程宫颈癌患者的宫颈管口位置,用无菌钡剂小棉球放入官颈管口内,测后取出。在模拟定位机下测量官颈口与人体中线(左右间)、前后中平面(前后野中间)相互距离的关系。结果宫颈口在正中线位的有10例,占4%(10/252);偏右的有53例,占21%(53/252);偏左的有189例,占75%(189/252)。其中偏移在2cm以上83例,占33%(83/252)。左右最大的偏移为6cm。宫颈口在正中平面位者(前后野中间)有5例,占2%(5/252);偏前者有199例,占79%(199/ 252);偏后者有48例,占19%(48/252)。偏移在2cm以上者有38例,占15%(38/252)。前后最大偏移为5cm。结论宫颈口前后移位对放射剂量分布、均匀性无影响;而左右偏移,对挡铅后,算量的放射剂量分布与均匀性有一定影响。

Result and influence of measuring uterus cervical excursion in radiotherapy

Objective To explore the effect of cervical excursion to dose distribution and homogene- ous of central Pb shield field and pelvic field.Methods 252 cases cervical tube position are measured ran- domly of uterus cervical carcinoma in radiotherapeutic late stage,axenic barium small cotton ball is put into cervical tube,taken it away after measuring.Under the simulator,measure distance interrelations between ute- rus cervix and the body middle line(between right and left),and the body front-back middle plane(be- tween front field and back filed).Results Uterus cervices in body middle line have 10 cases,only about 4%(10/252);lean to fight be about 53 cases,only 21%(53/252);lean to left be about 189 cases,only 75%(189/252).Removing more than 2cm have about 83 cases,only 33%(83/252).Maxi-excursion in the right and the left is 6cm.Uterus cervices in the body middle plane(between front field and back field) have 5 cases,only 2%(5/252),lean to front be 199 cases,only 79%(199/252);lean to back be 48 cases, only 19%(48/252).Removing more than 2cm have about 38 cases,only 15%(38/252).Maxi-excursion between the front and the back is 5cm.Conclusion Uterus cervix excursion between the front and the back has no influence on radial dose distribution and homogenous.Removing between the left and the right have some influence on radiologic dose distribution and homogenous in central Pb shield field.