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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。
Objective To investigate the effects of cervical deviation on the dose distribution and uniformity of both central and lateral lead and pelvic cavity. Methods Randomly measure the position of cervical orifice in 252 patients with cervical cancer after radiation therapy. In the simulation of positioning machine under the neck and neck measured between the body (left and right), before and after the plane (before and after the middle of the field) the relationship between the distance. Results There were 10 cases in the midline of the cervix, accounting for 4% (10/252), 53 cases (53/252) in the right side, 189 cases (75%) in the left side (189 / 252). Among them, 83 cases were offset by more than 2cm, accounting for 33% (83/252). The maximum offset around 6cm. 5 cases (2/252) had cervix in the median plane (middle of the anteroposterior range), 199 cases (79/252) in the former, 48 cases (19% (48/252). There were 38 cases (15% (38/252)) with deviation of 2cm or more. Before and after the maximum offset of 5cm. Conclusion There is no effect on the radiation dose distribution and uniformity of the cervix before and after the shift of the cervix. However, the left and right shifts have a certain effect on the dose distribution and uniformity of the calculated dose after blocking the lead.