摘要
目的利用CT模拟了解子宫颈癌常规盆腔照射野剂量分布与盆腔淋巴结的关系,探讨较合理的盆腔设野方法。方法对100例子宫颈癌患者进行CT模拟扫描,在放射治疗计划系统上按常规盆腔照射野制定治疗计划,得到常规盆腔照射野95%等剂量曲线图。测量髂总动脉长度和盆腔照射野内的髂总动脉长度,髂总动脉髂内外动脉分叉处内侧缘距盆腔中线的距离,95%等剂量曲线与照射野边界的距离。结果56例常规盆腔照射野内髂总动脉长度不足2cm。71例左髂总动脉或右髂总动脉分叉处到盆腔中线距离≤1.5cm。95%等剂量曲线与照射野上、下、左、右界中位距离分别为1.0cm、0.9cm、0.4cm和0.5cm。结论子宫颈癌常规的盆腔照射野存在一定的缺陷,可能造成盆腔淋巴结,特别是髂总淋巴结的照射剂量不足或漏照。建议在CT模拟定位下进行盆腔野的设计,或参考CT图像设计盆腔照射野,盆腔中线挡铅的照射用盆腔下段挡铅(子宫底平面以下)的替代。
Objective To determine if the conventional pelvic radiation fields are rational in relation to the pelvic lymph nodes coverage in radiotherapy of cervix cancer. Methods One hundred patients with cervix cancer underwent CT simulation. Conventional fields were outlined on treatment planning system （TPS） and 95% isodose was calculated and presented by computer. The following distances were measured： （1） bifurcation of abdominal aorta to bifurcation of common lilac artery （length of common lilac artery）. （2） bifurcation of abdominal aorta to upper margin of L5. （3） bifurcation of common iliac artery to upper margin of L5 （length of common iliac artery within conventional pelvic radiation fields）. （4） bifurcation of common iliac artery to midline of pelvis. （5） margins of 95% isodose to each border. Results Common iliac arteries of 56 patients within conventional pelvic radiation fields were shorter than 2 cm. Distance between left or right common iliac artery and pelvic midline was shorter than 1. 5 cm in 71 patients. Median distances from 95% isodose to superior,inferior,left and right border of anterior/posterior fields were 1. 0 cm, 0. 9 cm, 0. 4 cm and 0. 5 cm,respectively. Conclusions Conventional pelvic fields based on bony landmarks do not provide optimal lymph nodes coverage and 3 cm wide lead ,blocking at middle pelvis on anterior/posterior fields results in omitted lymph nodes in latter course of radiation treatment. Treatment plan based on CT simulation is suggested. Improved lower portion of middle pelvis blocked anterior/ posterior fields are more suitable than those of 3 cm wide lead blocking at middle pelvis.
出处
《实用肿瘤杂志》
CAS
北大核心
2009年第4期385-388,共4页
Journal of Practical Oncology
