宫颈癌调强放射治疗中膀胱体积对摆位误差影响研究

Bladder volume changes and set-up error during the course of intensity-modulated radiation therapy therapy of cervical cancer

目的研究宫颈癌患者调强放射治疗中膀胱体积对摆位误差的影响。方法随机选取30例接受宫颈癌根治性放射治疗患者,采集分次治疗前锥形束CT（CBCT）,采集频数大概为前5次治疗和其余每周采集1次。与原始治疗计划CT实施基于解剖结构的配准。分析定位时膀胱体积对摆位误差的影响。结果 30例患者共采集249次CBCT图像,初始膀胱体积变化较大（88.42~722.57 mL）,初始膀胱体积与摆位误差在左右、头脚、前后方向的Pearson相关系数分别为0.114、0.055、-0.187（P=0.073,0.389,0.003）。结论初始定位时的膀胱体积与摆位误差的前后方向仅存在弱相关性,保持治疗时的膀胱体积与定位时的一致性更有临床意义。

Objective To investigate bladder volume changes and set-up error in patients with cervical cancer.Methods Thirty patients were analyzed undergoing external beam radiotherapy scanning cone-beam CT（CBCT） the first five times,and almost once the following four weeks and derived the set-up error using registration,we correlated the original bladder volume with the set-up error. Results Two hundred and forty-nine CBCT images in 30 patients were collected. The original bladder volume changes from 88.42 mL to 722.57 mL. The Pearson coefficients in the left-to-right,superior-to-inferior,anterior-to-posterior direction were 0.114,0.055 and -0.187（P =0.073,0.389,0.003）.Conclusion The weak correlations with bladder volume suggest that measures to maintain the status of bladder maybe more effective in clinical practice.