锥形束CT在盆腔肿瘤放射治疗摆位中的临床应用

The application of cone-beam CT on setup in pelvic tumor radiotherapy

目的探讨锥形束CT(CBCT)在盆腔肿瘤放射治疗摆位中的应用效果。方法选取2012年6月至2013年6月间采用调强放疗技术的120例盆腔肿瘤患者,实施CBCT扫描,手动匹配获取的CT计划图像和CBCT图像,得出误差数据以判别摆位是否准确。结果盆腔肿瘤患者的头脚方向摆位误差较另两个方向大(P<0.05),最大的误差值高达12.6mm,其中>5mm的占据23.0%。在纠正后和治疗后的各方向摆位误差较首次摆位误差均明显下降,前后比较差异有统计学意义(P<0.05);依据计划靶区外放剂量值(MPTV)的推导公式进行计算,证明不低于90.0%的临床靶区达到了95.0%以上的处方剂量。在首次摆位匹配经纠正后,各方向的MPTV值均有所下降(P<0.05)。结论 CBCT能够对盆腔肿瘤放疗摆位的误差施以实时监测,同时予以校正,使照射靶区能够外放到计划靶区上,大大提高了放疗的精准性,降低不可逆严重并发症或后遗症的发生率,有效控制和治愈肿瘤。

Objective To explore the application of CBCT in pelvic tumor radiotherapy pendulum effect. Methods 120 cases with pelvic tumors hospitalized in our hospital from June 2012 to June 2013 were selected, during the courses of intensity modulated radiation therapy,techniques of CBCT scanning was implemented,and manual matching images and CBCT images for the CT plan were compared to identify whether placements were accurate. Results The head and foot direction of pelvic tumors had bigger pendu- lum position error than the other two directions （P 〈 0. 05 ） , the biggest error value was as high as 12. 6ram, occupying 23.0% of those 〉 5 mm. Corrected and after treatment in the direction of the beam position error of the initial placement error were significantly decreased, compared before and after the difference was sta- tistically significant （ P 〈 0. 05 ） ; Based on results of MPTV formula, not less than 90. 0% of the clinical tar- get area reached more than 95.0% of the prescribed dose. Placed in the first place match after correcting the direction of MPT~ values were decreased （ P 〈 O. 05 ）. Conclusions CBCT can of pelvic tumor radio- therapy beam position error with real-time monitoring, make correction at the same time, makes the target ir- radiation can on planning target, greatly improves the precision of radiation therapy, reduce the incidence of irreversible serious complications or sequela, effective control and cure cancer.