乳腺癌放射治疗真空垫固定摆位误差分析及优势

Analysis of position set-up tolerance and advantage for breast cancer radiotherapy immobilized by vacuum mold

背景与目的:目前国内乳腺癌放射治疗使用乳腺托架固定摆位的精度较高,但许多单位没有大孔径CT,因此乳腺托架无法使用。该研究旨在探讨在没有大孔径CT时,乳腺癌术后患者在放射治疗时使用真空垫固定的摆位误差和产生原因。方法:选取2011年11月—2012年2月期间上海交通大学医学院仁济医院放疗科收治的30例乳腺癌术后患者,接受放射治疗并用真空垫固定进行CT定位,使用医科达Precise型加速器上兆伏级电子射野影像系统(electron portal imaging device,EPID)对患者实施锁骨上野和胸壁切线野拍片,并与治疗计划中的射野位置对比验证,统计出X、Y、Z轴3个方向的平均误差及最大误差。结果:X、Y、Z轴平均误差分别为(1.61±1.12)、(1.56±1.12)和(1.50±0.9)mm。结论:乳腺癌术后患者使用真空负压成型垫固定,能保证摆位的精度,在没有固定架条件下实用性高。

Background and purpose： Using the breast bracket would bring patient low position set-up. But the breast bracket is too big to be scanned in normal aperture CT in many radiation centers. This study is to analyze the potision set-up tolerance, with no big aperture CT, for postoperated breast cancer immobilized by vacuum mold when CT scanning during the radiation therapy. Methods： Thirty post-operated breast cancer patients selected from Sep. 2011 to Feb. 2012 were enrolled in this study. EPID was used for taking the posision set-up verification film. Comparing the verification film will obtain the average tolerance and max tolerance. Results： The average tolerance of X, Y and Z axis were （1.61±1.12）, （1.56±1.12） and （1.50±0.98）mm. Conclusion： Using the vacuum mold wiU do favor to immobilize the patient position for breast cancer radiotherapy. It would bring patients comfortable position while under radiotherapy and very low tolerance.