非小细胞肺癌在线配准剂量残差回归式离线补偿技术的初步探讨  

Primary study of an offline dose compensation technique in a repeatable cyclic way to compensate for uncertainties after online correction with CBCT for NSCLC

作　　者：李洪升[1] 李宝生[1] 朱健[1] 李需[1] 

机构地区：[1]山东省肿瘤医院放疗科,山东济南250117

出　　处：《中华肿瘤防治杂志》2009年第3期210-212,共3页Chinese Journal of Cancer Prevention and Treatment

基　　金：国家自然科学基金面上项目(30670617)

摘　　要：目的:探讨非小细胞肺癌(NSCLC)锥形束CT(CBCT)图像引导在线摆位校正后,对残余误差导致的剂量学差异进行离线补偿的可行性。方法:2例NSCLC患者入组。每分次放疗前进行在线CBCT图像引导摆位校正,然后对在线CBCT图像数据进行回顾性分析。离线配准CBCT图像与计划CT图像,对比分析配准后CBCT图像上靶区的剂量分布与初始计划的差异,如果发现明显的剂量缺陷区域,则通过逆向调强技术制定新的放疗计划,下一分次放疗按新计划执行。结果:NSCLC患者经在线图像引导摆位校正后,仍然有多分次靶区存在欠剂量区,通过逆向调强技术可以给予欠剂量区以高剂量,从而实现对前次治疗所欠剂量的补偿。结论:离线逆向调强补量技术作为在线图像引导技术的补充,能够对在线图像引导后配准残差导致的剂量学误差进行有效补偿,有望进一步减小靶区外放,实现与每日计划相同的剂量学目标。OBJECTIVE： To investigate the feasibility of an offline dose compensation technique at every fraction to compensate for uncertainties for non-small cell lung cancer （NSCLC） after online correction with in-room cone beam CT （CBCT）. METHODS： Two NSCLC patients were studied. At each fraction, online CBCT scan, rigid image registration and setup correction were performed. Then the online CBCT images were retrospectively analyzed by registering offline between treatment CBCT imaging and planning CT imaging. Dose distribution was calculated and compared with the primary plan. The discrepancy, if found significantly, was repaired using the dose compensation technique, in which the dose discrepancy was incorporated in intensity modulated radiotherapy （IMRT） planning for next fraction. RESULTS： Dose discrepancy area in several clinical target volumes （CTV） after online correction for the patient with NSCLC was found. Offline compensation using IMRT made it possible to repair the dose deficit incurred during irradiation with a relatively high dose. CONCLUSIONS： Offline compensation using IM- RT can effectively repair the dose deficit incurred during early frac tions and therefore complements the online image guidance procedure. It offers the potential to further reduce compensate margins and gets the dose volume target of daily re planning.

关 键 词：癌 非小细胞肺 放射疗法 适形 图像引导放疗 锥形束CT 剂量补偿 

分 类 号：R734.2[医药卫生—肿瘤]