千伏锥形束CT测量脑转移瘤放疗计划靶区外放研究  

Measuring planning target volume margin in kV cone beam CT guided three-dimensional conformal radiotherapy of brain metastases carcinoma

作　　者：刘希军[1] 于金明[1] 于甬华[1] 岳金波[1] 李文武[1] 尹勇[1] 余宁莎[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4期299-301,304,共4页Chinese Journal of Cancer Prevention and Treatment

摘　　要：目的:测量千伏锥形束CT(CBCT)引导脑转移瘤放疗计划靶区设定过程中临床靶区(CTV)-计划靶区(PTV)边缘外放值。方法:14例脑转移瘤患者应用热塑面膜+头枕固定,静脉注射造影剂后行螺旋CT扫描,Eclipse计划系统制定治疗计划,应用影像引导放疗系统给予患者前10次治疗前CBCT和计划CT配准,治疗结束后再次给予CBCT和计划CT配准,记录X轴(左右)、Y轴(前后)以及Z轴(上下)3个方向偏移值。结果:总系统误差的标准差X轴为0.92 mm,Y轴为0.95 mm,Z轴为1.10 mm;其相对应的总随机误差的标准差X轴为2.19 mm,Y轴为1.87 mm,Z轴为1.94 mm。根据VanHerk公式,CTV-PTV外放结果X轴为3.2 mm,Y轴为3.5 mm,Z轴为4.0 mm。结论:增强扫描可以使脑转移瘤在kVCBCT中显像,脑转移瘤适形放疗CTV-PTV外放可以为4.0 mm。OBJECTIVE： To measure planning target volume margin in cone beam CT（CBCT） guided conformal radiotherapy（IGCRT） of brain metastases carcinoma. METHODS： Fourteen consecutive cases of brain metastases carcinoma were treated with IG-CRT. All the patients were immobilized on a head and neck support pad using a customized thermoplastic masks（ORFIT）. CRT technique was performed by using the Eclipse planning system. Before the radiotherapy, 3 dimentional CBCT/ planning CT was matched at every first ten fractions of each patient by using IGRT system. After CRT, 3 D CBCT/ planning CT was matched again. RESULTS： The standard deviation of overall systematic error was 0.92 mm in the rightleft （X axis）, 0.95 mm in the anterior-posterior （Y axis）, 1.10 mm in the superior-inferior（Z axis）directions. The corresponding SDs of the random errors were 2.19 mm（X）, 1.87 mm（Y）, 1.94 mm（Z）, respectively. The estimated margins required from clinical target volume （CTV）-planning target volume （PTV） were calculated according to the Van Herk formula being 3. 2 mm（X）, 3. 5 mm（Y）, 4.0 mm（Z）. CONCLUSION： Brain metastases carcinoma can display on KVCBCT with injecting a contrast medium into a vein. 4 mm CTV PTV margin has been adopted in IG-CRT on brain metastases carcinoma.

关 键 词：脑肿瘤/继发性 体层摄影术 X线计算机/方法 放射疗法 适形 

分 类 号：R739.4[医药卫生—肿瘤]