应用锥体束CT分析肝癌图像引导放疗的摆位误差及外放边界  

Cone Beam CT Applied to Analysis of Set-up Error and Safety Margin in Image-Guided Radiation Therapy for Liver Cancer

作　　者：卿莉萍[1] 梁世雄[1] 洪超善[1] 付庆国[1] 韩青[1] 

机构地区：[1]广西医科大学附属肿瘤医院放疗科,南宁市530021

出　　处：《广西医学》2014年第2期183-186,共4页Guangxi Medical Journal

基　　金：广西医药卫生科研课题(重2010071)

摘　　要：目的分析千伏级锥体束CT(KV-CBCT)肝癌图像引导放疗摆位误差,为肝癌放疗计划靶区(PTV)的外放边界提供参考。方法应用医科达Synergy直线加速器治疗31例肝癌患者,KV-CBCT扫描采集的X线容积图像(XVI)与计划CT图像的靶中心匹配,获得腹背(X)、头脚(Y)、左右(Z)三个方向的线性误差x、y、z和绕X、Y、Z轴旋转形成的旋转误差u、v、w。由公式计算出肝癌临床靶区(CTV)到计划靶区(PTV)的外放边界值(M PTV)。结果共进行275次CBCT扫描,其在X、Y、Z方向上摆位误差x、y、z中位数分别为1.70 mm、1.30 mm、0.80 mm,旋转误差u、v、w分别为0.65°、0.38°、0.31°。M PTV在X、Y、Z方向上分别为4.11 mm、8.49 mm、4.94 mm。结论采用KV-CBCT技术测量肝癌图像引导放疗的摆位误差,为肝癌放疗M PTV提供参考,提高了肝癌放疗的精准性。Objective To analyze the set-up errors in image-guided radiation therapy for liver cancer guided with kilo-voitage cone beam computed tomography （ CBCT ） to calculate the referential safety margin of plan target volume （ PTV） .Methods Thirty-one patients with liver cancer were involved in the treatment with Elekta Synergy linear accelerator , the kilo-voltage CBCT-collected volume of X-ray images（XVI） was matched with the center of target of planning CT images to obtain the linearity errors（x,y,z） and the rotational errors（u,v,w） in three directions：back-belly（X）,head-feet（Y）,left-right （Z）.The margin（MPTV） between clinical target volume（CTV） and PTV was calculated based on the formula .Results A total of 275 CBCT scans showed that in the X ,Y,Z directions,the mean linear errors （ x,y,z） were 1.70 mm, 1.30 mm,0.80 mm,respectively,and the rotational errors（u,v,w） were 0.65°,0.38°,0.31°,respectively.MPTV in three-dimensional directions（X,Y,Z） were 4.11 mm,8.49 mm,4.94 mm,respectively.Conclusion Kilo-voltage CBCT applied to evaluating the set-up errors of image-guided radiation therapy can provide the references for determining MPTV of radiotherapy for liver cancer ,which improves the accuracy of radiotherapy for liver cancer .

关 键 词：肝癌 锥体束CT 图像引导放疗 摆位误差 外放边界 

分 类 号：R730.55[医药卫生—肿瘤]