锥型束CT在鼻咽癌放疗的摆位误差及靶区外放边界的应用价值  

Role of cone-beam CT in setup errors and margin of planning target volume of radiotherapy for nasopharyngeal carcinoma

作　　者：徐久宏[1] 张军宁[1] 王建平[1] 郭建[1] 

机构地区：[1]苏州大学附属第一医院放疗科,江苏省215006

出　　处：《江苏医药》2015年第1期65-68,共4页Jiangsu Medical Journal

摘　　要：目的探讨锥型束CT(CBCT)在鼻咽癌调强放射治疗(IMRT)的摆位误差及靶区外放边界(MPTV)的应用价值。方法对15例鼻咽癌IMRT患者在每次摆位后治疗前、摆位误差校正后和治疗后行CBCT扫描,将获取的CBCT图像与计划CT图像进行匹配,得出左右(X)、上下(Y)和前后(Z)3个方向上的摆位误差。依据公式计算MPTV值。结果 15例患者共进行543次CBCT扫描。校正前的X、Y和Z方向摆位误差分别为(0.4±1.5)mm、(0.5±1.7)mm和(-0.6±1.6)mm;校正后分别为(0.2±0.7)mm、(0.1±0.7)mm和(-0.2±0.8)mm;治疗后分别为(0.2±0.8)mm、(0.2±0.9)mm和(-0.1±0.9)mm。X、Y和Z方向总MPTV(校正前和分次内误差)为4.0、3.5和4.5mm,校正后MPTV(校正后和分次内误差)为2.0、2.3mm和2.5mm。结论 CBCT能准确测量并提高鼻咽癌IMRT治疗精确性。Objective To explore the role of cone-beam CT（CBCT）in setup errors and margin of planning target volume（MPTV）of radiotherapy for nasopharyngeal carcinoma（NPC）.Methods Fifteen NPC patients treated with intensity modulated radiation therapy（IMRT）received CBCT scans before treatment,after correction of setup errors and after treatment.The CBCT images were matched to planning CT images to obtain setup errors in three directions of X（left-right）,Y（superior-inferior）and Z（anterior-posterior）.The value of MPTV was calculated according to the formulation.Results A total of 543 CBCT scans was performed in 15 patients.The setup errors on X,Y and Z directions before treatment were（0.4±1.5）mm,（0.5±1.7）mm and（-0.6±1.6）mm,respectively,which after correction were（0.2±0.7）mm,（0.1±0.7）mm and（-0.2±0.8）mm,and after treatment were（0.2±0.8）mm,（0.2±0.9）mm and（-0.1±0.9）mm,respectively.MPTV values of X,Y and Z directions for pre-correction and intra-fraction error were 4.0,3.5mm and 4.5mm,which for postcorrection and intra-fraction error were 2.0,2.3mm and 2.5mm.Conclusion CBCT is an effective modality to improve the accuracy of IMRT for NPC.

关 键 词：锥型束CT 调强放射治疗 鼻咽癌 摆位误差 

分 类 号：R445[医药卫生—影像医学与核医学]