摘要
目的分析千伏级锥形束CT引导下以真空垫为体位固定装置的宫颈癌患者图像引导放疗中的摆位误差。方法 50例宫颈癌患者分别于放疗第1周、第3周、第5周采用瓦里安直线加速器机载影像系统行锥形束CT(CBCT)扫描,与计划CT图像匹配获得左右、头足、腹背及旋转方向的摆位误差,并计算计划靶体积(PTV)外放边界。结果 50例患者共行150次扫描,左右、头足、腹背及旋转方向的摆位误差分别为(2.89±1.63)mm、(4.68±2.19)mm、(2.24±1.36)mm、(7.62±5.77)deg,左右、头足、腹背方向PTV外放边界分别为8.36、13.23、6.55 mm。结论应用锥形束CT扫描可测量宫颈癌患者的摆位误差并在线校正,以减少误差;还可估算PTV外扩边界值,为临床医师提供治疗依据。
Objective To evaluate setup errors of image guided radiation therapy（ IGRT） for cervical cancer with vacuum cushions using kilovolt cone beam CT（ KVCBCT）. Methods Varian-IX linear accelerator on-board imaging system was used to acquire CBCT scans before irradiation of 50 cervical cancer patients in the 1st,3rd,and 5th week,respectively.CBCT scans and planning CT scans were auto-matched to obtain the setup errors of left-right（ x）,superior-inferior（ y）,anterior-posterior（ z） and rotation（ r）. The value of the MPTV was calculated,meanwhile. Results 50 patients acquired 150 CBCT scans. The setup errors in x-,y-,z-,r-dimension were（ 2. 89 ± 1. 63） mm、（ 4. 68 ± 2. 19） mm、（ 2. 24 ± 1. 36） mm、（ 7. 62 ±5. 77） deg. The MPTV were 8. 36、13. 23、6. 55 mm in x-,y-,z-dimension. Conclusions CBCT on line correction could reduce the setup errors of cervical cancer patients,and estimate the MPTV,thereby provide the basis for clinicians.
出处
《中南医学科学杂志》
CAS
2015年第2期201-203,共3页
Medical Science Journal of Central South China
关键词
体层摄影术
锥形束
图像引导放疗
摆位误差
宫颈癌
Tomography
cone-beam
Image guided radiotherapy
Setup errors
Cervical cancer
