摘要
目的:研究不同部位肿瘤患者在X线立体定向放射治疗时摆位误差的影响因素,探讨精确放疗摆位实施过程中的质量控制方法。方法:2011年10月至2012年12月,应用瓦里安TrueBeam1103直线加速器立体定向放射治疗肿瘤患者63例,其中脑转移癌20例,肺癌32例,肝癌11例。所有患者在每次放疗前行KV-CBCT扫描,将CBCT扫描图像和计划CT图像及其靶中心匹配,分析靶中心在X、Y、Z轴方向上的误差值及其误差分布情况,以判断摆位的重复性。结果:系统误差(均数)±随机误差(标准差)在Lateral(左右,x轴)、Vertical(背腹,y轴)、Longitudinal(头脚,z轴)方向分别为脑转移癌x(0.82±0.83)mm,y(0.79±0.73)mm,z(0.88±0.81)mm;肺癌x(1.81±1.72)mm,y(1.08±1.02)mm,z(2.16±1.88)mm;肝癌x(1.64±1.79)mm,y(1.10±1.12)mm,z(2.89±2.42)mm。结论:肿瘤放疗中重复摆位存在一定误差,脑部肿瘤放疗体位重复性明显优于肺癌和肝癌。只有充分了解各个误差产生的原因,才能采取针对性的措施来减少误差。选择正确的体位固定技术及CBCT位置验证对于调强放射治疗的精确实施具有重要作用。
Objective： To investigate the influencing factors of positioning errors in X-ray stereotactic radiotherapy for different region tumors, and discuss the quantity control methods for the practice process of precision radiotherapy positioning.Methods： From October 2011 to December 2012,63 patients underwent the Varian TrueBeam1103 linear accelerator,The selected patients were all treated with stereotactic radiotherapy, including 20 cases metastatic brain tumors,32 cases lung cancers and 11 cases liver cancers.AU the patients were scanned by kilovoltage cone-beam computed tomography before the everytime radiotherapy.The acquired CBCT images were co-registered with planning CT and setup errors of iso-center positions on the axes of X, Y and Z were obtained for statistical analyses. Results： The systemic ＋random errors on lateral （x）, vertical（y）and longitudinal （z）directions were x（0.82＋0.83） ram,y（0.79±0.73） mm,z（0.88±0.81） mm for brain tumors;x（1.81 ±1.72） mm,y （1.08±1.02） mm,z（2.16±1.88） mm for the lung cancers;x（1.64±1.79） mm,y（1.10±l.12） mm,z（2.89±2.42） mm for the liver cancers,respectively. Conclusions： The replacement errors always occurs in the process of radiotherapy for different region tumors. The position reproducibilities of brain tumors were markedly better than those of different region tumors. Only by thorough understanding of the causes of errors can we adopt the specific measures to reduce it. Choosing correct body immobilization technology and CBCT verification of the target point for intensity modulated radiation therapy has an important role in the precise implementation.
出处
《中国医学物理学杂志》
CSCD
2013年第2期3988-3991,共4页
Chinese Journal of Medical Physics
关键词
立体定向放射治疗
图像引导放射治疗
摆位重复性
影响因素
质量控制
stereotactic radiotherapy
image guided radiotherapy
positioning repeatability
influencing factors
quality control
