基于投影数据的锥形束CT功能成像方法初探  

Functional cone-beam CT imaging based on projection data

作　　者：钱鹰[1] 周强[1] 韦庆杰[1] 

机构地区：[1]重庆邮电大学医学图像与信息系统研究中心,重庆400065

出　　处：《第三军医大学学报》2010年第16期1732-1735,共4页Journal of Third Military Medical University

基　　金：重庆市自然科学基金(2008BB2086)~~

摘　　要：目的建立计算机仿真系统,研究基于投影数据的锥形束CT(cone-beamCT,CBCT)灌注成像的方法,探索实现在线功能图像引导的放疗(biologic image guided radiation therapy,BIGRT)的可能性。方法通过计算机仿真技术,利用大白兔动态增强CT(dynamic contrast enhancedCT,DCE-CT)图像数据集模拟获取CBCT动态增强扫描的投影数据集;通过对扫描对象各体素的时间密度变化进行数学建模,基于获得的投影数据集,经最优化拟合求得各体素模型的参数,获取CBCT动态增强扫描下各体素的时间密度曲线(time-density curve,TDC)。结果对比仿真系统获得的锥形束CT下各体素的TDC和原DCE-CT获得的对应体素的TDC,发现在对比剂首次通过时的上升沿有较好吻合,在循环进入平衡后差异较大。结论基于投影数据可实现CBCT灌注成像,获得较为准确的血流灌注值,证明了利用集成在直线加速器上的CBCT实现在线的功能成像是可能的。Objective To establish a computer simulation system to investigate functional cone-beam CT imaging based on projection data in order to realize on-line biologic image guided radiation therapy.Methods Dynamic contrast enhanced CT （DCE-CT） scanning were performed on rabbit.Computer simulation system was built and the cone-beam CT projection data were obtained by using the program of transferring the fan-beam data to the cone-beam data.The change of time-density of each voxel was modeled as a uniform function.Parameters of this function were resolved by using curve fitting based on the projection data.Finally,functional parameters of rabbit were computed by using existent functional CT （fCT） model.Results Comparing the time-density curve （TDC） from cone-beam CT data in simulation system and the TDC at the same pixel from the original DCE-CT data,good fitting was found at the first increase of TDC and fault fitting was found at the other parts of TDC.Conclusion The functional cone-beam imaging can be implemented based on projection data,and then the perfusion is quantified.

关 键 词：图像引导的放疗 锥形束CT 功能成像 

分 类 号：R812[医药卫生—放射医学] R814.42[医药卫生—临床医学]