基于Ethos自适应放射治疗系统不同成像算法的图像质量分析  

Analysis of image quality based on different imaging algorithms of the Ethos adaption radiotherapy system

作　　者：刘晓宇 寇宇涵 阎长鑫 王金媛 班培超 张丹丹 陈恺文 解传滨 Liu Xiaoyu;Kou Yuhan;Yan Changxin;Wang Jinyuan;Ban Peichao;Zhang Dandan;Chen Kaiwen;Xie Chuanbin(Department of Radiotherapy,The First Medical Center,Chinese PLA General Hospital,Beijing 100053,China)

机构地区：[1]中国人民解放军总医院第一医学中心放射治疗科,北京100853

出　　处：《中国医学装备》2024年第11期1-6,共6页China Medical Equipment

基　　金：国家重点研发计划(2022YFC2409502,2022YFC2409503)。

摘　　要：目的:定量分析瓦里安Ethos自适应放射治疗(ART)系统上基于滤波反投影(FBP)和迭代重建(IR)技术的锥形束CT(CBCT)和迭代CBCT(iCBCT)的图像质量以及合成伪CT(sCT)的差异。方法:利用CT图像质量测试专用Catphan604模体,基于胸部扫描和腹部扫描完成CBCT和iCBCT各5次扫描,获取4套图像,每套图像包括CBCT图像、基于CBCT合成的sCT、iCBCT图像、基于iCBCT合成的sCT,分析其噪声功率谱(NPS)、图像均匀性指数(UI)、调制传递函数(MTF)、低对比度可见度(LCV)和对比度噪声比(CNR)。回顾性选取2023年8月至2024年5月解放军总医院第一医学中心收治的6例临床放疗患者,使用胸部扫描和腹部扫描获取6例患者的图像,分析基于CBCT和iCBCT图像形变配准所得sCT图像,并与定位CT图像进行对比,定量分析其绝对误差(MAE)和均方根误差(RMSE)。结果:iCBCT与CBCT相比,胸部图像NPS显著降低0.08,腹部图像降低0.06;iCBCT胸部、腹部图像UI分别为0.37和0.28,CBCT分别为0.65和0.39;iCBCT胸部、腹部图像LCV分别为0.67和0.56,CBCT分别为0.93和0.90;MTF50%除腹部iCBCT是0.29 lp/mm外,其余均为0.28 lp/mm,iCBCT和CBCT图像高对比度分辨率基本一致。基于CBCT和iCBCT生成的sCT与定位CT的相似度分析差异均无统计学意义(P>0.05)。结论:iCBCT图像质量优于传统CBCT,而基于CBCT和iCBCT生成的sCT,其CT值准确性皆符合要求,均可用于ART的剂量计算。Objective:To quantitatively analyze the differences in image quality and generated synthetic-computed tomography(sCT)between cone beam CT(CBCT)and iteration CBCT(iCBCT),which based on filtered back projection(FBP)and iterative reconstruction(IR)techniques of Varian Ethos adaption system.Methods:Using the special Catphan604 phantom of the test of CT image quality,five times of scanning series of CBCT and iCBCT were respectively performed based on thoracic and abdominal scanning protocols,so as to obtain four sets of images,and each set of image included the CBCT image,the composited sCT and iCBCT images based on CBCT,the composited sCT bases on iCBCT.The noise power spectrum(NPS),image uniformity(UI),modulation transfer function(MTF),low-contrast visibility(LCV)and contrast-to-noise ratio(CNR)of them were analyzed.Additionally,a retrospective analysis was conducted on images of six patients who underwent clinical radiotherapy,and the images of them were obtained by using thoracic and abdominal scanning protocols.The sCT images,which were generated by deformable registrations on the basis of CBCT and iCBCT,were analyzed,and they were compared with located CT images,and their mean absolute error(MAE)and root mean square error(RMSE)were further quantitatively analyzed.Results:Compared to CBCT,iCBCT significantly reduced NPS(thoracic images reduced by 0.08,abdominal images reduced by 0.06).The UI values of thoracic images and abdominal images of iCBCT were respectively 0.37 and 0.28,and those of CBCT were respectively 0.65 and 0.39.The LCV values of thoracic images and abdominal images of iCBCT were respectively 0.67 and 0.56,and those of CBCT were respectively 0.93 and 0.90.The MTF50%were 0.28 lp/mm except abdominal image of iCBCT was 0.29 lp/mm.The resolution rate of high contrast between iCBCT and CBCT was basic consistency.The differences of similarity analysis of the generated sCT and located CT bases on CBCT and iCBCT was no significant(P>0.05).Conclusion:The image quality of iCBCT is superior to conventional CB

关 键 词：自适应放射治疗(ART) 锥形束CT(CBCT) 迭代重建(IR)算法 图像质量 

分 类 号：R812[医药卫生—放射医学]