自由呼吸频率与运动幅度对CT与CBCT图像配准偏差分析  

Analysis of the registration deviation between CT and CBCT images with different breathing rates and motion amplitudes in the state of free breathing

作　　者：魏星[1] 徐欣 白龙 龚攀 钟仁明 Wei Xing;Xu Xin;Bai Long;Gong Pan;Zhong Renming(Division of Radio-chemotherapy for Oncology,West China Second University Hospital,Sichuan University,Key Laboratory of Birth Defects and Related Diseases of Women and Children(Sichuan University),Ministry of Education,Chengdu 610041,China)

机构地区：[1]四川大学华西第二医院肿瘤放化疗科/出生缺陷与相关妇儿疾病教育部重点实验室,成都610041

出　　处：《中华放射肿瘤学杂志》2022年第7期628-632,共5页Chinese Journal of Radiation Oncology

摘　　要：目的探讨自由呼吸状态下,不同呼吸频率、运动幅度对CT扫描图像与CBCT图像的配准偏差。方法使用QUASAR呼吸运动模体,改变运动频率和头脚方向上的运动幅度,模拟不同状态下的自由呼吸运动。在模体静止时、各种运动状态下分别行定位CT扫描和CBCT扫描,获取相应配准结果及CT定位靶区体积,进行定量分析。结果以模体静止时的定位CT图像为参考进行配准,当运动幅度一定时,频率的变化对图像的配准误差无明显影响。运动幅度分别为5 mm、10 mm、20 mm、30 mm时,配准误差分别为(0.213±0.020)cm、(0.351±0.009)cm、(0.654±0.010)cm与(0.972±0.022)cm。当运动幅度为5 mm、10 mm时,定位靶区体积变化为-16.92%~18.78%。当运动幅度为20 mm、30 mm时,定位靶区体积变化为-16.44%~81.70%。结论自由呼吸运动下频率变化对CBCT与定位CT图像之间的配准误差无明显影响。运动幅度为5 mm、10 mm时,配准误差小,定位靶区体积变化小;当运动幅度为20 mm、30 mm时,配准误差可超过0.5 cm,定位靶区体积变化可>20%。Objective To quantify the registration deviation between CT and cone-beam computed tomography(CBCT)images with different breathing rates and motion amplitudes under free breathing state.Methods Using the QUASAR respiratory motion phantom,breathing rate and motion amplitude in the superior-inferior(SI)direction were changed to simulate free breathing motion under different states.The CT and CBCT images were acquired under different breathing rates and motion amplitudes,and static states,then the registration errors between CT and CBCT images and CT target volume were obtained and subject to quantitative analysis.Results Using the static CT image as a reference,the changes in breathing rate exerted no significant effect on the registration error when the motion amplitude was constant.When the motion amplitude was 0.5,1.0,2.0,and 3.0 cm,the average registration errors were(0.213±0.020),(0.351±0.009),(0.654±0.010),and(0.972±0.022)cm,respectively.When the motion amplitude was 0.5 and 1.0 cm,the CT target volume varied from-16.92%to 18.78%.When the motion amplitude was 2.0 and 3.0 cm,the CT target volume changed from-16.44%to 81.78%.Conclusions The changes in breathing rate under free-breathing state has no significant effect on the registration error between CBCT and CT images.When the motion amplitude is 0.5 and 1.0 cm,the CT target volume changes and the registration errors are small.When themotion amplitude is 2.0 and 3.0 cm,the registration errors exceed 0.5 cm and the CT target volume changes may exceed 20%.

关 键 词：自由呼吸 图像配准 靶区体积 锥形束CT 

分 类 号：R816[医药卫生—放射医学]