摘要
目的结合四维CT(four-dimension computed tomography,4D-CT)技术,应用自由变形模型(free form deformation,FFD)形变配准算法分析呼吸运动对原发性肝癌患者肝脏及其靶区形态的影响。方法选取2010-08-01-2011-08-30山东省肿瘤医院8例接受放疗的原发性肝癌患者,获得患者4D-CT的模拟定位图像,将4D-CT图像依据呼吸周期均分为CT0、CT10、CT20、CT30、CT40、CT50、CT60、CT70、CT80和CT9010套CT图像。以呼气末时相图像CT50为参考图像,其他9幅图像采用基于B样条的自由变形模型FFD算法与其配准。然后用差分位图、Hausdroff距离及互信息技术分析呼吸运动对肝脏及其肿瘤形态的影响。结果从一个完整呼吸周期10个时相的CT图像及差分位图可以看出,呼吸运动对正常肝脏及肿瘤靶区形态造成的影响,其中吸气末和呼气末的变化最大。基于B样条的多分辨率网格自由变形模型FFD形变配准算法,可有效实现不同CT图像间的形变配准。其将肝脏和肿瘤靶区配准前CT0与CT50的Hausdroff距离由0.091 4减小到0.043 2,平均减小了54.1%;互信息从0.789 0提高到0.814 0;平均提高了3.17%。结论呼吸运动造成的肝脏及其肿瘤靶区的形变是显著的,基于B样条的多分辨率网格自由变形模型FFD形变配准算法可有效实现4D-CT图像间的形变配准。
OBJECTIVE Combined with four-dimension computed tomography （4D-CT）, we used free form deformable registration algorithm to discuss morphology of normal liver and tumor by breathing motion of hepatocellular carcinoma patients. METHODS Eight hepatocellular carcinoma patients from Shandong Cancer Hospital 2010-08-01- 2011-08-30 accepted radiotherapy were selected, then acquire 4D-CT simulate positioning images and 4D CT images were segmented into 10-series CT images which were named CT0 ,CT10 ,CT20 ,C%0 ,CT40 ,CT50 ,CT60 ,CT70 ,CT80 ,CT90 according to the respiratory phases. The free form deformable （FFD） model was used based on Prspline grid registration method to deform the other 9 set-image to CT50 and limited-memory Broyden Fletcher Goldfarb Shannon minimization （L BFGS） was utilized to enhance the registration accuracy and speed. Then the subtractions hausdroff distance and multi-information were used to analyze the influence of normal liver and tumor targets from breathing motion. RESULTS By the 10-series CT images and subtractions,We found the influence of mor- phology of normal liver and tumor targets from a whole breathing cycle was obvious, and the difference between CT0 and CT50 is the biggest. The FFD model based on B-spline grid registration method could deform 4D-CT images effectively. The hausdroff distance between CT0 and CT50 of normal liver and tumors was from 0. 091 4 to 0. 043 2 after registration, the average improvement proportion was 54.1%, and the multi-information was from 0. 789 0 to 0. 814 0, the average improvement proportion was 3.17%. CONCLUSIONS The breathing movement for deformation of normal liver and tumor targets is not ignored, and the FFD model based on B-spline grid registration method can deform 4D-CT images effectively.
出处
《中华肿瘤防治杂志》
CAS
北大核心
2015年第1期54-58,65,共6页
Chinese Journal of Cancer Prevention and Treatment
基金
国家自然科学基金(81272699)
山东省自然科学基金(ZR2009CL032
ZR2011HL060)
关键词
肝肿瘤
放射性肝损伤
四维CT
自由变形模型FFD
碘油辅助
liver neoplasms
radiation-induced liver disease
four-dimensional computed tomography
free form deformable model
iodipin-assisted
