4DCT与MR-T2图像形变配准引导原发性肝癌精确放疗的应用研究

发布时间：2018-03-24 11:00

本文选题：4DCT　切入点：形变配准　出处：《济南大学》2017年硕士论文

【摘要】：目的:研究应用形变配准技术联合4DCT和MR-T2图像进行肝癌IGTV制定的可行性,并分析该方法在HCC放疗中的剂量学特点。方法:选择2015-2016年间首次放疗的HCC患者10例,依次完成自由呼吸下4DCT扫描,深吸气状态下MR-T2像扫描,将4DCT依呼吸时相分为10个序列。应用MIM软件进行图像配准,评价指标为门静脉、腹腔干在三维方向的最大位移及肝脏交叠度。在各时相CT图像上勾画GTV,将4DCT各时相GTV融合为IGTV;将MR-T2图像形变配准到4DCT各时相图像上,获得10个GTVDR,并融合为IGTVDR。将IGTV与IGTVDR分别形变到CT00时相上,分别外扩安全边界得到PTV和PTVDR,以在此相位图像上进行放疗计划设计。配对t检验比较不同靶区体积和靶区、肝脏剂量差异。结果:门静脉和腹腔干在x、y、z轴向位移分别为(0.3±0.8)、(0.5±1.5)、(0.7±1.2)mm和(0.8±1.8)、(0.1±1.0)、(0.6±2.0)mm。肝脏交叠度为(115.4±13.8)%。形变配准后4DCT各时相GTV均大于配准前,平均增加8.18%(P0.05),且各分时相形变后的GTV与MR-T2图像中勾画体积基本一致。IGTVDR显著大于形变配准前IGTV体积,平均增加了9.67%(P0.05)。形变配准前PTV体积为626.76±494.12cm3,形变配准后PTVDR体积为528.87±441.58cm3,体积小于形变配准前,平均减少了15.65%。靶区D2、D98、D50、D95和CI、HI差异无统计学意义。形变配准后肝脏V5、V10、V20、V30、V40和平均剂量(Dmean)受量均低于形变配准前,分别降低5.92%、8.17%、8.04%、12.15%、9.98%和9.56%,差异有统计学意义。结论:MR图像能显示比CT更多的信息且表现出更高对比度。勾画GTV时应将MR图像与4DCT图像相结合,基于此获得的IGTV可更好地确定靶区范围和运动轨迹,提高肝癌靶区勾画精度。由此形成的剂量分布可降低正常肝脏的受照剂量。
[Abstract]:Objective: to study the feasibility of using deformational registration technique combined with 4DCT and MR-T2 images in the formulation of liver cancer IGTV, and to analyze the dosimetric characteristics of this method in HCC radiotherapy. Methods: ten patients with HCC were selected for the first time in 2015-2016. The 4DCT was divided into 10 sequences according to the breathing phase. The image registration was carried out by MIM software. The evaluation index was portal vein, portal vein, portal vein, portal vein, portal vein, portal vein, portal vein, portal vein, portal vein, portal vein, portal vein, portal vein and so on. The maximum displacement of the celiac trunk in three dimensional direction and the degree of hepatic overlap. The GTV of each phase of 4DCT was fused to IGTV on CT images of each phase of 4DCT, and the deformation of MR-T2 images was registered to the images of each phase of 4DCT. Ten GTVDRs were obtained and fused to IGTV DR.The IGTV and IGTVDR were deformed to the CT00 phase respectively, and the PTV and PTVDRs were obtained by expanding the security boundary, respectively, for the design of radiotherapy plan on this phase image. T test was used to compare the different target volume and target area. Results: the axial displacement of portal vein and celiac trunk in xanyyong z was 0. 3 卤0. 8 ~ 0. 5 卤1. 5 ~ 0. 5 卤0. 7 卤1.2)mm and 0. 8 卤1. 8 卤1. 0 卤1. 0 卤2. 0 mmm. the degree of hepatic overlap was 11. 4 卤13. 8. The GTV of each phase of 4DCT after deformation registration was higher than that before registration. The mean volume of GTV and MR-T2 images was basically the same. IGTVDR was significantly larger than that of IGTV before deformation registration. The volume of PTV before deformation registration is 626.76 卤494.12 cm 3, and the volume of PTVDR after deformation registration is 528.87 卤441.58 cm 3, which is smaller than that before deformation registration. There was no significant difference between the target area D2OD98 D50D95 and CIHI. After deformed registration, the liver V5 V10 V20 V20 V30 V40 and mean dose Dmean were lower than those before deformation registration. The difference is statistically significant. Conclusion GTV images can show more information than CT and show higher contrast. When drawing GTV, we should combine Mr images with 4DCT images. The obtained IGTV can better determine the target area and track of motion and improve the precision of drawing target area of liver cancer. The resulting dose distribution can reduce the radiation dose of normal liver.
【学位授予单位】：济南大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：R735.7;R730.55

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