自MR-T2图像勾画肝细胞癌患者放疗靶区精度研究

Target delineation accuracy of tumors for radiotherapy based on MR-T2 image in patients with hepatocellular carcinoma

目的研究MRI-T2加权像扫描(MR-T2)图像对肝细胞癌(HCC)患者放疗靶区勾画精度的影响。方法2019年5月~2020年5月我院诊治的36例HCC患者,在接受放疗前行CT和MRI检查,勾画大体肿瘤体积(GTV),经形变配准后获得大体内靶区(IGTV)和计划靶区(PTV)。应用Reg Refine图像形变配准。记录2%、50%、95%和98%PTV体积的受照剂量(分别记为D2、D50、D95和D98)。结果经Reg Refine配准后,门静脉x、y和z轴向位移分别为(0.5±0.2)mm、(0.8±0.3)mm和(0.7±0.3)mm,显著小于自动形变配准[分别为(2.9±0.4)mm、(4.8±0.5)mm和(3.9±0.6)mm,P<0.05],腹腔干x、y和z轴向位移分别为(0.8±0.4)mm、(0.7±0.3)mm和(0.6±0.3)mm,显著小于自动形变配准[分别为(3.2±0.5)mm、(3.0±0.7)mm和(2.4±0.4)mm,P<0.05];形变配准后GTV和IGTV分别为(379.8±103.9)cm^(3)和(430.1±120.6)cm^(3),显著大于形变配准前[分别为(330.4±92.8)cm^(3)和(375.2±95.5)cm^(3),P<0.05],PTV为(542.7±130.2)cm^(3),显著小于形变配准前[(690.2±150.3)cm^(3),P<0.05];形变配准后D2、D50、D95和D98靶区剂量分别为(56.0±12.9)Gy、(53.0±6.8)Gy、(49.8±5.3)Gy和(52.9±8.1)Gy,与形变配准前[(55.7±13.2)Gy、(52.8±7.3)Gy、(50.1±4.6)Gy和(53.3±7.7)Gy]比,差异均无统计学意义(P>0.05);形变配准后肝脏V5、V10、V20、V30和V40受照剂量分别为(52.7±9.4)%、(32.0±5.6)%、(20.1±4.6)%、(13.5±5.2)%和(7.4±3.8)%,显著低于配准前[分别为(58.2±10.1)%、(39.3±7.5)%、(24.8±5.8)%、(17.2±4.4)%和(10.1±3.9)%,P<0.05]。结论应用MR-T2图像勾画HCC放疗靶区有助于扩大靶区范围和运动轨迹,提高肝癌靶区勾画精度。

Objective The aim of this study was to investigate the target delineation accuracy of tumors for radiotherapy based on MR-T2 image in patients with hepatocellular carcinoma(HCC).Methods 36 patients with HCC were enrolled in this study between May 2019 and May 2020,and all patients underwent CT and MRI scan before radiotherapy.The gross tumor volume(GTV),internal gross tumor target volume(IGTV)and planning target volume(PTV)as well as 2%,50%,95%and 98%exposure dose of PTV(D2,D50,D95 and D98)were recorded.Results The x,y and z axial displacements of portal vein after Reg refine registration were(0.5±0.2)mm,(0.8±0.3)mm and(0.7±0.3)mm,significantly smaller than[(2.9±0.4)mm,(4.8±0.5)mm and(3.9±0.6)mm,respectively,P<0.05]by automatic deformation registration,and the x,y and z axial displacements of celiac trunk were(0.8±0.4)mm,(0.7±0.3)mm and(0.6±0.3)mm,significantly smaller than[(3.2±0.5)mm,(3.0±0.7)mm and(2.4±0.4)mm,respectively,P<0.05]by automatic deformation registration;the GTV and IGTV after deformation registration were(379.8±103.9)cm^(3) and(430.1±120.6)cm^(3),significantly larger than[(330.4±92.8)cm^(3) and(375.2±95.5)cm^(3),P<0.05]before deformation registration,while the PTV was(542.7±130.2)cm^(3),significantly smaller than[(690.2±150.3)cm^(3),P<0.05]before deformation registration;the exposure doses of D2,D50,D95 and D98 target tumors after deformation registration were(56.0±12.9)Gy,(53.0±6.8)Gy,(49.8±5.3)Gy and(52.9±8.1)Gy,not significantly different compared to[(55.7±13.2)Gy,(52.8±7.3)Gy,(50.1±4.6)Gy and(53.3±7.7)Gy]before deformation registration(P>0.05);the V5,V10,V20,V30 and V40 exposure doses of liver after deformation registration were(52.7±9.4)%,(32.0±5.6)%,(20.1±4.6)%,(13.5±5.2)%and(7.4±3.8)%,significantly lower than[(58.2±10.1)%,(39.3±7.5)%,(24.8±5.8)%,(17.2±4.4)%and(10.1±3.9)%,P<0.05]before deformation registration.Conclusion The target delineation based on MR-T2 imaging for radiotherapy in patients with HCC could help expand the target area and trajectory,and improve the accuracy of target delineation,which might improve the radiotherapy efficacy.