肝癌磁共振引导放疗新型腹部加压技术应用研究

Study of new abdominal pressure technique in magnetic resonance guided radiotherapy for liver cancer

目的 探讨磁共振兼容的新型腹压带固定装置在磁共振加速器肝癌放射治疗中的临床应用可行性。方法 随机选取30例山东省肿瘤医院2021-04-21-2022-04-18在医科达磁共振加速器(MR-Linac)接受放射治疗的肝癌患者。所有患者均采用真空负压袋固定体位进行MRI T2加权图像(T2WI)扫描,获取第1次MRI T2WI,与定位CT自动配准至系统最佳,获取三维方向误差数据,作为对照组;使用新型腹压带,获取第2次MRI T2WI,与定位CT自动配准至系统最佳,获取三维方向误差数据,作为实验组。测量2组肝脏上界在每次动态MRI T2WI头脚(SI)方向的最大位移距离。所有摆位误差的数据均行2组间的t或Z检验。结果 2组在左右(LR)方向上线性误差绝对值>0.5 cm的次数相同,且差异无统计学意义,Z=0.00,P=1.00。实验组在腹背(AP)和SI方向上线性误差绝对值>0.5 cm的次数明显少于对照组,Z值分别为-14.56和-15.65,均P<0.01。实验组LR、AP和SI方向摆位误差分别为(-0.17±0.30)、(0.01±0.58)和(0.22±0.66) cm,对照组分别为(-0.24±1.96)、(-0.02±0.58)和(-0.32±0.67) cm,Z值分别为-0.99、2.93和4.86,P值分别为0.33、0.01和<0.01。实验组和对照组肝脏在SI方向的运动幅度分别为(1.53±0.28)和(2.53±0.41) cm,差异有统计学意义,t=40.71,P<0.01。结论 磁共振兼容的新型腹压带装置能够减少肝脏肿瘤运动,降低摆位误差,提高患者的治疗精度。

Objective To explore the clinical feasibility of the MR-compatible novel abdominal pressure tape fixation device in the MR accelerator HCC radiation therapy.Methods A total of 30patients with liver cancer who received radiation treatment at the magnetic resonance accelerator(MR-Linac)from April 21,2021to April 18,2022were randomly selected.All patients underwent a MRI T2-weighted image(T2WI)scanning with a vacuum negative pressure bag for position fixation to obtain the first MRI T2WI,automatic registration with the positioning CT to the best system,to obtain 3Ddirection error data,as the control group;using the new abdominal pressure band,obtaining the second MRI T2WI,automatically register with the positioning CT to the best system,obtain the 3Ddirection error data as the experimental group;the maximum displacement distance of the upper liver boundary of the two groups in the direction of each dynamic MRI T2WI was measured.Data for all pendulum error were tested as either t-test or Z-test between two groups.Results The absolute value of the linear error>0.5cm in the left-right(LR)direction was the same times,and the difference was not statistically significant(Z=0.00,P=1.00).In the experimental group,the absolute values of linear errors >0.5cm in the anterior-posterior(AP)and suprior-inferior(SI)direction were significantly less than in the control group(Z=-14.56,P<0.01)and(Z=-15.65,P<0.01).The positioning errors of LR,AP and SI were(-0.17±0.30),(0.01±0.58)and(0.22±0.66)cm in the experimental group,and(-0.24±1.96),(-0.02±0.58)and(-0.32±0.67)cm in the control group,respectively.The difference was statistically significant(Z=-0.99,P=0.33;Z=2.93,P=0.01;Z=4.86,P<0.01).The motion amplitude of the liver in the SI direction in the experimental group and the control group were(1.53±0.28)and(2.53±0.41)cm respectively,and the difference was statistically significant(t=40.71,P<0.01).Conclusion Magnetic resonance compatible new abdominal pressure belt device can reduce liver tumor movement,reduce pendulum error,and improve the treatment accuracy of patients.