四维CT量化膈顶运动准确性和放疗前后呼吸运动稳定性临床验证

目的验证四维CT(4DCT)信息能否代表呼吸运动的实际情况,患者放疗前后呼吸活动是否有明显变化而影响4DCT在放疗中的应用。方法67例胸部肿瘤患者在GE discovery 16-slice PET/CT上行4DCT扫描,在AW 4.2 4D Advantage Sim 6.0工作站设计放疗计划。模拟机透视下观察放疗前后的呼吸频率、左右膈肌运动幅度、因呼吸不平稳导致膈肌运动超出4DCT测定范围的次数(脱靶率),比较呼吸频率和左右膈肌运动幅度在4DCT重建和模拟机透视下的差异。结果67例中58例能够重建出呼吸运动,其中32例放疗前后进行模拟机透视。放疗前后透视下呼吸频率和左右膈肌运动幅度的差异无统计学意义(P>0.100);4DCT重建与透视观察的呼吸频率差异无统计学意义(P>0.100);放疗前后脱靶率的差异有统计学意义(P<0.05);4DCT重建与透视下左右膈肌运动幅度的差异有统计学意义(P<0.05)。结论胸部肿瘤患者放疗前后呼吸状态基本一致,稳定性好;4DCT重建图像与患者呼吸保持一致性,但可能会遗漏部分信息。

Clinical verification of the accuracy of quantitative diaphragmatic dome movement on four-dimensional CT scan and the stabilization of respiratory movement before and after radiotherappy

Objective To verify the fidelity of four dimensional CT(4DCT) in assessing respiratory movement, and evaluate the influence of respiratory change between pre- and post-radiotherapy on 4DCT ap- plication in radiotherapy. Methods Patients with thoracic cancer received 4DCT scan with GE discovery 16-slice PET/CT. Radiotherapy plan was designed on AW 4.2 4D Advantage Sim 6.0 workstation. Respira- tory frequency, bilateral diaphragmatic amplitude and dis-target rate observed by 4DCT and X-ray fluorosco- py simulator were compared by paired-samples t-test. Results Totally 67 patients received 4DCT scan, including 54 males and 13 females. Reconstruction of respiratory movement was made in 87% (58/67) pa- tients, among whom 32 patients received fluoroscopy before and after radiotherapy. No statistically significant difference was observed in respiratory frequency and bilateral diaphragmatic amplitude between pre- and post- radiotherapy, or in the respiratory frequency between 4DCT reconstruction and fluoroscopy (P>0.1). Sta- tistically significant differences were observed in dis-target rate between pre- and post-radiotherapy, and in bilateral diaphragmatic amplitude between 4DCT reconstruction and fluoroscopy (P<0.05). Conclusions Respiratory status is fairly stable between pre- and post- radiotherapy in patients with thoracic carcinoma. The reconstruction image by 4DCT is conformal with the respiratory movement, but some information may be left out.