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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。
Objective To verify whether four-dimensional CT (4DCT) information can represent the actual situation of respiratory motion and whether there is a significant change in respiratory activity before and after radiotherapy, which affects the application of 4DCT in radiotherapy. Methods Sixty-seven patients with thoracic tumors were screened by GE Discovery 16-slice PET / CT for 4DCT scan, and AW 4.2 4D Advantage Sim 6.0 workstation was designed for radiotherapy. Simulations were performed to observe the respiratory rate before and after radiotherapy, the amplitude of left and right diaphragms, the frequency of diaphragmatic motion beyond the 4DCT range due to unsteady breathing (off-target rate), and the respiration rate and the amplitude of left and right diaphragms were compared under 4DCT reconstruction and simulator fluoroscopy The difference. Results Of 67 cases, 58 cases were able to reconstruct the respiratory movement, of which 32 cases were simulated before and after radiotherapy. There were no significant differences in the respiratory rate before and after radiography and the amplitude of left and right diaphragmatic motion (P> 0.100). There was no significant difference in respiratory rate between 4DCT and fluoroscopy (P> 0.100) (P <0.05). There was a significant difference in the amplitude of diaphragm motion between 4DCT reconstruction and fluoroscopy (P <0.05). Conclusions The respiratory status of patients with chest tumor before and after radiotherapy is basically the same, and the stability is good. The 4DCT reconstructed images are consistent with the patient’s breathing, but some information may be missed.