MRI用于脑肿瘤评估，而CT用于放射治疗模拟。本研究评估了固定设备对CT-MRI配准准确性和RT设置下MR图像质量的影响。我们包括了11名高级别胶质瘤患者的CT和MR图像，所有患者均使用热塑性面罩和头枕进行固定。使用MR头线圈在诊断设置（DS）和RT设置中采集了T1加权和T2加权MR图像。为了评估MR图像质量，我们考虑了一些感兴趣区域中的信噪比（SNR）和对比噪声比（CNR）。我们还使用线轮廓和外部轮廓方法评估了固定设备对CT-MRI刚性配准的影响。 CT-DS MRI和CT-RT MRI配准的Dice相似系数（DSC）分别为0.84和0.92。RT设置中的CNR和SNR降低是由于成像区域的解剖结构及其相对于应用线圈的位置而造成的。此现象在T1加权图像中比T2加权图像更为明显。T1加权图像的SNR下降了14.91%，而CNR下降了25.12%；T2加权图像的SNR下降了12.09%，而CNR下降了20.15%。RT设置中的固定设备使刚性配准的平均误差降低了1.02毫米。 图像质量在RT设置中的降低是由于成像区域的解剖和其相对于应用线圈的位置。此外，优化脉冲序列对于RT应用的MR成像至关重要。虽然在RT设置中使用固定设备可能会降低图像质量，但不会影响器官轮廓的确定，图像质量仍然令人满意。此外，RT设置中使用固定设备可以提高配准的准确性。 © 2023 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, LLC on behalf of The American Association of Physicists in Medicine.

MRI is preferred for brain tumor assessment, while CT is used for radiotherapy simulation. This study evaluated immobilization equipment's impact on CT-MRI registration accuracy and MR image quality in RT setup.We included CT and MR images from 11 patients with high-grade glioma, all of whom were immobilized with a thermoplastic mask and headrest. T1- and T2-weighted MR images were acquired using an MR head coil in a diagnostic setup (DS) and a body matrix coil in RT setup. To assess MR image quality, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were considered in some dedicated regions of interest. We also evaluated the impact of immobilization equipment on CT-MRI rigid registration using line profile and external contour methods.The CNR and SNR reduction was in the RT setup of imaging. This was more evident in T1-weighted images than in T2-weighted ones. The SNR decreased by 14.91% and 12.09%, while CNR decreased by 25.12% and 20.15% in T1- and T2-weighted images, respectively. The immobilization equipment in the RT setup decreased the mean error in rigid registration by 1.02 mm. The external contour method yielded Dice similarity coefficients (DSC) of 0.84 and 0.92 for CT-DS MRI and CT-RT MRI registration, respectively.The image quality reduction in the RT setup was due to the imaged region's anatomy and its position relative to the applied coil. Furthermore, optimizing the pulse sequence is crucial for MR imaging in RT applications. Although the use of immobilization equipment may decrease the image quality in the RT setup, it does not affect organ delineation, and the image quality is still satisfactory for this purpose. Also, the use of immobilization equipment in the RT setup has increased registration accuracy.© 2023 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, LLC on behalf of The American Association of Physicists in Medicine.