Department of Radiation Medicine, University of Kentucky, Lexington, KY, USA.
Department of Radiology, University of Kentucky, Lexington, KY, USA.
J Xray Sci Technol. 2018;26(2):303-309. doi: 10.3233/XST-17329.
Active x-ray collimation is well adopted in radiography and fluoroscopy for radiation dose reduction and image quality improvement. The application of this concept in computed tomography (CT) is significantly limited due to the truncation of projection data. Generally, an internal field of view (FOV) inside an imaging object cannot be exactly reconstructed only from the truncated projection data. Recent research shows that given some prior information of the FOV image, interior tomography can provide a unique and stable solution for image reconstruction of an internal FOV. The objective of this study is to evaluate the performance of interior reconstruction based on patient datasets obtained from a clinical CT scanner with dual x-ray tubes, which simultaneously gives full projections and truncated projections. Image reconstructions are performed from full and truncated projection data for the comparison of image quality, respectively. The reconstructed CT images were reviewed by a radiologist and a resident. The evaluation results of two observers showed that CT images reconstructed with truncated projections met clinically diagnostic requirements and were comparable to clinical images. This study demonstrates that with the development of interior tomography, active x-ray collimation in the imaging plane can be readily employed in CT imaging to further reduce patient radiation and improve image quality.
主动式射线准直在放射摄影和透视中被广泛应用，以降低辐射剂量并改善图像质量。由于投影数据的截断，该概念在计算机断层扫描（CT）中的应用受到了显著限制。通常情况下，仅从截断的投影数据无法准确重建成像物体内部的视野（FOV）。最近的研究表明，给定 FOV 图像的一些先验信息，内部层析成像可以为内部 FOV 的图像重建提供独特且稳定的解决方案。本研究旨在评估基于临床 CT 扫描仪（具有两个 X 射线管，可同时提供完整投影和截断投影）获得的患者数据集的内部重建性能。分别从完整和截断的投影数据进行图像重建，以比较图像质量。由放射科医生和住院医师对重建的 CT 图像进行了评估。两位观察者的评估结果表明，使用截断投影重建的 CT 图像符合临床诊断要求，与临床图像相当。这项研究表明，随着内部层析成像的发展，成像平面中的主动式射线准直可以在 CT 成像中得到广泛应用，以进一步降低患者的辐射剂量并提高图像质量。
