Affiliations: [a] Department of Radiation Medicine, University of Kentucky, Lexington, KY, USA
| [b] Department of Radiology, University of Kentucky, Lexington, KY, USA
| [c] Biomedical Imaging Center, Rensselaer Polytechnic Institute, Troy, NY, USA
Correspondence:
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Corresponding author: Jie Zhang, PhD, DABR, Associate Professor Chief, Division of Medical Physics, Department of Radiology, University of Kentucky, 800 Rose Street, Room HX 311A, Lexington, KY 40536-0293, USA. Tel.: +1 859 323 2146; Fax: +1 859 257 4480; E-mail: jnzh222@uky.edu.
Abstract: 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.
Keywords: Active x-ray collimation, computed tomography (CT) image reconstruction, internal field of view in CT images, interior tomography
