We consider detection of a small signal in fan-beam x-ray computed tomography (CT). In order to characterize the loss of intrinsic signal detectability from the projection data (sinogram) domain to the reconstructed image, we analyze the Hotelling observer SNR in each domain. Further, we characterize the loss of Hotelling observer SNR through decomposition into two components: loss of signal detectability which arises due to unequal variance in the noise of separate detector elements and loss of detectability arising from the fact that some noiseless signals have components which lie in the nullspace of a given reconstruction operator. The proposed methodology is investigated for the back-projection ltration (BPF) algorithm developed by our group [2].

Date Published: 28 March 2013
PDF: 4 pages
Proc. SPIE 8673, Medical Imaging 2013: Image Perception, Observer Performance, and Technology Assessment, 86731P (28 March 2013); doi: 10.1117/12.2007179

Published in SPIE Proceedings Vol. 8673:
Medical Imaging 2013: Image Perception, Observer Performance, and Technology Assessment
Craig K. Abbey; Claudia R. Mello-Thoms, Editor(s)