International Journal of Biomedical Imaging 
Volume 2006 (2006), Article ID 10427, 9 pages
doi:10.1155/IJBI/2006/10427

A General Formula for Fan-Beam Lambda Tomography

Hengyong Yu and Ge Wang

CT/Micro-CT Laboratory, Department of Radiology, The University of Iowa, Iowa City 52242, IA, USA

Received 4 September 2005; Revised 12 November 2005; Accepted 12 November 2005

Recommended by Guowei Wei

Abstract

Lambda tomography (LT) is to reconstruct a gradient-like image of an object only from local projection data. It is potentially an important technology for medical X-ray computed tomography (CT) at a reduced radiation dose. In this paper, we prove the first general formula for exact and efficient fan-beam LT from data collected along any smooth curve based on even and odd data extensions. As a result, an LT image can be reconstructed without involving any data extension. This implies that structures outside a scanning trajectory do not affect the exact reconstruction of points inside the trajectory even if the data may be measured through the outside features. The algorithm is simulated in a collinear coordinate system. The results support our theoretical analysis.