| Title | Exact reconstruction for unequally spaced triple-source helical cone-beam CT |
| Authors | Jin, Yannan Zhao, Jun Jiang, Ming Zhuang, Tiange Wang, Ge |
| Affiliation | Department of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, 200030, China LMAM, School of Mathematical Sciences, Peking University, Beijing 100871, China Department of Radiology, University of Iowa, Iowa City, IA 52242, United States |
| Issue Date | 2006 |
| Citation | Developments in X-Ray Tomography V.San Diego, CA, United states,6318. |
| Abstract | In a previous study, we proposed a helical scanning configuration with triple X-ray sources symmetrically positioned and established its reconstruction algorithm. Although symmetrically positioned sources are convenient in practice, artifacts can be produced in a reconstructed image if the physical sources are not equally spaced. In this work, we develop an exact backprojection filtration (BPF) type algorithm for the configuration with unequally spaced triple sources to reduce the artifacts. Similar to the Tam-Danielsson window, we define the minimum detection window as the region bounded by the most adjacent turns of two helices. The sum of the heights of the three consequent minimum detection windows is equal to that of the traditional Tam-Danielsson window for a single source. Furthermore, we prove that inter-helix PI-lines satisfy the existence and uniqueness properties (i.e., through any point inside the triple helices, there exists one and only one inter-helix PI-line for any pair of helices). The proposed algorithm is of the backprojection-filtration (BPF) type and can be implemented in three steps: 1) differentiation of the cone-beam projection from each source; 2) weighted backprojection of the derivates on the inter-helix PI-arcs; 3) inverse Hilbert transformation along one of the three inter-helix PI-lines. Numerical simulations with 3D Shepp-Logan phantoms are performed to validate the algorithm. We also demonstrate that artifacts are generated when the algorithm for the symmetric configuration is applied to the unequally spaced helices setting. |
| URI | http://hdl.handle.net/20.500.11897/328078 |
| DOI | 10.1117/12.681398 |
| Indexed | EI |
| Appears in Collections: | 数学科学学院 数学及其应用教育部重点实验室 |
