Document Type
Article
Language
eng
Format of Original
12 p.
Publication Date
6-2006
Publisher
American Association of Physicists in Medicine
Source Publication
Medical Physics
Source ISSN
0094-2405
Original Item ID
doi: 10.1118/1.2192887
Abstract
A table-top volumetric CT system has been implemented that is able to image a 5-cm-thick volume in one circular scan with no cone-beam artifacts. The prototype inverse-geometry CT (IGCT) scanner consists of a large-area, scanned x-ray source and a detector array that is smaller in the transverse direction. The IGCT geometry provides sufficient volumetric sampling because the source and detector have the same axial, or slice direction, extent. This paper describes the implementation of the table-top IGCT scanner, which is based on the NexRay Scanning-Beam Digital X-ray system (NexRay, Inc., Los Gatos, CA) and an investigation of the system performance. The alignment and flat-field calibration procedures are described, along with a summary of the reconstruction algorithm. The resolution and noise performance of the prototype IGCT system are studied through experiments and further supported by analytical predictions and simulations. To study the presence of cone-beam artifacts, a “Defrise” phantom was scanned on both the prototype IGCT scanner and a micro CT system with a ±5° cone angle for a 4.5-cm volume thickness. Images of inner ear specimens are presented and compared to those from clinical CT systems. Results showed that the prototype IGCT system has a 0.25-mm isotropic resolution and that noise comparable to that from a clinical scanner with equivalent spatial resolution is achievable. The measured MTF and noise values agreed reasonably well with theoretical predictions and computer simulations. The IGCT system was able to faithfully reconstruct the laminated pattern of the Defrise phantom while the micro CT system suffered severe cone-beam artifacts for the same object. The inner ear acquisition verified that the IGCT system can image a complex anatomical object, and the resulting images exhibited more high-resolution details than the clinical CT acquisition. Overall, the successful implementation of the prototype system supports the IGCT concept for single-rotation volumetric scanning free from cone-beam artifacts.
Recommended Citation
Schmidt, Taly Gilat; Star-Lack, Josh; Bennett, N. Robert; Mazin, Samuel R.; Solomon, Edward G.; Fahrig, Rebecca; and Pelc, Norbert J., "A Prototype Table-Top Inverse-Geometry Volumetric CT System" (2006). Biomedical Engineering Faculty Research and Publications. 76.
https://epublications.marquette.edu/bioengin_fac/76
ADA Accessible Version
Comments
Accepted version. Medical Physics, Vol. 33, No. 6 (June 2006): 1867-1878. DOI. © 2006 American Association of Physicists in Medicine. Used with permission.