A Proposed Cone Beam Version of Electron Beam CT

Abstract

Electron Beam CT (EBCT) is an ultra-fast variant of CT intended for cardiac imaging. The method employs a scanning electron beam x-ray source and a stationary detector. The prevailing form of EBCT uses a fan beam acquisition geometry and produces slice images. Volumes must be imaged slice by slice. In this paper, a cone beam version of EBCT is proposed. The underlying cone beam EBCT scanner has the same general layout as a fan beam EBCT scanner. Its distinctive features are the special curvature of the target ring scanned by the electron beam, a specially curved collimator slit, and a specially curved detector strip. Owing to the special geometry of the proposed source/detector arrangement, the cone beams emanating from the target ring are not blocked by intervening portions of the detector strip. The measured cone beam projections are axially, but not transversely, truncated. Suitable reconstruction algorithms for the resulting reconstruction problem are available. The proposed cone beam version of EBCT is able to acquire a full set of cone beam projections of a sizeable volume of interest with a single sweep of the electron beam along the target ring and to reconstruct a three-dimensional image of this volume with a fine, isotropoic resolution.