Local tomography property of residual minimization reconstruction with planar integral data

Abstract

Residual minimization with the well-known conjugate gradient (CG) algorithm has been applied to medical image reconstruction for years. The main advantage of this method is its fast convergence rate. In this paper, we point out that this method has another property-local tomography, when this image reconstruction method is applied to planar integral projections. By local tomography we mean the following: The object is relatively large, the entire object is not sufficiently measured, and the projections are truncated due to a small detector size. However, a small region-of-interest (ROI) is sufficiently measured. The small ROI is able to be exactly reconstructed. This local tomographic property is found for planar integral data only and is not found for line-integral measurements. Iterative local tomography has been applied to cos weighted planar integral data through computer simulations and phantom experiments. An efficient projector that models the cos weighting factor is also developed.

Tomographic image quality of rotating slat versus parallel hole-collimated SPECT

“…Analytic reconstruction methods for planar and tomographic acquisitions have been derived by Lodge (Lodge et al 1995, Lodge et al 1996. A 3D iterative reconstruction algorithm for the SOLSTICE camera has been proposed by Wang (Wang et al 2004) and by Zeng (Zeng et al 2003). A drawback of reconstructing plane integral data measured by a rotating slat collimator, to 3D images is the much longer computation time needed compared to a parallel hole reconstruction.…”

“…Analytic reconstruction methods for planar and tomographic acquisitions have been derived by Lodge (Lodge et al 1995(Lodge et al , 1996. A 3D iterative reconstruction algorithm for the SOLSTICE camera has been proposed by Wang (Wang et al 2004) and Zeng (Zeng et al 2003).…”

System characteristics of SPECT with a slat collimated strip detector

“…In contrast, if non-rectangular slats were used (e.g., circular slats like shown in figures of Zeng et al (2003)) this will not result in equal resolution in a plane parallel to the detection/collimator system. The resolution was calculated along three different lines perpendicular to the detector/collimator system (see figure 3).…”

Small field-of-view cardiac SPECT can be implemented on hybrid SPECT/CT platforms where data acquisition and reconstruction are guided by CT

“…However, the primary detractor to the acceptance of solid-state technology is high cost both for raw material and fabrication. Consequently, in an effort to reduce costs, several groups have explored the concept of using small detectors [5,6]. The challenge associated with reduced detector size is object truncation.…”