Reconstructing uniformly attenuated rotating slant-hole SPECT projection data using the DBH method

Abstract

cost of the small detector field-of-view (FOV). Figure l( b) shows the cross-sectional view of the collimator. The two segments shown in the figure have a common volume-ofview (CVOV) indicated by the shaded volume. For a specific imaging task, the region-of-interest (ROI) should be located within the CVOV. The high sensitivity and small FOV of the RMSSH collimator ensure that it can be applied in dedicated SPECT systems for imaging small organs, such as breast, cardiac, and brain imaging. In this paper, an RMSSH SPECT system for breast imaging is investigated through a simulation study.Abstract-This work applies a previously developed analytical algorithm to the reconstruction in a rotating multi-segment slanthole (RMSSH) SPECT system. The RMSSH SPECT data of a digital NCAT phantom with breast attachment are modeled as the uniformly attenuated Radon transform of the activity distribution. These data are reconstructed using an analytical algorithm called the DBH method, which is an acronym for the procedure of differentiation and backprojection followed by a finite weighted Hilbert transform. The projection data are first differentiated along a specific direction and then backprojected to the image space. The result from the first step is equal to a one-dimensional finite weighted Hilbert transform of the object; this transform is then numerically inverted to obtain the reconstructed image. With the limited common volume-of-view (CVOV) of the RMSSH collimator, the detector captures gamma photon emissions from the breast and from parts of the torso. A conventional filtered backprojection algorithm only reconstructs the high frequency components of the activity function. The DBH method is capable of exactly reconstructing the activity within a well defined region-of-interest (ROI) within the breast. Quantitative accuracy is shown in this ROI from the simulation results. Quadrant slant-hole collimator (a) RMSSH collimator. a \ \ \ I / / (b) Side view.

Aktuelle Entwicklungen in der Gammakameratechnik für die Myokardperfusionsszintigrafie

“…Durch die konvergenten Kollimatoren wird die Sensitivit ä t f ü r die Herzregion deutlich erh ö ht, sodass Aufnahmen in 4 -5 min m ö glich werden sollen [27] . Andere innovative Kollimatoren f ü r schnelle, sensitivere Aufnahmen mit konventionellen Gammakameras, so wie Slant-Hole- [17] oder Multi-Pinhole-Kollimatoren [12] , wurden ebenfalls entwickelt und vorgestellt, werden jedoch noch nicht kommerziell verfolgt. Ein anderer Fortschritt, der auch mit konventionellen Kameras anwendbar ist, liegt im Rekonstruktionsbereich.…”