Rotating quadrant slant-hole SPECT scintimammography: an initial investigation

Wessell, Daniel E.; Tsui, B.M.W.; Frey, Eric; Karimi, Seemeen

doi:10.1109/nssmic.1997.670513

Cited by 5 publications

(3 citation statements)

References 6 publications

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“…However, the artifacts were not severe near the heart, and the reconstructions suggest that the resolution is still very good in this region. Rotating slant-hole collimators for cardiac imaging (ectomography) [14] are similar in Orlov space to the VAOR orbit used here to image the breast, and simulation studies have been investigated with slant-hole collimators for breast imaging [6]. However, that approach suffers from large ROR [6] yielding poor resolution, which can be overcome by our dedicated VAOR approach and a tilted head camera.…”

Section: E Attenuation Corrected Versus Uncorrected Vaormentioning

confidence: 99%

“…A tilted camera head orbiting about 360 will not meet the Orlov condition because the curve of vantage angles exists within a hemisphere, allowing great circles that do not intersect the curve. Similarly, SPECT imaging using slant-hole collimators without tilt will not meet the Orlov condition [6]. A parallel-beam camera head without tilt meets the condition because the curve is an equator of the sphere.…”

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confidence: 99%

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SPECT breast imaging combining horizontal and vertical axes of rotation

Metzler

Bowsher

Tornai

et al. 2002

IEEE Trans. Nucl. Sci.

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Vertical-axis-of-rotation (VAOR) geometries, in which a gamma camera orbits a pendulous breast of a prone patient, have been proposed for SPECT breast imaging. Dedicated VAOR systems would be advantageous since they allow for minimal radius of rotation around the breast, which improves resolution-sensitivity tradeoffs, and there is less attenuation and scatter between the breast and the camera. However, the torso may not be viewed at enough angles to estimate contamination from torso activity. Also, VAOR geometries may involve camera tilt to scan for tumors near the chest wall. These tilted VAOR projections may be insufficient to establish even breast activity alone. Thus, we investigated the utility of designing VAOR systems to function inside some general-purpose horizontal-axis-of-rotation (HAOR) scanners, with the HAOR scanner orbiting a 192 angular range posteriorly, alleviating the insufficient-data problems. We simulated the expected projection data from six various-sized lesions with different activity concentrations in the breast and axilla, additionally considering the contribution from background activity from the torso. The data were then statistically reconstructed considering 360 HAOR, VAOR plus small additional arcs and combined HAOR-VAOR orbits, and the results were compared with the known activity concentration distribution. Substantial improvement in the noise versus bias was observed in the breast and axilla, an important and otherwise difficult region to image.

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Section: E Attenuation Corrected Versus Uncorrected Vaormentioning

confidence: 99%

mentioning

confidence: 99%

SPECT breast imaging combining horizontal and vertical axes of rotation

Metzler

Bowsher

Tornai

et al. 2002

IEEE Trans. Nucl. Sci.

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“…This acquisition mode constitutes the RSH SPECT geometry as described in Clack et al (1996). Although initial enthusiasm for RSH collimators died down in the late 1980s, there has been renewed interest recently (Clack et al 1996, Wessel et al 1998, Wessel 1999, Dale et al 1997, Persson et al 1998, 2002.…”

Section: Introductionmentioning

confidence: 99%

Exact inversion of the exponential x-ray transform for rotating slant-hole (RSH) SPECT

Noo

Clackdoyle

2002

Phys. Med. Biol.

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The RSH SPECT scanner provides parallel-beam attenuated projections for a fully 3D acquisition geometry. The geometry can be represented by circles on the unit sphere of projection directions, one circle for each position of the detector head. Unlike most other fully 3D geometries this one is particularly challenging because there are no 2D subsets in the data. When no attenuation is present, it is well known that an unmeasured projection can be synthesized if it lies inside one of the measured circles. The main result of this work is that under some assumptions on the attenuation distribution, attenuated projections within a circle can be synthesized from available attenuated projections. One consequence is that RSH SPECT projections can be rebinned into a conventional SPECT geometry for which analytic attenuation correction techniques are available.

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Three-dimensional geometric point response correction in rotating slant-hole (RSH) SPECT

Bal

Clackdoyle²,

Zeng³

et al.

1999 IEEE Nuclear Science Symposium. Conference Record. 1999 Nuclear Science Symposium and Medical Imaging Conference (Cat. No.

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The quality and quantitative accuracy of SPECT images are degraded by effects of attenuation, scatter, noise, geometric response, septal penetration and intrinsic crystal resolution. The geometric response has a significant degrading effect on spatial resolution, and can introduce spatial distortions because it is non-stationary. In this study we have characterized the geometric response function for RSH collimators and implemented depth dependent correction for this effect. The GRF for RSH was found to be asymmetric and shift invariant for a given depth. An analytical model for the GRF was developed and implemented into the projector and backprojector of an iterative reconstruction algorithm. GFW compensation was applied to a cardiac phantom simulation and was found to improve the resolution. This work successfully demonstrates that iterative compensation for resolution degradation in RSH SPECT can be performed.

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Rotating quadrant slant-hole SPECT scintimammography: an initial investigation

Cited by 5 publications

References 6 publications

SPECT breast imaging combining horizontal and vertical axes of rotation

SPECT breast imaging combining horizontal and vertical axes of rotation

Exact inversion of the exponential x-ray transform for rotating slant-hole (RSH) SPECT

Three-dimensional geometric point response correction in rotating slant-hole (RSH) SPECT

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