Application of spherical harmonics to image reconstruction for the Compton camera

Basko, R.; Zeng, G.L.; Gullberg, Grant T.

doi:10.1088/0031-9155/43/4/016

Cited by 102 publications

(96 citation statements)

References 5 publications

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“…The position and energy resolution can in principle be improved for better angular resolution but the electron on which the photon Compton scatters carries momentum, which is inherently unknown and will limit the best angular resolution attainable [9]. In order to improve image quality, a large number of image reconstruction algorithms have been developed [10][11][12][13]. The iterative List Mode Maximum Likelihood (LMML) algorithm which is well suited for low statistics data can improve angular resolution as shown later.…”

Section: Compton Imaging With a Hpge Detectormentioning

confidence: 99%

Gamma-ray imaging with a coaxial HPGe detector

Niedermayr¹,

Vetter²,

Mihailescu³

et al. 2005

Nuclear Instruments and Methods in Physics Research Section A:

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Abstract:We report on the first experimental demonstration of Compton imaging of gamma rays with a single coaxial high-purity germanium (HPGe) detector. This imaging capability is realized by two-dimensional segmentation of the outside contact in combination with digital pulse-shape analysis, which enables to image gamma rays in 4p without employing a collimator. We are able to demonstrate the ability to image the 662keV gamma ray from a 137 Cs source with preliminary event selection with an angular accuracy of 5 degree with an relative efficiency of 0.2%. In addition to the 4p imaging capability, such a system is characterized by its excellent energy resolution and can be implemented in any size possible for Ge detectors to achieve high efficiency.

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Section: Compton Imaging With a Hpge Detectormentioning

confidence: 99%

Gamma-ray imaging with a coaxial HPGe detector

Niedermayr¹,

Vetter²,

Mihailescu³

et al. 2005

Nuclear Instruments and Methods in Physics Research Section A:

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“…Regarding the data space, due to the high volume of data obtained from the planar detectors (5 dimensions), one tries to use only partial data for efficiency in implementations (see, e.g., [2,5,6,13,21,25,28]), but it requires considerable costs to store unnecessary data and this also causes additional costs to retrieve the target data. The Compton camera usually carries considerable noise in applications and utilizing full 5 dimensional data is advised to obtain accurate numerical results (see, e.g., [1]) although significant computational time and resources should be required.…”

Section: Introductionmentioning

confidence: 99%

“…Several inversion formulas for various types of cone transforms were derived in [2,5,6,11,12,13,16,19,21,24,25,28,31,34]. The cone transform with planar vertex positions and a fixed central axis was studied in [5,6,16,21,24,25,34].…”

Section: Introductionmentioning

confidence: 99%

Exact Inversion of the Cone Transform Arising in an Application of a Compton Camera Consisting of Line Detectors

Jung¹,

Moon²

2016

SIAM J. Imaging Sci.

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Abstract.A Compton camera has been suggested for use in single photon emission computed tomography because a conventional gamma camera has low efficiency. Here we consider a cone transform brought about by a Compton camera with line detectors. A cone transform takes a given function on the 3-dimensional space and assigns to it the surface integral of the function over cones determined by the 1-dimensional vertex space, the 1-dimensional central axis, and the 1-dimensional opening angle. We generalize this cone transform to n-dimensional space and provide an inversion formula. Also, numerical simulations are presented to demonstrate our suggested algorithm in three dimensions.Key words. Compton camera, SPECT, tomography, cone transform, inversion, gamma camera AMS subject classifications. 44A12, 65R10, 92C55DOI. 10.1137/15M10336171. Introduction. A Radon-type transform that assigns to a given function its surface integral over various sets of cones has been studied, since it is known that this kind of a transform relates to a Compton camera. A Compton camera, also called an electronically collimated γ-camera, was introduced for use in single photon emission computed tomography (SPECT) because of the low efficiency of a conventional γ-camera [26,32]. A Compton camera has very high sensitivity and flexibility of geometrical design, so it has attracted a lot of interest and applications in many areas including monitoring nuclear power plants and astronomy [1,3].A standard Compton camera consists of two planar detectors: a scatter detector and an absorption detector, positioned one behind the other. A photon emitted from a radioactive source toward the camera undergoes Compton scattering in the scatter detector, and is absorbed in the absorption detector positioned behind (see Figure 1). In each detector, the position of the hit and the energy of the photon are measured. The scattering angle or the

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“…Several analytic and iterative algorithms have been proposed for the CC reconstruction. [3][4][5][6] However, to this date, little progress has been achieved in implementing any of the corrections that would be required for a successful high-resolution image reconstruction. 7,8 It was recently demonstrated 9 that in the standard modeling of image resolution for CC using the shiftvariant point spread functions (PSFs), the recalculation of the PSF model required computing times of the order of months.…”

Section: Introductionmentioning

confidence: 99%

Resolution recovery for Compton camera using origin ensemble algorithm

Andreyev

Celler

Sitek

2011

2011 IEEE Nuclear Science Symposium Conference Record

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Purpose: Compton cameras (CCs) use electronic collimation to reconstruct the images of activity distribution. Although this approach can greatly improve imaging efficiency, due to complex geometry of the CC principle, image reconstruction with the standard iterative algorithms, such as ordered subset expectation maximization (OSEM), can be very time-consuming, even more so if resolution recovery (RR) is implemented. We have previously shown that the origin ensemble (OE) algorithm can be used for the reconstruction of the CC data. Here we propose a method of extending our OE algorithm to include RR. Methods: To validate the proposed algorithm we used Monte Carlo simulations of a CC composed of multiple layers of pixelated CZT detectors and designed for imaging small animals. A series of CC acquisitions of small hot spheres and the Derenzo phantom placed in air were simulated. Images obtained from (a) the exact data, (b) blurred data but reconstructed without resolution recovery, and (c) blurred and reconstructed with resolution recovery were compared. Furthermore, the reconstructed contrast-to-background ratios were investigated using the phantom with nine spheres placed in a hot background.Results: Our simulations demonstrate that the proposed method allows for the recovery of the resolution loss that is due to imperfect accuracy of event detection. Additionally, tests of camera sensitivity corresponding to different detector configurations demonstrate that the proposed CC design has sensitivity comparable to PET. When the same number of events were considered, the computation time per iteration increased only by a factor of 2 when OE reconstruction with the resolution recovery correction was performed relative to the original OE algorithm. We estimate that the addition of resolution recovery to the OSEM would increase reconstruction times by 2-3 orders of magnitude per iteration. Conclusions: The results of our tests demonstrate the improvement of image resolution provided by the OE reconstructions with resolution recovery. The quality of images and their contrast are similar to those obtained from the OE reconstructions from scans simulated with perfect energy and spatial resolutions. C

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Application of spherical harmonics to image reconstruction for the Compton camera

Cited by 102 publications

References 5 publications

Gamma-ray imaging with a coaxial HPGe detector

Gamma-ray imaging with a coaxial HPGe detector

Exact Inversion of the Cone Transform Arising in an Application of a Compton Camera Consisting of Line Detectors

Resolution recovery for Compton camera using origin ensemble algorithm

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