Optimization of convergent collimators for pixelated SPECT systems

Capote, R.; Matela, Nuno; Conceição, Raquel C.; Almeida, Pedro

doi:10.1118/1.4804053

Cited by 10 publications

(11 citation statements)

References 31 publications

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“…The collimator in SPECT is a crucial component of the imaging chain that controls the noise, resolution, and sensitivity of the final functional image. [ 1 2 3 4 5 6 7 8 ] Specialized collimators are used for a specific imaging task, for example the fan beam collimator for brain imaging,[ 9 ] cone beam collimator for posterior portion of the thalamus,[ 10 ] slit slat collimator for radionuclide imaging with high-energy gamma ray emission,[ 11 12 ] and parallel-hole collimators that routinely use in SPECT and planar imaging. The pinhole and multi-pinhole collimators used for research, preclinical study, small animal, and focal uptake nuclear medicine imaging.…”

Section: Introductionmentioning

confidence: 99%

Advances in Pinhole and Multi-Pinhole Collimators For Single Photon Emission Computed Tomography Imaging

et al. 2015

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The collimator in single photon emission computed tomography (SPECT), is an important part of the imaging chain. One of the most important collimators that used in research, preclinical study, small animal, and organ imaging is the pinhole collimator. Pinhole collimator can improve the tradeoff between sensitivity and resolution in comparison with conventional parallel-hole collimator and facilities diagnosis. However, a major problem with pinhole collimator is a small field of view (FOV). Multi-pinhole collimator has been investigated in order to increase the sensitivity and FOV with a preserved spatial resolution. The geometry of pinhole and multi-pinhole collimators is a critical factor in the image quality and plays a key role in SPECT imaging. The issue of the material and geometry for pinhole and multi-pinhole collimators have been a controversial and much disputed subject within the field of SPECT imaging. On the other hand, recent developments in collimator optimization have heightened the need for appropriate reconstruction algorithms for pinhole SPECT imaging. Therefore, iterative reconstruction algorithms were introduced to minimize the undesirable effect on image quality. Current researches have focused on geometry and configuration of pinhole and multi-pinhole collimation rather than reconstruction algorithm. The lofthole and multi-lofthole collimator are samples of novel designs. The purpose of this paper is to provide a review on recent researches in the pinhole and multi-pinhole collimators for SPECT imaging.

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Section: Introductionmentioning

confidence: 99%

Advances in Pinhole and Multi-Pinhole Collimators For Single Photon Emission Computed Tomography Imaging

et al. 2015

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“…11,40 Different formulae apply to different hole shapes, 37,41 and it has also been shown that hole tapering provides improved sensitivity at equal resolution. 42,43 When the object of interest is relatively large, it may be appropriate to use diverging collimators, 44 e.g., for kinetic modeling in mice, it is important to see the organ of interest and the heart within a single bed position in order to obtain an arterial input curve. 45 Although diverging collimators have not been very common in the past, with the arrival of new high-resolution detector technologies, it becomes possible to enlarge the FOV and still obtain a sufficiently high resolution.…”

Section: A2 Converging and Diverging Hole Collimatorsmentioning

confidence: 99%

“…Another approach that results in more conventional fan-and cone-beam collimator designs is presented in Ref. 43. This is based on the same principle of local optimization but it assumes that the optimal collimator thickness and hole diameter are constant and equal to their values near the center of the collimator and that the focal point lies as close as possible behind the object, given the constraint that the FOV must contain the whole body/organ.…”

Section: A Sensitivity Maximization For a Given Target Resolutionmentioning

confidence: 99%

“…with G the detector length, z 0 the point source distance, and L 0 the collimator height, as in the reference paper. 43 So, we looped over different values of L 0 , calculated f according to Eq. (16), calculated the hole sizes needed to obtain the target resolution using (2), (3), and (5) from Ref.…”

Section: A1 Optimized Resolution-sensitivity Trade-offmentioning

confidence: 99%

“…(16), calculated the hole sizes needed to obtain the target resolution using (2), (3), and (5) from Ref. 43, calculated the volume sensitivity using Eqs. (1), (4), (6), and (7) from Ref.…”

Section: A1 Optimized Resolution-sensitivity Trade-offmentioning

confidence: 99%

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Review of SPECT collimator selection, optimization, and fabrication for clinical and preclinical imaging

et al. 2015

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In single photon emission computed tomography, the choice of the collimator has a major impact on the sensitivity and resolution of the system. Traditional parallel-hole and fan-beam collimators used in clinical practice, for example, have a relatively poor sensitivity and subcentimeter spatial resolution, while in small-animal imaging, pinhole collimators are used to obtain submillimeter resolution and multiple pinholes are often combined to increase sensitivity. This paper reviews methods for production, sensitivity maximization, and task-based optimization of collimation for both clinical and preclinical imaging applications. New opportunities for improved collimation are now arising primarily because of (i) new collimator-production techniques and (ii) detectors with improved intrinsic spatial resolution that have recently become available. These new technologies are expected to impact the design of collimators in the future. The authors also discuss concepts like septal penetration, high-resolution applications, multiplexing, sampling completeness, and adaptive systems, and the authors conclude with an example of an optimization study for a parallel-hole, fan-beam, cone-beam, and multiple-pinhole collimator for different applications.

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Image quality parameters in brain imaging with fan-beam collimator: a Monte Carlo study on radiation scattering effects

Baghani

2019

Radiol Phys Technol

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Optimization of convergent collimators for pixelated SPECT systems

Abstract: These results demonstrate the potential of this kind of optimal convergent collimators for the use in small field of view imaging applications.

Cited by 10 publications

References 31 publications

Advances in Pinhole and Multi-Pinhole Collimators For Single Photon Emission Computed Tomography Imaging

Advances in Pinhole and Multi-Pinhole Collimators For Single Photon Emission Computed Tomography Imaging

Review of SPECT collimator selection, optimization, and fabrication for clinical and preclinical imaging

Image quality parameters in brain imaging with fan-beam collimator: a Monte Carlo study on radiation scattering effects

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