Wired collimator for single photon emitter

Ogawa, Kōichi; Kato, Juri

doi:10.1109/tns.2003.817949

Cited by 6 publications

(6 citation statements)

References 5 publications

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“…The newly proposed multilayer collimator in high-resolution mode is similar to the wire-mesh collimator. As a result, this study is consistent with previous reports [7][8][9][10][11][12].…”

Section: Discussionsupporting

confidence: 94%

“…8 [21]. That relation has been previously reported for a wire-mesh collimator [8]. The results are acceptable for clinical applications.…”

Section: Discussionsupporting

confidence: 80%

“…It is made from a series of wire grids [7][8][9][10][11][12]. Generally, a conventional collimator is overspecified in terms of its path length in the material composing the collimator [8].…”

Section: Discussionmentioning

confidence: 99%

“…Consequently, the aperture area is decreased by a factor of four. The septa in this mode have gaps similar to a wire-mesh collimator [7][8][9][10][11][12]. During use, the margin and sides of the collimator are shielded with a cover.…”

Section: Design Conceptmentioning

confidence: 99%

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Collimator for Variable Sensitivity and Spatial Resolution Without the Need for Exchange

Kubo

Tsuchiya

Shiga

et al. 2014

IEEE Trans. Nucl. Sci.

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Abstract-A new design of collimator is proposed that has variable sensitivity and spatial resolution, eliminating the need for exchanging collimators in a gamma camera. Using Monte Carlo simulations, the present article evaluates the shielding of undesirable gamma rays in a parallel-hole collimator. It consists of a number of layers of rectangular holes. These layers consist of alternately stacked fixed and movable collimators. In high-resolution mode, the movable collimators are shifted by half the aperture pitch along the diagonal direction. The first collimator (type A) has 50 layers with fixed thicknesses of 1.2 mm. The second collimator (type B) has 25 layers with a thickness of 1.0 mm on the object side and 25 layers with a thickness of 1.4 mm on the opposite side. The third collimator (type C) has 20 layers with non-uniform thicknesses. The ratios of the maximum artificial peak to the main-peak are calculated for point-source responses. The ratios for types A, B, and C collimators are 0.78, 0.08, and 0.03, respectively. The same performance for shielding undesirable gamma rays is achieved in the type C collimator as for a conventional collimator.

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“…The newly proposed multilayer collimator in high-resolution mode is similar to the wire-mesh collimator. As a result, this study is consistent with previous reports [7][8][9][10][11][12].…”

Section: Discussionsupporting

confidence: 94%

“…8 [21]. That relation has been previously reported for a wire-mesh collimator [8]. The results are acceptable for clinical applications.…”

Section: Discussionsupporting

confidence: 80%

Section: Discussionmentioning

confidence: 99%

Section: Design Conceptmentioning

confidence: 99%

See 2 more Smart Citations

Collimator for Variable Sensitivity and Spatial Resolution Without the Need for Exchange

Kubo

Tsuchiya

Shiga

et al. 2014

IEEE Trans. Nucl. Sci.

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“…In this code, source geometry, collimators, and detectors need to be defined in the input file-a cumbersome process (5,6). Recently, researchers have clinically compared parallel beam and fan beam collimators and simulated the parallel beam collimator by this code (7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22). In this study, fan beam parameters were deliberated by this code.…”

mentioning

confidence: 99%

Estimation of Fan Beam and Parallel Beam Parameters in a Wire Mesh Design

Khorshidi¹,

Ashoor²,

Hosseini³

et al. 2012

Journal of Nuclear Medicine Technology

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Special collimators used in imaging systems play an important part in obtaining qualified images to improve diagnosis in medicine. Methods: The primary aim of this study was to compare resolution between fan beam and parallel beam collimators using Monte Carlo simulation in the shape of cubic holes. Also, parameters such as geometric efficiency, geometric resolution, scatter, penetration, and full width at half maximum were studied to compare their special characteristics. Results: The simulation results demonstrated that the geometry efficiency of a fan beam collimator increased as the angle of the slant hole increased, and the geometric resolution decreased as the angle of the slant hole increased, at a distinct distance from a monoenergetic source of g-rays. In contrast, at a distinct angle, geometric resolution increased as the distance between the source and the collimator surface increased. For both collimators, scatter and penetration decreased as the distance increased. These results were in agreement with ADAC company data. Finally, fan beam collimators were found to have better resolution than parallel beam collimators with a cubic hole shape in a wire mesh design. Conclusion: Estimation of the fan beam by parallel beam parameters as cubic holes can be suitable in collimator design to improve resolution and efficiency. Col limation of low-energy photons, allowing detection of only those photons propagating in the appropriate direction, plays a key role in obtaining a suitable map in SPECT imaging. Some collimators, such as the parallel beam and fan beam types, are widely used in different applications and for organs centered within the field of view. Therefore, it is important to study collimator geometric properties to improve diagnosis in medicine. Fan beam collimators are a special type of converging collimator with the holes focusing toward a focal line parallel to the axis of rotation of the camera (1).For optimization of collimator design, photon interactions in g-camera collimators have been simulated by the Monte Carlo N-particle code (MCNP5) (2-4). In this code, source geometry, collimators, and detectors need to be defined in the input file-a cumbersome process (5,6). Recently, researchers have clinically compared parallel beam and fan beam collimators and simulated the parallel beam collimator by this code (7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22). In this study, fan beam parameters were deliberated by this code.To improve resolution and efficiency, it is helpful to model collimators of various hole shapes, edge effects, septal materials, and geometric configurations. The aim of this study was to investigate resolution between fan beam and parallel beam collimators using MCNP5 simulation in the shape of cubic holes. Also, distinctive parameters such as geometric efficiency, scatter, penetration, and full width at half maximum (FWHM) have been compared, with assessment of the fan beam and parallel beam collimator responses. MATERIALS AND METHODS Computation of Cubic Hole A...

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Monte Carlo design of optimal wire mesh collimator for breast tumor imaging process

Saad

Roslan

Mahdi

et al. 2011

Nuclear Instruments and Methods in Physics Research Section A:

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This paper presents the modeling of breast tumor imaging process using wire mesh collimator gamma camera. Previous studies showed that the wire mesh collimator has a potential to improve the sensitivity of the tumor detection. In this paper, we extend our research significantly, to find an optimal configuration of the wire mesh collimator specifically for semi-compressed breast tumor detection, by looking into four major factors: weight, sensitivity, spatial resolution and tumor contrast. The numbers of layers in the wire mesh collimator is varied to optimize the collimator design. The statistical variations of the results are studied by simulating multiple realizations for each experiment using different starting random numbers. All the simulation environments are modeled using Monte Carlo N-Particle Code (MCNP). The quality of the detection is measured directly by comparing the sensitivity, spatial resolution and tumor contrast of the images produced by the wire mesh collimator and benchmarked that with a standard multihole collimator. The proposed optimal configuration of the wire mesh collimator is optimized by selecting the number of layers in wire mesh collimator, where the tumor contrast shows a relatively comparable value to the multihole collimator, when it is tested with uniformly semi-compressed breast phantom. The wire mesh collimator showed higher number of sensitivity because of its loose arrangement while the spatial resolution of wire mesh collimator does not shows much different compared to the multihole collimator. With a relatively good tumor contrast and spatial resolution, and increased in sensitivity, a new proposed wire mesh collimator gives a significant improvement in the wire mesh collimator design for breast cancer imaging process. The proposed collimator configuration is reduced to 44.09% from the total multihole collimator weight.

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Wired collimator for single photon emitter

Cited by 6 publications

References 5 publications

Collimator for Variable Sensitivity and Spatial Resolution Without the Need for Exchange

Collimator for Variable Sensitivity and Spatial Resolution Without the Need for Exchange

Estimation of Fan Beam and Parallel Beam Parameters in a Wire Mesh Design

Monte Carlo design of optimal wire mesh collimator for breast tumor imaging process

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