The application of pinhole and coded aperture imaging in the nuclear environment

Durrant, P.T.; Dallimore, M.P.; Jupp, Ian; Ramsden, D.

doi:10.1016/s0168-9002(98)01014-6

Cited by 48 publications

(16 citation statements)

References 4 publications

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“…In MAP reconstruction, the solution achieved is also influenced by our a priori information about the object, represented by the function R(x). In order to control the amount of influence of this information on the final solution, a Lagrange multiplier is introduced, which results in an object function (3) In this study, we only used the quadratic roughness penalty with the form (4) where w ij is the weighting factor that takes into account the 26 neighbours and (5) The MAP estimator can be achieved by maximising this objective function Meng and Wehe Page 3 (6) By assuming the system is locally shift-invariant, the local-impulse response and variance at a particular pixel are:…”

Section: A Variance-resolution Trade-offmentioning

confidence: 99%

“…Amongst these efforts, the pinhole imager, such as EPSLON [3], has been proven to be capable of providing good angular resolution, whilst having drawbacks such as limited view angle and sensitivity [4]. Coded aperture has been studied, as a possible replacement of the pinhole, in an effort to improve system sensitivity [5].…”

Section: Introductionmentioning

confidence: 99%

“…However, the coded aperture may still be attractive in some particular situations. For example, when the non-FOV count-rate is too high to be effectively reduced by the shielding, the use of a coded aperture with relatively large open fraction may be used to counteract the effect of shielding penetration and therefore improve the overall Signal-to-Noise Ratio (SNR) [3].…”

Section: Introductionmentioning

confidence: 99%

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Feasibility study of using hybrid collimation for nuclear environmental imaging

Meng

Wehe

2003

IEEE Trans. Nucl. Sci.

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This paper presents a feasibility of a gamma ray imager using combined electronic and mechanical collimation methods. This detector is based on the use of a multiple pinhole collimator, a position sensitive scintillation detector with Anger logic readout. A pixelated semiconductor detector, located between the collimator and the scintillation detector, is used as a scattering detector. For gamma rays scattered in the first detector and then stopped in the second detector, an image can also be built up based on the joint probability of their passing through the collimator and falling into a broadened conical surface, defined by the detected Compton scattering event. Since these events have a much smaller angular uncertainty, they provide more information content per photon compared with using solely the mechanical or electronic collimation. Therefore, the overall image quality can be improved. This feasibility study adapted a theoretical approach, based on analysing the resolution-variance trade-off in images reconstructed using Maximum a priori (MAP) algorithm. The effect of factors such as the detector configuration, Doppler broadening and collimator configuration are studied. The results showed that the combined collimation leads to a significant improvement in image quality at energy range below 300keV. However, due to the mask penetration, the performance of such a detector configuration is worse than a standard Compton camera at above this energy.

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Section: A Variance-resolution Trade-offmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Feasibility study of using hybrid collimation for nuclear environmental imaging

Meng

Wehe

2003

IEEE Trans. Nucl. Sci.

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“…[4,5,9] are installed at the input face of the detector to provide an image of the radioactive sources. Position-sensitive photomultipliers [1,4,6}9] and charge-coupled devices (CCD) [3,5] are used as readout systems for the scintillators.…”

Section: Introductionmentioning

confidence: 99%

“…In most systems, 2D scintillator screens [1}5] and arrays [6}9], as well as semiconductor arrays [10}12] are applied. Pin-hole [3,6}8] and multiple-hole [1] collimators and coded apertures [4,5,9] are installed at the input face of the detector to provide an image of the radioactive sources. Position-sensitive photomultipliers [1,4,6}9] and charge-coupled devices (CCD) [3,5] are used as readout systems for the scintillators.…”

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confidence: 99%

Microchannel Plate Detector

Elam¹,

Lee²,

Wang³

et al. 2008

Encyclopedia of Genetics, Genomics, Proteomics and Informatics

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The`edge-ona illuminated microchannel plate (MCP) position-sensitive detector (PSD) is used for gamma-ray imaging for the "rst time. The superior position resolution of the MCP is combined with high detection e$ciency due to the`edge-ona illumination mode. The results of imaging a 15 Ci Cs source (662 keV quantum energy) are presented.2001 Elsevier Science B.V. All rights reserved. [4,5,9] are installed at the input face of the detector to provide an image of the radioactive sources. Position-sensitive photomultipliers [1,4,6}9] and charge-coupled devices (CCD) [3,5] are used as readout systems for the scintillators. Plate-like detectors are also used for the scanning and locating (but not imaging) of the radioactive sources [13].The applications of hard X-ray position-sensetive detectors (PSDs) in medicine are described in detail in review [14]. Although the parameters of E-mail address: pms@peterlink.ru (P.M. Shikhaliev).hard radiation PSDs are continuously optimized, there is a fundamental limitation: increasing the position resolution leads to decrease of detection e$ciency. At the same time, it is well known that microchannel plate (MCP) detectors provide a superior position resolution but the detection e$ciency of conventional MCP detectors is low for the hard radiation [15,16].Recently, we have suggested a novel hard X-ray detector based on MCPs that provides a higher hard X-ray detection e$ciency in comparison with conventional MCP detectors [17,18]. The`edgeona illumination of the MCP has been used to combine the superior position resolution of MCP with high detection e$ciency. It has also been predicted that the positon-sensitive performance of thè edge-ona MCP detector may be used for the hard X-ray imaging systems. Note that this`edge-ona illumination concept has also been applied for silicon strip detector [19] and CCDs [20].

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