Development of a 64 × 64 CdZnTe array and associated readout integrated circuit for use in nuclear medicine

Barber, H. Bradford; Barrett, Harrison H.; Augustine, F.L.; Hamilton, W. J.; Apotovsky, B.; Dereniak, Eustace L.; Doty, F. Patrick; Eskin, J.D.; Garcia, John Phillips; Marks, D.G.; Matherson, K.J.; Woolfenden, James M.; Young, Erick T.

doi:10.1007/s11664-997-0229-y

Cited by 36 publications

(17 citation statements)

References 15 publications

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“…They use 1.5 mm thick CdZnTe crystals as gamma detection medium arranged in a 64 x 64 matrix of 380 µm square pixels. The sensor is In bump-bonded to the Arizona Readout ASIC (Mitel 3 µm technology), which consists basically of a capacitive-feedback transimpedance amplifier, a correlated double sample and hold circuit, a buffer and a shift register [78]. The analogue signals are sent out to a digital signal processing board containing a 12-bit ADC and a processor.…”

Section: Arizona Readoutmentioning

confidence: 99%

Development of segmented semiconductor arrays for quantum imaging

Mikulec

2003

Nuclear Instruments and Methods in Physics Research Section A:

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The field of pixel detectors has grown strongly in recent years through progress in CMOS technology, which permits many hundreds of transistors to be implemented in a square area with a side of 50- This paper gives an introduction into the concept of quantum imaging using direct conversion in segmented semiconductor arrays. An overview of projects from this domain using strip, pad and in particular hybrid pixel detectors will be presented. One of these projects, the Medipix project, is described in more detail. The effect of different correction methods like threshold adjustment and flat field correction is illustrated and new measurement results and images presented.

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Section: Arizona Readoutmentioning

confidence: 99%

Development of segmented semiconductor arrays for quantum imaging

Mikulec

2003

Nuclear Instruments and Methods in Physics Research Section A:

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“…We have developed CdZnTe arrays for high-resolution imaging; details on design and construction of these pixel arrays have been reported elsewhere [7][8][9]. Briefly, these arrays consist of a 2.5 cm x 2.5 cm x 0.15 cm slab of CdZnTe with a continuous gold electrode on the top and a 64 x 64 array of gold electrodes on the bottom.…”

Section: A System Descriptionmentioning

confidence: 99%

Tomographic small-animal imaging using a high-resolution semiconductor camera

Kastis

Balzer

et al. 2002

IEEE Trans. Nucl. Sci.

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We have developed a high-resolution, compact semiconductor camera for nuclear medicine applications. The modular unit has been used to obtain tomographic images of phantoms and mice. The system consists of a 64 x 64 CdZnTe detector array and a parallel-hole tungsten collimator mounted inside a 17 cm x 5.3 cm x 3.7 cm tungsten-aluminum housing. The detector is a 2.5 cm x 2.5 cm x 0.15 cm slab of CdZnTe connected to a 64 x 64 multiplexer readout via indium-bump bonding. The collimator is 7 mm thick, with a 0.38 mm pitch that matches the detector pixel pitch. We obtained a series of projections by rotating the object in front of the camera. The axis of rotation was vertical and about 1.5 cm away from the collimator face. Mouse holders were made out of acrylic plastic tubing to facilitate rotation and the administration of gas anesthetic. Acquisition times were varied from 60 sec to 90 sec per image for a total of 60 projections at an equal spacing of 6 degrees between projections. We present tomographic images of a line phantom and mouse bone scan and assess the properties of the system. The reconstructed images demonstrate spatial resolution on the order of 1-2 mm.

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“…An example of the latter is the integrating cadmium zinc telluride hybrid detector developed at the University of Arizona. 1,2 When an integrating semiconductor detector is used for nuclear medicine, an absorbed gamma ray contributes charge to more than one pixel electrode, but if the number of absorbed photons per frame is small, it is possible to identify individual events and process the pixel signals just as with event-driven scintillation cameras. Thus the integrating detectors function as event-driven detectors at low count rate, and position and energy can be estimated for each event.…”

Section: Introductionmentioning

confidence: 99%

Non-Gaussian noise in x-ray and γ-ray detectors

Chen

Barrett

2005

Medical Imaging 2005: Physics of Medical Imaging

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Image statistics are usually modeled as Poisson in γ-ray imaging and as Gaussian in x-ray imaging. In nuclear medicine, event-driven detectors analyze the pulses from every absorbed gamma photon individually; the resulting images rigorously obey Poisson statistics but are approximately Gaussian when the mean number of counts per pixel is large. With integrating detectors, as in digital radiography, each x-ray photon makes a contribution to the image proportional to its pulse height. One pixel senses many photons in long exposures, so the image statistics approach Gaussian by the central limit theorem (CLT). If the exposure time is short enough, however, each pixel will usually respond to no more than one photon, and we can separate individual photons for position estimation. Integrating detectors are therefore event-driven when we use many short-exposure frames rather than one long exposure. In intermediate exposures, the number of photons in one pixel is too small to invoke CLT and apply Gaussian statistics, yet too large to identify individual photons and apply Poisson statistics. In this paper, we analyze the image quality in this intermediate case.Image quality is defined for detection tasks performed by the ideal observer. Because the frames in a data set are independent of each other, the probability density function (PDF) of the whole data set is a product of the frame PDFs. The log-likelihood ratio λ of the ideal observer is thus a sum across the frames and has Gaussian statistics even with non-Gaussian images. We compare the ideal observer's performance with the Hotelling observer's performance under this approximation. A data-thresholding technique to improve Hotelling observer's performance is also discussed.

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Development of a 64 × 64 CdZnTe array and associated readout integrated circuit for use in nuclear medicine

Cited by 36 publications

References 15 publications

Development of segmented semiconductor arrays for quantum imaging

Development of segmented semiconductor arrays for quantum imaging

Tomographic small-animal imaging using a high-resolution semiconductor camera

Non-Gaussian noise in x-ray and γ-ray detectors

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