Development of a Germanium Small-Animal SPECT System

Johnson, Lindsay C.; Ovchinnikov, O. S.; Shokouhi, Sepideh; Peterson, Todd E.

doi:10.1109/tns.2015.2448673

Cited by 5 publications

(3 citation statements)

References 29 publications

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“…Silicon drift detectors (SDD), invented in 1984 by , are also proposed for roomtemperature spectroscopic X-ray imaging, representing the best solution up to 20 keV (Bertuccio et al, 2015). Despite their excellent energy resolution and high detection efficiency, few ERPC prototypes based on high-purity germanium (HPGe) detectors have been developed, mainly due to their cumbersome cryogenic cooling (liquid and mechanical coolers) and the difficulties in fabricating small pixel devices (Johnson et al, 2015;Campbell et al, 2013;Krings et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

Digital fast pulse shape and height analysis on cadmium–zinc–telluride arrays for high-flux energy-resolved X-ray imaging

et al. 2018

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Cadmium-zinc-telluride (CZT) arrays with photon-counting and energy-resolving capabilities are widely proposed for next-generation X-ray imaging systems. This work presents the performance of a 2 mm-thick CZT pixel detector, with pixel pitches of 500 and 250 µm, dc coupled to a fast and low-noise ASIC (PIXIE ASIC), characterized only by the preamplifier stage. A custom 16-channel digital readout electronics was used, able to digitize and process continuously the signals from each output ASIC channel. The digital system performs on-line fast pulse shape and height analysis, with a low dead-time and reasonable energy resolution at both low and high fluxes. The spectroscopic response of the system to photon energies below (Cd source) and above (Am source) the K-shell absorption energy of the CZT material was investigated, with particular attention to the mitigation of charge sharing and pile-up. The detector allows high bias voltage operation (>5000 V cm) and good energy resolution at moderate cooling (3.5% and 5% FWHM at 59.5 keV for the 500 and 250 µm arrays, respectively) by using fast pulse shaping with a low dead-time (300 ns). Charge-sharing investigations were performed using a fine time coincidence analysis (TCA), with very short coincidence time windows up to 10 ns. For the 500 µm pitch array (250 µm pitch array), sharing percentages of 36% (52%) and 60% (82%) at 22.1 and 59.5 keV, respectively, were measured. The potential of the pulse shape analysis technique for charge-sharing detection for corner/border pixels and at high rate conditions (250 kcps pixel), where the TCA fails, is also shown. Measurements demonstrated that significant amounts of charge are lost for interactions occurring in the volume of the inter-pixel gap. This charge loss must be accounted for in the correction of shared events. These activities are within the framework of an international collaboration on the development of energy-resolved photon-counting systems for high-flux energy-resolved X-ray imaging (1-140 keV).

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Section: Introductionmentioning

confidence: 99%

Digital fast pulse shape and height analysis on cadmium–zinc–telluride arrays for high-flux energy-resolved X-ray imaging

et al. 2018

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“…Silicon drift detectors, invented in 1984 by ISSN 1600-5775 # 2017 International Union of Crystallography , are currently proposed for room-temperature spectroscopic X-ray imaging, representing the best solution up to 20 keV (Bertuccio et al, 2015). Despite their excellent energy resolution and high detection efficiency up to 140 keV, few ERPC prototypes, based on high-purity germanium (HPGe) detectors, have been developed, mainly due to their cumbersome cryogenic cooling (liquid and mechanical coolers) (Johnson et al, 2015;Campbell et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

Development of new CdZnTe detectors for room-temperature high-flux radiation measurements

et al. 2017

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Recently, CdZnTe (CZT) detectors have been widely proposed and developed for room-temperature X-ray spectroscopy even at high fluxes, and great efforts have been made on both the device and the crystal growth technologies. In this work, the performance of new travelling-heater-method (THM)-grown CZT detectors, recently developed at IMEM-CNR Parma, Italy, is presented. Thick planar detectors (3 mm thick) with gold electroless contacts were realised, with a planar cathode covering the detector surface (4.1 mm × 4.1 mm) and a central anode (2 mm × 2 mm) surrounded by a guard-ring electrode. The detectors, characterized by low leakage currents at room temperature (4.7 nA cm at 1000 V cm), allow good room-temperature operation even at high bias voltages (>7000 V cm). At low rates (200 counts s), the detectors exhibit an energy resolution around 4% FWHM at 59.5 keV (Am source) up to 2200 V, by using commercial front-end electronics (A250F/NF charge-sensitive preamplifier, Amptek, USA; nominal equivalent noise charge of 100 electrons RMS). At high rates (1 Mcounts s), the detectors, coupled to a custom-designed digital pulse processing electronics developed at DiFC of University of Palermo (Italy), show low spectroscopic degradations: energy resolution values of 8% and 9.7% FWHM at 59.5 keV (Am source) were measured, with throughputs of 0.4% and 60% at 1 Mcounts s, respectively. An energy resolution of 7.7% FWHM at 122.1 keV (Co source) with a throughput of 50% was obtained at 550 kcounts s (energy resolution of 3.2% at low rate). These activities are in the framework of an Italian research project on the development of energy-resolved photon-counting systems for high-flux energy-resolved X-ray imaging.

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“…Non-invasive in vivo small animal imaging plays a vital role in biomedical and pharmaceutical research [1][2][3]. In particular, single photon emission computed tomography (SPECT) and positron emission tomography (PET) has developed as an important tool for preclinical research that enables the assessment of molecular and functional processes of diseases with various radiopharmaceuticals and animal experimental pathology models [4][5][6].…”

Section: Introductionmentioning

confidence: 99%

Optimization of image reconstruction and performance evaluation for a small-animal SPECT and PET imaging

Kitasaka

Onoguchi

Shibutani

et al. 2023

Preprint

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Objective: In the field of small animal imaging, Versatile emission computed tomography/computed tomography (VECTor/CT) allows for fully simultaneous acquisition with SPECT and PET tracer using a clustered multi-pinhole collimator. We determined optimal image reconstruction parameter settings and assessed performance characteristics for 99mTc and 18F imaging. Methods: A line source phantom, a cylindrical phantom and a hot-rod phantom containing either 99mTc or 18F were used to perform quantitative analyses including the FWHM, uniformity, contrast and contrast-to-noise ratio and visual analysis. The number of subsets was set as 4, 8, 16 and 32 and the number of iterations was varied from 1 to 30. After the determination of the optimal reconstruction parameters, sensitivity and activity recovery coefficients was measured. Results: The optimal reconstruction parameters were 32 subsets and 8 iterations for 99mTc and 32 subsets and 17 iterations for 18F. Using optimal parameters, 1.1 mm and 1.3 mm hot-rod phantoms can be distinguished for 99mTc and 18F, respectively. In addition, sensitivity was 3606 cps/MBq for 99mTc and 2052 cps/MBq for 18F. The activity recovery coefficients of 99mTc and 18F were maintained above 1.0 for more than 2 mm diameter rod and more than 3 mm diameter rod, respectively. Conclusions: We conducted a performance evaluation with 3 phantoms while changing reconstruction parameters to determine optimal settings for 99mTc and 18F. When the optimal reconstruction parameters we found were used, it was able to visually distinguish small hot-rods diameter, compared with generally used parameter settings and then we could evaluate performance characteristics of the VECTor/CT equipped with the collimator newly designed for the size of a rat.

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Development of a Germanium Small-Animal SPECT System

Cited by 5 publications

References 29 publications

Digital fast pulse shape and height analysis on cadmium–zinc–telluride arrays for high-flux energy-resolved X-ray imaging

Digital fast pulse shape and height analysis on cadmium–zinc–telluride arrays for high-flux energy-resolved X-ray imaging

Development of new CdZnTe detectors for room-temperature high-flux radiation measurements

Optimization of image reconstruction and performance evaluation for a small-animal SPECT and PET imaging

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