Performance of a high‐sensitivity dedicated cardiac SPECT scanner for striatal uptake quantification in the brain based on analysis of projection data

Park, Mi Ae; Moore, Stephen; McQuaid, Sarah; Kijewski, Marie Foley

doi:10.1118/1.4794488

Cited by 10 publications

(12 citation statements)

References 23 publications

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“…The semiconductor in the D-SPECT system is equipped with nine CZT detector arrays, and each detector block consists of 16 × 64 individual pixels with a spacing of 2.46 mm in both dimensions resulting in a total detector surface of 39.4 × 157.6 mm. Each detector can rotate a maximum of 110°without moving parts and is equipped with a square tungsten parallel-hole collimator (thickness: 0.2 mm, pitch: 2.46 mm, and length: 21.7 mm) [8,15]. Data acquisition was completed in approximately two min in all of the phantom experiments.…”

Section: Spect Systemmentioning

confidence: 99%

Evaluation of Cadmium-Zinc-Telluride Detector-based Single-Photon Emission Computed Tomography for Nuclear Cardiology: a Comparison with Conventional Anger Single-Photon Emission Computed Tomography

Niimi

Nanasato

Sugimoto

et al. 2017

Nucl Med Mol Imaging

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Section: Spect Systemmentioning

confidence: 99%

Evaluation of Cadmium-Zinc-Telluride Detector-based Single-Photon Emission Computed Tomography for Nuclear Cardiology: a Comparison with Conventional Anger Single-Photon Emission Computed Tomography

Niimi

Nanasato

Sugimoto

et al. 2017

Nucl Med Mol Imaging

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“…For example, a recently introduced CZT-based SPECT system, D-SPECT (Spectrum Dynamics) heavily relies on swiveling (i.e., multistep acquisitions) small rectangular pixelated CZT detector modules and high aspect-ratio parallel-hole collimators 13 for cardiac applications, providing high sensitivity. The D-SPECT system was also studied for quantitative assessment of centrally located brain regions 14 to take advantage of its high sensitivity for other applications than the heart and the similar technology was extended for general purpose applications. 15,16 In this study, on top of the previously developed energyoptimized collimator design, we further evaluated a full-ring SPECT system design with eight large-area CZT detectors that can be used for a broad spectrum of single-photon emitting radiopharmaceuticals.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of a variable‐aperture full‐ring SPECT system using large‐area pixelated CZT modules: A simulation study for brain SPECT applications

et al. 2021

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Single photon emission computed tomography (SPECT) scanners using cadmium zinc telluride (CZT) offer compact, lightweight, and improved imaging capability over conventional NaI (Tl)-based SPECT scanners. The main purpose in this study is to propose a full-ring SPECT system design with eight large-area CZT detectors that can be used for a broad spectrum of SPECT radiopharmaceuticals and demonstrate the performance of our system in comparison to the reference conventional NaI(Tl)-based two-head Anger cameras. Methods: A newly designed full-ring SPECT system is composed of eight large-area CZT cameras (128 mm × 179.2 mm effective area) that can be independently swiveled around their own axes of rotation independently and can have radial motion for varying aperture sizes that can be adapted to different sizes of imaging volume. Extended projection data were generated by conjoining projections of two adjacent detectors to overcome the limited field-of-view (FOV) by each CZT camera. Using Monte Carlo simulations, we evaluated this new system design with digital phantoms including a Derenzo hot rod phantom and a Zubal brain phantom. Comparison of performance metrics such as spatial resolution, sensitivity, contrast-to-noise ratio (CNR), and contrast-recovery ratio was made between our design and conventional SPECT scanners having different pixel sizes and radii of rotation (one clinically well-known type and two arbitrary types matched to our proposed CZT-SPECT geometries). Results: The proposed scanner could result in up to about three times faster in acquisition time over conventional scan time at same acquisition time per step. The spatial resolution improvement, or deterioration, of our proposed scanner compared to the clinical-type scanner was dependent upon the location of the point source. However, there were overall performance improvements over the three different setups of the conventional scanner particularly in volume sensitivity (approximately up to 1.7 times). Overall, we successfully reconstructed the phantom image for both 99m Tc-based perfusion and 123 I-based dopamine transporter (DaT) brain studies simulated for our new design. In particular, the striatal/background contrast-recovery ratio in 3-to-1 reference ratio was over 0.8 for the 123 I-based DaT study. Conclusions: We proposed a variable-aperture full-ring SPECT system using combined pixelated CZT and energy-optimized parallel-hole collimator modules and evaluated the performance of this scanner using relevant digital phantoms and MC simulations. Our studies demonstrated the potential of our new full-ring CZT-SPECT design, showing reduced acquisition time and improved sensitivity with acceptable CNR and spatial resolution.

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“…We have also assessed the potential of a SPECT system with adaptive data acquisition (D-SPECT, Spectrum Dynamics, Caesarea, Israel) for brain imaging. 7 The results of this analytical study implied that the increased sensitivity of the D-SPECT over the conventional system would lead to significantly improved performance in estimating clinically important metrics, such as striatal uptake, binding ratio, and the left-right asymmetry index. A third approach to achieving centrally peaked collimator sensitivity, compatible with standard dual-or triple-head SPECT systems, is to use converging collimation, i.e., fanor cone-beam geometry; maximum sensitivity is achieved for a source at the focal point or along the focal line.…”

Section: A Brain Spectmentioning

confidence: 92%

“…In this study, the unknown parameters are the (assumed uniform) activity concentration values within four striatal structures and the background. This methodology, which we have used previously, 7 is analogous to the well-established mathematical observer approach which is standard in detectability studies, i.e., performance is assessed using a prototypical imaging task. The CRB are lower bounds on the variance with which these unknown parameters can be estimated by an unbiased estimator.…”

mentioning

confidence: 99%

Introduction of a novel ultrahigh sensitivity collimator for brain SPECT imaging

Park

Kijewski

Keijzers³

et al. 2016

Med. Phys.

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Purpose: Noise levels of brain SPECT images are highest in central regions, due to preferential attenuation of photons emitted from deep structures. To address this problem, the authors have designed a novel collimator for brain SPECT imaging that yields greatly increased sensitivity near the center of the brain without loss of resolution. This hybrid collimator consisted of ultrashort cone-beam holes in the central regions and slant-holes in the periphery (USCB). We evaluated this collimator for quantitative brain imaging tasks. Methods: Owing to the uniqueness of the USCB collimation, the hole pattern required substantial variations in collimator parameters. To utilize the lead-casting technique, the authors designed two supporting plates to position about 37 000 hexagonal, slightly tapered pins. The holes in the supporting plates were modeled to yield the desired focal length, hole length, and septal thickness. To determine the properties of the manufactured collimator and to compute the system matrix, the authors prepared an array of point sources that covered the entire detector area. Each point source contained 32 µCi of Tc-99m at the first scan time. The array was imaged for 5 min at each of the 64 shifted locations to yield a 2-mm sampling distance, and hole parameters were calculated. The sensitivity was also measured using a point source placed along the central ray at several distances from the collimator face. High-count projection data from a five-compartment brain phantom were acquired with the three collimators on a dual-head SPECT/CT system. The authors calculated Cramer-Rao bounds on the precision of estimates of striatal and background activity concentration. In order to assess the new collimation system to detect changes in striatal activity, the authors evaluated the precision of measuring a 5% decrease in right putamen activity. The authors also reconstructed images of projection data obtained by summing data from the individual phantom compartments. Results: The sensitivity of the novel cone-beam collimator varied with distance from the detector face; it was higher than that of the fan-beam collimator by factors ranging from 2.7 to 162. Examination of the projections of the point sources revealed that only a few holes were distorted or partially blocked, indicating that the intensive manual fabrication process was very successful. Better reconstructed phantom images were obtained from the USCB+FAN collimator pair than from either LEHR or FAN collimation. For the left caudate, located near the center of the brain, the detected counts were 9.8 (8.3) times higher for UCSB compared with LEHR (FAN), averaged over 60 views. The task-specific SNR for detecting a 5% decrease in putamen uptake was 7.4 for USCB and 3.2 for LEHR. Conclusions: The authors have designed and manufactured a novel collimator for brain SPECT imaging. The sensitivity is much higher than that of a fan-beam collimator. Because of differences between the manufactured collimator and its design, reconstruction of the data require...

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Performance of a high‐sensitivity dedicated cardiac SPECT scanner for striatal uptake quantification in the brain based on analysis of projection data

Abstract: This implies that PD can be detected earlier with the dedicated system than with the conventional system; therefore, earlier identification of PD progression should be possible with the high-sensitivity dedicated SPECT camera.

Cited by 10 publications

References 23 publications

Evaluation of Cadmium-Zinc-Telluride Detector-based Single-Photon Emission Computed Tomography for Nuclear Cardiology: a Comparison with Conventional Anger Single-Photon Emission Computed Tomography

Evaluation of Cadmium-Zinc-Telluride Detector-based Single-Photon Emission Computed Tomography for Nuclear Cardiology: a Comparison with Conventional Anger Single-Photon Emission Computed Tomography

Evaluation of a variable‐aperture full‐ring SPECT system using large‐area pixelated CZT modules: A simulation study for brain SPECT applications

Introduction of a novel ultrahigh sensitivity collimator for brain SPECT imaging

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