Design of a Multi-Pinhole Collimator for I-123 DaTscan Imaging on Dual-Headed SPECT Systems in Combination with a Fan-Beam Collimator

King, Michael A.; Mukherjee, Joyeeta Mitra; Könik, Arda; Zubal, I. George; Dey, Joyoni; Licho, Robert

doi:10.1109/tns.2016.2515519

Cited by 25 publications

(18 citation statements)

References 32 publications

(36 reference statements)

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“…Cone-beam and fanbeam collimators were used to make better usage of the detector area than parallel-hole collimators when imaging a structure such as the head which is of smaller area than the detector, thereby improving the sensitivity / spatial resolution trade-off for imaging [20,21]. More recently, studies have shown that customized multi-pinhole collimators may further enhance the performance of the existing clinical generalpurpose SPECT systems for brain imaging [22][23][24][25][26].…”

mentioning

confidence: 99%

Investigation of Axial and Angular Sampling in Multi-Detector Pinhole-SPECT Brain Imaging

Zeraatkar

Kalluri

Auer

et al. 2020

IEEE Trans. Med. Imaging

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We designed a dedicated multi-detector multipinhole brain SPECT scanner to generate images of higher quality compared to general-purpose systems. The system, AdaptiSPECT-C, is intended to adapt its sensitivity-resolution trade-off by varying its aperture configurations allowing both high-sensitivity dynamic and high-spatial-resolution static imaging. The current system design consists of 23 detector heads arranged in a truncated spherical geometry. In this work, we investigated the axial and angular sampling capability of the current stationary system design. Two data acquisition schemes using limited rotation of the gantry and two others using axial translation of the imaging bed were also evaluated concerning their impact on image quality through improved sampling. Increasing both angular and axial sampling in the current prototype system resulted in quantitative improvements in image quality metrics and qualitative appearance of the images as determined in studies with specifically selected phantoms. Visual improvements for the brain phantoms with clinical distributions were less pronounced but presented quantitative improvements in the fidelity (normalized root-mean-square error (NRMSE)) and striatal specific binding ratio (SBR) for a dopamine transporter (DAT) distribution, and in NRMSE and activity recovery for a brain perfusion distribution. More pronounced improvements with increased sampling were seen in contrast recovery coefficient, bias, and coefficient of variation for a lesion in the brain perfusion distribution. The negligible impact of the most cranial ring of detectors on axial sampling, but its significant impact on sensitivity and angular sampling in the cranial portion of the imaging volume-of-interest were also determined. Index Terms-AdaptiSPECT-C, angular and axial sampling, SPECT, pinhole, multi-pinhole. I. INTRODUCTION B RAIN SPECT imaging has been of interest for many clinical applications in neuroimaging including Alzheimer's, Parkinson's, and Huntington's diseases,

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confidence: 99%

Investigation of Axial and Angular Sampling in Multi-Detector Pinhole-SPECT Brain Imaging

Zeraatkar

Kalluri

Auer

et al. 2020

IEEE Trans. Med. Imaging

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“…The geometric variables such as collimator thickness, magnification, pinhole aperture sizes, positions, and tilt angles were fully parameterized to facilitate testing of different potential configurations. The simulations are based on the MPH design as described in [11]: a tungsten alloy collimator plate (20 × 20 × 2 cm 3 ) containing 9 knife-edge pinholes (1 direct and 8 oblique angles), with 2.2 mm square apertures at 0.5 cm depth from the face of the collimator plate (on the side closer to the brain), all focusing to the same central point. Image magnification of this system at the focal point is ~1.2, with the aperture center to crystal distance of 17.25 cm and axis of rotation (AOR) to aperture distance of 14 cm.…”

Section: Methodsmentioning

confidence: 99%

“…The cost of such dedicated systems, however, may be prohibitive for most clinics considering the relatively low number of procedures performed for brain imaging. Therefore, we proposed a relatively inexpensive approach to improve the performance of the existing dual-head SPECT systems for DAT imaging by using a specially designed MPH collimator on one detector head while keeping the existing fan-beam (or parallel-beam) collimator on the other head [11]. With this combined MPH/fan-beam system we aim for improved detection and quantification of structures in the interior region of the brain at a marginal cost.…”

Section: Introductionmentioning

confidence: 99%

Simulations of a Multipinhole SPECT Collimator for Clinical Dopamine Transporter (DAT) Imaging

Könik

Beenhouwer

Mukherjee

et al. 2018

IEEE Trans. Radiat. Plasma Med. Sci.

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SPECT imaging of the dopamine transporter (DAT) is used for diagnosis and monitoring progression of Parkinson’s Disease (PD), and differentiation of PD from other neurological disorders. The diagnosis is based on the DAT binding in the caudate and putamen structures in the striatum. We previously proposed a relatively inexpensive method to improve the detection and quantification of these structures for dual-head SPECT by replacing one of the fan-beam collimators with a specially designed multi-pinhole (MPH) collimator. In this work, we developed a realistic model of the proposed MPH system using the GATE simulation package and verified the geometry with an analytic simulator. Point source projections from these simulations closely matched confirming the accuracy of the pinhole geometries. The reconstruction of a hot-rod phantom showed that 4.8 mm resolution is achievable. The reconstructions of the XCAT brain phantom showed clear separation of the putamen and caudate, which is expected to improve the quantification of DAT imaging and PD diagnosis. Using this GATE model, point spread functions modeling physical factors will be generated for use in reconstruction. Also, further improvements in geometry are being investigated to increase the sensitivity of this base system while maintaining a target spatial resolution of 4.5–5 mm.

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“…Recently, efforts have been made to develop brain SPECT systems based on multi-pinhole collimation owing to its enhanced resolution-sensitivity tradeoff especially when imaging small objects. Simulation studies have been carried out to optimize multi-pinhole systems (Van Audenhaege et al 2011, King et al 2012, Mukherjee et al 2014, Chen et al 2017, however only a few systems have been built and/or acquired physical scans (Lee et al 2014. Our group initially developed various focused multi-pinhole SPECT systems for preclinical purposes, e.g.…”

Section: Introductionmentioning

confidence: 99%

Optimized sampling for high resolution multi-pinhole brain SPECT with stationary detectors

Chen¹,

Goorden²,

Vastenhouw³

et al. 2020

Phys. Med. Biol.

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Brain perfusion SPECT can be used in the diagnosis of various neurologic or psychiatric disorders, e.g. stroke, epilepsy, dementia and posttraumatic stress disorder. As traditional SPECT provides limited resolution and sensitivity, we recently proposed a high resolution focusing multi-pinhole clinical SPECT scanner dubbed G-SPECT-I (Beekman et al 2015). G-SPECT-I achieves data completeness in the scan region of interest by making small translations of the patient bed while using projections from all bed positions together for image reconstruction. A strategy to restrict the number of bed translations is desired to minimize overhead time. Previously we presented optimized bed translation paths for focused partial brain imaging, while here we focus on whole brain imaging which is the common procedure in perfusion studies. Thus, a series of noise-free scans using a reduced number of bed positions were simulated and compared to an oversampled reference scan acquired with 128 bed positions. Noisy simulations were included to validate the utility of the optimized sequences in more realistic situations. Brain Uptake Ratios (BURs) and left-right Asymmetry Indices (AIs) in 51 selected Regions of Interest (ROIs) were calculated for assessment. Results show that images were barely affected by decreasing the number of bed positions from 128 down to 18 (mean deviation from the reference of only 2.2% and 1.5% for the BUR and AI respectively) while slightly larger deviations (2.9% and 2.7% respectively) were obtained when using 12 positions. For both 18-and 12-position sequences these deviations due to sampling were much smaller than those induced by noise (mean deviation of 6.5% and 8.6% respectively). Given an associated total overhead for bed movement of half a minute (18 positions) or 20 seconds (12 positions), G-SPECT-I can be a clinical platform that brings new protocols for fast (dynamic) whole brain SPECT and motion correction into reach.

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Design of a Multi-Pinhole Collimator for I-123 DaTscan Imaging on Dual-Headed SPECT Systems in Combination with a Fan-Beam Collimator

Cited by 25 publications

References 32 publications

Investigation of Axial and Angular Sampling in Multi-Detector Pinhole-SPECT Brain Imaging

Investigation of Axial and Angular Sampling in Multi-Detector Pinhole-SPECT Brain Imaging

Simulations of a Multipinhole SPECT Collimator for Clinical Dopamine Transporter (DAT) Imaging

Optimized sampling for high resolution multi-pinhole brain SPECT with stationary detectors

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