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NaI gamma camera performance for high energies: Effects of crystal thickness, photomultiplier tube geometry and light guide thickness

Cosmi, V. (author), Wang, B. (author), Goorden, M.C. (author), Beekman, F.J. (author)

Background: Gamma camera imaging, including single photon emission computed tomography (SPECT), is crucial for research, diagnostics, and radionuclide therapy. Gamma cameras are predominantly based on arrays of photon multipliers tubes (PMTs) that read out NaI(Tl) scintillation crystals. In this way, standard gamma cameras can localize ɣ-rays...

journal article 2024

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A scanning focus nuclear microscope with multi-pinhole collimation

Nguyen, M.P. (author), Arif, M. (author), Oostenrijk, Bart (author), Goorden, M.C. (author), Beekman, F.J. (author)

Microscopic nuclear imaging down to spatial resolutions of a few hundred microns can already be achieved using low-energy gamma emitters (e.g. ¹²⁵I, ∼30 keV) and a basic single micro-pinhole gamma camera. This has been applied to in vivo mouse thyroid imaging, for example. For clinically used radionuclides such as ^99mTc,...

journal article 2023

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Point spread function of photon-counting detectors under pile-up conditions: a proposed framework

Leibold, D. (author), van der Sar, S.J. (author), Goorden, M.C. (author), Schaart, D.R. (author)

X-ray detectors with photon-counting capabilities promise to revolutionise medical imaging. For an efficient comparison of detectors of various materials and with different setup choices, reliable detector performance measures are needed. The detector point spread function (PSF) is a commonly used measure, which describes the spatial response...

journal article 2022

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Efficient Monte-Carlo based system modelling for image reconstruction in preclinical pinhole SPECT

Nguyen, M.P. (author), Goorden, M.C. (author), Ramakers, R.M. (author), Beekman, F.J. (author)

The use of multi-pinhole collimation has enabled ultra-high-resolution imaging of SPECT and PET tracers in small animals. Key for obtaining high-quality images is the use of statistical iterative image reconstruction with accurate energy-dependent photon transport modelling through collimator and detector. This can be incorporated in a system...

journal article 2021

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Convolutional neural network based attenuation correction for ¹²³I-FP-CIT SPECT with focused striatum imaging

Chen, Y. (author), Goorden, M.C. (author), Beekman, F.J. (author)

SPECT imaging with 123I-FP-CIT is used for diagnosis of neurodegenerative disorders like Parkinson's disease. Attenuation correction (AC) can be useful for quantitative analysis of 123I-FP-CIT SPECT. Ideally, AC would be performed based on attenuation maps (μ-maps) derived from perfectly registered CT scans. Such μ-maps, however, are most...

journal article 2021

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Positron range-free and multi-isotope tomography of positron emitters

Beekman, F.J. (author), Kamphuis, C. (author), Koustoulidou, S. (author), Ramakers, R.M. (author), Goorden, M.C. (author)

Despite improvements in small animal PET instruments, many tracers cannot be imaged at sufficiently high resolutions due to positron range, while multi-tracer PET is hampered by the fact that all annihilation photons have equal energies. Here we realize multi-isotope and sub-mm resolution PET of isotopes with several mm positron range by...

journal article 2021

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Automatic attenuation map estimation from SPECT data only for brain perfusion scans using convolutional neural networks

Chen, Y. (author), Goorden, M.C. (author), Beekman, F.J. (author)

In clinical brain SPECT, correction for photon attenuation in the patient is essential to obtain images which provide quantitative information on the regional activity concentration per unit volume (kBq). This correction generally requires an attenuation map (map) denoting the attenuation coefficient at each voxel which is often derived from...

journal article 2021

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Experimental Validation of a Gamma Detector With a Novel Light-Guide-PMT Geometry to Reduce Dead Edge Effects

Wang, B. (author), Kreuger, R. (author), Huizenga, J. (author), Beekman, F.J. (author), Goorden, M.C. (author)

Photomultiplier tube (PMT)-based scintillation cameras are predominant in molecular imaging but have the drawback that position estimation is severely degraded near the edges (dead edge effect). This leads to sensitivity losses and can cause severe problems in applications like molecular breast imaging and in certain SPECT devices. Using smaller...

journal article 2020

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EXIRAD-HE: Multi-pinhole high-resolution ex vivo imaging of high-energy isotopes

Nguyen, M.P. (author), Goorden, M.C. (author), Beekman, F.J. (author)

We recently developed a dedicated focusing multi-pinhole collimator for a stationary SPECT system that offers down to 120 m (or 1.7 nL) spatial resolution SPECT images of cryo-cooled tissue samples (EXIRAD-3D). This collimator is suitable for imaging isotopes that are often used in small animal and diagnostic SPECT such as 125I (27 keV),...

journal article 2020

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EXIRAD-3D: Fast automated three-dimensional autoradiography

Nguyen, M.P. (author), Ramakers, R.M. (author), Kamphuis, Chris (author), Koustoulidou, Sofia (author), Goorden, M.C. (author), Beekman, F.J. (author)

Introduction: Autoradiography is an established technique for high-resolution imaging of radiolabelled molecules in biological tissue slices. Unfortunately, creating a 3D image from a set of these 2D images is extremely time-consuming and error-prone. MicroSPECT systems provide such 3D images but have a low resolution. Here we present EXIRAD...

journal article 2020

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Accelerated image reconstruction by a combined dual-matrix dual-voxel approach

Goorden, M.C. (author), Kamphuis, Chris (author), Ramakers, R.M. (author), Beekman, F.J. (author)

Today, versatile emission computed tomography (VECTor) technology using dedicated high-energy collimation enables simultaneous positron emission tomography (PET) and single photon emission computed tomography (SPECT) down to 0.6 mm and 0.4 mm resolution in mice, respectively. We recently showed that for optimal resolution and quantitative...

journal article 2020

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

Chen, Y. (author), Goorden, M.C. (author), Vastenhouw, B. (author), Beekman, F.J. (author)

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...

journal article 2020

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Characterization of a multi-pinhole molecular breast tomosynthesis scanner

Wang, B. (author), van Roosmalen, J. (author), Kreuger, R. (author), Huizenga, J. (author), Beekman, F.J. (author), Goorden, M.C. (author)

In recent years, breast imaging using radiolabelled molecules has attracted significant interest. Our group has proposed a multi-pinhole molecular breast tomosynthesis (MP-MBT) scanner to obtain 3D functional molecular breast images at high resolutions. After conducting extensive optimisation studies using simulations, we here present a first...

journal article 2020

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Evaluation of pinhole collimator materials for micron-resolution ex vivo SPECT

Nguyen, M.P. (author), Goorden, M.C. (author), Kamphuis, Chris (author), Beekman, F.J. (author)

Pinhole collimation is widely recognized for offering superior resolution-sensitivity trade-off in SPECT imaging of small subjects. The newly developed EXIRAD-3D autoradiography technique (MILabs B.V.) based on a highly focusing multi-pinhole collimator achieves micron-resolution SPECT for cryo-cooled tissue samples. For such high resolutions...

journal article 2019

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Novel light-guide-PMT geometries to reduce dead edges of a scintillation camera

Wang, B. (author), Kreuger, R. (author), Beekman, F.J. (author), Goorden, M.C. (author)

Anger cameras based on monolithic NaI scintillators read out by an array of PMTs are predominant in planar gamma imaging and SPECT. However, position estimation of gamma interactions is usually severely degraded near the edges of the scintillator which can be extremely undesirable for applications like breast imaging. Here we propose a...

journal article 2018

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Optimized image acquisition for dopamine transporter imaging with ultra-high resolution clinical pinhole SPECT

Chen, Y. (author), Vastenhouw, B. (author), Wu, C. (author), Goorden, M.C. (author), Beekman, F.J. (author)

SPECT can be used to image dopamine transporter (DaT) availability in the human striatum, e.g. for diagnosis of Parkinson's disease (PD). As traditional SPECT provides limited resolution and sensitivity, we proposed a full ring focusing multi-pinhole SPECT system (G-SPECT-I (Beekman 2015 Eur. J. Nucl. Med. Mol. Imaging 42 S209)) which...

journal article 2018

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Comparison of fan-beam, slit-slat and multi-pinhole collimators for molecul breast tomosynthesis

van Roosmalen, J. (author), Beekman, F.J. (author), Goorden, M.C. (author)

Recently, we proposed and optimized dedicated multi-pinhole molecular breast tomosynthesis (MBT) that images a lightly compressed breast. As MBT may also be performed with other types of collimators, the aim of this paper is to optimize MBT with fan beam and slit-slat collimators and to compare its performance to that of multi-pinhole MBT to...

journal article 2018

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Non-diverging analytical expression for the sensitivity of converging SPECT collimators

van Roosmalen, J. (author), Goorden, M.C. (author)

Accurate analytical expressions for collimator resolution and sensitivity are important tools in the optimization of SPECT systems. However, presently known expressions for the sensitivity of converging collimators either diverge near the focal point or focal line(s), or are only valid on the collimator axis. As a result, these expressions...

journal article 2017

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Optimizing modelling in iterative image reconstruction for preclinical pinhole PET

Goorden, M.C. (author), van Roosmalen, J. (author), van der Have, F. (author), Beekman, F.J. (author)

The recently developed versatile emission computed tomography (VECTor) technology enables high-energy SPECT and simultaneous SPECT and PET of small animals at sub-mm resolutions. VECTor uses dedicated clustered pinhole collimators mounted in a scanner with three stationary large-area NaI(Tl) gamma detectors. Here, we develop and validate...

journal article 2016

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Utilizing high-energy γ-photons for high-resolution ²¹³Bi SPECT in mice

De Swart, Jan (author), Chan, Ho Sze (author), Goorden, M.C. (author), Morgenstern, Alfred (author), Bruchertseifer, Frank (author), Beekman, F.J. (author), de Jong, M. (author), Konijnenberg, Mark W. (author)

The combined α-, γ-, and x-ray emitter ²¹³Bi (half-life, 46 min) is promising for radionuclide therapy. SPECT imaging of ²¹³Bi is challenging, because most emitted photons have a much higher energy (440 keV) than common in SPECT. We assessed ²¹³Bi imaging capabilities of the Versatile Emission Computed...

journal article 2016