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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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Pouran, Behdad (author), Raoof, Amir (author), de Winter, D. A.Matthijs (author), Arbabi, V. (author), Bleys, Ronald L.A.W. (author), Beekman, F.J. (author), Zadpoor, A.A. (author), Malda, Jos (author), Weinans, Harrie (author)Recent insights suggest that the osteochondral interface plays a central role in maintaining healthy articulating joints. Uncovering the underlying transport mechanisms is key to the understanding of the cross-talk between articular cartilage and subchondral bone. Here, we describe the mechanisms that facilitate transport at the osteochondral...journal article 2021
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Sagastizabal, R.E. (author), Klaver, B. A. (author), Rol, M.A. (author), Negîrneac, V. (author), Zou, X. (author), Muthusubramanian, N. (author), Beekman, M. (author), Zachariadis, C. (author), Ostroukh, V.P. (author), Haider, S.N. (author), Bruno, A. (author), DiCarlo, L. (author)The preparation of thermal equilibrium states is important for the simulation of condensed matter and cosmology systems using a quantum computer. We present a method to prepare such mixed states with unitary operators and demonstrate this technique experimentally using a gate-based quantum processor. Our method targets the generation of...journal article 2021
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Negîrneac, V. (author), Ali, H.A.S. (author), Muthusubramanian, N. (author), Battistel, F. (author), Sagastizabal, R.E. (author), Moreira, M. S. (author), Ferreira Marques, J.M. (author), Vlothuizen, W.J. (author), Beekman, M.C. (author), Zachariadis, C. (author), Haider, S.N. (author), Bruno, A. (author), DiCarlo, L. (author)Simple tuneup of fast two-qubit gates is essential for the scaling of quantum processors. We introduce the sudden variant (SNZ) of the net zero scheme realizing controlled-Z (CZ) gates by flux control of transmon frequency. SNZ CZ gates realized in a multitransmon processor operate at the speed limit of transverse coupling between...journal article 2021
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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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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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Van der Heiden, K. (author), Barrett, H. E. (author), van Gaalen, K.C. (author), Krenning, B. J. (author), Beekman, F.J. (author), Verhagen, H. J.M. (author), Norenberg, J. P. (author), de Jong, M. (author), Gijsen, F.J.H. (author)Background: Calcification and inflammation are atherosclerotic plaque compositional biomarkers that have both been linked to stroke risk. The aim of this study was to evaluate their co-existing prevalence in human carotid plaques with respect to plaque phenotype to determine the value of hybrid imaging for the detection of these biomarkers....journal article 2021
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Beekman, Marian (author), Schutte, Bianca A.M. (author), van den Akker, E.B. (author), Noordam, Raymond (author), Dibbets-Schneider, Petra (author), de Geus-Oei, Lioe Fee (author), Deelen, Joris (author), Rest, Ondine van de (author), Heemst, Diana van (author)Scope: Abdominal obesity is one of the main modifiable risk factors of age-related cardiometabolic disease. Cardiometabolic disease risk and its associated high abdominal fat mass, cholesterol, and glucose concentrations can be reduced by a healthier lifestyle. Hence, the aim is to understand the relation between lifestyle-induced changes in...journal article 2020
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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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Barrett, Hilary E. (author), Meester, Eric J. (author), van Gaalen, Kim (author), van der Heiden, Kim (author), Krenning, Boudewijn J. (author), Beekman, F.J. (author), Verhagen, H. J. (author), de Jong, M. (author), Gijsen, F.J.H. (author)Purpose: Atherosclerotic plaque development and progression signifies a complex inflammatory disease mediated by a multitude of proinflammatory leukocyte subsets. Using single photon emission computed tomography (SPECT) coupled with computed tomography (CT), this study tested a new dual-isotope acquisition protocol to assess each radiotracer...journal article 2020
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Bultink, C.C. (author), O'Brien, T. E. (author), Vollmer, R. (author), Muthusubramanian, N. (author), Beekman, M. W. (author), Rol, M.A. (author), Fu, X. (author), Tarasinski, B.M. (author), Ostroukh, V.P. (author), Varbanov, B.M. (author), Bruno, A. (author), DiCarlo, L. (author)Protecting quantum information from errors is essential for large-scale quantum computation. Quantum error correction (QEC) encodes information in entangled states of many qubits and performs parity measurements to identify errors without destroying the encoded information. However, traditional QEC cannot handle leakage from the qubit...journal article 2020
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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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Rikkert, L. G. (author), Beekman, P. (author), Caro-Schuurman, J. (author), Coumans, F. A.W. (author), Enciso-Martinez, A. (author), Jenster, G. (author), Le Gac, S. (author), Lee, W. (author), Loozen, G.B. (author)Extracellular vesicles (EVs) have great potential as biomarkers since their composition and concentration in biofluids are disease state dependent and their cargo can contain disease-related information. Large tumor-derived EVs (tdEVs, >1μm) in blood from cancer patients are associated with poor outcome, and changes in their number can be...journal article 2020
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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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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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Ozsahin, Ilker (author), Chen, Ling (author), Könik, Arda (author), King, Michael A. (author), Beekman, F.J. (author), Mok, Greta S.P. (author)Single photon emission computed tomography (SPECT) is an important imaging modality for various applications in nuclear medicine. The use of multi-pinhole (MPH) collimators can provide superior resolution-sensitivity trade-off when imaging small field-of-view compared to conventional parallel-hole and fan-beam collimators. Besides the very...review 2020
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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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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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Yamoah, Grace Gyamfuah (author), Cao, Liji (author), Wu, C. (author), Beekman, F.J. (author), Vandeghinste, Bert (author), Mannheim, Julia G. (author), Rosenhain, Stefanie (author), Leonardic, Kevin (author), Kiessling, Fabian (author), Gremse, Felix (author)Purpose: In biomedical research, imaging modalities help discover pathological mechanisms to develop and evaluate novel diagnostic and theranostic approaches. However, while standards for data storage in the clinical medical imaging field exist, data curation standards for biomedical research are yet to be established. This work aimed at...journal article 2019
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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