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Ji, C. (author), Van der Have, F. (author), Gratama van Andel, H. (author), Ramakers, R. (author), Beekman, F.J. (author)Spatially registering SPECT with CT makes it possible to anatomically localize SPECT tracers. In this study, an accurate method for the coregistration of ultra-high-resolution SPECT volumes andmultiple cone-beam CT volumes is developed and validated, which does not require markers during animal scanning. Methods. Transferable animal beds were...journal article 2010
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Wu, C. (author), Van der Have, F. (author), Vastenhouw, B. (author), Dierckx, R.A.J.O. (author), Paans, A.M.J. (author), Beekman, F.J. (author)Purpose: In pinhole SPECT, attenuation of the photon flux on trajectories between source and pinholes affects quantitative accuracy of reconstructed images. Previously we introduced iterative methods that compensate for image degrading effects of detector and pinhole blurring, pinhole sensitivity and scatter for multi-pinhole SPECT. The aim of...journal article 2010
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Taskesen, E. (author), Beekman, R. (author), De Ridder, J. (author), Wouters, B.J. (author), Peeters, J.K. (author), Touw, I.P. (author), Reinders, M.J.T. (author), Delwel, R. (author)Background: Tiling-arrays are applicable to multiple types of biological research questions. Due to its advantages (high sensitivity, resolution, unbiased), the technology is often employed in genome-wide investigations. A major challenge in the analysis of tiling-array data is to define regions-of-interest, i.e., contiguous probes with...journal article 2010
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Schaart, D.R. (author), Seifert, S. (author), Vinke, R. (author), Van Dam, H.T. (author), Dendooven, P. (author), Löhner, H. (author), Beekman, F.J. (author)The use of time-of-flight (TOF) information in positron emission tomography (PET) enables significant improvement in image noise properties and, therefore, lesion detection. Silicon photomultipliers (SiPMs) are solid-state photosensors that have several advantages over photomultiplier tubes (PMTs). SiPMs are small, essentially transparent to 511...journal article 2010
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Branderhorst, W. (author), Vastenhouw, B. (author), Beekman, F.J. (author)Single photon emission computed tomography (SPECT) and positron emission tomography (PET) visualize distributions of radioactive tracer molecules in vivo. These distributions can be calculated from projection images with iterative image reconstruction algorithms. In each iteration an update of the image is calculated after comparing a set of...journal article 2010
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Van der Laan, D.J. (author), Schaart, D.R. (author), Maas, M.C. (author), Beekman, F.J. (author), Bruyndonckx, P. (author), Van Eijk, C.W.E. (author)Much research is being conducted on position-sensitive scintillation detectors for medical imaging, particularly for emission tomography. Monte Carlo simulations play an essential role in many of these research activities. As the scintillation process, the transport of scintillation photons through the crystal(s), and the conversion of these...journal article 2010
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Goorden, M.C. (author), Beekman, F.J. (author)State-of-the-art small-animal single photon emission computed tomography (SPECT) enables sub-half-mm resolution imaging of radio-labelled molecules. Due to severe photon penetration through pinhole edges, current multi-pinhole SPECT is not suitable for high-resolution imaging of photons with high energies, such as the annihilation photons...journal article 2010
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Golestani, R. (author), Wu, C. (author), Tio, R.A. (author), Zeebregts, C.J. (author), Petrov, A.D. (author), Beekman, F.J. (author), Dierckx, R.A.J.O. (author), Boersma, H.H. (author), Slart, R.H.J.A. (author)Preclinical cardiovascular research using noninvasive radionuclide and hybrid imaging systems has been extensively developed in recent years. Single photon emission computed tomography (SPECT) is based on the molecular tracer principle and is an established tool in noninvasive imaging. SPECT uses gamma cameras and collimators to form projection...journal article 2010
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Goorden, M.C. (author), Rentmeester, M.C.M. (author), Beekman, F.J. (author)Presently used clinical brain SPECT suffers from limited spatio-temporal resolution. Here we investigate the feasibility of high-resolution and high-sensitivity full-ring multi-pinhole brain SPECT (MP-SPECT). Using an analytical model we optimized pinhole-detector geometries of MP-SPECT for different detector intrinsic resolutions Ri. System...journal article 2009
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Westra, A.H. (author), Heemskerk, J.W.T. (author), Korevaar, M.A.N. (author), Theuwissen, A.J.P. (author), Kreuger, R. (author), Ligtvoet, K.M. (author), Beekman, F.J. (author)Charge Coupled Devices (CCDs) optically coupled to scintillation crystals can be used to construct high resolution gamma cameras. Previously, several groups have reported intrinsic detector spatial resolutions below 100 microns. When the CCD images can be read out fast enough, the energy and interaction position of individual gamma quanta can be...journal article 2009
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Beekman, F.J. (author), Vastenhouw, B. (author), Van der Wilt, G. (author), Vervloet, M. (author), Visscher, R. (author), Booij, J. (author), Gerrits, M. (author), Ji, C. (author), Ramakers, R. (author), Van der Have, F. (author)With the steadily improving resolution of novel small-animal single photon emission computed tomography (SPECT) and positron emission tomography devices, highly detailed phantoms are required for testing and optimizing these systems. We present a three-dimensional (3-D) digital and physical phantom pair to represent, e.g., cerebral blood flow,...journal article 2009
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- Xiao, J. (author), Verzijlbergen, F.J. (author), Viergever, M.A. (author), Beekman, F.J. (author) journal article 2009
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Korevaar, M.A.N. (author), Heemskerk, J.W.T. (author), Beekman, F.J. (author)The performance of pinhole single photon emission computed tomography (SPECT) depends on the spatial resolution of the gamma-ray detectors used. Pinhole cameras suffer from strong resolution loss due to the varying depth-of-interaction (DOI) of gamma quanta that enter the detector material at an angle. We eliminate DOI effects in a scintillation...journal article 2009
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Schaart, D.R. (author), Van Dam, H.T. (author), Seifert, S. (author), Vinke, R. (author), Dendooven, P. (author), Löhner, H. (author), Beekman, F.J. (author)Silicon photomultipliers (SiPMs) are of great interest to positron emission tomography (PET), as they enable new detector geometries, for e.g., depth-of-interaction (DOI) determination, are MR compatible, and offer faster response and higher gain than other solid-state photosensors such as avalanche photodiodes. Here we present a novel detector...journal article 2009
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Heemskerk, J.W.T. (author), Korevaar, M.A.N. (author), Kreuger, R. (author), Ligtvoet, C.M. (author), Schotanus, P. (author), Beekman, F.J. (author)High-resolution imaging of x-ray and gamma-ray distributions can be achieved with cameras that use charge coupled devices (CCDs) for detecting scintillation light flashes. The energy and interaction position of individual gamma photons can be determined by rapid processing of CCD images of individual flashes. Here we investigate the improvement...journal article 2009
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Maas, M.C. (author), Schaart, D.C. (author), Van der Laan, D.J. (author), Bruyndonckx, P. (author), Lemaître, C. (author), Beekman, F.J. (author), Van Eijk, C.W.E. (author)We developed positron emission tomography (PET) detectors based on monolithic scintillation crystals and position-sensitive light sensors. Intrinsic depth-of-interaction (DOI) correction is achieved by deriving the entry points of annihilation photons on the front surface of the crystal from the light sensor signals. Here we characterize the...journal article 2009
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Baiker, M. (author), Vastenhouw, B. (author), Branderhorst, W. (author), Reiber, J.H.C. (author), Beekman, F. (author), Lelieveldt, B.P.F. (author)Highly focused Micro-SPECT scanners enable the acquisition of functional small animal data with very high-resolution. To acquire a maximum of emitted photons from a specific structure of interest and at the same time minimize the required acquisition time, typically only a small subvolume of the animal is scanned that contains the organs of...conference paper 2009
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Korevaar, M.A.N. (author), Heemskerk, J.W.T. (author), Goorden, M.C. (author), Beekman, F.J. (author)Gamma cameras based on charge-coupled devices (CCDs) and micro-columnar CsI scintillators can reach high spatial resolutions. However, the gamma interaction probability of these scintillators is low (typically <30% at 141 keV) due to the limited thickness of presently available micro-columnar scintillators. Continuous scintillators can improve...journal article 2009
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Van der Have, F. (author), Vastenhouw, B. (author), Ramakers, R.M. (author), Branderhorst, W. (author), Krah, J.O. (author), Ji, C. (author), Staelens, S.G. (author), Beekman, F.J. (author)We present a new rodent SPECT system (U-SPECT-II) that enables molecular imaging of murine organs down to resolutions of less than half a millimeter and high-resolution total-body imaging. Methods: The U-SPECT-II is based on a triangular stationary detector set-up, an XYZ stage that moves the animal during scanning, and interchangeable cylindric...journal article 2009
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Baiker, M. (author), Vastenhouw, B. (author), Branderhorst, S.W. (author), Reiber, J.H.C. (author), Beekman, F.J. (author), Lelieveld, B.P.F. (author)Highly focused Micro-SPECT scanners enable the acquisition of functional small animal data with very high-resolution. To acquire a maximum of emitted photons from a specific structure of interest and at the same time minimize the required acquisition time, typically only a small subvolume of the animal is scanned that contains the organs of...conference paper 2009