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The increased statistical efficiency gained with TOF information can be used to decrease acquisition time, decrease injected dose, or improve image quality of a PET system. We are designing Tachyon TOF PET cameras (Tachyon I, II and III) to: (1) Construct “demonstration” single-ring TOF PET cameras that achieve significantly improved timing resolution; (2) Quantitatively measure the benefit for clinically...
PET detectors capable of measuring 511 keV photon time-of-fight (TOF) and depth-of-interaction (DOI) can improve resulting image quality and accuracy. In this work, we studied the timing performance of two TOF-DOI PET detector designs: (1) phoswich and (2) offset crystal arrays. The phoswich detector comprises a 3 × 3 × 20 mm3 element made from a 3 × 3 × 10 mm3 LYSO:Ce crystal with 42 ns decay time...
The easyPET concept proposed here, protected under a patent by the University of Aveiro, aims to realize a simple and affordable small dimension Positron Emission Tomography (PET) scanner. This innovative system is based on a single pair of detectors and a rotating mechanism with two degrees of freedom reproducing the functionalities of an entire PET ring. A 2D imaging prototype has been designed,...
Cerium Bromide (CeBr3) has high light output, a short decay time, and a very fast rise time—a combination of properties that should result in excellent timing resolution. Here we present results from several productions of Cerium Bromide (CeBr3) pixels investigated for use in the design of an ultra-fast TOF-PET detector. Compared to LSO/LYSO, CeBr3 also has the potential to be much less expensive...
Measuring system response matrix (SRM) by Monte Carlo method is time and resource consuming, even with high performance computer nodes. In this paper, we exploited symmetry properties available to drastically reduce the complexity in computing SRM of panel PET, which has two parallel panel detectors. By extending the original system and simulating 4 voxels every slice parallel to the PET detector,...
Medical PET scanners now exist in relatively large numbers around the world suggesting that certain physics experiments might be carried out during off-hours with these machines if organized into a global array of interlinked devices. Workers at Purdue, for example, have claimed to detect a possibly neutrino-induced annual periodicity in the decay rate of Cl-36 as the Earth traverses its elliptical...
PTSIM is a particle therapy system simulation framework based on Geant4 Monte Carlo simulation toolkit. It was originally developed as a reliable dose calculation tool to verify dose distributions inside patient and dose calculation algorithms in treatment planning systems. Besides such a reliable dose calculation, an irradiation field monitoring is desirable for delivering dose with more ideal distribution...
The electromagnetic calorimeter (EMC) of the PANDA detector at the future FAIR facility is composed of two endcaps and a barrel covering the major part of the solid angle consisting of more than 11.300 tapered PbWO4 crystals. The individual scintillator modules are readout via two large area avalanche photo diodes. The signal processing is performed with a custom made ASIC-preamplifier providing a...
A new method using a stopped cosmic-ray beam for the calibration of an electro-magnetic calorimeter which consists of several hundreds of modules has been established. Cosmic muons stop in the calorimeter, and positrons (and electrons) from the muon decays with the maximum energy of 53 MeV are used for the energy calibration. These events could be identified as double pulses observed by a flash ADC...
– The barrel part of the target EMC of the PANDA detector at the future FAIR facility will consist of 11 crystal geometries with a varying degree of tapering. The tapered shape introduces a focussing effect to the light collection, which in combination with the absorption of the scintillation light within the crystal causes a non-uniformity in light collection. For the most tapered crystals, light...
The Compact Muon Solenoid (CMS) experiment at the Large Hadron Collider (LHC) is currently operating with proton-proton collisions at 13 TeV center-of-mass energy and at a bunch spacing of 25 ns. Achieving and maintaining excellent energy resolution for electrons and photons is of primary importance for the CMS physics program for Standard Model measurements and beyond Standard Model searches. In...
The next generation of organ specific Positron Emission Tomography (PET) scanners, e.g. for breast imaging, will use partial ring geometries. We propose a component-based Maximum-Likelihood (ML) estimation of normalisation factors for 3D PET data reconstruction applicable to partial ring geometries. This method is based on the Software for Tomographic Image Reconstruction (STIR) for full ring PET...
The use of new PrLuAg and Ce:CAAG crystals, developed for PET scanners. and of more conventional LaBr3 crystals, with a SiPM array readout has been proposed, searching for compact X-rays detectors. The first two crystals are not-hygroscopic and have high photon yields, good energy resolution and fast decay time. Preliminary laboratory results are reported.
Two fourth-generation 3He replacement (HeRep Mk IV) detectors based on microstructured semiconductor neutron detector (MSND) technology have been fabricated and characterized against a 0.75-in diameter by 3.0-in long, 10-atm 3He neutron proportional counter. The HeRep Mk IV detectors have a 0.75-in by 0.75-in square form factor with one HeRep Mk IV measuring 3.1-in long and the other measuring 6.1-in...
We designed a novel PET insert based on monolithic LYSO crystals. From our first evaluation, we can conclude that sub-millimeter detector spatial resolution, combined with accurate photon DOI determination, make it possible to acquire high resolution reconstructed images. This enables us to combine simultaneously high resolution and sensitivity PET with high field preclinical MRI to extract simultaneously...
This work reports on the characterization of TlBr detectors for use in nuclear medicine. Several different detectors have been used to assess the potential performance of the material. A 12 mm thick detector with a Frisch collar has been used to achieve an energy resolution of 3.5% at 511 keV and 2.3% at 662 keV. A 0.4 mm thick detector biased at 200 V has been operated in coincidence with an LSO...
In recent years, a new generation of compact gamma cameras, based on monolithic scintillation crystals, has become increasingly widespread. The main advantages of small FoV gamma cameras with respect to the standard ones are high portability, low cost and low weight, allowing several clinical applications, from scintimammography to intraoperative tumor localization. In gamma cameras based on continuous...
In this work, a direct image reconstruction algorithm for PET is proposed. This method follows naturally from the concept of LOR, and easily admits depth of interaction and time of flight information. In addition, this algorithm does not require the computation of sinograms or a system matrix. Thus, it is not restricted in the formation of high pixel density images and allows the image formation in...
The effect of crystal surface finish on the performance of radiation detector has been studied many times mostly focused on a single isolated crystal coupled to a single photosensor. In this paper, we studied roughen crystal effect on light sharing crystal arrays using LYSO crystals of 3.95 × 5.3 × 25mm3. Four different types of crystal arrays were built: no light sharing and light sharing arrays...
Silicon photomultipliers (SiPMs) are attractive replacements for photomultiplier tubes (PMTs). However, many radiation detector applications require large volumes of monolithic scintillator and correspondingly large numbers of SiPMs. When multiples of SiPMs are used, the dark count noise and cost increase proportionally with the surface area covered. When too few SiPMs are used, non-uniformity of...
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