A5007449503- Medical Imaging Techniques and Applications
- Radiation Detection and Scintillator Technologies
- Advanced MRI Techniques and Applications
- Atomic and Subatomic Physics Research
- Nuclear Physics and Applications
- Particle Detector Development and Performance
- Advanced X-ray and CT Imaging
- Radiopharmaceutical Chemistry and Applications
- CCD and CMOS Imaging Sensors
- Radiomics and Machine Learning in Medical Imaging
- X-ray Spectroscopy and Fluorescence Analysis
- Cancer, Hypoxia, and Metabolism
- Photodynamic Therapy Research Studies
- Nanoplatforms for cancer theranostics
- Cardiac Imaging and Diagnostics
- Nuclear physics research studies
- Advanced Radiotherapy Techniques
- Analog and Mixed-Signal Circuit Design
- Diet and metabolism studies
- Estrogen and related hormone effects
- Cardiovascular Function and Risk Factors
- Microfluidic and Capillary Electrophoresis Applications
- Atomic and Molecular Physics
- Radiation Dose and Imaging
- Adipose Tissue and Metabolism
Université de Sherbrooke
2016-2025
Q & T Research
2020-2024
Imaging Center
2008-2023
Centre Hospitalier Universitaire de Sherbrooke
2010-2022
Institute of Pharmacology
2018
Cégep de Sherbrooke
2017
Université Laval
2013-2015
Centre Hospitalier Universitaire de Nantes
2012
Bishop's University
2011
University at Buffalo, State University of New York
2010
The National Electrical Manufacturers Association (NEMA) standard NU 4-2008 for performance measurements of small-animal tomographs was recently published. Before this standard, there were no testing procedures preclinical PET systems, and manufacturers could not provide clear specifications similar to those available clinical systems under NEMA 2-1994 2-2001. Consequently, evaluation papers used methods that modified ad hoc from the thus making comparisons between difficult. <b>Methods:</b>...
The present study was designed to investigate the effects of cold on brown adipose tissue (BAT) energy substrate utilization in vivo using positron emission tomography tracers [18F]fluorodeoxyglucose (glucose uptake), 14(R,S)-[18F]fluoro-6-thiaheptadecanoic acid [nonesterified fatty (NEFA) uptake], and [11C]acetate (oxidative activity). measurements were performed rats adapted 27°C, which acutely subjected (10°C) for 2 6 hours, chronically 10°C 21 days, returned 27°C hours. Cold exposure...
The design features and engineering constraints of a PET system based on avalanche photodiode (APD) detectors have been described in previous report. Here, the authors present initial results obtained with Sherbrooke APD-PET scanner, very high spatial resolution device designed for dynamic imaging small medium-sized laboratory animals such as rats, cats, rabbits monkeys. Its physical performance has evaluated terms resolution, sensitivity, count rate, random scatter fractions, contrast...
The luminescence and nuclear spectroscopic properties of the new cerium-doped rare-earth scintillator lutetium-yttrium oxyorthosilicate (Lu/sub 0.6/Y/sub 1.4/Si/sub 0.5/:Ce, LYSO) were investigated compared to those both recent older LSO crystals. UV-excited luminescent spectra outline important similarities between LYSO scintillators. two distinct Ce1 Ce2 mechanisms previously identified in are also present energy timing resolutions measured using avalanche photodiode (APD) photomultiplier...
The LabPETtrade is a fully digital avalanche photodiode (APD) based PET scanner designed for state-of-the-art molecular and genomic imaging of small animals. Two versions the were evaluated, having 3.75 (LabPET4) 7.5 cm axial FOV (LabPET8). detectors are made 2times2times12/14 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> LYSO LGSO crystals assembled in phoswich pairs read out by an APD. After crystal identification, average energy...
Classical brown adipocytes such as those found in interscapular adipose tissue (iBAT) represent energy-burning cells, which have been postulated to play a pivotal role energy metabolism. Brown can also be white (WAT) depots [e.g., inguinal WAT (iWAT)] following adrenergic stimulation, and they referred "beige" adipocytes. Whether the presence of these adipocytes, gives iWAT beige appearance, confer depot with some thermogenic activity remains seen. In consequence, we designed present study...
The highly multiplexed analog processing front-end of current Positron Emission Tomography (PET) scanners yields high accuracy for timing but adds significant dead time and offers little flexibility improvement. A new fully digital APD-based scanner architecture is proposed wherein nuclear pulses are sampled directly at the output Charge Sensitive Preamplifier (CSP) with one free-running ADC per channel. This approach opportunity to explore signal algorithms borrowed from other fields like...
Despite current advances in PET/CT systems, blood sampling still remains the standard method to obtain radiotracer input function for tracer kinetic modelling. The purpose of this study was validate use image-derived functions (IDIF) carotid and femoral arteries measure arterial (AIF) PET imaging. data were obtained from two different research studies, one using (18)F-FDG brain imaging other (11)C-acetate (18)F-fluoro-6-thioheptadecanoic acid ((18)F-FTHA) muscles.The validated with phantom...
Photodynamic therapy (PDT) is a treatment modality for range of diseases including cancer. The BF2-chelated tetraaryl-azadipyrromethenes (ADPMs) are an emerging class non-porphyrin PDT agent, which have previously shown excellent photochemical and photophysical properties therapeutic application. Herein, in vivo efficacy mechanism action studies been completed the lead ADMP06. A multi-modality imaging approach was employed to assess treatment, as well probe ADPM06-mediated PDT. Tumour...
The purpose of this study was to determine in vivo myocardial energy metabolism and function a nutritional model type 2 diabetes. Wistar rats rendered insulin-resistant mildly hyperglycemic, hyperinsulinemic, hypertriglyceridemic with high-fructose/high-fat diet over 6-wk period injection small dose streptozotocin (HFHFS) control were studied using micro-PET (microPET) without or euglycemic hyperinsulinemic clamp. During glucose clamp, metabolic rate measured [(18)F]fluorodeoxyglucose...
Abstract In response to cold, brown adipose tissue (BAT) increases its metabolic rate and expands mass produce heat required for survival, a process known as BAT recruitment. The mechanistic target of rapamycin complex 1 (mTORC1) controls metabolism, cell growth proliferation, but role in regulating recruitment chronic cold stimulation is unknown. Here, we show that activates mTORC1 BAT, an effect depends on the sympathetic nervous system. Adipocyte-specific loss mice completely blocks...
The measurement of depth interaction (DOI) within detectors is necessary to improve resolution uniformity across the FOV small diameter PET scanners. DOI encoding by pulse shape discrimination (PSD) has definite advantages as it requires only one readout per pixel and allows photoelectric Compton events. PSD time characteristics various scintillators were studied with avalanche photodiodes (APD) identification capability was tested in multi-crystal assemblies up four scintillators. In...
One limitation in a practical implementation of statistical iterative image reconstruction is to compute transition matrix accurately modeling the relationship between projection and spaces. Detector response function (DRF) positron emission tomography (PET) broad spatially-variant, leading large matrices taking too much space store. In this work, authors investigate effect simpler DRF models on quality maximum likelihood expectation maximization reconstruction. The studied 6 cases...
Anesthesia is currently required for positron emission tomography (PET) studies of the animal brain in order to eliminate motion artifacts. However, anesthesia profoundly affects neurological state animal, complicating interpretation PET data. Furthermore, it precludes use study during normal behavior. The rat conscious tomograph (RatCAP) designed need studies. It a miniaturized full-ring scanner that attached directly head, imaging nearly entire brain. RatCAP utilizes arrays 2 mm /spl...
Describes the Sherbrooke positron emission tomograph, a very high resolution device dedicated to dynamic imaging of small laboratory animals. Its distinctive features are: discrete scintillation detectors based on avalanche photodiodes (APD) achieve uniform, isotropic, spatial resolution; parallel processing for low deadtime and count rate capability; multispectral data acquisition hardware improve sensitivity scatter correction; modularity allow design flexibility upgradability. The system...
The lack of anatomical information in SPECT and PET images is one the major factors limiting ability to localize accurately quantify radionuclide uptake small regions interest. This problem could be resolved by using multi-modality scanners having capability acquire functional simultaneously. feasibility a novel detector suitable for measuring high-energy annihilation radiation PET, medium-energy /spl gamma/-rays low-energy X-rays transmission CT demonstrated its performance evaluated...
The current trend in positron emission tomography (PET) towards very high spatial resolution tomographs raises the problem of detecting energy gamma-rays with a accuracy while preserving overall sensitivity camera. It is purpose this paper to investigate effects some geometrical parameters on detection efficiency and intrinsic circular array narrow closely packed detectors. Two approaches were employed: first one uses Monte-Carlo technique simulate interactions detectors; second based linear...
The LabPET is an avalanche photodiode (APD) based digital PET scanner with quasi-individual detector read-out and highly parallel electronic architecture for high-performance in vivo molecular imaging of small animals. on LYSO LGSO scintillation crystals (2×2×12/14 mm3), assembled side-by-side phoswich pairs read out by APD. High spatial resolution achieved through the individual independent APD recording impinging annihilation photons. exists three versions, LabPET4 (3.75 cm axial length),...
The renewed interest in BGO scintillators for TOF-PET is driven by the improved Cherenkov photon detection with new blue-sensitive SiPMs. However, slower scintillation light from causes significant time walk leading edge discrimination (LED), which degrades coincidence resolution (CTR). To address this, a correction (TWC) can be done using rise measured second threshold. Deep learning, particularly convolutional neural networks (CNNs), also enhance CTR training digitized waveforms. It...
In non-insulin-dependent, type 2, diabetes mellitus (T2D), glucose metabolism is compromised, and the heart loses its metabolic flexibility. The Zucker Diabetic Fatty rat (ZDF) model, which replicates pathophysiology of T2D in patients, shows that as progresses so does failure. Heart ketone seems to play a role mitigating failure process. This study assesses ZDF model using cardiac PET imaging. Six lean rats (CTRL) six diabetic obese (T2D) were evaluated for coronary flow reserve (CFR)...