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This paper presents the development of a thermal model by forced convection flow for the LabPET II, a positron emission tomography scanner dedicated to small animal imaging. To address the mouse to rabbit requirements in size, scanners may contain up to 864 ASICs dissipating ∼600 mW each and 36 FPGAs. A thermal model was developed based on two digital techniques: the computational fluid dynamics (CFD)...
The existing pedestrian counting methods use the various keypoint detectors but there is no attempt to find a suitable keypoint detector for counting pedestrians. Therefore, in this paper, we compare the various keypoint detectors using a public dataset. Our evaluation framework uses the processing time of keypoint detection and matching as a performance measure. Also, we use the accuracy of moving...
A cadmium zinc telluride (CZT) based small animal positron emission tomography (PET) system is under development at the Molecular Imaging Instrumentation Laboratory (MIIL) at Stanford University (Fig. 1) [1,2]. A goal for this system is to advance the ability to detect, visualize, and quantify low concentration of molecular probes. Key technologies of this work are: (1) CZT detector technology, instead...
We are developing a time-of-flight (TOF) positron emission tomography (PET) scanner for brain imaging using SiPMs. In our development, we have adopted a strip-line based signal multiplexing method for efficient channel reduction for SiPMs; the method is using a single strip-line on which multiple SiPMs are connected for sharing readout, and the position of hit SiPM is decoded from the arrival time...
Spatial resolution is one of the most important performance in PET system. Higher spatial resolution can give more information about the region of interest in animal PET imaging. In this work, we implement a high resolution (approximate 0.7 mm) all digital animal PET system using improved Trans-PET detectors. The improved detector module uses 24×24 crystal array for higher intrinsic spatial resolution...
The future of positron emission tomography (PET) is systems with ultra-precise coincidence time resolution (CTR) to advance time-of-flight PET (TOF-PET) performance. Current state-of-the-art commercial PET systems have 350-800 ps fullwidth-at-half-maximum (FWHM) timing performance, constraining annihilation events to lie somewhere within a 5–12 cm region along system detector response lines (LORs)...
The purpose of the reported research is the elaboration of the method for construction of the cost-effective whole-body single-bed positron emission tomography scanner enabling simultaneous PET/CT and PET/MR imaging. The Jagiellonian Positron Emission Tomograph (J-PET) is built out of 192 scintillator strips arranged axially in three layers forming a cylindrical diagnostic chamber with the diameter...
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,...
Delivering precisely the desired dose distribution to the patient during radiotherapy is of crucial importance for treatment success and monitoring the actual distributed dose opens the possibility to correct for deposition inaccuracies and thus achieve better conformance to the treatment plan. Positron emission tomography has already been successfully used to measure the residual radioactivity from...
With the aim of improving the CNR of the LabPET II scanner, a method to correct the channel-to-channel coincidence time difference has been developed. The LabPET II, an avalanche photodiode-based PET scanner, features up to 55 000 channels which benefit from precise timing alignment. The correction process is fully automated and embedded in the scanner hardware and firmware. It uses a timing probe...
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 probe arrangement in positron emission tomography (PET) is a combination of a high resolution detector (probe) placed within a whole body PET scanner. An additional subset of high-resolution data is recorded that contains events where one of the annihilation photon pair interacted in the high resolution detector. A study was designed to evaluate impact of probe geometry and efficiency on the quality...
Within the German Plant Phenotyping Network (DPPN), we developed a novel PET scanner based on Philips Digital Photon Counters (DPCs, or dSiPMs = digital Silicon Photomultipliers). The scanner is dedicated for plant research and provides functional information on carbon transport within the plant. To this end the detector ring is oriented horizontally. It provides a Field-of-View of 18 cm dia. and...
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...
We have characterized a PET prototype based on monolithic scintillator detectors. The prototype has a modular design with 8 identical detector cassettes, each housing 4 monolithic blocks. The cassettes are mounted on a gantry in 2 groups of 4 cassettes facing each other, totaling 32 detectors. Each detector block is composed of a trapezoidal LYSO:Ce scintillator glued to a pair of Hamamatsu S8550-02...
In time-of-flight (TOF) positron emission tomography (PET), the coincidence resolving time (CRT) has a strong influence on the overall performance. Multichannel digital silicon photomultipliers (MD-SiPMs) are able to obtain several timestamps for gamma photon timemark estimation. Using this feature, the CRT is improved and the system robustness is significantly increased by utilizing multiple photoelectron...
Recently, several groups have proposed the use of scattered coincidences in positron emission tomography (PET), aiming at improved attenuation correction using the PET emission data, e.g., in PET-MRI. In this work, we analyzed the behavior of several algorithms, including reconstruction by two-branch scatter-to-attenuation back-projection (BP) and maximum likelihood expectation maximization with a...
In this paper we explore the application of anomaly detection techniques to tumor voxels segmentation. The developed algorithms work on 3-points dynamic FDG-PET acquisitions and leverage on the peculiar anaerobic metabolism that cancer cells experience over time. A few different global or local anomaly detectors are discussed, together with an investigation over two different algorithms aiming to...
Despite significant progress in pedestrian detection has been made in recent years, detecting pedestrians in crowded scenes remains a challenging problem. In this paper, we propose to use visual contexts based on scale and occlusion cues from detections at proximity to better detect pedestrians for surveillance applications. Specifically, we first apply detectors based on full body and parts to generate...
In Positron Emission Tomography (PET) and Quantum Optics, the quality of the reconstructed images is directly proportional to the quality of the employed coincidence detectors, which provide important timing information about the location of the emitted nuclear particles. This paper proposes a new circuitry, called precise coincidence detector (PCD). It consists of two RS latches, is of low complexity,...
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