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A one-step inversion algorithm for spectral computed tomography (CT) is developed that yields material decomposition maps from multi-energy X-ray transmission data as what could conceivably be measured with photon-counting X-ray detectors. This approach is potentially desirable because incorporation of many physical constraints can be implemented directly on the material maps. Use of such constraints...
The trigger readout electronics of the ATLAS Liquid Argon (LAr) Calorimeters will be improved for the Phase-I luminosity upgrade of the LHC, to enhance the trigger feature extraction. Signals with higher spatial granularity will be digitized and processed by newly developed front-end and back-end electronics. In order to evaluate the technical and performance aspects, a demonstrator system has been...
THE High Luminosity upgrade of the Large Hadron Collider will pose new challenges to the installed detectors. Higher beam background, combined with new requirements in terms of power supply for the upgraded detectors, and the presence of magnetic fields up to 1 T, make the choice of power supply electronic components a crucial point for the successful operation of the detectors for the new physics...
Proton therapy is supposed to be advantageous compared to classical radiation therapy in oncology. But range uncertainties can arise easily and have to be corrected for, preferably immediately during irradiation. Prompt gammas are a good means of instantaneous localization of the dose deposition. Detection systems have to cope with high counting rates, an energy region of up to several MeV and increased...
Beam Position Measurement (BPM) system is an indispensable diagnosis instrument that is used to monitor the beam position information. A digital BPM (DBPM) has been designed for Shanghai Synchrotron Radiation Facility (SSRF). Among the different types of data that the DBPM provides, the Close Orbit (CO) data is an important one which is applied to beam monitoring, as well as feedback to keep the beam...
X ray imaging can benefit from dynamic range enhancement methods developed initially for visible and infrared CMOS pixel sensors. An X-ray pixel design based on the folded multiple capture technique is presented. The influence of spatial and temporal noise on the determination of the photocurrent is discussed. The dynamic range can exceed 100db.
A successful OpenPET electronics system needs to provide electronics, especially front-end electronics that are powerful enough to accommodate cutting-edge research. While there are a tremendous number of variations, the relatively simple nature of the data ultimately collected implies that there can be a common set of requirements. In this paper, we describe a 32-channel high-performance Detector...
Compton scattering of gamma photons can give rise to inter-crystal crosstalk in detector arrays for positron emission tomography (PET). PET systems made of pixelated detectors with individual readout can recover inter-crystal scatter (ICS) events in the list-mode data file, but these events are generally ignored since their inclusion in the image reconstruction process leads to undesirable image noise...
For Time-of-Flight (TOF) PET detectors the timing resolution is one of the critical parameters for improving image quality. One of the effects degrading the timing resolution is the statistical fluctuation of the number of scintillation photons. The timing degradation is introduced by leading edge discriminator (LED) because the time of crossing the comparator threshold is signal-dependent. It is...
PET images suffer from partial volume effects (PVE) due to the poor spatial resolution of the PET system. Anatomy-enhanced PET reconstruction allows to restore such loss of resolution in PET images and attempt to reveal more accurately the actual tracer distribution [1] [4].
A major limitation of the currently available small animal PET and SPECT imaging is their relatively low sensitivity to the incident gamma rays. While providing high spatial resolution utilizing finely pitched scintillator arrays has been explored, the cost of array fabrication has been an issue. Moreover, high sensitivity has been traded off for high spatial resolution since fabrication of scintillator...
An NCI-sponsored program to allow qualification of PET imaging sites for use in Cancer Clinical trials has created a data set, assembled and maintained by the American College of Radiology Imaging Network (ACRIN), with a rich collection of PET phantom measurements assessing imaging quality. Previous work with the data has focused on systematic deviations between the actual activity value in the phantom...
We propose a new compact SiPM array designed and optimized for low energies (e.g. 140 keV) and multi-tracers gamma rays detection. The final purpose of the array is to populate MR compatible SPECT systems. Coupled to a 4 mm thick CsI(Tl) scintillator, the SiPM array presents a Field of View (FOV) of 25 mm × 25 mm, an Usefull Field of View (UFOV) of 20 mm × 20 mm and an intrinsic spatial resolution...
MR compatible PET is an attractive hybrid modality for preclinical small animal studies. Small ring diameter PET systems, such as those needed to fit inside an MR bore, tend to suffer from radial blurring due to parallax error away from the center of the FOV. To reduce this error a phoswich design can be adopted where layers of different scintillation materials are identified by decay time characteristics...
IQ.SPECT technology performs Myocardial Perfusion Imaging (MPI) in less than five minutes compared to conventional 20–25 minute scans. The aim of this study was to optimise the IQ.SPECT reconstruction and compare with conventional MPI scanning and Echocardiography using perfusion and ECG-gated imaging. 18 patients were imaged using IQ.SPECT in addition to conventional SPECT and the IQ.SPECT reconstruction...
In this study we quantify the depth of interaction (DOI) capabilities of unique dual light sharing arrays (DLSA) on digital silicon photomultipliers. Side and entrance surface DOI calibration methods were tested. Results showed timing resolutions of 350–370 ps and energy resolutions of 10–12% while achieving a DOI position estimation of 6–7 mm FWHM. Significant improvements in depth estimation error...
PET detectors based on light sharing, which can obtain spatial resolution smaller than the photo-detector size with a simple calculation to estimate the center of gravity, have often been studied, but the difficulty in identifying inter-crystal scattering (ICS) has not been resolved yet. In particular, ICS identification is strongly required to make full use of a minutely segmented crystal block such...
As digital signal has abilities like immunity for transmit distortion and feasibility to calibrate, digital architecture that samples the event waveform at the earliest possible stage shows promising potential for building next generation PET system. Multi-voltage threshold (MVT) is a digital sampling method that take time samples when pulses cross predefined thresholds and extracts event information...
In the framework of the German Plant Phenotyping Network (DPPN) we developed a novel PET scanner for imaging plants and crops. The observation of the carbon transport within the plant becomes possible by using 11CO2 as PET tracer. The use of the rather short living isotope C-11 asks for a scanner with high dynamic range. That means fast timing and high data rates are important features which let us...
Molecular Breast Imaging (MBI) systems fabricated using direct-conversion detectors have demonstrated very high sensitivity and specificity in detecting breast cancer. These systems are made possible by the development of Cadmium Zinc Telluride (CZT) gamma cameras that have superior energy resolution and intrinsic spatial resolution compared to scintillation-based cameras. Image quality and patient...
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