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In this work, we apply the theoretically convergent entropic mirror descent algorithm (EMDA) to the maximization of the list mode maximum likelihood objective function for time-of-flight (TOF) positron emission tomography (PET) image reconstruction. The algorithm also has a theoretically convergent ordered subsets implementation and is readily generalizable to priors. Here we demonstrate the algorithm...
A novel modular multiplatform software tool was developed for display, registration and fusion of cardiac electrophysiology (EP) voltage data with PET/SPECT cardiac images and their polar maps. The EP voltage measurements were acquired at discrete locations on the endocardial surface by a catheter-based electroanatomic mapping system as part of left ventricular tachycardia ablation procedures. These...
In the work, we investigate the feasibility of using sparse data from spectral CT systems with multiple data sets. We develop an optimization-based reconstruction method that may avoid the limitations of standard data-based decomposition methods in spectral CT, such as overlapping rays and dense angular sampling. We generated data from two distinct diagnostic range kVp spectra based on two non-overlapping...
Spatial resolution in positron emission tomography (PET) is still a limiting factor in many imaging applications. Mechanical movement (e.g., controlled scanner or bed motion) has been introduced to PET systems to increase sampling and improve spatial resolution. The objective of this work is to investigate super-sampling techniques with an advanced blob-based super-resolution reconstruction algorithm...
We are developing the OpenPET which can provide an open space to make the patient observable and accessible during PET measurements. One of the key technologies for realizing the OpenPET geometry is the depth of interaction (DOI) detectors because the geometry has many oblique lines of response (LORs). Even if the DOI detectors reduce the blurring effect of the thick crystals, it is important to model...
Digitizing scintillation pulses with the Multi-voltage threshold (MVT) method shows great potentials for building all-digital positron emission tomography (PET). In this paper, we introduce the MVT method into gamma-ray spectroscopy. An accurate scintillation pulse model used in pulse fitting is especially important to get precise energy when implementing the MVT in gamma-ray spectroscopy, since a...
14-bit Analog-to-Digital Converter ADC1413D as operated at 100 MS/s is here evaluated for high-resolution gamma-ray spectroscopy using the germanium crystals of the AGATA/GALILEO detectors. The performance of the chip in terms of noise is studied as a function of the amount of analog DC offset applied before digitization. Such a DC offset is considered for the purpose of dynamic range optimization...
This study estimated the performance of a multiple-scattering Compton camera (MSCC) in monitoring the dose distribution of therapeutic photons on a Korean Typical Man-2 (KTMAN-2) phantom. The MSCC was constructed with two CZT semiconductor detectors as scatter detectors and a CWO scintillator detector as an absorber detector. The two planar semiconductor arrays consisted of 40 × 40 pixels, each with...
ePix100 is the first variant of a novel class of integrating pixel ASICs architectures optimized for the processing of signals in second generation LINAC Coherent Light Source (LCLS) X-Ray cameras. ePix ASICs are based on a common platform composed of a random access analog matrix of pixel with global shutter, fast parallel column readout, and dedicated sigma-delta analog to digital converters per...
The paper presents radiation tolerance of the transistor TEG (TrTEG5) test structure fabricated in 200 nm fully depleted silicon on insulator technology dedicated to production of SOI detectors. The chip was irradiated with 60Cobalt gamma-ray source to total dose of 1.175 kGy at a rate of 67.8 Gy/h. During irradiation, current-voltage characteristics of seventeen different transistors were measured...
Foam materials saturated with neutron sensitive compounds are of interest as a viable replacement for 3He-based neutron detectors. Previous studies have shown the feasibility of 6LiF-saturated foam detectors as a valid replacement both experimentally and theoretically. However, the random geometry of foam material has previously limited the effective theoretical considerations for such materials to...
Microstructured semiconductor neutron detectors with large aspect-ratio, straight trenches backfilled with neutron sensitive material exhibit superior detection efficiencies over traditional thin-film-coated diodes for solid-state thermal neutron detection. The detectors operate as partial-conformal diffused pin-junction diodes with low leakage current and capacitance. The solid-state silicon substrate...
The aim of this work is to provide the characteristics of MPPC as a part of neutron detector based on scintillators with n/γ discrimination capabilities. Measurements presented in the work cover: characterization of n/γ discrimination properties by means of Figure of Merit (FOM); comparison of scintillation light pulse shape measured with MPPC and PMT (rise time and fall time) and its influence on...
A quasi-monoenergetic high-energy neutron field produced via 7Li(p,n) reaction consists of a high-energy peak and a continuum down to the low-energy region. The continuum is a background for the measurement for the peak neutrons. Spectral information is necessary to estimate the effect of it. Using a new beam chopping system, the spectral neutron fluence above ∼150 keV was measured by the TOF method...
A stilbene crystal was coupled to a silicon photomultiplier (SiPM) to assess the performance of the detector's pulse shape discrimination (PSD) between fast neutrons and gamma rays. Pulses were digitized from a measurement of Cf-252 and digital charge comparison was used to perform PSD. The stilbene crystal was then coupled to a photomultiplier tube (PMT) and the measurement was repeated. The PSD...
The ZnS scintillator-based two-dimensional detector was developed for time-of-flight neutron imaging with a high spatial resolution and with a low gamma-ray sensitivity. The developed detector based on neutron counting method exhibited a high spatial resolution of less than 100 µm in full width at half maximum with a moderate count rate capability of several tens kcps. Its low gamma-ray sensitivity...
In order to fulfil the need of cheap and high-resolution systems as radiation beam monitors we exploited the possibility of using commercial CMOS image sensors as X-rays and low-intensity particle beam monitors. The low cost of CMOS sensors make it possible to neglect the issue of radiation damage and consider the sensor somehow to be disposable after a given time. In perspective, the ability to combine...
In low-energy nuclear reactions of astrophysical and fusion interest the spatial- and time-correlated detection of two and more reaction products can be a useful tool to discern reaction mechanisms such as investigate reaction channels, measure angular distributions of reaction products and determine partial reaction widths. For this purpose we assembled a configurable array of Timepix detectors with...
A new hybrid pixel array detector, the ePix100, has been developed at SLAC for tender and hard x-ray experiments at the Linac Coherent Light Source (LCLS). It is intended for low noise and good spatial resolution applications, particularly X-ray Photon Correlation Spectroscopy (XPCS) and in combination with wavelength dispersive spectrometers. The detector has 50 µm pixel size and less than 100 e-...
One of the challenging applications of PET is implementing it for in-beam PET, which is an in situ monitoring method for charged particle therapy. For this purpose, we previously proposed the world's first open-type geometries which we named OpenPET. For in-beam PET, careful designing and testing of detectors are important because secondary particles generated in a target degrade detector performance...
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