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We have successfully developed a new high-resolution PMT-Quadrant-Sharing (PQS)[1] PET panel detector system. Each bank consists of 48 × 112 LYSO detector elements with a pixel size of 2.35 × 2.35 × 15.5 mm3. After grinding a regular detector bank into a half pentagon shape with tapered-end crystals, 24 half pentagon banks will form a gapless cylindrical ring with 87-cm in diameter and 27.6-cm in...
A novel DOI detector with a stack of planer scintillators (SOPS) allows easier position estimation and simpler fabrication. To investigate suitable optical characteristics of the proposed detector, we constructed a Monte Carlo simulator. In this paper, we studied the relationship between the surface roughness of monolithic scintillator and the spatial resolution. We defined the parameter of scintillator's...
PETiPIX is an ultra high spatial resolution small animal PET scanner designed for scanning of mouse brains. It utilises four state of the art pixellated silicon detectors, Timepix, in an edge-on configuration to provide a field of view (FoV) 15 mm in diameter. Each Timepix detector consists of 256×256 pixels, with pixel dimensions of 55µm×55µm×300µm. Monte Carlo simulations have been carried to evaluate...
High spatial resolution in x-ray computed tomography (CT) is paramount in many clinical applications. The realization of high-resolution CT requires both high-precision imaging hardware and well-designed image reconstruction algorithms. Compared to the conventional filtered backprojection (FBP), one attractive advantage of model-based iterative reconstruction (MBIR) is the ability to incorporate more...
We propose a method to improve spatial resolution in CT reconstruction. We show that the proposed method improves spatial resolution with both numerical simulations and real CT data, without side-effects of aliasing artifacts.
Gamma counting probes play an important role in radioguided sentinel lymph node biopsy surgical procedures. The miniaturization of gamma camera components and associated electronics has allowed the introduction of small handheld gamma cameras to be used in place of simple gamma counting probes in these procedures. We report here on the design of a compact handheld gamma camera and first results from...
A new multi-modality imaging tool is under development in the framework of the INSERT (INtegrated SPECT/MRI for Enhanced Stratification in Radio-chemoTherapy) project, supported by the European Community. A custom SPECT apparatus, used as an insert for commercially available MRI systems, will enhance the treatment of brain tumors (primarily glioma) by offering more effective and earlier diagnosis...
Technological advances in High-Purity Germanium (HPGe) detectors have given rise to compact, mechanically cooled gamma cameras that do not require bulky liquid nitrogen dewars to operate. When used in the double-sided strip configuration, spatial resolution finer than the strip width can be obtained using pulse signal analysis for position interpolation. With 3D position sensitivity and excellent...
Silicon photomultipliers (SiPM) are a promising alternative light sensor for the classic photomultiplier tubes currently used as single photon emission computed tomography (SPECT) detectors due to their compact dimensions and smaller pixelization. Furthermore, these SiPMs are also known to be MR-hard which brings on new possibilities for simultaneous SPECT-MR imaging. In contrast to other research...
Single Photon Emission Computed Tomography (SPECT) suffers limited efficiency due to the need for collimators. Collimator properties largely decide the data statistics and image quality. Various materials and configurations of collimators have been investigated in many years. The main thrust of our study is to evaluate the design of pixel-geometry-matching collimators to investigate their potential...
The LM-EM algorithm has the advantage to calculate the emission probabilities needed for the reconstruction process on the fly, without the need of a pre-calculated system matrix. The reconstruction time for this algorithm strongly depends on the used backprojector and the available statistics. This algorithm when implemented in systems using monolithic crystals to detect gamma radiation allows one...
The usage of long, axially oriented scintillator crystals in a PET scanner has been shown by the AX-PET Demonstrator as a possible solution for a high resolution and high sensitivity PET detector. In the AX-PET implementation, arrays of wavelength shifting (WLS) strips, placed orthogonally behind every crystal layer, are used to define the axial coordinate. After extensive characterization measurements,...
Calculations of responses for experimentally studied silicon planar structures (epitaxial single-strip silicon diodes) have been carried out for various profiles of microbeams. The spatial distribution of responses on the microbeam radiation therapy (MRT) beams has been calculated taken into account both electrical field distribution inside of the detector and recombination in the diffusion region...
A Time Projection Chamber (TPC) with its 3-dimensional tracking and particle identification capabilities is a very powerful detector for high multiplicity events. TPCs are used for tracking in several experiments such as ALICE, STAR and many others. A drawback of such devices is the restriction to trigger rates of the order of 1 kHz due to the necessity of a gating grid which prevents ions produced...
In the dual-head flat panel PET system (DHAPET), the unique detector arrangement leads to severe uncertainty of depth-of-interaction (DOI) and data truncation, which in turn result in poor image quality and data loss in the reconstructed images. To improve the distortions, we proposed a reconstruction strategy under the framework of the fast iterative shrinkage-thresholding algorithm (FISTA) for minimizing...
We are developing a human-brain imaging TOF PET detector with high sensitivity and lower radioactive dose to patients. The proposed detector design consists of 36 detector modules, and each module has 4×8 LYSO scintillators coupled to SiPMs individually. For signal readout for detector modules, the transmission-line readout with high speed waveform sampling is adopted to fully exploit the fast time...
The advanced depth-of-interaction positron emission tomography (PET) detectors have been improved to provide three-dimensionally uniform detector resolution. These detectors allow a geometry that places the detectors very close to imaging subjects, because they can maintain high spatial resolution even in the peripheral region in the field-of-view (FOV) without loss of sensitivity. In this study,...
Tachyon, a single-ring “demonstration” Time-of-Flight (TOF) PET scanner has been developed to measure the improvement in image quality as a function of the timing resolution. The design of the detector module is optimized for timing by coupling the 6.1×25 mm2 of 6.1×6.1×25 mm3 LSO scintillator crystals onto a 1-inch diameter Hamamatsu R-9800 PMT with super-bialkali photocathode. We characterized the...
The instantaneous luminosity of the Large Hadron Collider (LHC) is being increased in several steps over the next 10 years to maximize its discovery potential for new physics. However, at a luminosity of twice the design luminosity of the LHC of 1×1034 cm−2s−1, the performance of the current CMS pixel detector is degraded by substantial deadtime incurred by the readout chip (ROC). To make full use...
We present experimental results obtained with a two-head prototype of a small-animal positron emission tomograph based on resistive plate chamber detectors (RPC-PET). A planar 22Na disk source was imaged. The maximum-likelihood expectation maximization (MLEM) reconstruction of the acquired data yielded a resolution of 0.4mm full width at half maximum (FWHM). Each of the two detectors utilized in this...
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