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Development of simultaneous PET and Compton imaging using GAGG-SiPM based pixel detectors
摘要： Positron emission tomography (PET) is considered an important and powerful tool for molecular imaging and medical diagnosis with its high sensitivity. Further, single-photon emission CT (SPECT) is another important imaging modality providing different types of information in medical diagnosis. On the other hand, Compton imaging is a promising technique for future molecular imaging with multi-nuclides based on Compton scattering kinetics. In this regard, previously, we have developed gadolinium aluminum gallium garnet (GAGG)-scintillation-based PET systems and GAGG-scintillation-based Compton imaging systems for environmental applications. Here, we propose and develop a novel PET–Compton hybrid simultaneous imager based on a two-layer structure using thin scatterers and thick absorbers for multi-nuclide imaging, for e.g., simultaneous imaging of PET and SPECT tracers such as 18F-FDG and 111In, respectively. For achieving good spatial resolution of the Compton imager, the energy resolution of the utilized scintillators forms one of the most important characteristics. In this regard, GAGG is a promising scintillator because of its high light yield of over 50 000 photon/MeV and excellent energy resolution of 4% with no background radiation and moderate decay time. In this study, we present the development of a simultaneous PET–Compton detector that consists of an 8 × 8 multi-pixel photon counter/SiPM (MPPC) array individually coupled with a 2.5 × 2.5 × 9-mm3 Ce:Gd3Ga2.7Al2.3O12 scintillators (absorbers) for proof of concept of simultaneous PET and SPECT imaging. The pixel size of the MPPC is 3 mm × 3 mm, and it is operated at 55 V at room temperature. The signals from the MPPC scintillators are individually amplified and converted with a dynamic time over threshold (dTOT) circuit to record the energy and timing information. In image reconstruction, the data acquired with the use of the developed modules are classified into events of either Compton imaging or PET imaging by coincidence detection between scatterer and absorber or between absorber and absorber, respectively. The coincidence events between absorber and absorber are regarded as PET annihilation-gamma events and those between scatterer and absorber are used as Compton imaging events. In our experiment, images of 111In and 18F-FDG, which are used as multi-nuclide tracers, are acquired simultaneously using the developed detector for Compton imaging and PET imaging. We believe that our approach is a significant step forward for medical imaging and related fields.
关键词： Scintillator,Single-photon emission CT,SiPM,Positron emission tomography,Compton imaging
更新于2025-09-23 15:23:52
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Contactless parametric characterization of bandgap engineering in p-type FinFETs using spectral photon emission
摘要： In the last decade it has become increasingly popular to use germanium enriched silicon in modern field effect transistors (FET) due to the higher intrinsic mobility of both holes and electrons in SiGe as compared to Si. Whether used in the source/drain region (S/D) as compressive stressor, which is an efficient mobility booster on Si channel devices, or as channel material, the SiGe increases channel carrier mobility and thus enhancing device performance. Because the germanium content modifies the effective bandgap energy EG, this material characteristic is an important technology performance parameter. The bandgap energy can be determined in an LED-like operation of electronic devices, requiring forward biased p-n junctions. P-n junctions in FETs are source or drain to body diodes, usually grounded or reversely biased. This investigation applies a bias to the body that can trigger parasitic forward operation of the source/drain to body p-n junction in any FET. Spectral photon emission (SPE) is used here as a non-destructive method to characterize engineered bandgaps in operative transistor devices, while the device remains fully functional. Before applying the presented technique to a p-type FinFET device, it is put to the proof by verifying the nominal silicon bandgap on an (unstrained) 120 nm technology FET. Subsequently the characterization capability for bandgap engineering is then successfully demonstrated on a SiGe:C heterojunction bipolar transistor (HBT). In a final step, the bandgap energy EG of a 14/16 nm p-type FinFET was determined to be 0.84 eV, which corresponds to a Si0.7Ge0.3 mixture. The presented characterization technique is a contactless fault isolation method that allows for quantitative local investigation of engineered bandgaps in p-type FinFETs.
关键词： p-n junction,Heterojunction bipolar transistor,Bandgap characterization,p-channel FinFET,SiGe, strained Si,Body diode, parasitic operation,Bandgap engineering,Body bias voltage,HBT,Contactless fault isolation,Spectral photon emission,MOSFET
更新于2025-09-23 15:23:52
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Single-Photon-Emission Computed Tomography with Neutron Activation for Material Inspection
摘要： A single-photon-emission computed tomography (SPECT) system with a lanthanum-bromide (LaBr3:Ce) scintillator was proposed and simulated to detect neutron-activated prompt γ-rays from suspicious materials. The optimized parameters of the SPECT system were calculated to achieve the best performance. Under the optimized conditions, energy spectra, spatial images, and elemental ratios were obtained and employed to identify hidden materials. The carbon-to-oxygen ratios of the materials calculated through the simulations were consistent with the corresponding theoretical values while the calculated nitrogen-to-oxygen ratios were slightly different from the corresponding theoretical values. In the proposed system, not only the energy spectrum of each element but also the characteristic intensity ratios obtained using the reconstructed images were used to identify the unknown elements of hidden materials in the three-dimensional spatial domain. These results demonstrate the feasibility of using the SPECT system in field applications.
关键词： Characteristic elemental intensity ratio,Neutron-activated prompt γ-rays,Single-photon-emission computed tomography
更新于2025-09-23 15:23:52
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Novel SPECT Technologies and Approaches in Cardiac Imaging
摘要： Recent novel approaches in myocardial perfusion single photon emission CT (SPECT) have been facilitated by new dedicated high-efficiency hardware with solid-state detectors and optimized collimators. New protocols include very low-dose (1 mSv) stress-only, two-position imaging to mitigate attenuation artifacts, and simultaneous dual-isotope imaging. Attenuation correction can be performed by specialized low-dose systems or by previously obtained CT coronary calcium scans. Hybrid protocols using CT angiography have been proposed. Image quality improvements have been demonstrated by novel reconstructions and motion correction. Fast SPECT acquisition facilitates dynamic flow and early function measurements. Image processing algorithms have become automated with virtually unsupervised extraction of quantitative imaging variables. This automation facilitates integration with clinical variables derived by machine learning to predict patient outcome or diagnosis. In this review, we describe new imaging protocols made possible by the new hardware developments. We also discuss several novel software approaches for the quantification and interpretation of myocardial perfusion SPECT scans.
关键词： fast myocardial perfusion single photon emission computed tomography,quantification,single photon emission computed tomography,low dose,myocardial perfusion imaging,stress only
更新于2025-09-23 15:22:29
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Human Ultraweak Photon Emission: Key Analytical Aspects, Results and Future Trends – A Review
摘要： Living systems emit what is called ultraweak photon emission (UPE). This visually undetectable phenomenon has only been studied in humans for the last 30 years, finding that UPE is a complex process depending on multitude factors. Considering previous literature, this review discusses the in vivo UPE from human beings. To this aim, Analytical Approaches Employed for UPE Measurement section focuses on the analytical techniques employed (photomultipliers and charged coupled device cameras), summarizing analytical conditions and reporting figures of merit reached to date. Then, Human UPE Depending on External Factors and Human UPE Depending on Internal Factors sections address external and internal factors, which have proved to affect UPE, pointing out the important influence on oxidative processes outside and inside the body, and also highlighting some personal states of the individuals affecting UPE. Last section is devoted to give a general view on the goals and achieved up to date regarding UPE measurement, emphasizing some potential applications as well as recommendations which include: use of UPE spectra information together with UPE intensity, larger populations (≈50–100 subjects), studies on internal states of individuals, and use of statistical tools.
关键词： ultraweak photon emission,CCD camera,human bioemission,spectroscopy,disease
更新于2025-09-23 15:22:29
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Handbook of Neuro-Oncology Neuroimaging || Positron Emission Tomography (PET) and Single-Photon Emission Computed Tomography (SPECT) Physics
摘要： The purpose of emission tomography is to estimate the distribution of a radiotracer from external measurements of the pattern of photons emerging from the brain. Some of these photons are detected, and certain information about them recorded, by the scanner. These external measurements are termed “projections,” and each measurement in a projection represents, ideally, the sum of radioactivity concentration along a line through the brain. From these measured projection data sets and knowledge of certain aspects of the single-photon emission computed tomography (SPECT) or positron emission tomography (PET) instrument, estimated images of the distribution of radioactivity are mathematically reconstructed. All modern SPECT and PET scanners image the three-dimensional (3D) distribution of radioactivity, either as a stack of two-dimensional (2D) transaxial images or directly as a 3D volume.
关键词： Single-Photon Emission Computed Tomography,Positron Emission Tomography,Image Reconstruction,Radiotracer,SPECT,PET,Radioactivity Distribution,Physics
更新于2025-09-23 15:21:01
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[IEEE 2018 IEEE International Symposium on the Physical and Failure Analysis of Integrated Circuits (IPFA) - Singapore (2018.7.16-2018.7.19)] 2018 IEEE International Symposium on the Physical and Failure Analysis of Integrated Circuits (IPFA) - Defect Prediction Approach to enhance Static Fault Localization of Functional Logic Failure Defects using NIR Photon Emission Microscopy
摘要： Studies on defect induced emission characteristics have significantly enhanced the effectiveness of static fault localization on functional logic failures due to open and short defects. In this paper, using the distinctive differences in the defect-induced emission characteristic between open and short defects, together with layout trace and analysis, a defect prediction approach has been derived. It assisted in the hypothesis of the defect type, narrowing down the defect location within long failure net(s) and even pin-pointing the exact defect location in some cases. Successful case studies on advanced technology node devices were used to describe four different emission signatures of open and short defects and the effective application of aforementioned approach in isolating the defect.
关键词： Static Fault Localization,Short defect,Defect Prediction,Photon Emission Microscopy,Functional failures,Open defect
更新于2025-09-23 15:21:01
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Case Report: SPECT/CT as the New Diagnostic Tool for Specific Wrist Pathology
摘要： Introduction: Single photon emission computed tomography has been introduced as a promising new diagnostic tool in orthopaedic pathology since the early 90'. Computed tomography, the combined with SPECT, gives insight in the specific sight of wrist pathology. Literature already supports introduction of SPECT/CT in wrist pathology, but clinical application is lagging. Case Report: A 40yr old patient reported first in 2004 with persisting pain after a right distal radius fracture. Several diagnostics and operative interventions were performed, all unsuccessful. Because of the persisting pain a SPECT-CT was performed which showed a cyst in the hamate bone, which was successfully enucleated. The patient was finally pain free at recent follow-up. With a QDash-score of 43 and a PRW (H) E-DLV-score of 58/150. Discussion: In this case report, SPECT/CT proved a very sensitive diagnostic tool for specific pathology of the wrist. It offered precise localisation and thereby the clinically suspected diagnosis was confirmed and the patient successfully treated.
关键词： Capitate,Proximal row carpectomy,Wrist,SPECT/CT,Hamate,Single-Photon Emission-Computed Tomography
更新于2025-09-23 15:21:01
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Single-photon emission from single-electron transport in a SAW-driven lateral light-emitting diode
摘要： The long-distance quantum transfer between electron-spin qubits in semiconductors is important for realising large-scale quantum computing circuits. Electron-spin to photon-polarisation conversion is a promising technology for achieving free-space or fibre-coupled quantum transfer. In this work, using only regular lithography techniques on a conventional 15 nm GaAs quantum well, we demonstrate acoustically-driven generation of single photons from single electrons, without the need for a self-assembled quantum dot. In this device, a single electron is carried in a potential minimum of a surface acoustic wave (SAW) and is transported to a region of holes to form an exciton. The exciton then decays and creates a single optical photon within 100 ps. This SAW-driven electroluminescence, without optimisation, yields photon antibunching with g(2)(0) = 0.39 ± 0.05 in the single-electron limit (g(2)(0) = 0.63 ± 0.03 in the raw histogram). Our work marks the first step towards electron-to-photon (spin-to-polarisation) qubit conversion for scaleable quantum computing architectures.
关键词： quantum computing,GaAs quantum well,electron-spin qubits,surface acoustic wave,single-photon emission
更新于2025-09-23 15:19:57
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[IEEE 2018 IEEE International Symposium on the Physical and Failure Analysis of Integrated Circuits (IPFA) - Singapore (2018.7.16-2018.7.19)] 2018 IEEE International Symposium on the Physical and Failure Analysis of Integrated Circuits (IPFA) - Integrating EOP/EOFM as a Complimentary Localization Technique for Open Via/Contact
摘要： The paper describes as integrated technique of Electro Optical Frequency Mapping (EOFM) and Electro Optical Probing (EOP) to localize open failure mode with traditional FA analysis approach. The technique was performed in analog devices on advanced SOI-based circuits. Two case studies were presented to demonstrate on how the newly introduced fault localization techniques work. These techniques can help to isolate or narrow down the suspected failing components.
关键词： Open via,Propagation delay,Optical Beam Induced Resistance Change,Photon Emission Microscopy,Electro Optical Probing,Electro Optical Frequency Mapping
更新于2025-09-19 17:15:36