Search results for "SINGLE-PHOTON"
showing 10 items of 62 documents
Transmurality of scar influences the effect of a hybrid-intervention with autologous bone marrow cell injection and aortocoronary bypass surgery (MNC…
2010
Abstract Background Cell therapy (CTx) is a strategy to support cardiac regeneration after myocardial infarction (MI). Thus far, clinical studies provided mixed results. Here, we investigated whether transmurality of the infarct may play a relevant role. Methods 18 patients (63±3years, 15 male) undergoing elective coronary artery bypass graft (CABG) surgery 2.2±0.7months post MI participated. 10 had transmural and 8 non-transmural infarct scars assessed by Tc-99m-MIBI Single-Photon Emission Computed Tomography (SPECT) and F18-FDG-Positron-Emission-Tomography (PET). During surgery, 10ml of sternal bone marrow were obtained, mononuclear cells (MNC) were isolated. At the end of surgery MNC wer…
Role of Associated Cortical Lesions in Motor Partial Seizures and Lenticulostriate Infarcts
1995
In a population-based study, we evaluated seizures occurring in the first 15 days after strokes among 1,640 consecutive patients who had ischemic (814 infarcts with atheroma and 126 with cardiogenic embolism, 273 lacunar infarcts, 259 transient ischemic attacks) or hemorrhagic stroke (129 supratentorial hematomas and 24 subarachnoïd hemorrhage) on computed tomography (CT) scan. Ninety patients had an epileptic seizure in the first 15 days after stroke onset. Thirteen of the 90 had a lenticulostriate infarct, diagnosed on CT scan, without an apparent ipsilateral cortical ischemic lesion. No lenticulostriate hematoma was observed with seizures. To determine the possible existence of an ipsila…
PET Chemistry: An Introduction
2021
One major advantage of radioactivity is its extremely high sensitivity of detection. Regarding the medical applicability of radioactivity, it permits non-invasive in vivo detection of radiolabelled compounds at nano- to picomolar levels. The use of substances at such low concentrations usually precludes a physiological, toxic or immunologic response of the investigated biological system. Consequently, the considered physiological process or system is examined in an unswayed situation. Furthermore, a wide range of substances, even those which are toxic at higher concentrations, become considerable for the development of radiopharmaceuticals and use in nuclear medicine. In contrast to the wid…
DOTAGA-Trastuzumab. A New Antibody Conjugate Targeting HER2/Neu Antigen for Diagnostic Purposes.
2012
International audience; Improved bifunctional chelating agents (BFC) are required for indium-111 radiolabeling of monoclonal antibodies (mAbs) under mild conditions to yield stable, target-specific agents. 2,2',2″-(10-(2,6-Dioxotetrahydro-2H-pyran-3-yl)-1,4,7,10-tetraazacyclododecane-1,4,7-triyl)triacetic acid (DOTAGA-anhydride) was evaluated for mAb conjugation and labeling with indium-111. The DOTA analogue was synthesized and conjugated to trastuzumab-which targets the HER2/neu receptor-in mild conditions (PBS pH 7.4, 25 °C, 30 min) and gave a mean degree of conjugation of 2.6 macrocycle per antibody. Labeling of this immunoconjugate with indium-111 was performed in 75% yield after 1 h a…
Photon events with missing energy at root s=183 to 189 GeV
2000
The production of single photons has been studied in the reaction e+e- -> gamma + invisible particles at centre-of-mass energies of 183 GeV and 189 GeV. A previously published analysis of events with multi-photon final states accompanied by missing energy has been updated with 189 GeV data. The data were collected with the DELPHI detector and correspond to integrated luminosities of about 51 pb^{-1} and 158 pb^{-1} at the two energies. The number of light neutrino families is measured to be 2.84 +/- 0.15(stat) +/- 0.14(syst). The absence of an excess of events beyond that expected from Standard Model processes is used to set limits on new physics as described by supersymmetric and compos…
Search for Production of Invisible Final States in Single-Photon Decays of Υ(1S)
2010
We search for single-photon decays of the Upsilon(1S) resonance, Upsilon->gamma+invisible, where the invisible state is either a particle of definite mass, such as a light Higgs boson A0, or a pair of dark matter particles, chi chi-bar. Both A0 and chi are assumed to have zero spin. We tag Upsilon(1S) decays with a dipion transition Upsilon(2S)->pi+pi-Upsilon(1S) and look for events with a single energetic photon and significant missing energy. We find no evidence for such processes in the mass range m_A0<=9.2 GeV and m_chi<=4.5 GeV in the sample of 98e6 Upsilon(2S) decays collected with the BaBar detector and set stringent limits on new physics models that contain light dark ma…
Engineering light emission of two-dimensional materials in both the weak and strong coupling regimes
2017
Abstract Two-dimensional (2D) materials have promising applications in optoelectronics, photonics, and quantum technologies. However, their intrinsically low light absorption limits their performance, and potential devices must be accurately engineered for optimal operation. Here, we apply a transfer matrix-based source-term method to optimize light absorption and emission in 2D materials and related devices in weak and strong coupling regimes. The implemented analytical model accurately accounts for experimental results reported for representative 2D materials such as graphene and MoS2. The model has been extended to propose structures to optimize light emission by exciton recombination in…
Time response of avalanche photodiodes as a function of the internal gain
1998
Abstract Using a red LED and a blue laser as a light source, time response of avalanche photodiodes and Metal-Resistive Silicon (MRS) layer avalanche photodiodes [1] has been measured. A strong dependence of the time resolution on the internal gain has been observed. The obtained results show that the increase of the internal gain improves the time resolution. However, there exists a critical value for the internal gain. Beyond this value a deterioration of the time resolution is observed.
Preliminary assessment of the imaging capability of the YAP–(S)PET small animal scanner in neuroscience
2006
The new and fully engineered version of the YAP–(S)PET small animal scanner has been tested at the University of Mainz for preliminary assessment of its imaging capability for studies related to neuropharmacology and psychiatry. The main feature of the scanner is the capability to combine PET and SPECT techniques. It allows the development of new and interesting protocols for the investigation of many biological phenomena, more effectively than with PET or SPECT modalities alone. The scanner is made up of four detector heads, each one composed of a 4 � 4c m 2 of YAlO3:Ce (or YAP:Ce) matrix, and has a field of view (FOV) of 4 cm axially � 4c m + transaxially. In PET mode, the volume resoluti…
Validation of the Monte Carlo Simulation of a Siemens Biograph mCT PET
2016
Geant4 Application for Tomography Emission (GATE) is a simulation platform based on GEANT4. It is designed to perform numerical simulations in medical imaging and radiotherapy. It is also used to simulate Emission Tomography (Positron Emission Tomography, PET and Single Photon Emission Computed Tomography, SPECT), Computed Tomography (CT) and Radiotherapy experiments. The purpose of this study is to validate a GATE model of the commercial PET/CT Siemens Biograph, the latest acquisition of the Clinical Hospital of Salamanca. The geometry of the system has been implemented in GATE, including the detector ring, the crystal blocks, the PMTs etc. Radionuclides for all measurements shall be \(^{1…