Search results for "SINGLE-PHOTON"
showing 10 items of 62 documents
Drug Distribution to Retinal Pigment Epithelium: Studies on Melanin Binding, Cellular Kinetics, and Single Photon Emission Computed Tomography/Comput…
2016
Melanin binding is known to affect the distribution and elimination of ocular drugs. The purpose of this study was to evaluate if the extent of drug uptake to primary retinal pigment epithelial (RPE) cells could be estimated based on in vitro binding studies with isolated melanin and evaluate the suitability of single photon emission computed tomography/computed tomography (SPECT/CT) in studying pigment binding in vivo with pigmented and albino rats. Binding of five compounds, basic molecules timolol, chloroquine, and nadolol and acidic molecules methotrexate and 5(6)-carboxy-2',7'-dichlorofluorescein (CDCF), was studied using isolated melanin from porcine choroid-RPE at pH 5.0 and 7.4. The…
Sentinel Node Identification in Melanoma: Current Clinical Impact, New Emerging SPECT Radiotracers and Technological Advancements. An Update of the L…
2020
Background: Melanoma is the most lethal skin cancer with a mortality rate of 262 cases per 100.000 cases. The sentinel lymph node (SLN) is the first lymph node draining the tumor. SLN biopsy is a widely accepted procedure in the clinical setting since it provides important prognostic information, which helps patient management, and avoids the side effects of complete lymph node dissection. The rationale of identifying and removing the SLN relies on the low probability of subsequent metastatic nodes in case of a negative histological exam performed in the SLN. Discussion: Recently, new analytical approaches, based on the evaluation of scintigraphic images are also exploring the possibility …
First bodipy–DOTA derivatives as probes for bimodal imaging
2010
The synthesis and the photophysical studies of the first bodipy-DOTA and its In(III), Ga(III) and Cu(II) complexes are reported. The introduction of an isothiocyanate handle generates a new bimodal imaging agent capable of both optical and nuclear imaging.
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.
Measurements of Silicon Photomultipliers Responsivity in Continuous Wave Regime
2013
We report on the electrical and optical characterization, in continuous wave regime, of a novel class of silicon photomultipliers fabricated in standard planar technology on a silicon p-type substrate. Responsivity measurements, performed with an incident optical power down to tenths of picowatts, at different reverse bias voltages and on a broad (340–820 nm) spectrum, will be shown and discussed. The device temperature was monitored, allowing us to give a physical interpretation of the measurements. The obtained results demonstrate that such novel silicon photomultipliers are suitable as sensitive power meters for low photon fluxes.
High performance 3D CZT spectro-imager for BNCT-SPECT: preliminary characterization
2018
The National Institute of Nuclear Physics (INFN) is supporting the 3CaTS project with the aim of developing a new Single Photon Emission Computed Tomography (SPECT) system for real time 10 B therapeutic dose monitoring in the binary experimental hadron therapy called Boron Neutron Capture Therapy (BNCT). BNCT is a highly selective tumour treatment based on the neutron capture reaction 10 B(n,α) 7 Li. The secondary particles have a high LET with ranges in tissues of the order of 10 μm (thus less than the mean cell diameter of few tens μm). Targeting the 10 B delivery towards cancer, the released energy lethally damages only the malignant cells sparing the normal tissues, thus enabling a cell…
Decreased benzodiazepine receptor binding in panic disorder measured by IOMAZENIL-SPECT. A preliminary report.
1994
Single photon emission tomography (SPECT) imaging of the central benzodiazepine receptor (BZr) became possible with the newly developed ligand 123I-IOMAZENIL. The BZr binding was investigated in ten patients with panic disorder (PP) compared to ten epileptic patients (EP). Panic patients had lower IOMAZENIL uptake rates in the frontal, occipital and temporal cortex than EP indicating the involvement of the BZr complex in panic disorder.
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…
Evaluation of left ventricular mass on cadmium-zinc-telluride imaging: Validation against cardiac magnetic resonance
2017
Background. Single-photon emission computed tomography has shown relevant limitations in the quantification of left ventricular (LV) mass. We sought to compare the estimates of LV mass on Cadmium-Zinc-Telluride (CZT) myocardial perfusion imaging (MPI) as compared to cardiac magnetic resonance (CMR). Methods and results. Twenty-five patients underwent MPI on a CZT camera and CMR on a 1.5 T scanner within 12 ± 3 weeks. LV mass was quantified on CZT images using two softwares: 4D-MSPECT (4DM) and Emory Cardiac Toolbox (ECTb). LV mass by CMR was quantified using MASS software (Medis, Leiden, The Netherlands). LV mass values obtained with 4DM and ECTb were highly reproducible [intraclass correla…
Critical single proximal left arterial descending coronary artery stenosis to mimic chronic myocardial ischemia: a new model induced by minimal invas…
2008
<i>Background/Aims:</i> The present report examines a new pig model for progressive induction of high-grade stenosis, for the study of chronic myocardial ischemia and the dynamics of collateral vessel growth. <i>Methods:</i> Thirty-nine Landrace pigs were instrumented with a novel experimental stent (GVD stent) in the left anterior descending coronary artery. Eight animals underwent transthoracic echocardiography at rest and under low-dose dobutamine. Seven animals were examined by nuclear PET and SPECT analysis. Epi-, mid- and endocardial fibrosis and the numbers of arterial vessels were examined by histology. <i>Results:</i> Functional analysis showed a…