Biomedical subjects

G Germano

Publications and source records attributed to G Germano.

At least 127 records · Page 7Linked to original sources

PubMedDate not supplied

Investigation of count rate and deadtime characteristics of a high resolution PET system.

Count rate and deadtime characteristics were investigated for a whole body positron emission tomography system by measuring prompt, delayed, and multiple (three or more detectors) coincidence rates and single detector rates as a function of input count rate by imaging a variety of short-lived positron emitting sources as a function of time. Data were collected with cylinder, ring, and point sources for a range of energy thresholds and fields of view. The largest source of deadtime loss involved processes that led to multiple coincidences, which are primarily true or accidental events in coincidence with an unrelated event. In measuring the count rate as a function of time for each type of event, components, with decay constants of 1, 2, or 3 times that of the isotope being measured, could be resolved corresponding to 1 (true events), 2 (accidental and some multiple events), or 3 (multiple events) independent nuclear disintegrations, respectively. Analysis of true, accidental, and multiple coincidence and singles count rate data allowed identification and evaluation of the magnitude of the sources of deadtime losses and provided a basis for a deadtime correction from data available from the PET system.

Equipment Design↗

PubMedDate not supplied

Cefetamet in the treatment of acute sinusitis in adult patients.

Cefetamet, an oral third-generation cephalosporin, was investigated in a prospective, randomized, open, comparative trial in 41 outpatients with acute sinusitis. The efficacy of 500 mg cefetamet given orally twice daily for 7 days to 22 patients was compared with that of 500 mg cefaclor given orally three times daily for 7 days to 19 patients. Sinus punctures were performed before antimicrobial therapy in 10 patients from each treatment group. A successful bacteriological response was obtained in all the 21 assessable patients treated with cefetamet and in the cefaclor-treated group 18 assessable patients were cured and two were improved, but one failed to respond to therapy. The tolerability of both drugs was good and no withdrawals from treatment were necessary.

Acute Disease↗

PubMedDate not supplied

The microvasculature of the lingual mucosa in Capra hircus.

The microvasculature of the lingual mucosa of the goat was studied by SEM using microvascular corrosion casts. A complex microcirculatory system was observed to supply the large number of papillae, which had a wide structural variety. Generally, the organization of the vascular network in the lingual papillae was found to be influenced by the nature of the microcirculation in the lamina propria. Another characteristic feature noted was the presence of numerous valves in the venules situated in the lamina propria. They were oriented toward the broader side of the venules and probably control the rapid outflow of blood. This in turn most probably leads to an increased mucosal blood supply, which might sustain both mechanical and gustatory functions.

Animals↗

PubMedDate not supplied

Geometric mispositioning in positron emission tomography.

The phenomenon of geometric mispositioning (defined as having a geometric proper plus a parallax component) was studied and characterized on Neuro- and whole body PET systems employing 2-D modular detectors (CTI/Siemens ECAT-831/08 and 931/08) as well as an older system (CTI ECAT-911). Measurements taken with precisely spaced line sources showed image distortions of objects away from the center of the field of view (FOV), with global mispositionings of -1.4, 1.5 and 14 mm (931 and 911), and -0.5, 10 mm (831) at 10, 20 and 30 cm (931 and 911) and 10, 20 cm (831) from the center of the FOV. Structures as close as 5 cm (931/911) or 4 cm (831) to the center of the FOV are mispositioned by more than 1 mm. This is clearly inacceptable in cases where accurate correlation of PET and NMR images is needed to acquire anatomical information in neurological studies, or when gated cardiac studies are performed in order to precisely determine myocardial wall thickness. A fast, on-line geometric correction was performed by creating new, uniformly spaced sinograms to be mapped to the original sinograms. Geometric mispositioning was mathematically derived, while parallax mispositioning was estimated by a linear fit of the data partially corrected for sampling non-uniformity. Our correction technique can be easily tailored to any PET system available on the market.

Mathematics↗

PubMedDate not supplied