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Biomedical subjects

F Soussaline

Publications and source records attributed to F Soussaline.

5 recordsLinked to original sources
PubMed1979

The physical performances of a single slice positron tomographic system and preliminary results in a clinical environment.

Metabolic phenomena can be studied and measured non-invasively using positron emitting radionuclides and a suitably adapted tomographic system. The choice of a single slice ring camera is justified by its physical performance, which is presented here and discussed. A series of measurements with geometrical phantoms and analytical simulations have been performed to determine the critical characteristics of the system. This has permitted optimization of certain parameters enabling very interesting clinical results to be obtained at SHFJ, particularly in the area of cerebral physiopathology. In addition, the potential of obtaining absolute quantitative values of regional activity is presented. The calibration of the regional activity is presented. The calibration of the system, spatial non-stationarities, and attenuation correction, which represent the main sources of error, are considered in detail. A precision of the order of 10% should be obtainable. Such a quantitation method has been successfully applied to the in vivo study of the regional extraction of cerebral oxygen.

Brain↗
PubMed1979

Brain distribution and kinetics of 11C-chlorpromazine in schizophrenics: positron emission tomography studies.

The positron emitter 11C (20 minutes half-life) permits the labeling of chlorpromazine (CPZ) and the study of its distribution in humans by external counting. Trace amounts of 11C-CPZ were injected intravenously into 22 schizophrenic patients all untreated for several months with neuroleptics. The brain uptake was 6.04 +/- 1.6% of the injected dose 15 minutes after the injection, and it remained constant for 45 minutes. By positron emission tomography, the drug distribution was shown to be in the gray matter, and such structures as the cortex, caudate nucleus, thalamus and putamen could be identified. This new methodology will be helpful in studying specific receptors in humans in a noninvasive way.

Adolescent↗
PubMed1978

[Tomographic study in humans of blood flow and oxygen consumption of the brain by continuous inhalation of oxygen 15. Preliminary findings in cerebral ischemic accidents].

Transverse axial tomographic imaging of regional cerebral blood flow (rCBF) and regional oxygen extraction fraction (rOEF) were obtained in 13 patients hospitalizedfor ischemic strokes (eleven middle cerebral artery territory infarcts, one capsular or pontine lacune, one transient hemispheric attack) by continuous inhalation of 15O2 and C15O2 to equilibrium and exclusive detection of the gamma rays emitted in coincidence by means of a tomograph for positron emitting agents. In the transient ischemic attack and in the case of lacune the rCBF and the rOEF images were found to be normal, and they were abnormal in all cases of middle cerebral artery territory infarcts. In recent infarcts, rOEF was always strikingly decreased in the clinically suspected area, whilst the rCBF was either decreased, normal or increased. In infarcts older than 30 days rCBF was always clearly decreased over the clinically suspected area whilst rOEF was in most cases normal or only slightly decreased. These results are briefly discussed. Some practical and theoretical limitations of this method are mentioned. The potential of the present technique appears great however, since it is possible to simultaneously visualize in tomographic fashion the blood flow and the oxygen metabolism in areas of the brain that are of small volume, and however deep they are. A quantification of these parameters is presently under investigation, as well as the verification of the theoretical model on which such method is based. The non-invasiveness of the present method, the feasibility of repeating it at regular intervals of time, and the possibility of measuring the immediate effects of a given therapeutic mode on the regional metabolism of brain all constitute further advantages whose action apply preeminently in the field of the cerebral ischemic diseases.

Aged↗
PubMed1977

Detection of hepatoma in liver cirrhosis.

The analogic liver scintigram using 99mTc sulfur colloid in cirrhotic patients does not permit determination of the nature of the areas of decreased uptake. Scintigrams with 67Ga citrate generally show increased activity in cases of hepatoma. In some cases, however, 67Ga citrate is less concentrated in neoplasic tissue, and it is not possible to detect a tumoral lesion in a cirrhotic liver. This is why we used double isotope scintigraphies with 67Ga citrate and 99mTc sulfur colloid, with digital subtraction, after simultaneous recording of 99mTc and 67Ga data on magnetic tape by means of an interface. In our series of 22 patients, the comparison of the results obtained by this double isotope technique with histology showed no false positive in substraction scintigrams. There was one false negative because of the lack of significance in the subtracted image for one of the six patients with cancer of the liver. For three of the six patients with hepatoma, the gallium scintigram showed an increased uptake in the tumor area. For the three other cases, the gallium uptake was equilibrated throughout the liver scintigraphy. It was therefore in cases where the gallium scintigram showed no increased activity that the subtraction technique was of greatest value, for it permitted the diagnosis of hepatoma in two cases.

Carcinoma, Hepatocellular↗