Nuclear-Medizin最新文献

Two new radiopharmaceuticals were developed as possible agents for demonstrating the presence of hepatic amebic abscesses by selective accumulation of these agents in the abscess contents. These agents are: 131I-labeled Bromometronidazole, that has been shown to possess some of the antibiotic activity of metronidazole or Flagyl; and a Technetium 99m-penicillamine-Flagyl complex. A method of radioiodination has been devised which can be performed in radiopharmaceutical laboratories. Both radiopharmaceuticals are of very low toxicity. Distribution studies in animals show accumulation in the liver and elimination by way of the gallbladder. Scintillation camera studies depict a rapid uptake by the liver with subsequent biliary excretion. Animal models for the study of hepatic amebic abscesses are not available. A human patient with suspected amebic abscesses has been studied with negative findings that were confirmed at surgery. Collaborative studies are now in progress in several areas of the world where amebiases is endemic.

The cerebral sequential scintigraphy enables a process to be described according to its hemodynamics (Stage I), its degree of vascularization (Stage II), and the extent of the localized disturbance of the blood-brain barrier function (Stage III). For a given lesion, typical scintigraphic behaviour patterns can be described. This report presents the results of a prospective series with 1722 patients examined using this method. The accuracy of the different scintigraphic diagnoses, according to tumor type, was: cerebrovascular accident with brain infarction - 92% (= CVA), metastasis - 90%, bone or meningital process - 89%, malignant glioma - 91%, meningioma - 74%, highly differentiated glioma - 67%, chronic subdural hematoma - 54%, A-V angioma - 54%, brain abscess - 45%. The differential diagnosis between brain tumor and CVA with infarction was possible in approximately 97% of the patients, the differential diagnosis of intracranial space-occupying lesion versus CVA with infarction in approximately 95%. There were 14 false positive results recorded (0.8% of the 1722 patients).

Tracer quantities of colloidal 198Au were used to estimate the hepatic blood flow in normal children and in children with active or progressive chronic hepatitis and also to obtain scintigrams of the liver. In active chronic hepatitis a significant decrease in HBF values was observed, suggesting that the method may be used as a diagnostic criterion which is superior to hepatic scintigraphy. In progressive chronic hepatitis HBF values even lower than those in active hepatitis were observed. Together with more characteristic clinical findings and abnormal results of biochemical function tests, they underline the value of the method in estimating the severity and the evolution of the disease.

In 65 patients with uni- or bilateral nephroptosis the 131I-hippurate-clearance of each kidney was determined in combination with sequential gammacamera scintigraphy. The clearance values were normal in 65% without changing due to patient position. In 35% of the ptotic kidneys clearance values were lower than normal as well as in 17,5% of the nonptotic contralateral kidneys. 23% of the ptotic kidney showed diminished clearance values in the upright position, whereas a significant increase was found in prone position. Such short-time changes of the 131I-hippurate-clearance indicate diminished perfusion of the kidney when it is moving downward.

99mTc-labelled phosphates are the bone seeking agents of choice. The comparison of 99mTc-polyphosphate (Poly-P) and 99mTc-ethane-1-hydroxy-1,1-diphosphonate (EHDP) shows a better in vitro stability of the latter during the first two hours after preparation. The blood clearance of EHDP is superior to Poly-P resulting in reduced background activity at scanning time. Renal excretion over a 4-hour period of urine sampling showed no significant differences between both substances. Blood activity is independent of diuresis.

Using an own formula (VI) or the formula (VII) of Karran et al. for the determination of liver size from scintigrams, a good correlation was demonstrated to the measured weight in rats. Also the liver size of 44 healthy subjects estimated by the same method (VI) was compared to the ideal liver weight derived from the "Geigy Tables" and showed good correlation. This demonstrates the value of the proposed empirical formula: G equals 0.141 g/cm-3 D1 D2 D3 + 950 g for the calculation of liver weight using scintigraphy.

After intravenous injection of 99m-Tc-labelled HSA-microspheres indicator dilution curves of vena cava superior, total right heart and lungs are recorded, using a Nuclear Chicago Pho Gamma II camera and a Hewlett Packard 5407 A computer system. A method is described, which permits the determination of the distribution of transit times, the mean transit time and the ejection fraction of the right heart on the basis of these three curves. The usefulness of the method for cardiac investigations is discussed.

This paper outlines the method of preparation of 99m-Tc-phytate and its use for scanning the reticuloendothelial system. The tissue distribution studies in mice and rats indicate that 99m-Tc-phytate is a safe and effective liver imaging agent. This was confirmed by preliminary studies in human subjects. The stability of the aqueous tin-phytate complex is remarkably good, and it could be successfully used for more than two months to prepare the labelled product.

Carbon-11 (t1/2 equals 20.4 min, beta-+) labelled DL-alpha-phenylalanine and DL-alpha-phenylglycine were administered intravenously to rats and the distribution of the radioactive amino acids over pancreas, liver, spleen, kidneys and blood was measured after several time intervals. From these results the ratios of the concentration in pancreas and liver were calculated and compared with the corresponding ratios from the literature for some 18-F-labelled aromatic amino acids and L-selenomethionine-75-Se. On the basis of this study it appears that DL-alpha-phenylglycine-1-11-C, in spite of a small percentage of the administered dose reaching the pancreas, and DL-alpha-phenylalanine-1-11-C are better suited to pancreas scintigraphy than L-selenomethionine-75-Se.

Comparative studies between radiological (equals R; x-ray, thermography, angiography) and nuclear medical examinations (equals NM; scanner-, scintillation camera-sequential scintigraphy) in 339 patients with different bone diseases led to the following results: Thermography proved to be inferior to scanning in detecting of bone diseases. Angiography was the procedure of choice in detecting malignant bone tumors. Sequential scintigraphy performed by means of the Anger-HP-scintillation camera and Intertechnique-Cine-System allowed to establish the kinetic behaviour of tumors: an early increased TcPoP accumulation was observed in tumors with high perfusion (sarcoma), a late accumulation in those with low perfusion (osteoid osteoma).