Biomedical subjects
Publications and source records attributed to E Schumann.
A measuring unit is presented for the measurement of dose rate values around an iridium-192 source. The values determined by measurements are compared to the calculated values. Both show a good conformity, so they can be used as basis for a computer program.
The distribution pattern of 111In-labelled autologous platelets was investigated in 50 patients. Imaging was performed with a scintillation camera connected to a computer system. 20 patients suffering from obliterative arterial disease showed a normal platelet distribution. Endothelial lesions after arteriography were found in 6 out of 10 patients. 15 of 20 patients with suspected venous thrombosis showed local platelet deposition. 10 of these patients with local platelet depositions were investigated by phlebography. Positive findings (fresh thrombi) were found in 8 patients. Optimum results were obtained by injecting platelets distal to the venous thrombus. Signs of thrombosis are interruption of blood flow, collateral formation and platelet deposition. This new method offers possibilities of radioisotopic diagnosis of parietal thrombus and venous thrombosis despite anticoagulation or fibrinolysis.
A method for radio-nuclide labelling of histo-acryl/lipiodol with 133Xe gas is described. The method consists of dissolving the gas in lipiodol under sterile conditions. After embolization and angiography, the localisation of the embolizing material can be determined by means of a scintillation camera. The labelling method was used in 15 patients. In all patients the position of the embolizing material, as demonstrated by scintigraphy, corresponded with the radiological findings. It was not possible to demonstrate escape of the material by scintigraphy.
111Indium-labelled thrombocytes were used for radionuclide venography in ten patients. All types of thrombi could be demonstrated with a high degree of accuracy, particularly if the marked thrombocytes were injected distally. In cases of complete occlusion by thrombus, the peripheral end of the clot appeared as a 'hot spot'. Non-occluding thrombi with a thrombogenic surface can be differentiated from lesions of the endothelium. Compared with venography using labelled microspheres, labelled thrombocytes have the advantage of demonstrating the degree of activity of the thrombotic process.
Spread of infection to the spine following urological surgery is extremely rare. The diagnosis is therefore often made at a late stage resulting in delayed treatment. Four patients observed by the authors are described and the diagnosis is discussed.
In 1981, percutaneous transluminal angioplasty (PTA) of the subclavian artery was performed in 10 patients. 8 stenotic lesions were localized in the first segment and two in the third segment respectively. Dilatation was performed with the Grüntzig balloon-catheter ranging from 4 to 7 French. PTA was successful in 9 of the 10 cases. Success of dilatation was documented by recording blood pressure, normalization in the pre- and poststenotic segment and by clinical results. Success of PTA depends on exact angiographic studies, adequate indication and subsequent anticoagulation treatment. Early results after PTA are excellent. PTA of stenotic subclavian arteries has proved an alternative to surgical management.
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The kidneys of 117 patients were examined before and after (immediately until several weeks) a telecobalt irradiation of the aortal lymph nodes. In 36 out of them, another control examination could be performed after 1 1/2 years. In 17 patients, the early examinations showed functional troubles of the kidneys which regressed in nine cases. The late examinations showed in 19 cases functional restrictions which have to be considered to be irreversible. The conclusion must be drawn that it is necessary to examine the kidneys before and until several years after a radiotherapy of the aortal lymph nodes and that the dose distribution has to be optimized with respect to a conservation of the kidneys, as far as this is oncologically possible.
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The authors give a report on their first results of percutaneous transluminal angioplasty of aortic arch branches in 4 patients. In 3 cases, stenosis of left subclavian arteries were treated by PTA with good result. One patient had a stenosis of both carotid arteries which were dilated with moderate effect. In all patients symptoms were removed. There were no complications.
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The conditions were examined under which little and medium computer systems not having been primarily developed for radiotherapy can be used in order to make sufficiently precise calculations of dose distributions. The adapted accuracy of the principal factors influencing the dose distribution renders possible a time-saving calculation of several dose distributions and a final calculation. By comparison with a reference calculation made as accurately as possible, the isodose curve shows only little deviations. The following factors were examined in order to find out an eventual influence exerted upon an isodose displacement: number of scan points in the cross-section, correction of the oblique ray incidence, inhomogeneities, dissociations of the rotation field. To our opinion, the isodose displacements found for a dose calculation with adapted accuracy are acceptable when related to influencing factors depending on the individual patients.
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This paper deals with 492 patients suffering from cranio-cerebral injuries. Intracranial haematomas were assumed to exist. The angiographic findings were compared with operation reports and postmortem findings respectively. It could be stated that extracerebral haematomas were detected by angiography in a percentage of more than 95.
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