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[en] Introduction: In the Paris brachytherapy system, to deliver a prescribed dose to the isodose contour associated with the 85% of the basal dose and equally-spaced array of ribbons or wires of the same strength is commonly used. Implant parameters such as uniformity and treated volume outside the treatment isodose contour, depend critically on the distance between ribbons and planes and the seed strength. We want to know the distance that optimizes implant parameters for any seed strength between 0.4 and 2 mCi. Materials and Methods: The distribution of volume as function of dose rate of a configuration of three ribbons per plane of five seeds each, was analysed varying both distance from 0.2 to 2.5cm and strength from 0.4 to 2mCi. Volume-dose data were obtained from Monte-Carlo calculations, considering point isotropic sources and a third order polynomial to describe attenuation in water. In order to evaluate implant parameters, the corresponding Anderson's volume-dose histograms were performed. Those configurations with higher uniformity and minimum peripheral treated volume were chosen as optimum. Results: Distance-strength data corresponding to those optimized configurations were plotted and a fifth order polynomial resulted from curve fitting. Conclusion: For any seed strength between 0.5 and 2.5 mCi, optimum distance can be extrapolated from the curve. However, for lower values than 0.5 mCi no optimum distance has been found. A comparison between implant parameters corresponding to optimized configurations show that increasing strength results on lower values of uniformity and treated volume outside the treatment isodose contour

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[en] The electron beam process is mainly based on the conversion of the harmful molecules SO₂ and NO_x into the corresponding acids by irradiation with electrons. These acids are converted into salts by a suitable means of neutralisation and are separated from the flue gas. The reactions occur mainly in the gas phase. The product occurs in a dry solid form, so that there are no waste water problems with this process. (orig./PW)

[en] A demonstration unit with two low energy (300kV), high power (90kW) accelerators was installed at the bypass loop of Badenwerk AG power plant in Karlsruhe. The main elements of the process for removal of toxic gases and details of the installation are given. Some results obtained during the initial testing period are also included. The most important finding is the unambiguous proof of the suitability of the electron beam process for flue gas purification. The objectives of further tests are discussed. (author)

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[en] The results were compared of electroencephalography (EEG) and computerized tomography (CT) examinations of 250 patients with different brain affections. In intracranial expansive processes the pre-operative CT findings were positive in 100% cases, the EEG findings in 89.7% of cases. In severe traumatic affections the EEG and CT findings were positive in all cases, in mild injuries and post-traumatic conditions the EEG findings were more frequently positive than the CT. In focal and diffuse vascular affections the EEG and CT findings were consistent, in transitory ischemic conditions the EEG findings were more frequently positive. In inflammatory cerebral affections and in paroxymal diseases the EEG findings were positive more frequently than the CT. The same applies for demyelinating and degenerative affections. Findings of other authors were confirmed to the effect that CT very reliably reveals morphological changes in cerebral tissue while EEG records the functional state of the central nervous system and its changes. The two methods are complementary. (author)

[en] Molecular emission spectra of the OH rotational bands were measured to determine a two dimensional temperature profile of a microwave heated air plasma torch. The method is based on the simulation of rotational line intensities and the comparison with experimental results. A very high accuracy in simulation was obtained by the implementation of the Λ-doubling. The torch itself can be divided into a small (few millimetres in diameter) plasma and a flame which can reach up to 30 mm in diameter and 250 mm in height. While the plasma centre emits a variety of spectral lines, the whole flame is only accessible with the A² Σ⁺, v' = 0 → X² Π, v-prime = 0 transition in the free radical OH at 306.36 nm