Abstract: An improved filtered back-projection technique for operating a medical imaging apparatus as disclosed wherein image noise and artifacts are reduced. In the improved method, back-projection image contributions are obtained from regions which lie outside the primary examination region. Correction projections are produced from these outside regions. The image produced by back-projection of the correction projections in the examination region is subtracted from an original, uncorrected image. The integrations which are undertaken when producing the correction projections are made along respective straight lines which are also used to characterize the projection values in the original, uncorrected image.

Abstract: A computer tomography apparatus has an x-ray source with a focus, with the focus being periodically deflected during data acquisition, specifically during mean value formation of the signals obtained by the radiation detector. The mean value formation is not undertaken simultaneously for all detector elements, but instead is undertaken chronologically offset from detector element to detector element. A memory in which the analog measured values available at the end of an interval would be stored is thus not needed.

Abstract: In an exemplary embodiment, a radiation source emits a fan-shaped beam of rays, and a radiation receiver has a row of photoelectric transducers. Before each photoelectric transducer at least three like scintillation crystals are arranged in the row which are separated from one another by thin, opaque layers. Between each photoelectric transducer and the associated scintillation crystals, a medium is arranged which has a light transmission decreasing from the center of the respective photoelectric transducer in the direction of the outer edges of said transducer.

Abstract: This invention is an electronic kilowatthour meter with a time-division multiplier, wherein a proportional first current is derived from the load voltage without a voltage transformer and a proportional second current is derived by means of an inverting amplifier, with a polarity opposite to that of the first current and instantaneous values halved as compared to the first current, and that the first current is added to the second current in one of two switching conditions by means of a switch which is operated by a pulse width-frequency modulator controlled by the load current, so that the average value of the sum current is proportional to the product of the load current and the load voltage.