Abstract: In a method and CT apparatus and software product for reconstructing incomplete projection data sets for dose-reduced sectional spiral scanning along a z axis of a patient on a table that is movable in the z direction in the CT apparatus that has a radiation source supplied with tube current so as to emit a beam that strikes a detector system to obtain scanning data from which in an image computing device generates two-dimensional and three-dimensional scanning images of the examination subject, at a pitch greater or equal to one. For z positions having an incomplete projection data set for reconstruction of the image, in a preprocessing step data from another row of this projection and/or data for a previous or subsequent 360° rotation are used to compute a complete projection data set therefor.

Abstract: A method is for restoring a signal of a defective channel of a beam detector, which has a multitude of channels and by means of which projections are recorded from different directions of projection. The channels of the beam detector each have a detector element with channel electronics connected downstream thereform. The signal of the defective channel is restored while using neighboring signals of an M-neighborhood of the same projection and from adjacent signals of an M-neighborhood of additional projections.

Abstract: In a method and CT apparatus and software product for reconstructing incomplete projection data sets for dose-reduced sectional spiral scanning along a axis of a patient on a table that is movable in the z direction in the CT apparatus that has a radiation source supplied with tube current so as to emit a beam that strikes a detector system to obtain scanning data from which in an image computing device generates two-dimensional and three-dimensional scanning images of the examination subject, at a pitch greater or equal to one. For z positions having an incomplete projection data set for reconstruction of the image, in a preprocessing step data from another row of this projection and/or data for a previous or subsequent 360° rotation are used to compute a complete projection data set therefor.

Abstract: The invention relates to a method for restoring a signal of a defective channel of a beam detector, which has a multitude of channels and by means of which projections are recorded from different directions of projection. The channels of the beam detector each have a detector element with channel electronics connected downstream therefrom. The signal of the defective channel is restored while using neighboring signals of an M-neighborhood of the same projection and from adjacent signals of an M-neighborhood of additional projections.

Abstract: A phantom for measuring slice thicknesses, slice sensitivity profiles and the axial modulation transfer function in an X-ray computed tomography apparatus contains a foil of a material that highly attenuates X-radiation that is arranged parallel to the image plane of the X-ray computed tomography apparatus given employment of the phantom and which had an axial expanse that is small compared to the thinnest slice to be measured. The expanse of the foil in the direction of the image plane is on the order of magnitude of a few millimeters.

Abstract: A computed tomography method and apparatus conduct a spiral scan of a subject wherein non-uniformities of noise and topical resolution are greatly reduced. A power spectrum S.sub.o for interpolated projections is identified, from which a frequency characteristic H(f,.theta.), of an optimum filter for the projections interpolated from complementary data is determined, with ##EQU1## with .sigma..sub.o.sup.2 being the variance of the quantum noise associated with a projection and w(.theta.) being the spiral weighting.

Abstract: In a diagnostics system wherein a radiological image is generated of a patient who has been injected with a contrast agent, the arrival of the contrast agent bolus at the imaging site is identified either directly by detecting the contrast agent, or indirectly by detecting a dye injected with the contrast agent, so that a synchronization of the imaging exposures with the arrival of the contrast agent can be assured. If a dye is used, the dye can be an optically detectable dye which is injected via the contrast agent syringe in addition to the contrast agent. A densitometer identifies the arrival of the contrast agent or of the dye at a predetermined location of the patient, and controls triggering of the exposures.

Abstract: A computer tomography apparatus has an x-ray source and a radiation detector which permit a patient to be helically scanned to obtain a tomogram of the patient. Since it is frequently desirable to obtain a conventional x-ray image (shadowgraph) of the patient as well, a method is disclosed which permits the computer used to generate the tomogram to calculate such a shadowgraph of the patient from the data acquired for the tomogram, for desired projection directions. This data is acquired, and the shadowgraph obtained, simultaneously with the exposure used to produce the tomogram.

Abstract: A phantom for use in calibrating dual energy X-ray absorptiometry and quantitative computed-tomography includes one or more sections which are equivalent to bone to X-rays and which have a shape resembling a lumbar vertebra. Each section includes a substantially cylindrical main body simulating the vertebra centrum, a band simulating the neural arch, and transverse and posterior processes extending from the band. The transverse processes are formed in a define wedge shape which tapers down from its attachment to the neural arch band. The section, or stacked sections, are embedded in a matrix of plastic material equivalent to water or tissue.

Abstract: A device for generating trigger signals for a medical apparatus, used for diagnosis and/or therapy, based on the respiratory activity of a patient includes a spirometer with a measurement transducer disposed therein for measuring respiratory air of a patient, and a signal generator connected to the transducer for generating trigger signals based on the respiratory measurement. A closure device can be provided in the spirometer in the respiratory path, which can be closed so that the flow respiratory air is briefly interrupted when a predetermined set value, for example obtained from the measured value, is reached.

Abstract: Patient support elements, such as pillows, are disposed on opposite sides of an examination subject lying on a supporting bed in a tomographic apparatus. The patient support bodies include one or more reference elements having known composition and characteristics which are reproduced in the image at a display unit. Standardization of the measured values is thereby achieved in a manner which is independent of the apparatus itself.

Abstract: In an exemplary embodiment, the measuring arrangement including the x-ray tube and radiation receiver, is capable of being locked against rotation, and the patient support is capable of being locked against longitudinal movement. The x-ray beam is selectively limited in extent by means of an adjustable diaphragm. In the case of a locked measuring arrangement and patient support and a limited x-ray beam, the measured values of the radiation receiver are detected by a computer which, from them and from information regarding the cross section of a vessel to be examined, determines the concentration and/or quantity of an x-ray contrast agent therein. The information regarding the cross section is obtained with a normal computer tomographic scanning operation.