Abstract: In a method for image reconstruction for a CT apparatus and CT apparatus for the implementation of such a method, acquisition of the data underlying an image reconstruction for an image plane at a specific position on the system axis ensues by combining measured values, for each individual projection angle needed for this image reconstruction, that are registered exclusively for this projection angle with different lines of detector elements, to form data apparently registered with a detector having only one line of detector elements, with a weighting of the measured values ensuing. The image reconstruction is then undertaken using a conventional algorithm for operating on data from a detector having only one line of detector elements.

Abstract: In a method and CT apparatus for producing CT images of a body region periodically moving with resting or motion phases, data corresponding to a number of projections serving the purpose of imaging are analyzed to determine whether each projection was acquired during a resting or motion phase, and only those data that were acquired during a resting phase are employed for image reconstruction.

Abstract: In a method for image reconstruction in a computed tomography apparatus, whereby only the minimally possible projection angle range &agr;g(&bgr;) for the respective fan angle &bgr; is employed for all measured values S(&bgr;, &agr;) of the same fan angle &bgr;.

Abstract: In a method for image reconstruction in a computed tomography (CT) device, which picks up projections of a region located in a measuring field of an examination subject having an extent which exceeds this measuring field, the projections are identified in which the measuring field was exceeded, and extrapolated measurement points representing the detected cut-off projections, are added to the series of “actual” measurement points in such a way that each series of measurement points representing a detected projection is completed in an optimally realistic manner, and begins and ends with a measurement point whose measurement value is substantially zero.

Abstract: An x-ray examination apparatus with a detector array having a number of detector elements includes a data correction computer in which the subject-scattered radiation can be numerically determined and corrected. The forward scatter intensity is determined by multiplication of the measured intensities, windowed with a window function, with the natural logarithm of the intensity normalized with the unattenuated primary intensity. The subject-scattered radiation can then be calculated and corrected through filtering of the forward scatter intensity with a convolution kernel and a suitable scaling.

Abstract: The frequency of a pulse signal is measured with the aid of a reference signal generated in an oscillator (11). Both the pulses of the frequency to be measured and the pulses of the reference frequency are counted by separate counters (12, 13) and the counts or counted results are stored in separate memories (14, 15). A flip-flop (21) is set and reset to determine each measuring duration. The difference between two successive counts of the measured frequency counter (14) corresponds to the pulses or rather periods counted during the measuring time duration. The difference between two successive counts of the reference frequency counter (15) corresponds to the length of the measuring time duration whereby the resolution is determined by the reference frequency. A microprocessor (16) divides the number of periods counted by the measuring time duration to ascertain the frequency to be measured which may then be displayed.