Device for computer tomography
AssigneeU.S. Philips Corporation
InventorCornelius B. J. D. Albrecht
Life of this patent
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Abstract
A device for computer tomography, comprising an X-ray source, a number of X-ray detectors and a signal processing network which includes a comparator for comparing detector output signals with data obtained during measurement of a calibration material and stored in a memory. The comparator determines, by way of interpolation, the thicknesses of calibration material which correspond to detector output signals and provides computer input signalswhich are a function of these thicknesses. By means of these computer input signals, an image of the density distribution of an irradiated patient is calculated. This image is free from interference patterns caused by differences between the detectors, by non-linearity of the detectors or by hardening of the radiation.
Claims8
A device for computed tomography examinations comprising:
- X-ray source means which irradiate a patient position from different directions;
- a plurality of X-ray detectors;
- and
- signal processing network means, including a memory, which process output signals from the detectors to form computer input signals, the signal processing network means including comparator means which function to compare a first group of output signals from the detectors, which are obtained during examination of a patient with a second group of output signals from the detectors, which are obtained during radiation of a number of layer thicknesses of a calibration material, the second group being stored in the memory, the calibration material having substantially the same X-ray absorption properties as human tissue, the network means functioning to determine, by interpolation, a calibration value which is a function of the layer thickness of the calibration material which corresponds to a measured output signal in the second group and to generate a computer input signal which is a function of the determined calibration value.
A device as claimed in any of the preceding claims further comprising means which monitor the output power of the X-ray source means and which supply a third group of output signals characteristic thereof, and wherein the signal processing network means further function to modify the value of the computer input signal as a function of the values of the third group of signals.
Dependencies are inferred from the claim text.