Patent ID: 6421410
Filing Date: 2002-07-16
Classification: A61B,G01N,G03B,Y10S

Abstract:
A computed tomography apparatus comprising:an x-ray source which emits x-rays; a detector array on which said x-rays are incident and which emits output signals dependent on x-rays incident thereon, said detector array having a longitudinal direction &bgr;; a patient support adapted to receive an examination subject thereon and having a longitudinal direction Z; a displacement arrangement for producing a relative displacement between said x-ray source and said detector array, and said patient support, in said Z-direction with output signals from said detector array being acquired with said x-ray source and said detector array in a predetermined angular position around said patient support; and a computer to which said output signals are supplied, said computer convolving said output signals in said Z-direction according to bl&af;(k)=&Sum;Îº=-n/2n/2&it;â€ƒ&it;Ul&af;(k-Îº)*h&af;(Îº)and extrapolating missing readings Ul(kâˆ’&kgr;) with (kâˆ’&kgr;)>kr from existing readings Ul(kâˆ’&kgr;) with (kâˆ’&kgr;)&lE;kr, and wherein * means â€œconvolved withâ€ l is the index in the &bgr;-direction, k is the index in the Z-direction, &kgr; is the count index for the convolution, Ul(k) are readings convolved in the &bgr;-direction representing measurement of the attenuation, values of a slice of the subject, Ul(kr) is a most recently registered reading, bl(k) are readings additionally convolved in the Z-direction, h is the convolution kernel, n is the degree of the convolution kernel.