X-ray CT scanner

Abstract

An X-ray CT scanner includes an X-ray tube which irradiates an object, a variable X-ray limiting device which limits the X-ray beam thickness, an X-ray detector which detects X rays transmitted through the object and has a plurality of detecting elements arrayed in a matrix manner, a storing unit which stores a plurality of calibration data files corresponding to a plurality of beam thicknesses, a correcting unit which corrects an output from the X-ray detector on the basis of at least one calibration data file read out from the storing unit, a reconstructing unit which reconstructs image data concerning the object on the basis of an output from the correcting unit, and a control unit which controls the variable X-ray limiting device to change the beam thickness of the X rays, independently of the beam thicknesses to which the calibration data files stored correspond.

What is claimed is:  
     
         1 . An X-ray CT scanner for reconstructing a CT image of an object to be examined, based on projection data obtained by scanning the object using an X-ray source for radiating an X-ray beam and an X-ray detector for detecting an X-ray transmitted through the object, comprising: 
 a setting unit configured to arbitrarily set a thickness of the X-ray beam with respect to a slice direction of the object.    
     
     
         2 . A scanner according to  claim 1 , further comprising a displaying unit configured to display information about the thickness of the X-ray beam.  
     
     
         3 . A scanner according to  claim 2 , wherein said displaying unit displays lines pertaining to the thickness of the X-ray beam, and wherein the scanner further comprises an input device configured to manipulate the lines by an operator.  
     
     
         4 . A scanner according to  claim 3 , wherein the lines show ends of the X-ray beam with respect to a slice thickness.  
     
     
         5 . A scanner according to  claim 3 , wherein the lines show a center and ends of the X-ray beam with respect to a slice thickness.  
     
     
         6 . A scanner according to  claim 1 , further comprising a displaying unit configured to display at least one of numerical values and cursors on a scanogram to support an inputting of a desired thickness of the X-ray beam.