| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide an X-ray CT imaging apparatus for adaptively changing conditions of X-ray projection according to the attenuation of X-rays due to the subject. <P>SOLUTION: The X-ray CT apparatus comprises X-ray generating means 101 and 102 capable of generating X-rays having a plurality of X-ray energy distributions; an X-ray detector 108 for detecting X-rays transmitting through the subject 116; and a rotating gantry 100 rotating with the X-ray generating means and the X-ray detector mounted and irradiates the same cross section of the subject with X-rays having the plurality of X-ray energy distributions to acquire internal information from an projection image of the subject. More specifically. the X-ray CT apparatus has a control means 114 for performing at least one control over the amount of insertion of an X-ray filter 103 in an X-ray path based on the intensity of a transmitting X-rays signal through the subject; control over transmitting X-rays incident onto the X-ray detector by the width of the opening of an X-ray collimator 106; or control over the rotating speed of the gantry and irradiates X-rays having a X-ray energy distribution different from a prescribed one to detect the X-rays transmitting through the subject. By this apparatus, it is possible to prevent degradation of CT image quality due to quantum noise. <P>COPYRIGHT: (C)2004,JPO</p> |
