Patent ID: 7953263

Claim:
An X-ray CT apparatus wherein projection data on a patient are acquired, and an original image of the patient is reconstructed based on the acquired projection data, the X-ray CT apparatus comprising: a high contrast extraction unit configured to extract a high-contrast region having a comparatively high X-ray attenuation coefficient from the original image; a convolution unit configured to generate an unsharp image concerning the high-contrast region based on a position of the extracted high-contrast region and a point spread function peculiar to the CT apparatus, wherein said convolution unit includes a unit configured to convolute the point spread function into a position image of the extracted high-contrast region, and a unit configured to normalize the convoluted position image of the high-contrast region in accordance with a standard CT number of the high-contrast region; and a unit which configured to subtract the unsharp image from the original image to generate a low-contrast image concerning a low-contrast region of comparatively low X-ray attenuation coefficient.