Patent ID: 7756240

Claim:
An X-ray CT apparatus comprising: an X-ray tube for applying, to a subject, X rays having a first energy spectrum and X rays having a second energy spectrum different from the first energy spectrum; an X-ray data acquisition unit for acquiring X-ray projection data of the first energy spectrum applied to the subject and X-ray projection data of the second energy spectrum applied thereto; a dual energy image reconstructing unit for reconstructing tomographic images indicative of X-ray tube voltage-dependent information at X-ray absorption coefficients related to a distribution of atoms based on the X-ray projection data of the first energy spectrum and the X-ray projection data of the second energy spectrum; and an adjusting unit for adjusting conditions related to the X-ray projection data of the first energy spectrum and for adjusting conditions related to the X-ray projection data of the second energy spectrum such that noise of the X-ray projection data of the first energy spectrum and noise of the X-ray projection data of the second energy spectrum are made approximately equal to each other.