Patent ID: 7873141

Claim:
An X-ray tomographic imaging apparatus comprising: an image comparison information calculating section configured to calculate ratios of pixel values between a first-energy tomographic image of a subject and a second-energy tomographic image of the subject, said first-energy tomographic image reconstructed based on a first-energy projection dataset obtained using X-rays at a first energy and said second-energy tomographic image reconstructed based on a second-energy projection dataset obtained using X-rays at a second energy different than the first energy; a region-of-interest defining section configured to define a region of interest including a predetermined material in at least one of said first-energy tomographic image and said second-energy tomographic image; a weighting factor determining section configured to determine a weighting factor based on a peak value of a distribution of the ratios of pixel values; and a dual-energy image reconstructing section configured to reconstruct said dual-energy image by conducting a weighted subtraction processing between at least one of said first-energy projection dataset and said second-energy projection dataset and said first-energy tomographic image and said second-energy tomographic image using said weighting factor determined at said weighting factor determining section.