Patent ID: 7783001

Claim:
An X-ray CT apparatus comprising: a scan device comprising: an X-ray source; an X-ray detection unit configured to detect X-rays irradiated from said X-ray source, said X-ray detection unit comprising a plurality of detector elements; an imaging table for placing a subject thereon and configured to dispose the subject between said X-ray source and said X-ray detection unit; a controller configured to control irradiation of the subject with X-rays from said X-ray source while said imaging table, said X-ray source, and said X-ray detection unit are relatively moved along a body axis of the subject; an X-ray data acquisition section configured to acquire projection data of the X-rays detected by said X-ray detection unit; and an image reconstructing device configured to: specify a first imaging range, a second imaging range, and a third imaging range located between the first imaging range and the second imaging range, in association with a position on the body axis of the subject; image-reconstruct a first tomographic image included in the first imaging range using a first projection data amount corresponding to an amount of projection data necessary for image reconstruction of the first tomographic image; image-reconstruct a second tomographic image included in the second imaging range using a second projection data amount less than the first projection data amount and corresponding to an amount of projection data necessary for image reconstruction of the second tomographic image; and image-reconstruct a third tomographic image included in the third imaging range using a third projection data amount less than the first projection data amount and greater than the second projection data amount.