X-RAY CT APPARATUS AND IMAGE RECONSTRUCTION METHOD

In an FFS method that improves spatial resolution by moving an X-ray focal spot to multiple positions to acquire projection data, in order to provide an X-ray CT apparatus and an image reconstruction method that enables to improve spatial resolution of the entire effective field of view without reducing a rotational speed, the X-ray focal spot in the X-ray tube device 101 is shifted to acquire focal shift projection data (FFS projection data), the virtual view generation unit 126 up-samples the FFS projection data (generates a virtual view) in the view direction, and the reconstruction computing unit 127 reconstructs an image using actual data of the FFS projection data in the central region 604 closer to the image center than a predetermined boundary and using the up-sampled projection data in the peripheral region 603 outside the boundary in an image reconstruction computing process.