X-RAY CT APPARATUS AND IMAGE RECONSTRUCTION METHOD

摘要

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.

主权项

1. An X-ray CT apparatus comprising:
an X-ray tube device that irradiates X-rays to an object from a plurality of focal spots; an X-ray detector that is disposed oppositely to the X-ray tube device for detecting transmission X-rays transmitted through the object; a rotary disk that is equipped with the X-ray tube device and the X-ray detector and rotates around the object; a focal shift X-ray controller that shifts the focal spots in the X-ray tube device to arbitrary positions; a focal shift projection data generation unit that generates focal shift projection data in combination with the transmission X-rays by each of the irradiated X-rays whose focal spots were shifted to a plurality of positions by the focal shift X-ray controller; a virtual view generation unit that generates a virtual view in the view direction of the focal shift projection data to generate up-sampled projection data using the virtual view; and a reconstruction computing unit that reconstructs an image using actual data of the focal shift projection data in a central region closer to the image center than a predetermined boundary in the image plane and using the up-sampled projection data in a peripheral region outside the boundary.