公开(公告)号：US20180350113A1

公开(公告)日：2018-12-06

申请号：US15562325

申请日：2016-02-29

Applicant: HITACHI, LTD.

Inventor： Taiga GOTO ,  Hisashi TAKAHASHI ,  Hideaki FUJII

IPC: G06T11/00 ,  A61B6/03 ,  A61B6/00

CPC classification number: G06T11/008 ,  A61B6/032 ,  A61B6/5258 ,  A61B6/5282 ,  G06T11/006

Abstract: In order to reduce a metal artifact using a short process, without causing image quality deterioration, when a subject containing metal is imaged in an X-ray CT apparatus, the invention is such that a high frequency component is extracted utilizing the fact that a high frequency component is a structure in error projection data, which are a difference between primary corrected projection data wherein at least one portion of an artifact component caused by metal has been removed and photographed projection data acquired by imaging. The high frequency component, extracted while carrying out weighting in order to suppress the metal artifact, is restored to the primary corrected projection data, after which an image is reconstructed. Also, metal projection data used when compiling the primary corrected projection data are calculated from a value that is a CT value corresponding to soft tissue subtracted from a CT value of a metal region.

公开(公告)号：US20170231589A1

公开(公告)日：2017-08-17

申请号：US15518933

申请日：2015-11-13

Applicant: HITACHI, LTD.

Inventor： Hideaki FUJII ,  Taiga GOTO ,  Tetsuo NAKAZAWA

IPC: A61B6/00 ,  A61B6/04 ,  A61B6/03

CPC classification number: A61B6/5205 ,  A61B6/032 ,  A61B6/0457 ,  A61B6/4452 ,  A61B6/461 ,  A61B6/469

Abstract: In a case where helical scanning, etc., is performed in an X-ray CT apparatus, upsampled projection data that more approximates to an observed value is obtained. There is provided an X-ray CT apparatus that improves spatial resolution of an overall effective field of view without reducing rotation speed, in an FFS method of acquiring projection data through moving of an X-ray focus position to a plurality of positions. The X-ray CT apparatus: converts projection data acquired through helical scanning into projection data of normal scanning performed by one rotation; generates a virtual-counter-data space in which virtual counter data are acquired on substantially coincident X-ray transmission path in the converted projection data; performs upsampling in a view direction; and similarly upsamples FFS projection data in the view direction for focus-shifted projection data obtained by performing the helical scanning while causing the X-ray focus position to shift (virtual counter data space generation).