公开(公告)号：US20210113178A1

公开(公告)日：2021-04-22

申请号：US15929155

申请日：2019-10-18

Applicant: CANON MEDICAL SYSTEMS CORPORATION

Inventor： Jian ZHOU ,  Xiaohui ZHAN ,  Zhou YU

IPC: A61B6/00 ,  A61B6/03 ,  G01T1/24

Abstract: An apparatus and method are described using a forward model to correct pulse pileup in spectrally resolved X-ray projection data from photon-counting detectors (PCDs). The forward model represents pulse pileup effects using an integral in which the integrand includes a term that is a function of a count rate, which term is called a spectrum distortion correction function. This correction function can be represented as superposition of basis energy functions and corresponding polynomials of the count rate, which are defined by the polynomial coefficients. To calibrate the forward model, the polynomial coefficients are adjusted to optimize an objective function, which uses calibration data having known projections lengths for the material components of a material decomposition. To determine projection lengths for projection data from a computed tomography scan, the calibrated polynomial coefficients are held constant and the projection lengths are adjusted to optimize an objective function.

公开(公告)号：US20210012541A1

公开(公告)日：2021-01-14

申请号：US16509429

申请日：2019-07-11

Applicant: Canon Medical Systems Corporation

Inventor： Tzu-Cheng LEE ,  Jian ZHOU ,  Zhou YU

IPC: G06T11/00 ,  G06T5/20 ,  G06T5/00 ,  G01N23/046 ,  A61B6/03

Abstract: A method and apparatus is provided to improve the image quality of images generated by analytical reconstruction of a computed tomography (CT) image. This improved image quality results from a deep learning (DL) network that is used to filter a sinogram before back projection but after the sinogram has been filtered using a ramp filter or other reconstruction kernel.