公开(公告)号：US11879856B2

公开(公告)日：2024-01-23

申请号：US17571087

申请日：2022-01-07

Applicant: CANON MEDICAL SYSTEMS CORPORATION

Inventor： Xiaohui Zhan ,  Xiaofeng Niu

IPC: G01N23/046 ,  A61B6/03 ,  A61B6/00 ,  G01N23/083

CPC classification number: G01N23/046 ,  A61B6/032 ,  A61B6/4241 ,  A61B6/582 ,  G01N23/083 ,  G01N2223/04 ,  G01N2223/20 ,  G01N2223/303 ,  G01N2223/419 ,  G01N2223/50

Abstract: A method and a system for providing calibration for a photon counting detector forward model for material decomposition. The flux independent weighted bin response function is estimated using the expectation maximization method, and then used to estimate the pileup correction terms at each tube voltage setting for each detector pixel.

公开(公告)号：US12111433B2

公开(公告)日：2024-10-08

申请号：US18306773

申请日：2023-04-25

Applicant: CANON MEDICAL SYSTEMS CORPORATION

Inventor： Xiaohui Zhan ,  Xiaofeng Niu ,  Ilmar Hein

IPC: A61B6/58 ,  A61B6/00 ,  A61B6/03 ,  A61B6/40 ,  A61B6/42 ,  G01T7/00 ,  G06T7/10 ,  G06T11/00

CPC classification number: G01T7/005 ,  A61B6/032 ,  A61B6/4035 ,  A61B6/4241 ,  A61B6/4447 ,  A61B6/583 ,  A61B6/585 ,  G06T7/10 ,  G06T11/005 ,  G06T2207/10081 ,  G06T2207/30004 ,  G06T2211/448

Abstract: A method and a system for providing calibration for a polychromatic photon counting detector forward counting model. Measurements with multiple materials and known path lengths are used to calibrate the photon counting detector counting response of the forward model. The flux independent weighted bin response function is estimated using the expectation maximization method, and then used to estimate the pileup correction terms at plural tube voltage settings for each detector pixel. The beam hardening corrections are then applied to the measured projection data sinogram, and the corrected sinogram is reconstructed to the counting image at the selected single energy.

公开(公告)号：US12102471B2

公开(公告)日：2024-10-01

申请号：US17720977

申请日：2022-04-14

Applicant: CANON MEDICAL SYSTEMS CORPORATION

Inventor： Xiaohui Zhan ,  Xiaofeng Niu ,  Ruoqiao Zhang

IPC: A61B6/58 ,  A61B6/03 ,  A61B6/42 ,  G01T7/00 ,  G06T7/00 ,  G06T11/00

CPC classification number: A61B6/585 ,  A61B6/032 ,  A61B6/4241 ,  G01T7/005 ,  G06T7/0012 ,  G06T11/005 ,  G06T2207/10081 ,  G06T2207/30004 ,  G06T2207/30168

Abstract: A photon counting computed tomography (CT) method including receiving a first forward model including a set of first parameters and a set of second parameters corresponding to a plurality of materials and path lengths by scanning a slab at plural tube voltages and plural tube currents of an X-ray tube; evaluating an image quality of a material decomposition image reconstructed by the set of first parameters and the set of second parameters; and updating at least one second parameters from the set of second parameters if the image quality of the material decomposition image does not satisfy a predetermined threshold, wherein the updating is achieved by updating the at least one second parameter from the set of second parameters to an energy dependent parameter from a constant value.

公开(公告)号：US11249035B2

公开(公告)日：2022-02-15

申请号：US16915575

申请日：2020-06-29

Applicant: CANON MEDICAL SYSTEMS CORPORATION

Inventor： Xiaohui Zhan ,  Xiaofeng Niu

IPC: G01N23/046 ,  A61B6/03 ,  A61B6/00 ,  G01N23/083

Abstract: A method and a system for providing calibration for a photon counting detector forward model for material decomposition. The flux independent weighted bin response function is estimated using the expectation maximization method, and then used to estimate the pileup correction terms at each tube voltage setting for each detector pixel.

公开(公告)号：US11944484B2

公开(公告)日：2024-04-02

申请号：US17218924

申请日：2021-03-31

Applicant: CANON MEDICAL SYSTEMS CORPORATION

Inventor： Xiaohui Zhan ,  Xiaofeng Niu

IPC: A61B6/00 ,  A61B6/03 ,  A61B6/42 ,  A61B6/58

CPC classification number: A61B6/583 ,  A61B6/032 ,  A61B6/4241

Abstract: A method and a system for providing calibration for a photon counting CT detector forward model for material decomposition. Various slabs of predetermined material and path lengths are placed in the photon counting CT detector and scanned using one or more stationary X-rays to obtain calibration data and parametrize the forward model.

公开(公告)号：US11653892B2

公开(公告)日：2023-05-23

申请号：US17156089

申请日：2021-01-22

Applicant: CANON MEDICAL SYSTEMS CORPORATION

Inventor： Xiaohui Zhan ,  Xiaofeng Niu ,  Ilmar Hein

IPC: A61B6/00 ,  A61B6/03 ,  G06T7/10 ,  G01T7/00 ,  G06T11/00

CPC classification number: A61B6/585 ,  A61B6/032 ,  A61B6/4035 ,  A61B6/4241 ,  A61B6/4447 ,  A61B6/583 ,  G01T7/005 ,  G06T7/10 ,  G06T11/005 ,  G06T2207/10081 ,  G06T2207/30004 ,  G06T2211/40

Abstract: A method and a system for providing calibration for a polychromatic photon counting detector forward counting model. Measurements with multiple materials and known path lengths are used to calibrate the photon counting detector counting response of the forward model. The flux independent weighted bin response function is estimated using the expectation maximization method, and then used to estimate the pileup correction terms at plural tube voltage settings for each detector pixel. The beam hardening corrections are then applied to the measured projection data sinogram, and the corrected sinogram is reconstructed to the counting image at the selected single energy.

公开(公告)号：US11490874B2

公开(公告)日：2022-11-08

申请号：US17206873

申请日：2021-03-19

Applicant: CANON MEDICAL SYSTEMS CORPORATION

Inventor： Xiaohui Zhan ,  Ilmar Hein ,  Xiaofeng Niu

IPC: A61B6/00

Abstract: An apparatus, system and method for calibrating an x-ray apparatus including acquiring sinogram data by scanning a symmetrical phantom using a plurality of detector channels; generating mirror-copied sinogram data by mirror-copying at least one of first sinogram data and second sinogram data of the acquired sinogram data, wherein the first sinogram data and the second sinogram data are generated by dividing the sinogram data at a center detector channel of the plurality of detector channels; outputting a first reconstructed image by reconstructing the mirror-copied sinogram data; and determining a calibration parameter based on the first reconstructed image.

公开(公告)号：US11644587B2

公开(公告)日：2023-05-09

申请号：US17153524

申请日：2021-01-20

Applicant: CANON MEDICAL SYSTEMS CORPORATION

Inventor： Xiaohui Zhan ,  Xiaofeng Niu

IPC: G01N23/00 ,  A61B6/00 ,  G01T7/00 ,  G01N23/046 ,  G01T1/20 ,  G06T7/00 ,  A61B6/03

CPC classification number: G01T7/005 ,  A61B6/035 ,  A61B6/4241 ,  G01N23/046 ,  G01T1/20184 ,  G06T7/0012 ,  G01N2223/303 ,  G01N2223/5055 ,  G06T2207/10081 ,  G06T2207/30168

Abstract: A method and a system for a two-step calibration method for the polychromatic semiconductor-based PCD forward counting model, to account for various pixel summing readout modes for imaging at different resolutions. The flux independent weighted bin response function is estimated using the expectation maximization method, and then used to estimate the pileup correction terms at plural tube voltage settings for each detector pixel. To correct the variation of the detector response due to different PCD sub-pixel summing schemes, the embodiments calibrate forward model parameters based on the various pixel readout modes.

公开(公告)号：US20210404975A1

公开(公告)日：2021-12-30

申请号：US16915575

申请日：2020-06-29

Applicant: CANON MEDICAL SYSTEMS CORPORATION

Inventor： Xiaohui Zhan ,  Xiaofeng Niu

IPC: G01N23/046 ,  A61B6/03 ,  A61B6/00 ,  G01N23/083

Abstract: A method and a system for providing calibration for a photon counting detector forward model for material decomposition. The flux independent weighted bin response function is estimated using the expectation maximization method, and then used to estimate the pileup correction terms at each tube voltage setting for each detector pixel.