Systems and methods for a stationary ct imaging system

Patent metadata

Field	Value
Publication number	US-2021378619-A1
Application number	US-202117342441-A
Country	US
Kind code	A1
Filing date	Jun 8, 2021
Priority date	Jun 8, 2020
Publication date	Dec 9, 2021
Grant date	—

Abstract

Various methods and systems are provided for stationary CT imaging. In one embodiment, a method for an imaging system includes activating an emitter of a plurality of emitters of a stationary distributed x-ray source unit to emit an x-ray beam toward an object within an imaging volume, where the x-ray source unit does not rotate around the imaging volume, receiving the x-ray beam at a subset of detector elements of a plurality of detector elements of one or more detector arrays, sampling the plurality of detector elements to generate a total transmission profile, an attenuation profile, and a scatter measurement, generating a scatter-corrected attenuation profile by entering the total transmission profile, the attenuation profile, and the scatter measurement as inputs to a model, and reconstructing one or more images from the scatter-corrected attenuation profile.

First claim

1 . A method for a stationary computed tomography (CT) system, comprising:
activating an emitter of a plurality of emitters of a stationary distributed x-ray source unit to emit an x-ray beam toward an object within an imaging volume, where the x-ray source unit does not rotate around the imaging volume; receiving the x-ray beam at a subset of detector elements of a plurality of detector elements of one or more detector arrays; sampling the plurality of detector elements to generate a total transmission profile, an attenuation profile, and a scatter measurement; generating a scatter-corrected attenuation profile by entering the total transmission profile, the attenuation profile, and the scatter measurement as inputs to a model; and reconstructing one or more images from the scatter-corrected attenuation profile.

2 . The method of claim 1 , wherein the total transmission profile is generated from detector output from each detector element of the plurality of detector elements, the attenuation profile is generated from output from only the subset of detector elements, and the scatter measurement is generated from output from only one or more detector elements of the plurality of detector elements outside the x-ray beam.

3 . The method of claim 2 , wherein the model is trained to output the scatter-corrected attenuation profile.

4 . The method of claim 2 , wherein the model is trained to output a scatter profile representing scatter of the x-ray beam detected by the plurality of detector elements, and wherein generating the scatter-corrected attenuation profile comprises correcting the attenuation profile with the scatter profile to generate the scatter-corrected attenuation profile.

5 . The method of claim 1 , wherein the model is trained with training data pairs comprising, for a given view, scatter-corrupted data and scatter-reduced data.

6 . The method of claim 5 , wherein the scatter-corrupted data is acquired with a full fan-beam x-ray beam and the scatter-reduced data is acquired with a partial fan-beam x-ray beam.

7 . The method of claim 1 , wherein the scatter-corrected attenuation profile represents a first view, and further comprising activating one or more additional emitters of the plurality of emitters to generate one or more additional attenuation profiles each representing a respective different additional view, scatter-correcting each additional attenuation profile based on the scatter-corrected attenuation profile via interpolation to generate one or more additional scatter-corrected attenuation profiles, and wherein reconstructing one or more images from the scatter-corrected attenuation profile comprises reconstructing one or more images from the scatter-corrected attenuation profile and the one or more additional scatter-corrected attenuation profiles.

8 . A stationary computed tomography (CT) system, comprising:
a stationary distributed x-ray source unit comprising a plurality of emitters positioned to emit x-ray beams toward an object in an imaging volume; a plurality of detector elements forming one or more detector arrays extending around at least a portion of the imaging volume; and one or more computing devices configured to:
activate a first emitter of the plurality of emitters to emit a first x-ray beam shaped and positioned to be intercepted by a subset of detector elements of the plurality of detector elements;
measure scatter of the first x-ray beam caused by the object;
activate one or more additional emitters of the plurality of emitters to emit one or more additional x-ray beams shaped and positioned to be intercepted by one or more additional subsets of detector elements of the plurality of detector elements;
obtain projection data from the subset of detector elements and the one or more additional subsets of detector elements;
correct the projection data with the measured scatter to form scatter-corrected projection data; and
reconstruct one or more images from the scatter-corrected projection data.

9 . The stationary CT system of claim 8 , wherein the first emitter is configured to emit the first x-ray beam with a fan-beam spanning the subset of detector elements, and further comprising a lead blocker positioned proximate the first emitter, the lead blocker configured to attenuate a portion of the first x-ray beam in a center of the fan-beam such that a portion of detector elements within the subset of detector elements do not intercept the first x-ray beam, and wherein the scatter of the first x-ray beam caused by the object is measured by the portion of the detector elements that do not intercept the first x-ray beam.

10 . The stationary CT system of claim 8 , wherein the scatter of the first x-ray beam is measured by one or more detector elements outside the subset of detector elements that are not positioned to intercept the first x-ray beam.

11 . The stationary CT system of claim 8 , further comprising a modulator positioned proximate the first emitter, the modulator comprising a plurality of attenuating blockers configured to attenuate portions of the first x-ray beam while not attenuating other portions of the first x-ray beam, and wherein the one or more computing devices are configured to measure the scatter of the first x-ray beam by sampling the output from the subset of the detector elements and demodulating the sampled output to separate detector signals resulting from interception of the first x-ray beam and detector signals resulting from interception of the scatter.

12 . The stationary CT system of claim 8 , wherein correcting the projection data with the measured scatter to form scatter-corrected projection data comprises entering the measured scatter and projection data from the subset of detector elements into a model trained to provide a scatter estimation, and correcting the projection data from the subset of detector elements and the one or more additional subsets of detector elements with the scatter estimation.

13 . The stationary CT system of claim 8 , wherein correcting the projection data with the measured scatter to form scatter-corrected projection data comprises entering the measured scatter and projection data from the subset of detector elements into a model trained to provide scatter-corrected projection data, and correcting projection data from the one or more additional subsets of detector elements based on the scatter-corrected projection data via interpolation.

14 . A method for a stationary computed tomography (CT) system, comprising:
obtaining a plurality of views of projection data by sequentially activating a plurality of emitters of a stationary distributed x-ray source unit to emit a plurality of x-ray beams toward an object within an imaging volume and intercepting the plurality of x-ray beams, after attenuation by the object, at a plurality of detector elements of one or more detector arrays; for a first view of the plurality of views obtained by activating a first emitter of the plurality of emitters to emit a primary x-ray beam, generating a transmission profile, an attenuation profile, and a scatter measurement based on output from the plurality of detector elements, where the attenuation profile includes output from only detector elements positioned to intercept the primary x-ray beam, the scatter measurement includes output from only detector elements positioned outside of the primary x-ray beam, and the transmission profile includes output from detector elements positioned to intercept the primary x-ray beam and detector elements positioned outside of the primary x-ray beam; entering the transmission profile, the attenuation profile, an

Assignees

• Ge Prec Healthcare Llc

Inventors

• De Man Bruno Kristiaan Bernard
• Pack Jed Douglas
• Wu Mingye
• Smith Chad Allan
• Thibault Jean-Baptiste

Classifications

• G06T12/20

  Inverse problem, i.e. transformations from projection space into object space · CPC title

• G06T12/00

  Tomographic reconstruction from projections · CPC title

• A61B6/032

  Transmission computed tomography [CT] · CPC title

• A61B6/4275

  using a detector unit almost surrounding the patient, e.g. more than 180° · CPC title

• A61B6/4078

  Fan-beams · CPC title