# US 9,872,663 B2 · Methods, systems, apparatuses, and computer programs for removing marker artifact contribution from a tomosynthesis dataset > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,872,663 B2 - Document ID: US9872663B2 - Status: Granted - Kind: B2 - Application number: 14/613,618 - Filed: 2015-02-04 - Published: 2016-08-04 - Granted: 2018-01-23 - Earliest claimed: 2015-02-04 - Assignees: DENTSPLY SIRONA Inc. - Applicants: Sirona Dental, Inc. - Inventors: Fred Duewer - Web page: https://patentgrep.com/patent/US9872663B2 ## CPC - A61B 6/5258: {involving detection or reduction of artifacts or noise} - A61B 6/025: {Tomosynthesis} - A61B 6/027: {characterised by the use of a particular data acquisition trajectory, e.g. helical or spiral} - A61B 6/51: for dentistry - A61B 6/5252: {removing objects from field of view, e.g. removing patient table from a CT image} - A61B 6/584: {determining position of components of the apparatus or device using images of the phantom} - A61B 90/39: {Markers, e.g. radio-opaque or breast lesions markers} - G06T 5/50: using two or more images, e.g. averaging or subtraction - G06T 5/77: Retouching; Inpainting; Scratch removal - G06T 7/337: {involving reference images or patches} - G06T 12/30: Image post-processing, e.g. metal artefact correction - A61B 6/512: {Intraoral means} - A61B 2090/3966: {Radiopaque markers visible in an X-ray image} - G06T 2207/10116: X-ray image - G06T 2207/30036: Dental; Teeth - G06T 2207/30204: Marker - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) - G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL ## Abstract Method, system, apparatus, and computer program products for removing marker artifacts from a tomosynthesis dataset. In the method, a first plurality of projection images are acquired by tomosynthesis x-ray imaging, the first plurality of projection images containing at least one imaged representation of at least one alignment marker. In one aspect, the imaged representation of the at least one alignment marker on the first plurality of projection images is minimized to generate a second plurality of projection images. In another aspect, a plurality of tomographic images are reconstructed from the second plurality of projection images. ## Claims ### Claim 1 A method for removing marker artifacts from a tomosynthesis dataset in a tomosynthesis imaging system comprising: positioning at least one alignment marker anywhere within a field of view of the tomosynthesis imaging system; acquiring a first plurality of projection images by tomosynthesis x-ray imaging, the first plurality of projection images containing at least one imaged representation of the at least one alignment marker; minimizing the imaged representation of the at least one alignment marker on the first plurality of projection images to generate a second plurality of projection images; and reconstructing a plurality of tomographic images from the second plurality of projection images wherein if the at least one alignment marker is more than one, then a correlation between each alignment marker is not predetermined. ### Claim 2 (depends on 1) The method of claim 1, further comprising locating the imaged representation of the at least one alignment marker on the first plurality of projection images. ### Claim 3 (depends on 2) The method of claim 2, further comprising generating a calibration to convert x-ray attenuation to bone thickness; and estimating an estimated representation of the at least one alignment marker based on a known geometry of the at least one alignment marker and the calibration, wherein the minimizing includes subtracting the estimated representation of the at least one alignment marker from the imaged representation of the at least one alignment marker. ### Claim 4 (depends on 2) The method of claim 2, wherein the minimizing includes in-painting the imaged representation of the at least one alignment marker with information from an area of the first plurality of projection images surrounding the imaged representation of the at least one alignment marker. ### Claim 5 (depends on 1) The method of claim 1, further comprising aligning the plurality of projection images relative to each other based on the at least one imaged representation of the at least one alignment marker. ### Claim 6 (depends on 1) The method of claim 1, wherein the at least one alignment marker is spherical or near-spherical. ### Claim 7 (depends on 1) The method of claim 1, wherein the at least one alignment marker is a sphere having a radiopaque exterior and a radiolucent interior. ### Claim 8 (depends on 1) The method of claim 1, wherein the at least one alignment marker is provided on an aiming ring. ### Claim 9 (depends on 1) The method of claim 1, wherein at least three alignment markers are provided. ### Claim 10 (depends on 9) The method of claim 9, wherein the at least three alignment markers are non-collinear. ### Claim 11 A tomosynthesis imaging system for removing marker artifacts from a tomosynthesis dataset, the system comprising at least one processor operable to: acquire a first plurality of projection images by tomosynthesis x-ray imaging, the first plurality of projection images containing at least one imaged representation of at least one alignment marker; minimize the imaged representation of the at least one alignment marker on the first plurality of projection images to generate a second plurality of projection images; and reconstruct a plurality of tomographic images from the second plurality of projection images, wherein the at least one alignment marker is positioned anywhere within a field of view of the tomosynthesis imaging system, and wherein if the at least one alignment marker is more than one, then a correlation between each alignment marker is not predetermined. ### Claim 12 (depends on 11) The system of claim 11, wherein the processor is further operable to locate the imaged representation of the at least one alignment marker on the first plurality of projection images. ### Claim 13 (depends on 12) The system of claim 12, wherein the processor is further operable to generate a calibration to convert x-ray attenuation to bone thickness, and estimate an estimated representation of the at least one alignment marker based on a known geometry of the at least one alignment marker and the calibration, wherein to minimize the imaged representation, the processor is operable to subtract the estimated representation of the at least one alignment marker from the imaged representation of the at least one alignment marker. ### Claim 14 (depends on 12) The system of claim 12, wherein, to minimize the imaged representation, the processor is operable to perform in-painting of the imaged representation of the at least one alignment marker with information from an area of the first plurality of projection images surrounding the imaged representation of the at least one alignment marker. ### Claim 15 (depends on 11) The system of claim 11, wherein the processor is further operable to align the plurality of projection images relative to each other based on the at least one imaged representation of the at least one alignment marker. ### Claim 16 An aiming ring of a tomosynthesis imaging system comprising: an aperture; and at least one alignment marker disposed within the aperture such that the at least one alignment marker appears anywhere within a field of view of the tomosynthesis imaging system, the at least one alignment marker capable of being imaged in a plurality of projection images by tomosynthesis x-ray imaging, and wherein if the at least one alignment marker is more than one, then a correlation between each alignment marker is not predetermined. ### Claim 17 (depends on 16) The aiming ring of claim 16, further comprising an attachment surface provided within the aperture, the attachment surface including the at least one alignment marker. ### Claim 18 (depends on 17) The aiming ring of claim 17, wherein at least two attachment surfaces are provided, each of the attachment surfaces being affixed to opposite sides of the aiming ring, and each of the attachment surfaces including at least one alignment marker. ### Claim 19 (depends on 16) The aiming ring of claim 16, wherein the at least one alignment marker is spherical or near-spherical. ### Claim 20 (depends on 16) The aiming ring of claim 16, wherein the at least one alignment marker is a sphere having a radiopaque exterior and a radiolucent interior. ### Claim 21 (depends on 16) The aiming ring of claim 16, wherein at least three alignment markers are provided. ### Claim 22 (depends on 21) The aiming ring of claim 21, wherein the at least three alignment markers are non-collinear. ### Claim 23 (depends on 21) The aiming ring of claim 21, wherein the at least three alignment markers are non-coplanar.