# US 11,432,789 B2 · Self-calibrating technique for x-ray imaging scanners

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- Number: US 11,432,789 B2
- Document ID: US11432789B2
- Status: Granted
- Kind: B2
- Application number: 17/115,869
- Filed: 2020-12-09
- Published: 2021-04-22
- Granted: 2022-09-06
- Earliest claimed: 2017-05-17
- Assignees: Carestream Health, Inc.
- Applicants: Carestream Health, Inc.
- Inventors: William J. Sehnert; Yuan Lin; Levon O. Vogelsang
- Web page: https://patentgrep.com/patent/US11432789B2

## CPC

- A61B 6/4007: {characterised by using a plurality of source units}
- A61B 6/582: {Calibration}
- A61B 6/025: {Tomosynthesis}
- A61B 6/032: {Transmission computed tomography [CT]}
- A61B 6/06: Diaphragms
- A61B 6/08: Auxiliary means for directing the radiation beam to a particular spot, e.g. using light beams
- A61B 6/4405: {the apparatus being movable or portable, e.g. handheld or mounted on a trolley}
- A61B 6/482: {involving multiple energy imaging}
- A61B 6/5205: {involving processing of raw data to produce diagnostic data}
- A61B 6/547: {involving tracking of position of the device or parts of the device}
- A61B 6/584: {determining position of components of the apparatus or device using images of the phantom}
- A61B 6/588: {Setting distance between source unit and detector unit}
- A61B 90/39: {Markers, e.g. radio-opaque or breast lesions markers}
- A61B 6/0421: {with immobilising means}
- A61B 2017/0092: {for X-rays}
- A61B 2090/3966: {Radiopaque markers visible in an X-ray image}
- A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D)

## Abstract

A mobile radiography apparatus includes radiopaque markers disposed in a radiation path that extends from an x-ray source to a digital radiographic detector, which detector is mechanically uncoupled from the x-ray source or x-ray sources. A processing system calculates a position of the detector relative to the x-ray source or x-ray sources according to identified marker positions in acquired x-ray projection images, and reconstructs a volume image according to the acquired x-ray projection images.

## Claims

### Claim 1

A mobile radiography system comprising:
a plurality of x-ray sources;
a radiographic detector mechanically uncoupled from the x-ray sources;
a plurality of radiopaque markers, the radiopaque markers disposed in one or more radiation paths each extending from one of the x-ray sources to the radiographic detector; and
a processor programmed to calculate a position of the radiographic detector relative to one or more of the plurality of x-ray sources according to positions of the radiopaque markers in x-ray projection images captured by the radiographic detector.

### Claim 2 (depends on 1)

The system of claim 1, wherein the processor is further programmed to reconstruct a volume image according to the acquired projection images.

### Claim 3 (depends on 1)

The system of claim 1, wherein the x-ray sources are arranged in a linear or curvilinear pattern.

### Claim 4 (depends on 1)

The system of claim 1, wherein the x-ray sources are arranged in a geometric pattern shaped as a rectangle, circle, cross or triangle.

### Claim 5 (depends on 1)

The system of claim 1, wherein the plurality of x-ray sources are fixed in position relative to each other.

### Claim 6 (depends on 1)

The system of claim 1, wherein one or more of the radiopaque markers are fixed in position relative to one or more of the x-ray sources.

### Claim 7 (depends on 6)

The system of claim 6, wherein the radiopaque markers are fixed in position relative to each other.

### Claim 8 (depends on 7)

The system of claim 7, wherein the radiopaque markers are secured in a fixed position relative to each other by a radiolucent support member.

### Claim 9 (depends on 8)

The system of claim 8, wherein the radiolucent support member is made from glass.

### Claim 10 (depends on 9)

The system of claim 9, wherein the radiolucent support member is secured in a fixed position relative to one or more of the x-ray sources during image exposure.

### Claim 11 (depends on 8)

The system of claim 8, wherein the radiolucent support member is secured in the fixed position by a rigid arm connected to the support member and to a tube head containing the one or more x-ray sources.

### Claim 12 (depends on 8)

The system of claim 8, wherein the radiolucent support member is secured in the fixed position by a rigid arm connected to the support member and to any one of a floor, a ceiling, a wall and a mobile cart.

### Claim 13 (depends on 1)

The system of claim 1, wherein one or more of the x-ray sources are movable to acquire one or more of the acquired projection images at a different acquisition angle.

### Claim 14 (depends on 1)

The system of claim 1, wherein two or more of the x-ray sources are sealed within a single vacuum chamber.

### Claim 15 (depends on 1)

The system of claim 1, wherein the processor is further programmed to digitally remove the radiopaque markers from the acquired projection images or from the reconstructed volume image.

### Claim 16 (depends on 1)

The system of claim 1, wherein the radiopaque markers are each shaped as a sphere, ellipse, cylinder, cross, cube, donut, or a combination thereof.

### Claim 17 (depends on 1)

The system of claim 1, wherein at least three of the radiopaque markers are disposed in each of the radiation paths during image exposure.

### Claim 18 (depends on 1)

The system of claim 1, wherein each of the radiation paths includes no radiopaque markers or at least three radiopaque markers during image exposure.

### Claim 19 (depends on 1)

The system of claim 1, wherein the radiopaque markers are positioned such that a different subset of the plurality of radiopaque markers are disposed in each radiation path from each of the plurality of x-ray sources during image exposure.