# US 11,992,348 B2 · Machine learning model to adjust C-arm cone-beam computed tomography device trajectories

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- Number: US 11,992,348 B2
- Document ID: US11992348B2
- Status: Granted
- Kind: B2
- Application number: 17/634,597
- Filed: 2020-09-04
- Published: 2022-10-13
- Granted: 2024-05-28
- Earliest claimed: 2019-09-05
- Assignees: The Johns Hopkins University
- Applicants: The Johns Hopkins University
- Inventors: Mathias Unberath; Jan-Nico Zaech
- Web page: https://patentgrep.com/patent/US11992348B2

## CPC

- A61B 6/032: {Transmission computed tomography [CT]}
- A61B 6/12: Arrangements for detecting or locating foreign bodies
- A61B 6/4085: {Cone-beams}
- A61B 6/4441: {the rigid structure being a C-arm or U-arm}
- A61B 6/505: {for diagnosis of bone}
- A61B 6/5258: {involving detection or reduction of artifacts or noise}
- A61B 6/563: {involving image data transmission via a network}
- G16H 20/40: relating to mechanical, radiation or invasive therapies, e.g. surgery, laser therapy, dialysis or acupuncture
- G16H 30/20: for handling medical images, e.g. DICOM, HL7 or PACS
- G16H 30/40: for processing medical images, e.g. editing
- A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D)
- G16H: HEALTHCARE INFORMATICS, i.e. INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR THE HANDLING OR PROCESSING OF MEDICAL OR HEALTHCARE DATA

## Abstract

A device may receive an X-ray image captured by a C-arm CBCT device at a particular position defined by a six-degree of freedom pose relative to an anatomy, and may process the X-ray image, with a machine learning model, to determine a predicted quality of next possible X-ray images provided by the C-arm CBCT device. The device may utilize the machine learning model, to identify a particular X-ray image, of the next possible X-ray images, with a greatest predicted quality and to update the six-degree of freedom pose based on the particular X-ray image. The device may provide, to the C-arm CBCT device, data that identifies the updated six-degree of freedom pose to cause the C-arm CBCT device to adjust to a new position based on the updated six-degree of freedom pose.

## Claims

### Claim 1

A method comprising:
receiving, by a device, an X-ray image captured by a C-arm cone-beam computed tomography (CBCT) device at a particular position defined by six-degree of freedom pose relative to an anatomy;
processing, by the device, the X-ray image, with a machine learning model, to determine a predicted quality of next possible X-ray images provided by the C-arm CBCT device;
utilizing, by the device, the machine learning model, to:
identify a particular X-ray image, of the next possible X-ray images, with a greatest predicted quality, and
update the six-degree of freedom pose based on the particular X-ray image and to generate an updated six-degree of freedom pose; and
providing, by the device and to the C-arm CBCT device, data that identifies the updated six-degree of freedom pose,
wherein the data that identifies the updated six-degree of freedom pose cause the C-arm CBCT device to adjust to a new position based on the updated six-degree of freedom pose.

### Claim 2 (depends on 1)

The method of claim 1, wherein the data that identifies the updated six-degree of freedom pose cause the C-arm CBCT device to acquire a new X-ray image at the new position.

### Claim 3 (depends on 1)

The method of claim 1, wherein the X-ray image is captured by the C-arm CBCT device to verify screw placement in a spine of a patient during spinal fusion surgery.

### Claim 4 (depends on 1)

The method of claim 1, wherein the six-degree of freedom pose includes an in-plane angle that is defined according to a circular trajectory where a source and a detector of the C-arm CBCT device move in a plane for an entire scan, and
wherein the six-degree of freedom pose includes an out-of-plane angle that is associated with tilting a C-arm, of the C-arm CBCT device, relative to the plane.

### Claim 5 (depends on 1)

The method of claim 1, wherein the machine learning model includes a visual geometry group (VGG) convolutional neural network model.

### Claim 6 (depends on 1)

The method of claim 1, wherein processing the X-ray image, with the machine learning model, to determine the predicted quality of the next possible X-ray images provided by the C-arm CBCT device comprises:
regressing a detectability index for the next possible X-ray images to determine the predicted quality of the next possible X-ray images.

### Claim 7 (depends on 6)

The method of claim 6, wherein regressing the detectability index for the next possible X-ray images to determine the predicted quality of the next possible X-ray images comprises:
determining a local modulation transfer function based on the X-ray image;
determining a local noise power spectrum based on the X-ray image;
determining a task function describing properties of an object, provided in the X-ray image, with a quality in Fourier space; and
regressing the detectability index for the next possible X-ray images to determine the predicted quality of the next possible X-ray images based on the local modulation transfer function, the local noise power spectrum, and the task function.

### Claim 8

A device, comprising:
one or more memories; and
one or more processors, communicatively coupled to the one or more memories, configured to:
receive an X-ray image captured by a C-arm cone-beam computed tomography (CBCT) device at a particular position defined by a six-degree of freedom pose relative to an anatomy;
process the X-ray image, with a machine learning model, to determine a predicted quality of next possible X-ray images provided by the C-arm CBCT device;
utilize the machine learning model, to identify a particular X-ray image, of the next possible X-ray images, with a greatest predicted quality;
utilize the machine learning model to update the six-degree of freedom pose based on the particular X-ray image and to generate an updated six-degree of freedom pose; and
provide, to the C-arm CBCT device, data that identifies the updated six-degree of freedom pose,
wherein the data that identifies the updated six-degree of freedom pose cause the C-arm CBCT device to:
adjust to a new position based on the updated six-degree of freedom pose, and
acquire a new X-ray image at the new position.

### Claim 9 (depends on 8)

The device of claim 8, wherein the machine learning model includes a convolutional neural network model adapted to perform regression instead of classification.

### Claim 10 (depends on 8)

The device of claim 8, wherein the updated six-degree of freedom pose includes an updated in-plane angle that is approximately five degrees greater that an in-plane angle, and
wherein the updated six-degree of freedom pose includes an updated out-of-plane angle is in a range of approximately twenty-five degrees less than an out-of-plane angle to approximately twenty-five degrees greater than the out-of-plane angle.

### Claim 11 (depends on 8)

The device of claim 8, wherein the one or more processors are further configured to:
train the machine learning model based on a first dataset and a second dataset, and prior to receiving the X-ray image,
wherein the first dataset is based on historical human chest CT images, and
wherein the second dataset is based on a semi-anthropomorphic representation of a human chest.

### Claim 12 (depends on 8)

The device of claim 8, wherein the one or more processors are further configured to:
utilize a synthetic dataset to test the machine learning model prior to receiving the X-ray image;
utilize a real dataset to train the machine learning model prior to receiving the X-ray image; and
utilize batch normalization and data augmentation with the machine learning model prior to receiving the X-ray image.

### Claim 13 (depends on 8)

The device of claim 8, wherein the data that identifies the updated six-degree of freedom pose reduces artifacts in future X-ray images captured by the C-arm CBCT device.

### Claim 14 (depends on 8)

The device of claim 8, wherein the one or more processors are further configured to:
identify a problem with a spinal fusion surgery based on one or more of the X-ray image or the next possible X-ray images; and
provide a notification that identifies the problem.

### Claim 15

A non-transitory computer-readable medium storing a set of instructions, the set of instructions comprising:
one or more instructions that, when executed by one or more processors of a device, cause the device to:
train a machine learning model based on a first dataset and a second dataset and to generate a trained machine learning model;
receive an X-ray image captured by a C-arm cone-beam computed tomography (CBCT) device at a particular position defined by a six-degree of freedom pose relative to an anatomy;
process the X-ray image, with the trained machine learning model, to determine a predicted quality of next possible X-ray images provided by the C-arm CBCT device;
utilize the trained machine learning model to identify a particular X-ray image, of the next possible X-ray images, with a greatest predicted quality;
utilize the trained machine learning model to update the six-degree of freedom pose based on the particular X-ray image and to generate an updated six-degree of freedom pose; and
provide, to the C-arm CBCT device, data that identifies the updated six-degree of freedom pose,
wherein the data that identifies the updated six-degree of freedom pose cause the C-arm CBCT device to adjust to a new position based on the updated six-degree of freedom pose.

### Claim 16 (depends on 15)

The non-transitory computer-readable medium of claim 15, wherein the six-degree of freedom pose includes an in-plane angle that is defined according to a circular trajectory where a source and a detector of the C-arm CBCT device move in a plane for an entire scan, and
wherein the six-degree of freedom pose includes an out-of-plane angle that is associated with tilting a C-arm, of the C-arm CBCT device, relative to the plane.

### Claim 17 (depends on 15)

The non-transitory computer-readable medium of claim 15, wherein the one or more instructions, that cause the device to process the X-ray image, with the trained machine learning model, to determine the predicted quality of the next possible X-ray images provided by the C-arm CBCT device, cause the device to:
determine a local modulation transfer function based on the X-ray image;
determine a local noise power spectrum based on the X-ray image;
determine a task function describing properties of an object, provided in the X-ray image, with a quality in Fourier space; and
regress a detectability index for the next possible X-ray images, to determine the predicted quality of the next possible X-ray images based on the local modulation transfer function, the local noise power spectrum, and the task function.

### Claim 18 (depends on 15)

The non-transitory computer-readable medium of claim 15, wherein the updated six-degree of freedom pose includes an updated in-plane angle is approximately five degrees greater that an in-plane angle, and
wherein the updated six-degree of freedom pose includes an updated out-of-plane angle is in a range of approximately twenty-five degrees less than an out-of-plane angle to approximately twenty-five degrees greater than the out-of-plane angle.

### Claim 19 (depends on 15)

The non-transitory computer-readable medium of claim 15, wherein the first dataset is based on historical human chest CT images, and
wherein the second dataset is based on a semi-anthropomorphic representation of a human chest.

### Claim 20 (depends on 15)

The non-transitory computer-readable medium of claim 15, wherein the data that identifies the updated six-degree of freedom pose reduces artifacts in future X-ray images captured by the C-arm CBCT device.
