Sparse Background Correction for X-Ray Imaging Artifacts

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Solution Overview

Problem

Existing imaging systems using keV and MeV x-ray sources face issues such as streak artifacts, photon starvation, beam hardening, and low contrast-to-noise ratio, particularly when imaging dense tissues, and transient detector effects from charging cause anomalous features in images.

Innovation Solution

A multimodal imaging system combining keV and MeV x-ray sources with a rotatable gantry and data processor that collects background data to correct image errors, using algorithms to determine optimal angles for error removal and interpolation, and synchronizes x-ray source and detector operations for high-quality imaging.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If MeV x-ray sources are used for imaging during radiotherapy, then imaging can be performed during treatment, but the contrast-to-noise ratio is low

Engineering Contradiction:
Improveimaging capability during treatmentVSAvoidcontrast-to-noise ratio
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent combines keV and MeV x-ray imaging systems into a single integrated platform. The keV source provides high-contrast reference images, while the MeV source provides treatment-specific imaging. By merging the data from both energy ranges and applying corrective algorithms, the system achieves both treatment integration and improved image quality.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent uses keV x-ray images as an intermediary to correct MeV x-ray images. The high-contrast keV images serve as a reference that mediates the low-contrast MeV images, allowing the system to transfer anatomical detail information from the keV domain to enhance the MeV images while maintaining treatment relevance.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If keV x-ray sources are used for imaging, then good contrast with soft tissue is achieved, but performance deteriorates with dense tissue

Engineering Contradiction:
Improvesoft tissue contrastVSAvoidstreak artifacts and photon starvation
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent creates a composite imaging approach by combining data from two different x-ray energy domains (keV and MeV). Each energy range has complementary strengths: keV provides superior soft tissue contrast while MeV penetrates dense tissue more effectively. By fusing these complementary data sources, the system overcomes the limitations of each individual energy range.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent changes the energy parameter of the x-ray source, utilizing both low-energy (keV) and high-energy (MeV) ranges. By adjusting and combining results from different energy parameters, the system achieves robust imaging across varying tissue densities, overcoming the photon starvation and artifact problems that plague single-energy systems when imaging through dense material.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If background data collection is performed at every angle, then complete error correction is achieved, but the number of image-collection angles is reduced

Engineering Contradiction:
Improveerror correction accuracyVSAvoidnumber of image-collection angles
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent applies partial action by collecting background data at only a subset of angles rather than at every angle. The system determines that background measurements at strategically selected angles (e.g., every other angle or at specific reference positions) are sufficient to correct errors across all image angles through interpolation and correction algorithms, thereby maintaining adequate correction accuracy while preserving more image-collection angles.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The patent performs preliminary background data collection at selected angles before full image acquisition. These preliminary measurements establish a background model that can then be applied to correct all subsequent images, eliminating the need to pause for background measurements at every single angle while still achieving comprehensive error correction across the complete angular dataset.

Inventive Principle:
Principle #10Preliminary action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The system provides high-quality images by correcting for detector charging effects and enhancing contrast and noise ratio, enabling accurate target visualization and treatment planning in radiotherapy.

Implementation Method 1

keV sources tend to provide good contrast with most kinds of soft tissue

Methodology Applied
Scientific EffectX-ray production: X-Ray

Implementation Method 2

MeV x-ray sources primarily used for treatment can also generate images

Methodology Applied
Scientific EffectHigh-energy x-ray production: X-Ray

Implementation Method 3

MeV images can place a detector opposite the therapeutic source to image the patient

Methodology Applied
Scientific EffectX-ray detection: Photoelectric Effect

Data Source

PatentEP4373404B1Sparse background measurement and correction for improving imaging
Publication Date: 2025.11.12 ACCURAY LLC
  • EP4373404B1 patent drawingFigure 1
  • EP4373404B1 patent drawingFigure 2A
  • EP4373404B1 patent drawingFigure 2B

AI summary

Disclosed herein is an imaging system including a first x-ray source configured to produce first x-ray photons in a first energy range suitable for imaging, project the first x-ray photons onto an area designated for imaging, a rotatable gantry configured to rotate the first x-ray source such that the first x-ray source traverses an angular path, and a data processor having an analytical portion. The analytical portion is configured to collect first data relating to the transmission of the first x-ray photons through the area designated for imaging at a set of image-collection angles along the angular path, collect background data at a set of background-collection angles along the angular path, wherein the system acquires more than one image of the designated area for imaging between background angles. The analytical portion is also configured to remove errors in the first data using the background data, and generate a corrected image based on the removal of errors in the first data.