CBCT Metal Artifact Correction Using Enlarged Volume Projections

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Solution Overview

Problem

CBCT imaging is hindered by metal artifacts caused by metallic objects, which distort the reconstructed volumes and fail to capture complete patient anatomy due to streaks, shadows, and incorrect geometries, and increasing the scanned volume to address this issue increases x-ray dosage.

Innovation Solution

The method involves projecting x-rays to generate CBCT image data, reconstructing an enlarged volume including the scanned region and its surroundings, creating maximum intensity projections, detecting metal-related attenuated areas, and reconstructing a final volume by suppressing these areas to mitigate metal artifacts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of information

If the scanned volume is increased to capture complete patient anatomy and reduce metal artifacts, then the visualization completeness is improved, but the x-ray dosage increases

Engineering Contradiction:

Improvepatient anatomy visualization completenessVSAvoidx-ray dosage

Core Design Contradiction:

Loss of informationVSUse of energy by moving object

Solution Approach 1:

The patent segments the imaging process into two distinct phases: first acquiring a limited-volume CBCT scan, then performing a separate metal detection and artifact correction process. This segmentation allows the system to maintain low x-ray dosage for the primary scan while addressing metal artifacts through computational methods rather than increasing the scanned volume or dosage.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces maximum intensity projections (MIPs) as an intermediary representation between the raw CBCT data and the final corrected images. By generating MIPs from the limited-volume scan, the system can detect metal locations and use this information to guide artifact correction algorithms, eliminating the need to scan larger volumes to detect metals outside the primary field of view.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If conventional CBCT scanning is used without metal detection, then the imaging process is simple and fast, but metal artifacts distort the reconstructed volumes

Engineering Contradiction:

Improveimaging speedVSAvoidimage accuracy

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent performs metal detection and artifact identification as a preliminary step before final image reconstruction. By generating MIPs and detecting attenuated areas corresponding to metal objects before the main reconstruction process, the system can prepare correction masks and parameters in advance, allowing the final reconstruction to proceed efficiently without sacrificing image accuracy.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces physical/mechanical approaches to metal artifact reduction (such as increasing scan volume or using physical shields) with computational methods. The artifact correction is achieved through software-based processing including MIP generation, metal detection algorithms, and iterative reconstruction techniques that substitute for hardware-based solutions.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

This approach effectively reduces metal artifacts in CBCT imaging, ensuring complete patient anatomy visualization without increasing x-ray dosage by detecting and correcting metal artifacts within and outside the scanned volume.

Implementation Method 1

projecting x-rays to scan a volumetric region of an object and generate cone beam computed tomography (CBCT) image data

Methodology Applied

Scientific EffectX-ray attenuation: Absorption (EM radiation)

Data Source

PatentUS20260030818A1Metal artifact correction

Publication Date: 2026.01.29 DENTSPLY SIRONA INC

AI summary

Metal artifact correction including projecting x-rays to scan a volumetric region of an object, the projecting generates corresponding cone beam computed tomography (CBCT) image data, reconstructing an enlarged CBCT volume from the CBCT image data, the enlarged CBCT volume representative of the volumetric region and a volume outside the volumetric region, generating from the enlarged CBCT volume and a projection geometry, maximum intensity projections on a virtual plane, detecting attenuated image areas in the maximum intensity projections corresponding to metal, corresponding the detected attenuated image areas corresponding to the metal to areas of the CBCT image data, and reconstructing a final CBCT volume using the CBCT image data by suppression of the areas of the CBCT image data corresponding to the detected attenuated image areas of the maximum intensity projections. Systems for metal artifact correction are also disclosed.