Spectral X-Ray Bone Density Tomography for Small Dental Volumes
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Solution Overview
Problem
Conventional DXA and QCT methods are inadequate for dental applications due to their inability to accurately characterize bone mineral density (BMD) and trabecular bone structure (TBS) in small volumes-of-interest (VOI), leading to insufficient diagnostic assessment of trabecular bone structure for implant placement and overall bone health.
Innovation Solution
A dental imaging method and apparatus that uses spectral X-ray imaging with multiple energy spectra or energy resolving detectors to segment and characterize bone-like tissue within a limited VOI, combining BMD and TBS information for accurate 3D reconstruction, employing techniques like filtered backprojection, algebraic reconstruction, and dual-energy scans to correct for beam hardening and scatter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional QCT methods are used to obtain 3D bone density information, then detailed bone density quantification is achieved, but the method cannot be applied to small volumes-of-interest in dental applications because the whole scanned object cannot be fully reconstructed
Solution Approach 1:
The patent segments the imaging problem into two parts: (1) acquiring projections over a limited angular range suitable for small VOI, and (2) using iterative reconstruction with scatter estimation to achieve quantitative accuracy without requiring full 360-degree scanning. This segmentation allows QCT principles to be adapted to dental applications with limited fields-of-view.
Solution Approach 2:
The patent performs preliminary scatter estimation and correction before final image reconstruction. By estimating scatter contributions from surrounding structures and correcting projections in advance, the method enables accurate bone density quantification even when the complete object cannot be scanned, thus adapting QCT to small VOI scenarios.
2Measurement precision
If conventional QCT methods are used with scatter correction, then accurate bone density information is obtained, but the correction process is too complex for clinical dental applications
Solution Approach 1:
The patent uses simplified, computationally efficient scatter estimation models that can be quickly calculated and discarded after correction, replacing complex iterative scatter correction methods. This allows accurate enough bone density measurement without the computational burden of full Monte Carlo simulations, making the method suitable for clinical dental workflows.
Solution Approach 2:
The patent changes the approach from attempting to perfectly model all scatter parameters to using simplified scatter estimation based on key geometric parameters and empirical relationships. This parameter simplification reduces computational complexity while maintaining sufficient accuracy for dental bone density assessment.
3Measurement precision
If conventional QCT methods are used to characterize bone structure, then averaged bulk density values are obtained, but local trabecular bone structure information is lost
Solution Approach 1:
The patent segments the bone tissue into different compartments (cortical bone, trabecular bone, marrow spaces) and reconstructs images with sufficient resolution to visualize trabecular structures. By maintaining high spatial resolution in the reconstruction process, the method preserves local trabecular architecture information while still providing accurate bulk density measurements for each segmented region.
Solution Approach 2:
The patent transitions from providing only averaged 1D density values to generating 3D volumetric images that preserve spatial distribution of bone structures. This dimensional enhancement allows simultaneous assessment of both bulk density properties and local trabecular architecture, preventing information loss about bone structure.
4Productivity
If DXA is used for bone density measurement, then 2D projection radiography is obtained, but overlapping tissue cannot be distinguished
Solution Approach 1:
The patent transitions from 2D projection imaging to 3D volumetric reconstruction, adding the depth dimension to separate overlapping tissues. This allows the system to maintain the efficiency of single-scenario scanning while achieving the tissue differentiation capability of multi-planar imaging through iterative reconstruction and scatter correction.
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
Provides precise 3D imaging of bone mineral density and trabecular bone structure, enhancing the accuracy of implant placement and overall bone health assessment by overcoming limitations of conventional methods in small VOI scenarios.
Implementation Method 1
an x-ray source is configured to direct toward an x-ray detector x-ray radiation of at least a first wavelength and a second wavelength
Implementation Method 2
The imaging detector is disposed to generate image content according to acquired energy of at least the first and second wavelengths
Data Source
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AI summary
A method for characterizing bone structure for a patient, method executed at least in part on a computer, acquires one or more 2D x-ray projection images of a volume, wherein image content is acquired at two or more spectral frequencies. The acquired x-ray image content is processed to calculate one or more metrics that characterize bone structure within the imaged volume. The one or more calculated metrics are displayed.