Dual-Energy Bone Density Correction for Fat-Dependent Beam Hardening
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Solution Overview
Problem
Existing bone density measurement methods, such as DXA, are prone to errors due to variations in fat percentage, leading to inaccuracies in bone density estimation.
Innovation Solution
A radiation image processing device and method that derives a bone part image and fat/muscle percentage distribution from images with different energy distributions, converts body thickness to a standard soft part distribution, and corrects pixel values using conversion coefficients to accurately calculate bone density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If bone density is calculated from radiation images without correcting for fat percentage, then the measurement process is simple, but the bone density accuracy deteriorates due to beam hardening variations
Solution Approach 1:
The soft part of the subject is segmented into fat tissue regions and non-fat tissue regions based on the radiation images. This segmentation allows separate analysis and correction of fat-related beam hardening effects from other soft tissue effects, improving bone density measurement accuracy while managing processing complexity through regional differentiation
Solution Approach 2:
The fat percentage distribution is derived and the body thickness distribution is corrected to a standard soft part distribution before performing the final bone density calculation. This preliminary correction of soft tissue variations eliminates beam hardening errors caused by fat percentage variations, ensuring accurate bone density measurements are obtained from the corrected images
2Illumination intensity
If the energy of transmitted radiation is lower due to higher fat percentage, then the contrast of bone region is increased, but the bone density value becomes erroneously larger
Solution Approach 1:
The attenuation coefficient used for body thickness correction is changed based on the derived fat percentage distribution. When fat percentage is high, a different attenuation coefficient is applied compared to when fat percentage is low. This dynamic adjustment of the attenuation coefficient parameter compensates for fat-related beam hardening effects, preventing erroneous bone density values while maintaining the beneficial contrast enhancement
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
Enables precise bone density determination by accounting for fat and muscle percentages, reducing errors and improving accuracy in bone density measurements.
Implementation Method 1
a dual x-ray absorptiometry (DXA) method is known as one of typical bone mineral quantification methods used for diagnosing a bone density in a bone system disease
Implementation Method 2
which is attenuated by an attenuation coefficient μ (cm2/g), density (g/cm3) and a thickness t (cm), which depend on a substance (for example, a bone) that configures the human body
Implementation Method 3
an influence of beam hardening of the radiation is changed in accordance with the fat percentage. Specifically, the energy of the transmitted radiation is lower as the fat percentage is higher, so that a contrast of the bone region in the acquired radiation image is increased
Data Source
AI summary
A processor derives a bone part image of a subject including a bone part based on a first radiation image and a second radiation image acquired by imaging the subject with radiation having different energy distributions, derives a fat percentage distribution or a muscle percentage distribution of the subject based on the first radiation image and the second radiation image, and derives a bone density in a bone region of the subject based on the bone part image, and the fat percentage distribution or the muscle percentage distribution.