Transverse Scanning Bone Densitometer for Atypical Femoral Fracture Detection
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Solution Overview
Problem
Current bone densitometry techniques, such as central DXA scans, have limitations in imaging the entire femur, missing atypical femoral fractures (AFFs) due to restricted scanning areas and parallax issues with broad beam radiography, which can lead to incomplete detection of AFFs.
Innovation Solution
A transverse scanning method using a compact fan beam that moves the radiation source and detector perpendicular to the patient's longitudinal axis, allowing for the merging of multiple images to form a composite image, reducing parallax and enhancing the detection of AFFs by imaging the entire femur.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a broad area cone beam is used for radiography, then a large area can be imaged at once, but parallax issues occur and image accuracy deteriorates
Solution Approach 1:
The broad area imaging is divided into multiple narrow fan beam segments that are acquired sequentially. The scanner moves the narrow beam across the imaging area in steps, capturing multiple images that are later merged to form a complete composite image. This segmentation eliminates parallax errors while achieving comprehensive area coverage.
Solution Approach 2:
The imaging process transitions from a single broad 2D area capture to a 3D scanning approach where the narrow fan beam moves along a third dimension (scan path). This dimensional transformation allows complete area coverage through sequential scanning while maintaining the geometric accuracy of narrow beam imaging.
2Measurement precision
If a narrow fan beam is used for scanning radiography, then image accuracy improves by reducing parallax, but the imaging area is limited
Solution Approach 1:
Multiple images acquired with the narrow fan beam at different positions along the scan path are merged into a single composite image. This merging process combines the advantages of narrow beam geometric accuracy with comprehensive area coverage, as each narrow beam image contributes to the complete final image.
Solution Approach 2:
The imaging system becomes dynamic by moving the narrow fan beam source and detector along a scan path. This dynamic scanning allows the limited narrow beam to progressively cover a much larger area over time, transforming a static limitation into a dynamic solution.
3Area of stationary object
If multiple images are acquired along a scan path and merged, then complete femur coverage is achieved, but image alignment difficulty increases
Solution Approach 1:
The system uses dual-energy imaging where images are acquired at two different x-ray energies. This energy differentiation allows sophisticated software algorithms to distinguish and align anatomical structures across multiple images by analyzing energy-specific attenuation patterns, significantly improving alignment accuracy.
Solution Approach 2:
The image merging process incorporates feedback mechanisms where the system continuously evaluates alignment quality and adjusts the merging algorithm accordingly. Software analyzes the overlap and consistency of anatomical features across images, providing feedback that optimizes the final composite image quality.
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 method optimizes the assessment of AFFs in both femurs by reducing patient motion and improving image alignment and accuracy, enabling more comprehensive bone density measurements and early detection of AFFs.
Implementation Method 1
emitting a beam of radiation from the radiation source; detecting the beam of radiation at the radiation detector
Implementation Method 2
The electronic detector elements receiving the transmitted radiation produce electrical signals
Data Source
AI summary
A method includes moving a radiation source and a radiation detector along a scan path substantially transverse to a longitudinal axis of a patient. A beam of radiation is emitted from the radiation source. The beam of radiation is detected at the radiation detector. The detected beam is processed so as to form a first image of a first area of the patient along the scan path.