X-ray Image Correction Using Multi-Phantom Nonlinear Calibration
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Solution Overview
Problem
Current X-ray diagnostic systems face challenges in accurately quantifying contrast agent concentrations in perfusion examinations due to influences from scattered X-rays, beam hardening, respiratory motion, and fluctuations in tube current and exposure time, requiring complex corrections and calibrations.
Innovation Solution
A medical image processing apparatus and method that uses multiple phantoms with different X-ray absorption factors to correct X-ray image data using a nonlinear function, allowing for precise estimation of contrast agent concentrations by accounting for various factors such as body thickness and imaging conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complex corrections and calibrations are performed to account for scattered X-rays, beam hardening, respiratory motion, and tube current fluctuations, then measurement precision of contrast agent concentration is improved, but device complexity increases
Solution Approach 1:
A phantom object with known X-ray absorption characteristics is introduced as an intermediary between the X-ray source and the subject. The phantom contains reference materials that simulate tissue properties, allowing the system to measure and correct for variations in imaging conditions without requiring complex real-time corrections during actual imaging. This mediator enables accurate concentration measurement by providing reference data for calibration.
Solution Approach 2:
The system performs preliminary calibration measurements using the phantom before actual contrast agent imaging. By pre-measuring the X-ray absorption characteristics of the phantom under the same imaging conditions, the system establishes correction factors in advance that account for scattered X-rays, beam hardening, and tube current variations. This preliminary action eliminates the need for complex real-time corrections during patient imaging.
2Measurement precision
If multiple phantoms with different X-ray absorption factors are used to correct image data, then measurement precision is improved, but the time required for calibration and processing increases
Solution Approach 1:
Instead of using an excessive number of phantoms with many different absorption factors, the invention uses a minimal set of phantoms (typically 3-5) with strategically selected absorption characteristics that cover the range of tissue types encountered in practice. This partial action approach achieves sufficient measurement precision for clinical purposes while minimizing calibration time and processing requirements.
3Measurement precision
If calibrations are performed in advance using phantoms, then measurement precision is improved, but the ease of operation decreases due to additional setup requirements
Solution Approach 1:
The calibration phantom is designed to be integrated with the imaging setup in a unified manner. The phantom can be positioned within the same field of view as the patient without requiring separate calibration sessions or additional equipment. This merging of calibration and imaging procedures allows both functions to be performed in a single setup, improving ease of operation while maintaining measurement precision.
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 simplifies the quantification of contrast agent concentrations with higher accuracy by using phantoms to correct image signal values, effectively addressing the limitations of existing systems by minimizing errors and variations in imaging conditions.
Implementation Method 1
not less than three phantoms whose X-ray absorption factors are different from each other
Data Source
AI summary
According to one embodiment, a medical image processing apparatus includes an image acquisition part and a data processing part. The image acquisition part is configured to obtain X-ray image data of an object including not less than three phantoms whose X-ray absorption factors are different from each other. The data processing part is configured to generate corrected X-ray image data of the object by correcting the obtained X-ray image data or other X-ray image data. The obtained X-ray image data or the other X-ray image data are corrected using a nonlinear function obtained based on pixel values of the obtained X-ray image data. The pixel values correspond to the phantoms.