CT Phantom Variable Width Cross-Section CNR Evaluation
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Solution Overview
Problem
Current methods for evaluating the contrast-to-noise ratio (CNR) in computed tomography (CT) systems are cumbersome and costly, often requiring dedicated phantoms and additional phantom components, which increase operational costs and measurement duration.
Innovation Solution
The method involves positioning a phantom with a variable width cross-section within a CT system, adjusting its position to change the pathlength through the phantom, and calculating the CNR based on measurements from the detector array without adding or removing phantom components, using routinely available phantoms like water or acrylate plastic.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If dedicated phantoms and additional phantom components are used for CNR evaluation, then measurement precision is improved, but device complexity and operational costs increase
Solution Approach 1:
The patent makes the CT system's own phantom serve multiple functions: it is used for both calibration purposes and for CNR measurements. By configuring the phantom in different positions (first and second configurations) within the CT system, the same phantom object provides both calibration data and contrast-to-noise ratio data, eliminating the need for separate dedicated CNR phantoms and reducing overall system complexity
Solution Approach 2:
The patent uses routinely available phantoms (such as water phantoms or acrylate plastic phantoms) that are already present in the CT system, rather than requiring specialized dedicated CNR evaluation phantoms. These existing phantoms are effectively 'copied' or repurposed for dual use in calibration and CNR measurement, reducing the need for additional hardware components
2Measurement precision
If multiple phantom components and configurations are used, then measurement precision is improved, but loss of time increases
Solution Approach 1:
The patent performs calibration of the CT system in advance using the phantom, storing the calibration data for later use. This preliminary calibration action allows subsequent CNR measurements to be performed more quickly, as the system is pre-configured and does not require repeated calibration procedures for each measurement session
Solution Approach 2:
The same phantom configuration serves dual purposes: it is used for both calibration and for acquiring CNR measurement data. By acquiring both calibration data and measurement data during the same phantom positioning, the patent eliminates the need for separate calibration and measurement sessions, thereby reducing total measurement time
3Measurement precision
If additional phantom components are added, then measurement precision is improved, but ease of operation deteriorates
Solution Approach 1:
The patent utilizes the CT system's existing routinely available phantom instead of requiring additional dedicated CNR phantom components. This universal use of existing equipment simplifies operation, as technicians do not need to source, assemble, or manage separate specialized phantom components, while still achieving accurate CNR measurements through proper positioning in different configurations
4Measurement precision
If complex data processing is performed, then measurement precision is improved, but computing power requirements increase
Solution Approach 1:
The patent extracts and utilizes calibration data that has already been acquired during the imaging process. By separating the calibration data acquisition from the CNR measurement data acquisition, and reusing the calibration information, the patent avoids redundant data processing and reduces the computational burden required for CNR calculation, 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 allows for faster and more efficient CNR evaluation, reducing computing power requirements and enabling easier maintenance and upgrading of CT systems by identifying changes in CNR over time without additional data processing or phantom modifications.
Implementation Method 1
technologies such as computed tomography (CT) use various physical principles, such as the differential transmission of x-rays through a target volume
Implementation Method 2
the differential transmission of x-rays through a target volume
Data Source
AI summary
Methods and systems are provided for contrast-to-noise evaluation in medical imaging systems. In one embodiment, a method includes positioning a phantom having a variable width cross-section within a gantry of a computed tomography (CT) system so that the variable width cross-section is perpendicular to a central axis of the CT system, adjusting the phantom within the gantry of the CT system to a first imaging configuration having a first position and a first translation within the gantry, acquiring a first set of measurements from the phantom in the first imaging configuration, and calculating a contrast-to-noise ratio (CNR) of the CT system based on at least the first set of measurements and a first material density of an imaged slice of the phantom in the first imaging configuration.