Photon Counting Detector Calibration for Tissue Discrimination
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Solution Overview
Problem
Current radiation imaging technologies using photon counting detectors lack the capability to accurately discriminate between soft and adipose tissues, which is crucial for medical imaging and diagnosis.
Innovation Solution
A radiation imaging apparatus and calibration method that utilize photon counting detectors to calculate and normalize linear attenuation coefficients, selecting appropriate basal materials based on these coefficients to enhance the discrimination between soft and adipose tissues by storing relationships between linear attenuation coefficients and photon energy, and using specific combinations of basal materials like polyethylene and PTFE for accurate tissue differentiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional basal materials (PMMA and aluminum, polyethylene and PVC) are used for calibration, then the calibration process is simple and straightforward, but the accuracy of discriminating between soft and adipose tissues deteriorates
Solution Approach 1:
The patent changes the parameters of the basal materials by selecting materials with specific atomic numbers (Z=6 for carbon, Z=8 for oxygen, Z=12 for magnesium, Z=14 for silicon) that closely match the atomic composition of soft and adipose tissues. This parameter change enables the calibration to achieve high accuracy in tissue discrimination while maintaining ease of manufacture through the use of readily available materials.
Solution Approach 2:
The patent employs composite material strategies by using combinations of basal materials that replicate the complex composition of biological tissues. Specifically, it uses combinations involving carbon, oxygen, magnesium, and silicon materials to create calibration phantoms that accurately represent soft and adipose tissue compositions, thereby improving discrimination accuracy while keeping the calibration process manageable.
2Measurement precision
If photon counting detectors are used to measure photon energy, then material discrimination capability is improved, but the complexity of calibration increases
Solution Approach 1:
The patent segments the calibration process into discrete, manageable steps: selecting basal materials with specific atomic numbers, preparing calibration phantoms with controlled thicknesses, measuring photon energy spectra, and calculating normalized attenuation coefficients. This segmentation reduces the overall calibration complexity while maintaining the enhanced material discrimination capability provided by photon counting detectors.
Solution Approach 2:
The patent introduces normalized attenuation coefficients as an intermediary parameter that simplifies the calibration process. By normalizing the linear attenuation coefficients with respect to photon energy, the patent creates a standardized metric that facilitates easier calibration while preserving the high material discrimination capability of the photon counting detectors.
3Reliability
If multiple basal materials with known compositions and thicknesses are used for calibration, then the relationship between output and photon energy can be established, but the time required for calibration increases
Solution Approach 1:
The patent applies partial action by selecting and using only the essential basal materials needed for accurate tissue discrimination (carbon, oxygen, magnesium, silicon) rather than using all possible materials. This selective approach maintains calibration reliability for the specific application of soft and adipose tissue discrimination while significantly reducing the time required for calibration compared to using comprehensive material sets.
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 high-accuracy discrimination between soft and adipose tissues, improving diagnostic imaging by effectively evaluating fat proportions in body tissues through precise material decomposition and reduced residual errors.
Implementation Method 1
photon counting detectors which output an electric signal corresponding to photon energy which is energy of radiation photons incident thereon
Implementation Method 2
storage unit which stores relationships between linear attenuation coefficients and the photon energy with regard to multiple materials
Data Source
AI summary
With the aim of providing a radiation imaging apparatus and a calibration method for photon counting detectors, being able to discriminate between soft and adipose tissues with high accuracy, there is disclosed a radiation imaging apparatus equipped with photon counting detectors which output an electric signal corresponding to photon energy which is energy of radiation photons incident thereon, the radiation imaging apparatus including a storage unit which stores relationships between linear attenuation coefficients and the photon energy with regard to multiple materials; a calculation unit which calculates normalized attenuation coefficients which are linear attenuation coefficients normalized by dividing linear attenuation coefficients per unit of photon energy by a linear attenuation coefficient at given photon energy with respect to each material; and a selection unit which selects basal materials which are used in relation to materials to be discriminated which are intended to be discriminated, based on the normalized attenuation coefficients.