Radiation System Drift Correction via Theoretical Projection
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Solution Overview
Problem
Radiation imaging systems, particularly CT scanners, face challenges in accurately detecting areas of interest due to system drift caused by changes in operating parameters such as temperature, which affects image quality and the ability to distinguish between different densities or materials within an object.
Innovation Solution
A method and system for correcting object projections in radiation imaging systems by measuring the degree of drift through a calibration process, comparing a calibration projection to a theoretical projection, and applying correction factors to the object projections to account for system drift, thereby improving image accuracy and consistency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a copper filter is used to measure drift, then drift measurement capability is provided, but placement accuracy is reduced due to human error and detector degradation
Solution Approach 1:
The patent creates a theoretical projection (a digital copy or model of expected radiation detection) that represents the ideal detector response under reference conditions. This theoretical projection serves as a stable reference that does not degrade over time, replacing the need for physical filters that are subject to placement errors and detector degradation. By comparing actual calibration projections against this theoretical model, the system achieves reliable drift measurement without the reliability issues associated with physical filter methods.
2Adaptability or versatility
If system operating parameters change over time, then system adaptability is improved, but image consistency deteriorates due to drift
Solution Approach 1:
The patent implements a feedback mechanism where the system continuously measures drift by comparing calibration projections against the theoretical projection, calculates correction factors based on the measured drift, and applies these corrections to maintain image consistency. This closed-loop feedback system allows the radiation imaging system to adapt to changing operating parameters (temperature, voltage, etc.) while automatically compensating for their effects, thereby maintaining stable and consistent images despite operational flexibility and environmental variations.
3Measurement precision
If drift correction is applied to maintain image accuracy, then measurement precision is improved, but system complexity increases
Solution Approach 1:
The patent replaces complex physical correction mechanisms with a computational approach. Instead of using hardware adjustments or multiple physical filters to correct drift, the system uses software-based processing: generating a theoretical projection through calculation, comparing it with actual measurements, computing correction factors algorithmically, and applying these corrections digitally to the projection data. This substitution of mechanical/physical correction systems with computational methods achieves accurate drift correction while minimizing additional hardware complexity.
Data Source
AI summary
Among other things, one or more techniques and/or systems for correcting projection data representative of an object under examination to account for drift in a radiation system are provided. System drift is measured by performing a drift calibration on the radiation system. During the drift calibration, a temperature of the radiation system is measured and one or more calibration tables, such as an air table and/or offset table, are corrected based upon the measured temperature to derive a theoretical projection (e.g., indicative of measurements that are expected to be acquired from the radiation system during the drift calibration). The theoretical projection is compared to an actual projection acquired during the drift calibration to measure a degree of drift. Based upon the measured degree of drift, one or more correction factors are determined to correct and/or otherwise adjust for system drift in a projection respective of the object.