AEC Dose Weighting for X-Ray Exposure Cut-Off Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing automatic exposure control (AEC) systems in x-ray imaging struggle to maintain high image quality when patients are not perfectly positioned, leading to early termination of radiation due to uneven dose distribution across sub-chambers, especially when imaging areas with high attenuating materials like bone, resulting in noisy and grainy images.
Innovation Solution
A method and system that utilize weighted time-courses of accumulated doses from multiple sub-chambers to determine a weighted overall applied dose, adjusting weights based on the temporal gradient of dose accumulation to ensure adequate exposure for high-quality imaging, particularly in areas with high attenuating materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the measured accumulated dose of all sub-chambers is summed up without weighting, then the cut-off dose is reached faster and radiation exposure is reduced, but image quality deteriorates due to early termination of radiation in areas with high attenuating materials
Solution Approach 1:
The patent applies local quality by assigning different weights to different sub-chambers based on their individual dose accumulation characteristics. Sub-chambers behind high attenuating materials (like bone) receive higher weights, while sub-chambers behind low attenuating materials receive lower weights. This localized weighting ensures that the dose control adapts to the specific attenuation properties of different body regions, preventing early termination of radiation in areas requiring higher exposure while still protecting against overexposure in other areas.
Solution Approach 2:
The patent implements dynamics by continuously monitoring the time-course of dose accumulation in each sub-chamber and dynamically adjusting the weights based on the temporal gradient of dose accumulation. The weighting factors are not static but are adapted in real-time during the imaging process, allowing the system to respond to changing dose distribution patterns and maintain optimal image quality throughout the exposure.
2Measurement precision
If all sub-chambers are used for dose measurement, then the dose control is more comprehensive, but the complexity of dose calculation and control increases
Solution Approach 1:
The patent simplifies the complex multi-sub-chamber dose control problem by transforming it into a weighted sum calculation. Instead of managing multiple independent dose control parameters for each sub-chamber, the system uses a single weighted accumulated dose parameter that combines information from all sub-chambers. The complexity is reduced by changing the control parameter from multiple individual doses to a single weighted aggregate dose, making the control system more manageable while preserving measurement precision.
3Loss of time
If the cut-off dose is reached based on unweighted summation, then the radiation exposure time is reduced, but the accumulated dose behind dense materials is insufficient for high-quality imaging
Solution Approach 1:
The patent addresses this contradiction by applying local quality through region-specific weighting. Sub-chambers positioned behind dense materials (which require longer exposure times to achieve adequate penetration) are assigned higher weights, while sub-chambers behind less dense materials are assigned lower weights. This ensures that the overall cut-off dose threshold accounts for the varying exposure requirements of different body regions, preventing premature termination of radiation in areas needing longer exposure.
Solution Approach 2:
The system dynamically monitors the time-course of dose accumulation in each sub-chamber and adjusts the weighted sum accordingly. By tracking the temporal evolution of dose in each region and applying appropriate weights, the system can determine when the cumulative weighted dose reaches the cut-off threshold, ensuring that sufficient dose has been delivered to high-attenuation areas before termination, while still minimizing overall exposure time.
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
Ensures high image quality by accurately determining the weighted overall applied dose, preventing early termination of radiation and reducing the need for repeated imaging, thereby saving time, costs, and minimizing patient dose.
Implementation Method 1
The detector is configured for detecting the radiation which passed the patient
Data Source
AI summary
One or more example embodiments relates to a computer-implemented method for dose control with an automatic exposure control. The method comprises receiving a first time-course, receiving a second time-course, and receiving a cut-off dose. The method comprises determining a first weight, determining a second weight, multiplying a latest value of the first time-course with the first weight, wherein a first weighted accumulated dose is determined and multiplying a latest value of the second time-course with the second weight, wherein a second weighted accumulated dose is determined. The method comprises adding the first and the second weighted accumulated dose, wherein a weighted overall applied dose is determined, comparing the weighted overall applied dose with the cut-off dose, and providing a result of the comparison.