X-ray Collimator for Dynamic Radiation Control
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Solution Overview
Problem
In multiple frames imaging systems, there is a challenge in controlling x-ray radiation distribution effectively to minimize exposure to both patients and medical teams while maintaining image quality, particularly during long periods of x-ray activity where the treating physician is exposed to radiation.
Innovation Solution
An x-ray system that includes an x-ray source, detector, monitor, and a collimator configured to adjust x-ray radiation levels based on user focus coordinates, using tone-correction functions and variable absorption phantoms to optimize image quality and reduce radiation exposure, with features such as multiple filament elements, rotatable and translatable cathodes/anodes, and partially transparent collimator designs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a collimator is used to block redundant x-ray radiation, then radiation exposure to patient and medical team is reduced, but the x-ray signal to noise ratio deteriorates
Solution Approach 1:
The collimator is configured to provide different levels of x-ray attenuation in different regions of the image intensifier field. The ROI area receives full or enhanced x-ray exposure while non-ROI areas receive reduced exposure through the collimator's selective blocking, achieving both radiation reduction and maintained image quality in critical areas
Solution Approach 2:
The collimator is made movable to dynamically adjust the exposed areas based on the changing ROI position during MFI procedures. This allows the system to adapt radiation distribution in real-time, maintaining optimal signal-to-noise ratio in the ROI while minimizing exposure elsewhere
2Object-affected harmful factors
If the collimator limits the solid angle of x-ray radiation to reduce exposure, then radiation intensity to non-ROI areas is reduced, but the uniformity of image quality across the entire field of view deteriorates
Solution Approach 1:
The collimator creates non-uniform radiation distribution by design, with different transmission characteristics for different spatial regions. This intentionally produces varied image quality across the field, with optimized quality in ROI areas and reduced quality in non-essential areas, rather than attempting to maintain uniform quality everywhere
Solution Approach 2:
The collimator periodically moves to different positions during the MFI session, scanning across the field of view. This periodic motion ensures that different areas receive enhanced exposure at different times, and when images are combined, achieves both radiation reduction and acceptable overall image quality
3Object-affected harmful factors
If digital image enhancement is used to compensate for reduced signal to noise ratio, then radiation exposure can be reduced, but image processing complexity increases
Solution Approach 1:
The collimator performs preliminary spatial filtering of x-ray radiation before the imaging process, physically directing full exposure to ROI areas and reduced exposure to non-ROI areas. This pre-processing approach eliminates the need for complex post-processing enhancement algorithms, as the optimal signal-to-noise ratio is achieved during the imaging acquisition itself
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
The system effectively reduces radiation exposure to medical teams while maintaining high image quality by dynamically adjusting x-ray radiation levels and distribution, ensuring adequate exposure for Region of Interest (ROI) areas while minimizing exposure to other areas.
Implementation Method 1
collimators of x-ray absorbing materials such as lead are used to block the redundant radiation
Implementation Method 2
collimators with partially-transparent to x-ray materials are used to manipulate the x-ray energy distribution
Implementation Method 3
using tone-correction functions and variable absorption phantoms to optimize image quality
Data Source
AI summary
A multiple frames imaging system is disclosed with capability of differential x-ray exposure of different input areas of an image intensifier or other x-ray detector. Collimators are provided to control the amount of radiation in various regions of the image and image processing is provided to provide the display of images of different qualities. Motion methods are provided to move the collimators to produce optimal image frames.