X-ray ROI Exposure Control via Coordinate Translation
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Solution Overview
Problem
Current X-ray imaging systems face challenges in accurately aligning body parts with fixed exposure measurement devices, leading to misalignment issues, especially in pediatric and extremity imaging, resulting in inadequate radiation dosage control.
Innovation Solution
The technique involves defining a region of interest within the X-ray imaging system's field of view, translating it into system coordinates, and controlling X-ray exposure based on this definition, using either open-loop or closed-loop methods, with optional exposure sensors for integrated dose monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If automatic exposure control with fixed ion chambers is used, then exposure timing can be automated, but misalignment occurs with pediatric and extremity imaging leading to inaccurate dosage control
Solution Approach 1:
The imaging system divides the field of view into multiple selectable regions of interest (ROIs) rather than treating the entire field uniformly. Each ROI can be independently defined and mapped to specific detector elements, allowing automated exposure control to focus on the actual anatomy of interest rather than relying on fixed ion chamber locations. This segmentation enables accurate dosage control for pediatric and extremity imaging by isolating the relevant anatomical region.
Solution Approach 2:
The system transitions from static, fixed ion chamber locations to dynamic, software-defined regions of interest that can be flexibly positioned and sized according to the specific anatomy being imaged. The ROI can be adaptively defined based on patient size, anatomy type, and imaging protocol, allowing the automated exposure control to dynamically adjust to different clinical scenarios including pediatric and extremity imaging.
2Reliability
If manual fixed time exposures are used to avoid misalignment issues, then operator control is maintained, but operator skill and subjective estimation become critical factors
Solution Approach 1:
The system enables automated exposure control to serve itself by using the defined region of interest to automatically determine appropriate exposure parameters. The software calculates the required exposure based on the ROI characteristics and system measurements, eliminating the need for operator skill and subjective estimation while maintaining reliable and consistent exposure control across different operators and patients.
3Area of stationary object
If the entire field of view is imaged, then complete coverage is achieved, but radiation dosage cannot be optimized for specific regions of interest
Solution Approach 1:
The system applies different exposure parameters and radiation dosage levels to different regions of the field of view based on the defined region of interest. By concentrating the radiation dose on the specific anatomical region of interest rather than uniformly irradiating the entire field of view, the system optimizes image quality for the area of clinical interest while minimizing unnecessary radiation exposure to surrounding tissues.
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 precise control of radiation dosage, reducing the reliance on operator skill and subjective estimation, thereby improving image quality and consistency across various patient sizes and anatomies.
Implementation Method 1
X-rays are generated by an X-ray source and are directed to a patient or other subject. The X-rays transfer through the subject, and are absorbed or attenuated by internal features.
Data Source
AI summary
A radiography system allow for user determination of a region of interest on a subject prior to X-ray exposure. The region of interest is defined by user interaction with an image, a pointer system, or the like. The region of interest is then translated to the imaging coordinate system, such as in the plane of a digital detector. The region is then used for exposure control during an imaging sequence, either in an open or closed-loop manner.