CT Scanner VOI Alignment Using Stereo X-Ray Imaging
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Solution Overview
Problem
Conventional CT scanners require time-consuming and inconvenient positioning procedures for aligning patients, especially for cardiac imaging, due to the lack of motorized lateral alignment and reliance on manual adjustments, which affects image quality and efficiency.
Innovation Solution
The use of stereo X-ray image data to align a volume of interest (VOI) relative to the scanner's field of view (FOV) through multiple X-ray beams, allowing for rapid electronic switching and ECG-triggered image acquisition to freeze heart and breathing motion, enabling automatic or semi-automatic positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual positioning adjustments are used in conventional CT scanners, then the device complexity is reduced, but the positioning precision and image quality deteriorate
Solution Approach 1:
The patent replaces manual mechanical positioning adjustments with an automated computer-controlled positioning system. The system uses a controller to automatically adjust the platform position based on stereo image data analysis, eliminating the need for operator manual intervention and achieving higher positioning precision consistently.
Solution Approach 2:
The positioning system performs self-positioning by automatically acquiring stereo images, analyzing the image data to determine subject position, and adjusting the platform accordingly. This self-service capability eliminates the need for external manual positioning operations while maintaining high precision.
2Productivity
If rapid electronic switching between multiple X-ray beams is implemented, then the productivity of positioning is improved, but the device complexity increases
Solution Approach 1:
The patent implements periodic action by rapidly alternating between multiple X-ray beams in a systematic sequence. The controller switches between beams at high speed to acquire multiple projections, enabling rapid volumetric imaging and positioning while managing system complexity through structured periodic operation.
Solution Approach 2:
The multiple X-ray beam system serves multiple functions: it enables rapid volumetric imaging, provides stereo positioning capability, and allows for motion freezing through ECG triggering. This multi-functionality justifies the increased device complexity by delivering multiple benefits from a single integrated system.
3Measurement precision
If ECG-triggered image acquisition is used to freeze heart motion, then the measurement precision of cardiac imaging is improved, but the loss of time for synchronization increases
Solution Approach 1:
The system performs preliminary action by pre-synchronizing the X-ray beam switching with the ECG signal before image acquisition begins. The controller is configured to trigger beam activation at specific ECG phases, ensuring that the heart is frozen in a consistent state throughout the acquisition process without requiring real-time adjustment delays.
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 method enables precise and efficient alignment of the VOI within the scanner's FOV, improving image quality and reducing radiation exposure by allowing for automatic or operator-assisted positioning in real-time, even for cardiac imaging.
Implementation Method 1
A source 104 of one or more X-ray beams... illuminating a region of the subject encompassing the VOI... to provide stereo image data
Implementation Method 2
Attenuation data from all the detector elements 112 is gathered for a succession of angular positions
Data Source
AI summary
An apparatus and method for optimally positioning a region of interest of a subject for imaging by a CT scanner. The scanner provides a source of one or more X-ray beams, at least one of which is used for acquiring a CT image of the subject, a movable support for the subject, and a controller that controls the X-ray source. To position the region of interest of the subject, the controller operates to illuminate the subject with X-rays to acquire stereo image data for the region of interest and controls the position of the support responsive to the stereo image data.