Imaging Tabletop Deflection Measurement
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Solution Overview
Problem
In imaging systems like CT scanners, the cantilevered tabletop deflects under the weight of subjects or objects, causing misalignment and degradation of image quality due to shifted positions away from the iso-center, leading to artifacts and poor image reconstruction.
Innovation Solution
A tabletop deflection determiner is integrated into the rotating gantry portion of the imaging system, using an emitter, reflector, and sensor to measure deflections and adjust scan parameters such as dose modulation and image alignment, ensuring accurate alignment with the iso-center even during cantilevered positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the tabletop is extended into the examination region in a cantilevered position, then the subject can be positioned for scanning, but the tabletop deflects under weight causing misalignment and image degradation
Solution Approach 1:
The system performs preliminary measurement of tabletop deflection using an optical sensor before the actual scan. The emitter projects a light pattern onto the tabletop surface, and the sensor detects the reflected pattern to calculate deflection. This preliminary measurement allows the system to compensate for deflection by adjusting scan parameters, ensuring accurate image reconstruction despite the cantilevered position.
Solution Approach 2:
The system implements a feedback mechanism where the optical sensor continuously monitors tabletop deflection during the scanning process. The measured deflection data is fed back to the control system, which then adjusts scan parameters in real-time to compensate for the measured deflection. This closed-loop feedback ensures that images are accurately reconstructed despite dynamic changes in tabletop position under subject weight.
2Device complexity
If the tabletop deflection is not compensated, then the system operation is simple, but image quality degrades due to misalignment and artifacts
Solution Approach 1:
The patent introduces an optical pattern as an intermediary element between the emitter and the tabletop surface. The light pattern serves as a mediator that reflects off the tabletop and carries information about its deflection state to the sensor. This intermediary approach enables non-contact, precise measurement of deflection without adding mechanical complexity to the tabletop structure itself, maintaining system simplicity while improving image quality.
3Measurement precision
If an optical measurement system is added to measure tabletop deflection, then alignment accuracy improves, but device complexity increases
Solution Approach 1:
The optical measurement system is designed with multi-functionality to reduce overall device complexity. The same optical components (emitter and sensor) used for deflection measurement can also be integrated with the existing scanning system's coordinate system. The light pattern projection and detection mechanism serves both as a measurement tool and as part of the overall imaging coordinate reference system, allowing one system to perform multiple functions rather than adding separate dedicated components.
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 solution effectively corrects for tabletop deflections, maintaining image quality by ensuring precise alignment and optimizing scan parameters, reducing artifacts and improving reconstruction accuracy.
Implementation Method 1
A tabletop deflection determiner integrated into the rotating gantry portion includes an emitter that projects a light pattern onto the tabletop and a sensor that detects the reflected light
Data Source
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AI summary
Described herein is an approach to determine a deflection of a portion of an imaging system tabletop located at iso-center utilizing a tabletop deflection determiner with a least a first portion located on a rotating gantry portion of the imaging system. In one non- limiting instance, an imaging system includes a rotating gantry portion (606) with an aperture defining an examination region, a tabletop (620) that supports a subject or object in the examination region, wherein the tabletop cantilevers into and deflects in the examination region, and a tabletop deflection determiner (622) that determines a deflection of the tabletop in the examination region, wherein a first portion (702, 706) of the tabletop deflection determiner is located on the rotating gantry portion.