CT Gantry Motion Detection Using Multi-Sensor Signal Merging

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Solution Overview

Problem

Existing CT imaging systems face challenges in detecting gantry motion accurately due to noise floors of motion sensors, which can lead to image quality issues and unnecessary radiation exposure, especially when imbalances occur during manufacturing, installation, or maintenance.

Innovation Solution

A CT imaging system employs multiple motion sensors to concurrently detect gantry motion and combines their signals to reduce the overall noise floor, allowing for the detection of lower magnitude motions that would otherwise be undetectable, facilitating balance adjustments and ensuring proper mounting and ongoing stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a single motion sensor is used to detect gantry motion, then the device complexity is low, but the measurement precision is insufficient because the motion signal falls within the noise floor of the sensor

Engineering Contradiction:
Improvemotion detection precisionVSAvoidsensor system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines multiple motion sensors (at least two sensors) to detect the same gantry motion. By merging the signals from multiple sensors and processing them together, the system achieves a lower effective noise floor and improved measurement precision. The signals are combined through correlation processing that identifies common motion components while rejecting uncorrelated noise, thereby resolving the contradiction between using a simple single sensor and achieving precise motion detection.

Inventive Principle:
Principle #5Merging (Combining)

2Productivity

If the rotation speed of the rotating frame is increased to improve productivity, then the scanning efficiency improves, but the motion signal level decreases and falls within the noise floor of the motion sensor

Engineering Contradiction:
Improvescanning efficiencyVSAvoidmotion signal detectability
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent applies signal combining from multiple sensors to detect the motion signals generated at higher rotation speeds. By processing correlated signals from multiple sensors together, the system maintains the ability to detect motion signals even at higher rotation speeds where individual sensor signals would be too weak, thus resolving the contradiction between improved scanning efficiency and motion signal detectability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The system uses the combined motion signal feedback to monitor and detect imbalances in the rotating frame. The processed motion signals provide feedback about the actual gantry motion, enabling detection of imbalance conditions even at high rotation speeds where the motion signals would otherwise be lost in noise.

Inventive Principle:
Principle #23Feedback

3Reliability

If motion sensors are used to detect gantry motion, then the reliability of motion detection improves, but the measurement precision deteriorates because the motion signal cannot be distinguished from the noise floor

Engineering Contradiction:
Improvemotion detection reliabilityVSAvoidmotion signal resolution
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent merges signals from multiple motion sensors and applies correlation processing to distinguish the true motion signal from noise. By combining multiple reliable sensor readings and identifying correlated components, the system maintains high reliability while improving measurement precision through noise rejection, resolving the contradiction between reliable detection and precise measurement.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP4656138A1Computed tomography (CT) imaging system gantry motion detection
Publication Date: 2025.12.03 GE PRECISION HEALTHCARE LLC
  • EP4656138A1 patent drawingFigure 1
  • EP4656138A1 patent drawingFigure 2~4
  • EP4656138A1 patent drawingFigure 5~6

AI summary

A computed tomography imaging system includes a gantry and a rotating frame rotatably supported in the gantry and carrying at least one component for producing, transmitting or receiving X-ray radiation, a first motion sensor configured to sense a first motion of the gantry in a first plane and generate a first signal indicative of the first motion and that has a first noise floor, a second motion sensor configured to concurrently sense the first motion of the gantry in the first plane and generate a second signal indicative of the first motion and that has a second noise floor, and motion signal processing circuitry configured to combine the first signal and the second signal to generate a first combined signal indicative of the first motion, wherein the first combined signal has a third noise floor that is lower than the first noise floor and the second noise floor.