CT Scanner Gantry Tilt Control Using Inclination Sensor

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Solution Overview

Problem

Conventional X-ray CT scanners require complex and time-consuming decoder calibration for tilting mechanisms, leading to unwanted gantry movement and reduced precision due to reliance on mechanical components prone to thermal expansion and wear, especially as resolution increases.

Innovation Solution

Incorporation of an inclination sensor independent of mechanical components to determine the tilting angle precisely, combined with a low-pass filter for vibration detection and spectral analysis, allowing for improved long-term stability and reduced calibration needs, and enabling early detection of potential failures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a relative position encoder is used to measure the angular position of the lifting spindle, then the device complexity is reduced, but a calibration run is required which increases loss of time and causes unwanted gantry movement

Engineering Contradiction:

Improveencoder complexityVSAvoidcalibration time

Core Design Contradiction:

Device complexityVSLoss of time

Solution Approach 1:

The patent replaces the mechanical relative position encoder system with a non-contacting inclination sensor that uses optical or electromagnetic fields to measure gantry tilt angle directly, eliminating the need for mechanical encoders and their associated calibration procedures

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces an intermediary inclination sensor that indirectly measures the gantry tilt angle through gravitational reference rather than directly measuring encoder position, thereby avoiding the need for calibration runs and mechanical reference systems

Inventive Principle:

Principle #24Intermediary (Mediator)

2Device complexity

If mechanical components like lifting spindles are used for tilting, then the device complexity is reduced, but long-term stability deteriorates due to thermal expansion and wear

Engineering Contradiction:

Improvemechanical system simplicityVSAvoidlong-term stability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent substitutes mechanical measurement components with non-contacting inclination sensors that use optical or electromagnetic fields, eliminating wear and thermal expansion issues inherent in mechanical systems while maintaining simplicity

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent extracts the measurement function from the mechanical lifting spindle system by introducing a separate inclination sensor that independently measures gantry tilt angle, thereby removing the instability source from the mechanical components

Inventive Principle:

Principle #2Taking out (Extraction)

3Measurement precision

If a decoder is mounted and aligned for detector tilt angle measurement, then measurement precision is improved, but device complexity and ease of manufacture worsen due to alignment requirements

Engineering Contradiction:

Improvedetector tilt angle precisionVSAvoiddecoder alignment difficulty

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent replaces mechanical decoder systems requiring precise alignment with non-contacting inclination sensors that automatically reference gravitational vertical, eliminating alignment requirements while maintaining or improving measurement precision

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The inclination sensor automatically establishes its measurement reference by sensing gravitational direction, eliminating the need for manual alignment procedures and making the system self-calibrating without external intervention

Inventive Principle:

Principle #25Self-service

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 solution provides precise and stable tilting adjustments, reduces calibration time, enhances long-term mechanical stability, and allows for early detection of vibrations and potential failures, improving the quality and reliability of CT scanner operations.

Implementation Method 1

An inclination sensor is provided at the tiltable frame to determine the angle of a vector at a right angle to the rotation axis of the rotating part with respect to the center of gravity of the earth

Methodology Applied

Scientific EffectGravitation: Gravitation

Data Source

PatentUS8985852B2Monitoring device for a CT scanner gantry

Publication Date: 2015.03.24 SCHLEIFRING & APPBAU

AI summary

A CT scanner gantry comprises a base with a tiltable frame holding a rotating part, the rotating part having a rotation axis and drive means for tilting the tiltable frame with respect to the base. Furthermore, a tilt drive control unit is provided to control the drive means. In inclination sensor is provided at the tiltable frame to indicate the inclination of the tiltable frame with respect to the center of gravity of earth to the tilt drive control unit.