SPECT Gantry Deflection Compensation for Detector Misalignment

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Solution Overview

Problem

Existing SPECT imaging systems face inaccuracies due to mechanical misalignments and gravity-induced deflections in gantry and detector components, which are not adequately addressed by current correction methods, especially when trying to achieve high-resolution imaging.

Innovation Solution

The technology involves determining gantry angle-dependent deflections for a class of systems using a first method and angle-independent deviations for specific systems, applying these to improve image reconstruction by using a combination of gantry angle-dependent and angle-independent deflection results, and implementing this in a calibrated system with computer program products for real-time processing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If detectors are mounted to a gantry and rotatable thereon to enable multi-angle imaging, then imaging versatility is improved, but mechanical misalignments and gravity-induced deflections cause measurement precision to deteriorate

Engineering Contradiction:

Improveimaging versatilityVSAvoiddetector position accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent applies preliminary action by pre-determining gantry angle-dependent deflections for a class of systems and angle-independent deviations for specific systems before actual imaging. These pre-characterized deflection values are stored and automatically applied during image reconstruction to compensate for mechanical misalignments and gravity-induced deflections, thereby maintaining measurement precision while enabling versatile multi-angle imaging.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent employs parameter changes by introducing deflection compensation parameters (gantry angle-dependent deflections and angle-independent deviations) that are applied to correct detector position data. By varying these compensation parameters based on gantry angle and specific system characteristics, the system maintains accurate measurements across different imaging configurations and angles.

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If complex correction methods are applied to mitigate mechanical misalignments, then measurement precision is improved, but device complexity increases

Engineering Contradiction:

Improveimage reconstruction accuracyVSAvoidcorrection system complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the deflection correction into two distinct components: gantry angle-dependent deflections (affecting all systems of a class) and angle-independent deviations (specific to individual systems). This segmentation allows each component to be characterized and corrected separately, simplifying the overall correction process while maintaining high measurement precision.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent uses copying by creating a deflection model for a class of systems based on measurements from representative systems. Once the gantry angle-dependent deflections are determined for one or more systems, this information can be copied and applied to other systems of the same class, reducing the need for extensive individual characterization while maintaining accuracy.

Inventive Principle:

Principle #26Copying

3Productivity

If real-time processing is implemented to correct deflections during imaging, then productivity is improved, but computational resources and device complexity increase

Engineering Contradiction:

Improveimage processing speedVSAvoidprocessing system complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by pre-calculating and storing deflection compensation values before actual imaging occurs. During real-time image reconstruction, these pre-determined values are simply applied rather than calculated, enabling fast processing without requiring complex real-time computational resources.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces complex real-time mechanical correction mechanisms with a computational approach. Instead of physically adjusting detector positions during imaging, the system uses software-based deflection compensation that applies pre-determined correction values during image reconstruction, achieving real-time correction with minimal additional hardware complexity.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS7968852B1Mitigation of errors in an imaging system with detectors mounted to a gantry and rotatable thereon

Publication Date: 2011.06.28 SIEMENS MEDICAL SOLUTIONS USA INC

AI summary

Implementations of the present technology include error mitigation processes that determine gantry angle-dependent measures of detector deflections for a given class of systems using a first method, then determine gantry angle-independent deviations from the class measures using a second method on a specific system; then apply, to the specific system of the second method, the gantry angle-dependent class deflection results of the first method modified by the system-specific gantry angle independent deflections of the second method; and further include a system calibrated by such combinations of processes and computer program products for performing at least portions of the combination of processes.