Emission Tomography With Movable Attenuator for Resolution and Sensitivity

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Solution Overview

Problem

Existing emission tomography systems face a trade-off between high directional accuracy and sensitivity, leading to noisy data and artifacts due to the use of parallel hole collimators, which limits spatial, contrast, and temporal resolution.

Innovation Solution

Replace the collimator with a movable attenuator having interior through-holes of varying shapes and sizes, using the shadows cast on the sensor as a time-encoded aperture to reconstruct emissions with enhanced resolution and sensitivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a parallel hole collimator is used to ensure directional accuracy, then spatial resolution is improved, but sensitivity deteriorates due to the limited number of emissions detected

Engineering Contradiction:

Improvespatial resolutionVSAvoidnumber of emissions detected

Core Design Contradiction:

Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent employs a movable attenuator that dynamically changes position during data acquisition. The attenuator moves between multiple known positions, creating time-varying shadow patterns on the detector. This dynamic approach allows the system to collect directional information from multiple angles while maintaining large aperture openings, thereby improving both spatial resolution and sensitivity simultaneously.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The attenuator performs periodic motion between discrete positions, creating a time-encoded sequence of shadow patterns. Each position provides a different projection of the source distribution, and the periodic sampling across multiple positions enables reconstruction of high-resolution images while accumulating counts from all positions, thus resolving the sensitivity-resolution tradeoff.

Inventive Principle:

Principle #19Periodic action

2Measurement precision

If a parallel hole collimator is used to maintain directional information, then spatial resolution is improved, but sensitivity deteriorates due to noise and artifacts in the detected data

Engineering Contradiction:

Improvespatial resolutionVSAvoiddata quality

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The movable attenuator serves as an intermediary element between the source and detector. It modulates the gamma ray flux by casting time-varying shadow patterns, encoding spatial information in the temporal sequence of detected events. This intermediary approach preserves directional information through the shadow patterns while allowing much higher count rates to reach the detector, improving data quality and reducing noise.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Quantity of substance

If larger holes are used in the attenuator to increase sensitivity, then more emissions are detected, but directional information is lost

Engineering Contradiction:

Improvenumber of emissions detectedVSAvoiddirectional information

Core Design Contradiction:

Quantity of substanceVSLoss of information

Solution Approach 1:

The system performs preliminary encoding of directional information through the known geometric relationship between the attenuator positions and detector. The large holes in the attenuator are positioned and sized such that their shadow patterns at different known positions pre-encode the directional information. During reconstruction, this pre-encoded information is decoded to recover spatial distribution, allowing large holes to be used without losing directional information.

Inventive Principle:

Principle #10Preliminary action

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 system achieves improved sensitivity and resolution by extracting directional information from the moving shadows, allowing for better detection and reconstruction of gamma ray emissions.

Implementation Method 1

The movable attenuator is between a source of the emissions and the sensor such that a moving shadow of the through-holes is cast on the sensor

Methodology Applied

Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Data Source

PatentUS20250216562A1Emission tomography with generalized time encoded aperture imaging

Publication Date: 2025.07.03 SIEMENS MEDICAL SOLUTIONS USA INC

AI summary

For emission tomography, a greater number of emissions are detected. To detect a greater number of emissions and provide better resolution than provided by a parallel hole collimator, the collimator is replaced by an attenuation object with exterior and interior edges. Rather than enforcing directionality, larger holes with different shapes may be used to allow a greater number of emissions to be detected. By moving the attenuation object, the differences in the shadows on the sensor may be used as a time-encoded aperture to reconstruct the source of emissions with greater resolution and sensitivity than where a fixed parallel hole collimator is used.