CBM Normalization Matrix for PET Gating Artifacts

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Continuous bed motion in PET scanning complicates normalization for cardiac/respiratory gating protocols, leading to image non-uniformity and incorrect quantification due to the integration of counts from different gating windows in virtual LORs.

Innovation Solution

A method involving the calculation of a CBM normalization matrix using gating signals to reconstruct images from continuous bed motion data, filtering data acquired during specific phases of the gate cycle to compensate for gating effects and improve image uniformity and quantification.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If continuous bed motion (CBM) method is used to obtain whole body images, then productivity and flexibility are improved, but normalization accuracy deteriorates due to integration of counts from different gating windows in virtual LORs

Engineering Contradiction:

Improvewhole body imaging efficiencyVSAvoidnormalization accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The patent divides the CBM data into multiple segments corresponding to different gating windows. By segmenting the continuous data stream based on gating signals, the system can process and normalize each segment separately, thereby maintaining the efficiency of CBM while restoring the precision needed for accurate normalization in gated protocols.

Inventive Principle:

Principle #1Segmentation

2Reliability

If gating windows are applied to reduce motion artifacts, then image quality is improved, but image uniformity deteriorates in CBM scans due to different virtual LORs receiving contributions from different gating windows

Engineering Contradiction:

Improvemotion artifact reductionVSAvoidimage uniformity

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent applies local quality by assigning different normalization factors to different regions of the image based on their specific gating window contributions. Each virtual LOR is normalized according to its local gating characteristics rather than applying a global normalization factor, thereby maintaining image uniformity while preserving the motion artifact reduction benefits of gating.

Inventive Principle:

Principle #3Local quality

3Device complexity

If simple scaling methods are used for normalization in CBM scans, then device complexity is reduced, but quantification accuracy deteriorates due to inability to properly account for gating effects

Engineering Contradiction:

Improvenormalization method complexityVSAvoidquantification accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent performs preliminary action by pre-calculating normalization factors for each virtual LOR based on its specific gating window contributions before image reconstruction. This preliminary normalization step ensures that quantification accuracy is maintained while avoiding the need for complex real-time corrections during reconstruction, thus balancing simplicity and precision.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS9262844B2Method to compensate gating effects on image uniformity and quantification for PET scan with continuous bed motion

Publication Date: 2016.02.16 SIEMENS MEDICAL SOLUTIONS USA INC

AI summary

Methods and systems for processing data for medical imaging are disclosed. The method includes obtaining a set of continuous bed motion (CBM) data from a first imaging modality. The set of CBM data includes a plurality of gating signals. A CBM normalization matrix is calculated. The CBM normalization matrix calculation includes the plurality of gating signals. An image is reconstructed from the CBM data and the CBM normalization matrix. The first imaging modality can be a PET imaging device.