Respiratory Marker for 4D CT Phase Sorting

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Solution Overview

Problem

Current methods for spatial registration of computed tomography images with respiratory motion require separate respiratory monitoring and imaging datasets, which can lead to synchronization errors and necessitate additional sensors, obstructing patient access and increasing system bulk, while being incompatible with certain imaging modalities like magnetic resonance scanners.

Innovation Solution

A respiratory marker with an elongated detectable portion that moves with respiration and is embedded within the imaging data, allowing for direct detection and synchronization of respiratory phases within the imaging process, eliminating the need for separate sensors and reducing geometrical constraints.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If separate respiratory monitoring sensors (optical markers, CCD cameras, strain gauges) are used to track respiratory motion, then respiratory phase information can be obtained, but the system becomes more complex, requires additional equipment that obstructs patient access, and introduces synchronization errors between respiratory and imaging datasets

Engineering Contradiction:

Improverespiratory phase detection accuracyVSAvoidsystem complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines respiratory monitoring functionality directly into the imaging system by using imaging fiducials that are detected within the imaging data itself. Instead of separate respiratory sensors, the system uses the imaging modality's own detection capabilities to track fiducial markers, merging two functions (imaging and respiratory monitoring) into one integrated system.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The imaging system is made multi-functional by enabling it to perform both primary imaging and respiratory phase detection using the same hardware. The imaging scanner detects both anatomical structures and respiratory fiducials, eliminating the need for dedicated respiratory sensors and making the system compatible with various imaging modalities including MRI.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Measurement precision

If dedicated respiratory sensors (CCD cameras, optical markers) are positioned adjacent to the imaging region, then respiratory motion can be monitored, but patient access is obstructed and system bulk increases

Engineering Contradiction:

Improverespiratory motion trackingVSAvoidpatient access

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

The patent extracts the respiratory monitoring function from external dedicated sensors and relocates it within the imaging data stream itself. By detecting fiducials directly in the imaging acquisitions, the system eliminates the need for external sensors positioned near the patient, thereby improving patient access while maintaining respiratory tracking capability.

Inventive Principle:

Principle #2Taking out (Extraction)

3Measurement precision

If separate respiratory and imaging datasets are recorded and correlated using time stamps, then respiratory phase binning can be performed, but time offset errors between datasets introduce substantial systematic error

Engineering Contradiction:

Improverespiratory phase assignmentVSAvoidsynchronization accuracy

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent merges respiratory phase information and imaging data into a single synchronized dataset by detecting fiducials within the same imaging acquisitions. This eliminates the need for separate dataset correlation and time stamp synchronization, removing the source of time offset errors and improving reliability.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The imaging system performs self-synchronization by automatically detecting fiducials within its own imaging data stream. The system uses its inherent time-stamped imaging acquisitions to simultaneously capture both anatomical information and respiratory phase information, eliminating the need for external synchronization mechanisms.

Inventive Principle:

Principle #25Self-service

4Measurement precision

If optical markers and cameras are used for respiratory monitoring, then respiratory phase can be derived, but the system is incompatible with magnetic resonance scanners and requires periodic recalibration

Engineering Contradiction:

Improverespiratory phase detectionVSAvoidimaging modality compatibility

Core Design Contradiction:

Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent creates a universal respiratory monitoring solution that works across multiple imaging modalities by using fiducials detectable within the imaging data itself. Different imaging modalities (CT, MRI, PET, SPECT) can all detect appropriate fiducial types, making the system compatible with various scanners without requiring modality-specific respiratory sensors.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS8160675B2Retrospective sorting of 4D CT into breathing phases based on geometric analysis of imaging fiducials

Publication Date: 2012.04.17 KONINKLIJKE PHILIPS NV

AI summary

A respiratory marker (40, 140, 240, 340, 440) includes an elongated detectable portion (42, 342, 442) that is operatively coupled with respiration of an imaging subject such that the elongated detectable portion moves with the respiration. The elongated detectable portion is arranged to intersect images acquired by an imaging scanner (10) at different times and at different positions along a scanner axis (20), and is detectable as a marker feature in the images. A marker position finder (52, 54) is configured to determine positions of the marker features in the images.