Hyperpolarized Gas Delivery System for Lung Imaging

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Solution Overview

Problem

Current methods for delivering hyperpolarized gaseous MRI contrast agents, such as helium-3 and xenon-129, face challenges in maintaining the polarization of these gases due to premature mixing with oxygen, leading to inaccurate oxygen tension measurements in lung imaging, as the existing separation methods do not guarantee uniform mixing and can result in non-physiological oxygen gradients.

Innovation Solution

A system that includes first and second gas containers for hyperpolarized gas and oxygen, respectively, with a flow meter and flow control valve to monitor and control the flow rates, ensuring real-time mixing and maintaining the desired fraction of inspired oxygen, allowing for precise delivery and synchronization with imaging device activation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If hyperpolarized gas is mixed with oxygen immediately after dispensing from the polarizer, then the gas can be delivered to the subject without delay, but the polarization decays rapidly due to interactions with oxygen molecules

Engineering Contradiction:

Improvedelivery timeVSAvoidpolarization maintenance

Core Design Contradiction:

Loss of timeVSReliability

Solution Approach 1:

The system pre-mixes the hyperpolarized gas with oxygen in controlled proportions before the subject inhales, rather than mixing immediately upon dispensing. This preliminary mixing action allows the gas to maintain polarization longer while still being delivered without significant delay, resolving the contradiction between timely delivery and polarization maintenance.

Inventive Principle:

Principle #10Preliminary action

2Measurement precision

If oxygen is added to hyperpolarized gas to achieve normoxic ratio for physiological measurements, then accurate oxygen tension measurements can be obtained, but the depolarization rate increases due to paramagnetic properties of oxygen

Engineering Contradiction:

Improveoxygen tension measurement accuracyVSAvoidpolarization stability

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The system precisely controls the concentration ratio of hyperpolarized gas to oxygen to achieve the normoxic ratio (approximately 79:21). By adjusting this parameter, the system maintains physiological relevance for accurate oxygen tension measurements while minimizing the depolarization effect caused by oxygen's paramagnetic properties.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If hyperpolarized gas and oxygen are stored in separate containers and mixed immediately before inhalation, then polarization is preserved during storage, but non-uniform mixing occurs leading to non-physiological oxygen gradients

Engineering Contradiction:

Improvepolarization preservationVSAvoidmixing uniformity

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The system uses a controlled mixing chamber as an intermediary between the separate storage containers of hyperpolarized gas and oxygen. This intermediary mixing environment ensures uniform blending of the gases in the correct proportions before delivery to the subject, eliminating non-physiological oxygen gradients while preserving polarization during storage.

Inventive Principle:

Principle #24Intermediary (Mediator)

4Ease of operation

If the mixing and inspiration process takes several seconds, then the subject can inhale the gas mixture comfortably, but substantial polarization is lost during this time

Engineering Contradiction:

Improvesubject comfortVSAvoidpolarization retention

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The system prepares and mixes the gas mixture in advance before the subject begins inhalation, rather than mixing during the inhalation process. This preliminary preparation allows the mixing to occur outside the subject's breath-hold time, maintaining polarization retention while still allowing comfortable inhalation over several seconds.

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

This system ensures accurate and uniform delivery of the gas mixture, reducing depolarization and enhancing the accuracy of oxygen tension measurements by maintaining the desired oxygen concentration, thereby improving the quality of lung imaging and diagnostic precision.

Implementation Method 1

A flow meter and flow control valve are provided downstream of the first and second gas containers respectively, for monitoring and controlling the flow rates of the gaseous components

Methodology Applied

Scientific EffectFlow rate measurement:

Implementation Method 2

A flow control valve is provided downstream of the flow meter for selectively providing fluid communication between the flow meter and a delivery tube

Methodology Applied

Scientific EffectFluid flow control: Valve