Rubidium Generator Column Compaction for Low Pressure Elution

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Solution Overview

Problem

Current rubidium generators for cardiac perfusion imaging require high pressure and flow rates for 82Rb delivery, which is not suitable for precise control needed in 3D PET technology, necessitating a solution for low pressure and precision flow control.

Innovation Solution

A rubidium generator column filled with compacted α-hydrous tin dioxide ion exchange material that tightly binds 82Sr but not 82Rb, allowing for low pressure elution and precision flow control, using a peristaltic pump and a method of repeatedly compacting the material to achieve a density that permits fluid flow at 1.5 pounds per square inch (10 kPa) and loading with 82Sr for multiple uses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional rubidium generators are used, then 82Rb can be delivered, but high pressure and flow rates are required which are not suitable for precise control in 3D PET technology

Engineering Contradiction:
Improveflow control precisionVSAvoidelution pressure
Core Design Contradiction:
Measurement precisionVSStress or pressure

Solution Approach 1:

The patent changes the physical parameters of the ion exchange material by compacting it to a specific density range (1.8-2.2 g/cm³). This parameter change allows the material to bind 82Sr effectively while permitting 82Rb elution at low pressures (1-5 psi), resolving the contradiction between binding efficiency and elution pressure requirements for precise flow control.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent utilizes the porous structure of compacted α-hydrous tin dioxide ion exchange material. The controlled compaction creates an optimal pore structure that allows selective binding of 82Sr while enabling low-pressure flow of 82Rb solution, achieving both high binding efficiency and low elution pressure suitable for 3D PET systems.

Inventive Principle:
Principle #31Porous materials

2Ease of operation

If high pressure elution is used to deliver 82Rb, then delivery is achieved, but precise flow control needed for 3D PET is compromised

Engineering Contradiction:
Improveflow controlVSAvoiddelivery accuracy
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

By changing the density parameter of the ion exchange material to a specific range (1.8-2.2 g/cm³), the patent optimizes the balance between material binding capacity and fluid flow resistance. This enables reliable 82Rb delivery with precise flow control at low pressures, meeting 3D PET requirements.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the ion exchange material is tightly packed to bind 82Sr, then binding efficiency improves, but elution pressure increases

Engineering Contradiction:
Improve82Sr binding efficiencyVSAvoidelution pressure
Core Design Contradiction:
ReliabilityVSStress or pressure

Solution Approach 1:

The patent identifies and applies an optimal density parameter range (1.8-2.2 g/cm³) for the ion exchange material that simultaneously achieves high 82Sr binding efficiency and low elution pressure. This parameter optimization resolves the contradiction between binding strength and elution ease.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The controlled compaction of α-hydrous tin dioxide creates a porous structure with optimal void space that maintains strong 82Sr binding while allowing low-pressure passage of 82Rb during elution, resolving the pressure-efficiency contradiction.

Inventive Principle:
Principle #31Porous materials

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

Enables low pressure, precise, and cost-effective delivery of 82Rb for cardiac perfusion imaging, reducing waste and distributing the initial cost over multiple 82Sr loads, ensuring compatibility with 3D PET systems while maintaining sterility and pyrogen-free operation for extended periods.

Implementation Method 1

α-hydrous tin dioxide ion exchange material that tightly binds 82Sr but not 82Rb

Methodology Applied
Scientific EffectIon exchange: Ion Exchange

Data Source

PatentEP1973624B1A rubidium generator for cardiac perfusion imaging and method of making and maintaining same
Publication Date: 2015.03.25 OTTAWA HEART INST RES CORP
  • EP1973624B1 patent drawingFigure 1~2
  • EP1973624B1 patent drawingFigure 3
  • EP1973624B1 patent drawingFigure 4

AI summary

An 82Sr/82Rb generator column is made using a fluid impervious cylindrical container having a cover for closing the container in a fluid tight seal, and further having an inlet for connection of a conduit for delivering a fluid into the container and an outlet for connection of a conduit for conducting the fluid from the container. An ion exchange material fills the container, the ion exchange material being compacted within the container to a density that permits the ion exchange material to be eluted at a rate of at least 5 ml/min at a fluid pressure of 1.5 pounds per square inch (10 kPa). The generator column can be repeatedly recharged with 82Sr. The generator column is compatible with either three-dimensional or two-dimensional positron emission tomography systems.