Cryoablation Apparatus Diagnostics and Purge Control

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Solution Overview

Problem

Existing cryoablation systems are inefficient due to separate systems, multiple controls, and independent measurement devices, leading to reduced treatment effectiveness and increased costs.

Innovation Solution

A cryoablation apparatus with a capacitance-based liquid level sensor and pressure control system that continuously monitors and adjusts cryogen levels and pressures in real-time, optimizing cryogen delivery and minimizing surrounding tissue freezing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple separate systems and independent measurement devices are used in cryoablation systems, then system functionality is maintained, but device complexity increases and treatment effectiveness decreases

Engineering Contradiction:
Improvetreatment effectivenessVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines multiple separate measurement devices into a single integrated sensor assembly that simultaneously measures liquid level, temperature, and pressure. This consolidation reduces system complexity while maintaining comprehensive monitoring capabilities, directly resolving the contradiction between system functionality and complexity

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The sensor assembly performs multiple functions (liquid level detection, temperature measurement, pressure monitoring) within a single integrated component. This multi-functionality eliminates the need for separate measurement devices, reducing device complexity while preserving treatment effectiveness through comprehensive system monitoring

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If real-time continuous monitoring of cryogen liquid level is implemented, then treatment effectiveness is improved, but device complexity increases

Engineering Contradiction:
Improvetreatment effectivenessVSAvoidmonitoring system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces mechanical level sensing mechanisms with a capacitance-based electrical measurement system. The capacitance sensor provides real-time continuous liquid level monitoring through electrical field detection, eliminating complex mechanical linkages while enabling precise, continuous monitoring that improves treatment effectiveness

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system implements real-time feedback monitoring where the capacitance sensor continuously measures liquid level and provides data to the control system. This feedback mechanism enables dynamic adjustment of cryogen delivery, improving treatment effectiveness while the integrated nature of the sensor assembly keeps complexity manageable

Inventive Principle:
Principle #23Feedback

3Measurement precision

If capacitance-based liquid level sensing is used, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improveliquid level measurement precisionVSAvoidsensor system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent employs capacitance-based electrical measurement to replace mechanical level sensing, achieving high measurement precision through electrical field detection. The capacitance sensor provides accurate, continuous liquid level data without complex mechanical components, resolving the contradiction between precision and complexity

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system changes the measurement parameter from mechanical position detection to electrical capacitance measurement. This parameter transformation enables precise liquid level sensing through electrical properties, which are easier to measure continuously and accurately, thereby improving measurement precision while keeping the sensor system relatively simple

Inventive Principle:
Principle #35Parameter changes

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

Improves treatment efficiency, reduces costs, and enhances the effectiveness of cryoablation procedures by ensuring precise cryogen management and minimizing unnecessary freezing of healthy tissues.

Implementation Method 1

a capacitance-based liquid level sensor positioned in the Dewar. The capacitance-based liquid level sensor may be coupled to a cryo-control that can determine a cryogen liquid level based on the capacitance of the liquid level sensor in the Dewar

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 2

a heating assembly positioned at a distal end of the supply tube and configured to heat the liquid cryogen to convert the liquid cryogen to cryogen gas

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 3

a pump assembly positioned proximate the heating assembly and configured to pressurize the liquid cryogen to a pressure greater than a pressure in the Dewar

Methodology Applied
Scientific EffectPressure Increase: Pressure Increase

Implementation Method 4

A cryoablation system may include an extremely cold cryogen (liquid, gas, or mixed phase Nitrogen, Argon, Helium, or the like) that may be passed through a probe that is in thermal contact with the target tissue. Heat from the tissue passes from the tissue, through the probe, and into the cryogen that removes heat from the targeted tissue

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 5

This removal of heat causes tissue to freeze, resulting in the destruction of the targeted tissue

Methodology Applied
Scientific EffectFreezing: Freezing

Data Source

PatentEP4527326A1Apparatuses for cryoablation system diagnostics and purge
Publication Date: 2025.03.26 VARIAN MEDICAL SYSTEMS INC
  • EP4527326A1 patent drawingFigure 1
  • EP4527326A1 patent drawingFigure 2~3B
  • EP4527326A1 patent drawingFigure 4

AI summary

A cryoablation apparatus includes a Dewar, a cryogen flow path fluidly coupled to the Dewar to supply cryogen to a cryoprobe, a first pressure sensor and a second pressure sensor positioned at a first portion of the cryogen flow path and at a second portion of the cryogen flow path, respectively, a first valve and a second valve each positioned along the cryogen flow path and each configured to operate in an open position and in a closed position, and a diagnostics control operatively coupled to the first pressure sensor, the second pressure sensor, the first valve, and the second valve. The diagnostics control is configured to determine whether a blockage or leak exists in the first portion and the second portion of the cryogen flow path. The apparatus also includes a gas assembly configured to supply a cryogen gas to purge the flow path.