Cryoprobe Return-Line Heat Exchanger for Smaller Ablation Probes

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Solution Overview

Problem

Existing cryoprobes suffer from inefficient heat exchange structures, bulkiness, and difficulty in manipulation due to large size and mass, which hinder effective cryogen temperature achievement and stable positioning during cryoablation treatments.

Innovation Solution

Incorporation of a heat exchanger into the flexible cryogen lines, eliminating the need for a handle-based exchanger, allowing for smaller and more maneuverable cryoprobes with improved thermal energy transfer through counterflow designs, including flexible conduits and Joule-Thompson expansion chambers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If traditional heat exchange structures are used in cryoprobes, then the structure can achieve sufficient cooling, but the probe becomes bulky and difficult to manipulate

Engineering Contradiction:

Improvecryogen temperatureVSAvoidprobe manipulation

Core Design Contradiction:

TemperatureVSEase of operation

Solution Approach 1:

The heat exchanger is extracted from the handle portion and relocated to the flexible cryogen line. This separation allows the handle to be small and maneuverable while the heat exchange function is performed in the flexible line that can be positioned away from the insertion site.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The heat exchange function is moved from the spatial dimension of the handle to the flexible line dimension. The flexible line can extend and position the heat exchanger in three-dimensional space away from the probe insertion point, resolving the conflict between compact handle design and effective heat exchange.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Temperature

If traditional heat exchange structures are used in cryoprobes, then the structure can achieve sufficient cooling, but the probe becomes larger than desired

Engineering Contradiction:

Improvecryogen temperatureVSAvoidprobe size

Core Design Contradiction:

TemperatureVSVolume of moving object

Solution Approach 1:

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The heat exchanger is integrated within the flexible cryogen line structure itself, nesting the heat exchange function within the existing conduit rather than adding it as a separate external component to the handle.

Inventive Principle:

Principle #7Nested doll (Nesting)

3Temperature

If traditional heat exchange structures are used in cryoprobes, then the structure can achieve sufficient cooling, but the manufacturing complexity and cost increase

Engineering Contradiction:

Improvecryogen temperatureVSAvoidprobe manufacturing

Core Design Contradiction:

TemperatureVSEase of manufacture

Solution Approach 1:

The heat exchanger is implemented as a flexible structure within the flexible cryogen line, allowing it to be manufactured as an integrated component of the line rather than requiring complex assembly of rigid heat exchange components into the handle.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The heat exchange function is merged with the flexible cryogen line structure, combining two functions (cryogen transport and heat exchange) into a single integrated component that simplifies manufacturing and reduces part count.

Inventive Principle:

Principle #5Merging (Combining)

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

The solution enables faster and more efficient temperature reduction at the cryoprobe tip, reducing the risk of healthy tissue damage and improving clinical maneuverability by achieving lower temperatures with smaller, less intrusive probes.

Implementation Method 1

The counterflow heat exchanger is configured to transfer thermal energy from the supply cryogen to the return cryogen

Methodology Applied

Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 2

the needle of the cryoprobe where it may undergo Joule-Thompson expansion that drops the temperature of the needle to perform a cryoablation treatment

Methodology Applied

Scientific EffectJoule-Thompson expansion: Joule-Thomson Effect

Data Source

PatentUS20260041476A1Cryoablation probes with heat exchanger in return cryogen line

Publication Date: 2026.02.12 VARIAN MEDICAL SYSTEMS INC

AI summary

A cryoprobe assembly includes a needle, a flexible conduit, and a handle portion configured to couple the needle to the flexible conduit to create a cryogen flow path. The flexible conduit includes a counterflow heat exchanger to transfer thermal energy from supply cryogen to return cryogen prior to reaching the needle in order to achieve a predetermined temperature during Joule-Thompson expansion in the needle.