Microwave Ablation Probe Choke Locking for Stable Ablation Zones

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Solution Overview

Problem

Existing microwave ablation probes face issues with relative movement and deformation between the inner insulating layer and outer conductive layer of the choke, leading to unpredictable and non-repeatable ablation zones, which can cause damage to surrounding tissues.

Innovation Solution

A choke design for microwave ablation probes that includes an inner layer mechanically locked to an outer casing using lock openings, preventing relative movement and ensuring a stable, repeatable ablation zone.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the microwave ablation antenna is made small to minimize damage to surrounding tissues, then the size of the antenna is reduced, but the ability to produce a repeatable and known ablation zone deteriorates

Engineering Contradiction:

Improvesize of microwave ablation antennaVSAvoidrepeatability of ablation zone

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

The choke is divided into two separate layers: an inner insulating layer and an outer conductive layer. These layers are mechanically locked together using lock openings and protrusions to prevent relative movement. This segmentation allows each layer to perform its specific function while maintaining a stable, repeatable ablation zone pattern even in a small antenna design.

Inventive Principle:

Principle #1Segmentation

2Device complexity

If the inner insulating layer and outer conductive layer of the choke are not mechanically locked, then the device complexity is reduced, but relative movement and deformation occur during assembly leading to unpredictable ablation zones

Engineering Contradiction:

Improvestructure of chokeVSAvoidposition stability of choke layers

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

Lock openings are pre-formed in the outer conductive layer at specific positions. The inner insulating layer is designed with protrusions that correspond to these lock openings. During assembly, the protrusions automatically engage with the lock openings, preliminarily securing the relative position of the layers before final assembly is complete. This prevents movement and deformation during the assembly process.

Inventive Principle:

Principle #10Preliminary action

3Reliability

If mechanical lock openings are added to the choke design, then the stability of the ablation zone is improved, but the device complexity increases

Engineering Contradiction:

Improvestability of ablation zoneVSAvoidstructure of choke

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The mechanical locking function is merged into the existing choke structure by forming lock openings in the outer conductive layer and corresponding protrusions on the inner insulating layer. This integration allows the locking mechanism to work seamlessly with the electrical shielding function of the choke, maintaining ablation zone stability without requiring separate locking components or complex assembly procedures.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentEP4681671A1Microwave ablation probe choke

Publication Date: 2026.01.21 VARIAN MEDICAL SYSTEMS INC

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AI summary

A microwave ablation probe (200) includes an outer shell (302) defining an inner cavity axially extending to a probe tip (304), a cable (306) extending in the inner cavity and comprising an antenna (312), and a choke (308) coupled to the cable in the inner cavity. The choke (308) comprising an inner layer (404) mechanically locked to an outer casing (402).