Mechanically Locked Microwave Probe Choke for Stable Ablation Zones

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Solution Overview

Problem

Existing microwave ablation probes experience relative movement or deformation between the inner insulating layer and outer conductive layer of the choke, affecting the size and shape of the ablation zone, which is undesirable for precise thermal treatments.

Innovation Solution

A choke design for microwave ablation probes that includes an outer conductive casing and an inner insulating layer, mechanically locked in place using lock openings, to prevent relative movement and ensure a known, repeatable ablation zone.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the choke elements are not mechanically locked, then the assembly is simpler and easier to manufacture, but relative movement or deformation occurs between the inner insulating layer and outer conductive layer, affecting ablation zone consistency

Engineering Contradiction:

Improveablation zone consistencyVSAvoidchoke structure complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The choke is divided into separate inner insulating layer and outer conductive layer components that can be manufactured independently and then assembled together with mechanical locking features, allowing for precise manufacturing of each component while maintaining overall structural integrity

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Mechanical locking features are pre-formed on the choke components during manufacturing, ensuring that when assembly occurs, the components are immediately secured in their correct positions, preventing any relative movement or deformation that would compromise ablation zone consistency

Inventive Principle:

Principle #10Preliminary action

2Volume of moving object

If the microwave ablation antenna is made smaller to minimize damage to surrounding tissues, then the probe size is reduced, but maintaining a repeatable and known ablation zone becomes more difficult

Engineering Contradiction:

Improveprobe sizeVSAvoidablation zone repeatability

Core Design Contradiction:

Volume of moving objectVSManufacturing precision

Solution Approach 1:

Instead of trying to control the ablation zone by adjusting antenna properties alone, the patent inverts the approach by using a mechanically locked choke structure to define and constrain the electromagnetic field boundaries, thereby ensuring repeatable ablation zones regardless of antenna size variations

Inventive Principle:

Principle #13The other way round (Inversion)

Data Source

PatentUS20260020905A1Microwave ablation probe choke

Publication Date: 2026.01.22 VARIAN MEDICAL SYSTEMS INC

AI summary

A microwave ablation probe includes an outer shell defining an inner cavity axially extending to a probe tip, a cable extending in the inner cavity and comprising an antenna, and a choke coupled to the cable in the inner cavity. The choke comprising an inner layer mechanically locked to an outer casing.