Microwave Ablation Electrode Cooling for Stable Lesion Shaping
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Solution Overview
Problem
Conventional microwave ablation electrodes face issues with overheating at the working end, leading to adhesive melting, ceramic needle body detachment, irregular ablation shapes, and reduced efficacy due to tissue carbonization, which poses medical risks and affects treatment effectiveness.
Innovation Solution
A microwave ablation electrode with a non-working end circulation cooling structure and a working end liquid injection structure to cool and inject refrigerant medium, reducing working end temperature, enhancing tissue wettability, and enabling dual ablation through steam thermal and microwave ablation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If microwave energy is continuously input to achieve ablation, then ablation effect is improved, but working end temperature rises causing adhesive melting and ceramic needle body detachment
Solution Approach 1:
The electrode is divided into multiple functional segments: a working end needle body for microwave transmission, an outer needle tube for structural support, and a circulation cooling structure for temperature control. This segmentation allows each component to perform its specific function independently while working together to solve the temperature problem.
Solution Approach 2:
A refrigerant medium is introduced as an intermediary substance to transfer heat away from the working end. The circulation cooling structure enables the refrigerant to flow through channels in the outer needle tube, absorbing excess heat and preventing adhesive melting and ceramic detachment while allowing continuous microwave input.
2Productivity
If high temperature is generated at the working end to achieve ablation, then ablation efficiency is improved, but tissue carbonization occurs leading to irregular ablation shapes
Solution Approach 1:
The cooling system is designed with spatially differentiated characteristics: the circulation cooling structure provides localized cooling at the working end through refrigerant flow in the outer needle tube, while the inner needle tube maintains microwave transmission. This local quality differentiation allows high temperature ablation at the tip while preventing excessive carbonization of surrounding tissues.
Solution Approach 2:
The refrigerant medium undergoes phase transition (evaporation) within the circulation cooling structure, absorbing latent heat from the working end and surrounding tissues. This phase transition mechanism efficiently controls temperature, preventing tissue carbonization while maintaining adequate ablation temperature at the working end tip.
3Strength
If the working end is cooled to prevent adhesive melting, then bonding strength is maintained, but microwave energy transmission is hindered
Solution Approach 1:
The electrode structure is segmented into thermally isolated zones: the outer needle tube contains the circulation cooling structure for heat dissipation, while the inner needle tube and working end needle body maintain temperatures suitable for microwave transmission. This segmentation allows simultaneous cooling of external components while preserving thermal conditions for energy transmission at the working end.
Solution Approach 2:
The refrigerant medium serves as a thermal intermediary that selectively removes heat from the outer needle tube and surrounding tissues without directly contacting the working end needle body. The circulation cooling structure acts as a thermal barrier, preventing heat transfer to the working end while maintaining adhesive bonding strength.
4Temperature
If conventional cooling structure is used to cool the coaxial semi-rigid wire, then wire temperature is reduced, but the working end and surrounding tissues remain uncooled
Solution Approach 1:
The circulation cooling structure is designed with multi-functionality: it cools the coaxial semi-rigid wire, the outer needle tube, and the surrounding tissues simultaneously through refrigerant flow in the outer needle tube. The working end liquid injection structure additionally cools the working end needle body and adjacent tissues, providing comprehensive cooling coverage throughout the entire electrode system.
Solution Approach 2:
The cooling approach transitions from a single-point cooling of the coaxial wire to a distributed three-dimensional cooling system. The circulation cooling structure creates cooling channels throughout the outer needle tube, while the working end liquid injection structure adds point-source cooling at the working end, achieving volumetric temperature control throughout the electrode and surrounding tissues.
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 electrode achieves reduced working end temperature, prevents adhesive melting, expands ablation range, and ensures regular ablation shapes by combining microwave and steam thermal ablation, improving treatment efficiency and safety.
Implementation Method 1
Microwave ablation is mainly used for the treatment of nodules, tumors in tissues and organs and other diseases of the human body, mainly relying on the friction and collision of polar molecules (water molecules) in a microwave field to generate heat
Implementation Method 2
Microwave radiates energy to a surrounding space after being emitted from a microwave generator
Implementation Method 3
the refrigerant medium can reach the working end of the main needle body to cool the working end of the main needle body and the surrounding tissues
Implementation Method 4
a refrigerant medium to reach a front end of a non-working end of the main needle body to cool the non-working end of the main needle body and the surrounding tissues
Implementation Method 5
the refrigerant medium can be injected into the lesion tissues and absorb microwave energy to form steam, so that steam thermal ablation is realized
Implementation Method 6
dual ablation of steam thermal ablation and microwave ablation is realized
Data Source
AI summary
A microwave ablation electrode is provided. The microwave ablation electrode mainly comprises a main needle body. A working end of the main needle body can release microwave energy to realize microwave ablation. A non-working end circulation cooling structure and a working end liquid injection structure are arranged on the main needle body, wherein the non-working end circulation cooling structure can allow a refrigerant medium to reach a front end of a non-working end of the main needle body to cool the non-working end of the main needle body and the surrounding tissues, and the non-working end circulation cooling structure can allow the refrigerant medium to flow back. The working end liquid injection structure can allow the refrigerant medium to reach the working end of the main needle body to cool the working end and the surrounding tissues.