Microwave Ablation Antenna Impedance Matching
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Solution Overview
Problem
Current electrosurgical instruments for tissue ablation in the pancreas are invasive and lack the necessary precision and efficiency for effective microwave energy delivery, particularly in accessing and treating tumors with minimal invasiveness.
Innovation Solution
An electrosurgical instrument with a microwave ablation antenna designed for insertion through a surgical scoping device, featuring a half-wavelength transformer configuration and dielectrically or magnetically loaded radiating tip, which minimizes reflections and impedance mismatch, allowing for precise and efficient energy delivery to biological tissue.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional RF ablation wire is used, then the procedure can be performed with simple equipment, but the treatment time is long (90-120 seconds) and requires removal and repositioning of the wire
Solution Approach 1:
The patent replaces the conventional RF mechanical ablation system with a microwave electromagnetic field-based system. The microwave antenna delivers energy through electromagnetic radiation rather than thermal conduction, enabling faster ablation (reducing treatment time from 90-120 seconds to significantly shorter durations) while maintaining procedural effectiveness through a more complex but highly efficient microwave generation and delivery system.
2Productivity
If a microwave antenna is introduced for rapid ablation, then treatment speed improves, but the instrument structure becomes more complex requiring precise impedance matching and transmission line design
Solution Approach 1:
The patent employs precise control of electromagnetic parameters including impedance matching (designing the antenna and transmission line with specific impedance values), frequency selection (operating at standard microwave frequencies like 2.45 GHz), and power level regulation. These parameter optimizations enable rapid ablation while managing the inherent complexity through engineered precision rather than structural simplification.
Solution Approach 2:
The patent introduces an intermediate transmission line system with impedance matching sections between the microwave generator and the ablation antenna. This intermediary structure facilitates efficient energy transfer by minimizing reflections and impedance mismatches, enabling fast ablation speeds while the complex matching network manages the overall system complexity.
3Measurement precision
If the antenna is made rigid for stability, then positioning accuracy improves, but the ability to navigate through flexible endoscope channels is reduced
Solution Approach 1:
The patent divides the antenna structure into multiple segments or sections, allowing the distal portion to be relatively rigid for stable positioning and accurate energy delivery, while proximal sections can be more flexible to navigate endoscope channels. This segmented approach enables the antenna to maintain positioning accuracy at the target site while adapting to the flexible navigation requirements of endoscopic delivery systems.
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
Enables rapid and accurate ablation of tumors in the pancreas with minimal invasiveness, reducing healing time and minimizing the risk of collateral damage, while providing a curative and palliative treatment option.
Implementation Method 1
The probe is configured to be insertable through a channel of a surgical scoping device or catheter that can be introduced to a treatment site in a non-invasive manner. The probe may be arranged to ablate tissue, such as a tumour, cyst or other lesion.
Implementation Method 2
By enabling tumours within the pancreas to be ablated using a minimally invasive procedure can make viable the option of ablation treatment for both curative as well as palliative reasons.
Data Source
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AI summary
An electrosurgical instrument having a microwave ablation antenna dimensioned to be suitable for insertion into a pancreas via a surgical scoping device, to provide a rapid and accurate alternative to known RF ablation techniques. The instrument comprises a radiating tip portion connected at a distal end of a flexible coaxial cable that conveys microwave energy. The radiating tip portion comprises a proximal coaxial transmission line for conveying the microwave energy and a distal needle tip mounted at a distal end of the coaxial transmission line, wherein the distal needle tip operates as a half wavelength transformer. The length of the radiating tip portion may be in the range from 5 mm to 80 mm.