Electronically Tunable Transformer for RF Tissue Ablation
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Solution Overview
Problem
Current microwave tissue ablation systems face inefficiencies due to impedance mismatches between the RF power supply and the tissue being treated, as the dielectric properties of tissues like heart and liver tissue vary, leading to suboptimal energy delivery.
Innovation Solution
An electronically tunable transformer is integrated between the RF generator and the transmission line, connected with a directional coupler and detection device to adjust impedance in real-time based on reflected signals, minimizing return losses and maximizing energy transfer to the tissue.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a fixed impedance RF power supply is used, then the system structure is simple, but the energy delivery to tissue is suboptimal due to impedance mismatch
Solution Approach 1:
The patent applies dynamics by transforming the fixed impedance system into a dynamic, adjustable impedance system. An electronically tunable transformer is introduced that can modify its impedance characteristics in real-time based on tissue conditions, allowing the system to adapt to varying tissue dielectric properties during ablation procedures.
Solution Approach 2:
The patent implements parameter changes by enabling the RF power supply impedance to vary dynamically. The electronically tunable transformer adjusts impedance parameters based on detected tissue characteristics, optimizing energy transfer efficiency across different tissue types and treatment stages.
2Device complexity
If impedance matching is not implemented, then the device complexity is low, but reflected power increases reducing treatment effectiveness
Solution Approach 1:
The patent implements feedback by using a directional coupler to sample reflected power from the tissue and feeding this information back to the control system. This feedback loop enables the electronically tunable transformer to adjust impedance settings dynamically, minimizing reflected power and maximizing energy delivery to the target tissue.
Solution Approach 2:
The patent introduces an electronically tunable transformer as an intermediary component between the RF power supply and the tissue. This mediator device facilitates optimal energy transfer by adapting impedance levels, reducing reflections, and protecting the RF generator from excessive reflected power while ensuring efficient energy delivery to the tissue.
3Productivity
If dielectric properties of tissue are considered, then energy delivery can be optimized, but the system cannot adapt to variations in tissue load
Solution Approach 1:
The patent applies dynamics by enabling real-time adaptation to tissue variations. The system continuously monitors reflected power and adjusts impedance settings dynamically, allowing it to respond to changing tissue dielectric properties, tissue type variations, and treatment progression throughout the ablation procedure.
Solution Approach 2:
The patent implements parameter changes by allowing the system to modify impedance parameters in response to detected tissue characteristics. This enables optimization of energy delivery across different tissue types (e.g., heart tissue, liver tissue) and throughout the ablation process as tissue properties evolve.
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
This solution allows for dynamic impedance matching, reducing reflected power and increasing energy delivery to the tissue, thereby enhancing the effectiveness of the microwave ablation system across varying tissue types and properties.
Implementation Method 1
a RF generator adapted for communicating radio frequency energy to a waveguide or probe
Implementation Method 2
The dielectric constants of different types of tissue, for example heart tissue and liver tissue, are different. Also, the dielectric properties of the tissue change as the tissue is treated.
Implementation Method 3
a bi-directional coupler samples the forward pulses supplied to the microwave transmission line or co-axial cable and the reflected pulses which are reflected from the target ablation tissue
Data Source
AI summary
An ablation system which transmits radio frequency (RF) energy for the ablation of biological tissues has a transmission line and an RF antenna disposed at the distal portion of the transmission line. An RF signal generator supplies RF energy to the proximal end of the cable for transmission to the antenna, and an electrically tunable transformer is connected between the signal generator and the antenna. The transformer is tuned based on detection of the reflected power level from the antenna so as to reduce or minimize reflected power, thereby increasing RF energy coupling between the antenna and tissue.