Dielectric Loaded Coaxial Aperture for Directional Microwave Ablation
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Solution Overview
Problem
Existing electrosurgical devices face challenges in precisely directing microwave energy to target tissue volumes, often leading to unintended damage to healthy tissues due to non-directional radiation patterns, making it difficult to accurately ablate small or hard-to-reach tumors.
Innovation Solution
The development of an electrosurgical device featuring a coaxial feedline with a dielectric loaded coaxial aperture and a distally positioned resonant structure, which includes a balun structure and strategically positioned dielectric segments to create a directional radiation pattern, allowing for focused energy delivery to a target volume of tissue.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional monopole or dipole antenna assemblies are used, then microwave energy can be delivered to tissue, but the radiation pattern is non-directional causing damage to healthy tissues surrounding the target
Solution Approach 1:
The patent applies local quality by creating a directional radiation pattern through the use of a waveguiding structure with a specific aperture orientation. The aperture is positioned and oriented to direct microwave energy preferentially in one direction (toward the target tissue) while minimizing radiation in other directions (protecting healthy tissues). This localized control of energy distribution resolves the contradiction between delivering sufficient energy and protecting surrounding healthy tissues.
Solution Approach 2:
The patent employs asymmetry through the asymmetric positioning and orientation of the aperture in the waveguiding structure. Rather than a symmetric omnidirectional radiator, the aperture is configured to create an asymmetric radiation pattern with maximum intensity in the desired direction and reduced intensity in other directions. This asymmetric design enables selective targeting of tumor tissue while sparing adjacent healthy structures.
2Measurement precision
If ablation probes are inserted directly into tumors, then precise targeting is achieved, but small or hard-to-reach tumors cannot be effectively treated
Solution Approach 1:
The patent achieves universality by designing a waveguiding structure with an aperture that can be positioned at various distances from the tumor target. The directional radiation pattern allows the same device structure to effectively treat tumors of different sizes and locations without requiring direct insertion. The adjustable positioning capability along the waveguiding structure provides versatility for treating both small and large tumors, as well as tumors in difficult-to-reach locations.
Solution Approach 2:
The patent applies dimensionality change by transitioning from direct probe insertion (zero-dimensional point contact) to a directional radiation approach (one-dimensional beam propagation). The aperture in the waveguiding structure creates a directed energy beam that can reach tumors at a distance, adding the dimension of spatial reach while maintaining targeting precision through directional control.
3Device complexity
If non-directional ablation probes are used, then simple device construction is maintained, but healthy tissue on the non-tumor side of the probe is damaged
Solution Approach 1:
The patent resolves this contradiction by implementing local quality through the aperture configuration in the waveguiding structure. The aperture is specifically positioned and oriented to create a localized directional radiation pattern. This maintains relatively simple device construction while fundamentally changing the radiation characteristics from omnidirectional to directional, thereby protecting healthy tissue on the non-tumor side without requiring complex multi-element antenna arrays.
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 enables precise and controlled tissue ablation, reducing the risk of damaging healthy tissues by allowing clinicians to target tumors without penetrating them directly, thereby improving the accuracy and effectiveness of microwave ablation procedures.
Implementation Method 1
electromagnetic energy is passed through the probes into surrounding tissue. Microwave energy is sometimes utilized to perform these methods
Implementation Method 2
distally positioned resonant structure
Implementation Method 3
coaxial feedline having an inner conductor, an outer conductor coaxially disposed around the inner conductor, and a dielectric material disposed therebetween
Implementation Method 4
electromagnetic radiation can be used to heat and destroy tumor cells
Implementation Method 5
certain types of tumor cells have been found to denature at elevated temperatures that are slightly lower than temperatures normally injurious to healthy cells
Implementation Method 6
coaxial feedline having an inner conductor, an outer conductor coaxially disposed around the inner conductor, and a dielectric material disposed therebetween
Data Source
AI summary
An electrosurgical device for directing energy to a target volume of tissue includes a coaxial feedline having an inner conductor, an outer conductor and a dielectric material disposed therebetween. A proximal cylindrical dielectric sleeve is coupled to the inner conductor at a distal end of the coaxial feedline. A distal cylindrical dielectric sleeve is coupled to the inner conductor. First and second dielectric segments are coupled to the inner conductor and disposed between the proximal cylindrical dielectric sleeve and the distal cylindrical dielectric sleeve. The device also includes an elongated shaft overlying the proximal cylindrical dielectric sleeve, the first dielectric segment, the second dielectric segment and the distal cylindrical dielectric sleeve. The elongated shaft includes an opening defined therethrough, wherein the opening is at least partially aligned with the first dielectric segment. A balun structure is disposed on the elongated shaft, at least partially overlying the opening in the elongated shaft.