Thermal Accelerant for Microwave Ablation Zone Extension
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Solution Overview
Problem
Microwave hyperthermal ablation techniques face challenges with incomplete or irregular ablation due to limited effective range, tissue-dependent temperature variations, and heat sink effects, leading to high tumor recurrence rates.
Innovation Solution
The use of a thermal accelerant with a high dipole moment, such as cesium chloride, combined with a reverse phase transition polymer, which is injected near the target site and activated by microwave energy to enhance heating and extend the ablation zone, while also acting as a contrast agent for image-guided verification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If microwave ablation is used to treat tumors, then the treatment is minimally invasive and cost-effective, but the ablation zone is limited to only 2-4 cm from the antenna resulting in incomplete ablation
Solution Approach 1:
The patent introduces a thermal accelerant (chaotrope) as an intermediary substance that is injected into the tumor tissue to enhance microwave energy absorption. The thermal accelerant acts as a mediator between the microwave antenna and the tumor tissue, enabling extended and more uniform heating beyond the limited 2-4 cm range of conventional microwave ablation, thereby achieving complete ablation of larger tumors while maintaining the minimally invasive approach
2Power
If microwave energy is applied to heat tissue, then tumor cells are destroyed, but heat sink effects from blood vessels limit temperature rise in portions of the targeted region
Solution Approach 1:
The thermal accelerant serves as an intermediary that concentrates microwave energy directly in the tumor tissue, creating a more localized and intense heating effect that overcomes the heat sink effect of blood vessels. By enhancing the dielectric properties of the tumor tissue itself rather than relying on conventional heat conduction, the system achieves more uniform temperature distribution throughout the ablation zone
3Area of stationary object
If the ablation zone is extended to cover larger tumors, then complete ablation is achieved, but the effective range of microwave energy drops off rapidly beyond a few centimeters
Solution Approach 1:
The patent fundamentally changes the physical parameters of the target tissue by introducing a thermal accelerant with enhanced dielectric properties. This parameter change enables the tissue to absorb microwave energy more efficiently at greater distances from the antenna, counteracting the rapid energy attenuation that normally limits the ablation zone to only 2-4 cm. The thermal accelerant modifies the electrical conductivity and permittivity of the tissue, allowing for extended effective treatment range
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 approach significantly increases the temperature in the ablation zone, achieving more complete and uniform ablation, reducing tumor recurrence by extending the effective range of microwave energy and mitigating heat sink effects.
Implementation Method 1
The thermal accelerant may include material having a high dipole moment that is configured to convert radiofrequency to thermal energy
Implementation Method 2
acting as a contrast agent for image-guided verification
Data Source
AI summary
A thermal accelerant is delivered to a tissue site and localized to modulate the shape, extent or other characteristic of RF or microwave-induced hyperthermic tissue ablation. The accelerant may be provided via an image-guided hand piece or via a lumen added to a microwave antenna, and promotes faster heating, more complete ablation and/or a more extensive treatment region to reduce recurrence of treated cancers, overcoming natural limitations, variations in tissue response and drop-off or thermal loss away from the antenna. The accelerant is delivered as a viscous but heat sensitive fluid, and is fixed in place to provide regions of preferential absorption or heating. Shorter exposure times to heat the far field may allow survival of vulnerable tissue such as vessels, and multiple antennae may be used for effective treatment of irregular or large tumors.