A method for non-destructive microwave focusing for deep brain and tissue stimulation

Area of Science:

• Biomedical Engineering
• Electromagnetics
• Medical Physics

Background:

• Non-invasive biological tissue stimulation is crucial for tumor treatment, endometrial ablation, and neuro-modulation.
• Traditional transcranial stimulation methods struggle with precise signal focusing.
• Microwave (MW) methods offer improved spatial focusing for minimally invasive treatments.

Purpose of the Study:

• To demonstrate a 3D array of MW antennas for tightly focusing signals within biological tissues.
• To develop an algorithm for optimizing MW signal delivery for targeted applications.
• To achieve sub-centimeter focusing at depths of several centimeters within the human body.

Main Methods:

• Utilized a 3D array of small MW loop antennas placed around the body.
• Employed numerical Green's functions (NGF) to model field penetration.
• Drove an optimization algorithm with NGF to determine optimal antenna amplitude and phase.

Main Results:

• Successfully focused MW fields at 1 GHz to sub-centimeter "hot spots".
• Demonstrated focusing at depths of several centimeters in simplified human body models.
• Validated the capability of precise MW energy delivery for localized biological effects.

Conclusions:

• A 3D MW antenna array can achieve highly localized energy deposition in biological tissues.
• The developed NGF-driven optimization algorithm enables precise control over MW field profiles.
• This method holds potential for advanced, non-invasive biomedical treatments and applications.