A Low-complexity Programmable Ultrasound Stimulation System: Design and Safety Evaluation

Area of Science:

• Neuroscience
• Biomedical Engineering
• Acoustic Engineering

Background:

• Existing transcranial focused ultrasound (tFUS) platforms lack comprehensive support for precise control, acoustic power monitoring, and flexible waveform generation, hindering safe and reproducible neuromodulation.
• Accurate control and monitoring are crucial for the clinical translation of tFUS therapies.

Purpose of the Study:

• To develop and validate a low-complexity, programmable tFUS stimulation system.
• To achieve flexible waveform generation, efficient transducer excitation, and accurate acoustic power monitoring.
• To assess the in vivo safety of the developed tFUS system.

Main Methods:

• Integrated a direct digital synthesis module, programmable DC-DC supply, full-bridge driver, and impedance matching network.
• Employed a nonuniform discrete Fourier transform method for acoustic power monitoring at the driving frequency.
• Evaluated in vivo safety in mice using acute and chronic stimulation protocols, analyzing behavioral and histological outcomes.

Main Results:

• Achieved highly linear pressure control up to 4.85 MPa with direct amplitude regulation.
• Impedance matching improved excitation voltage by 2.4x and reduced total harmonic distortion by 19.19 dB.
• Power monitoring demonstrated <5% error for outputs >3 W; no abnormalities were observed in preclinical safety studies across various stimulation intensities.

Conclusions:

• The developed tFUS system offers flexible waveform generation and efficient transducer excitation.
• The system provides accurate acoustic power monitoring and linear pressure control, crucial for neuromodulation.
• Preclinical safety evaluations confirm the system's feasibility and safety for neuromodulation applications, extending typical safety margins.