Integrated HIFU Drive System on a Chip for CMUT-Based Catheter Ablation System

Area of Science:

• Biomedical Engineering
• Ultrasound Technology
• Medical Devices

Background:

• Conventional High Intensity Focused Ultrasound (HIFU) is typically administered extracorporeally.
• Intravascular HIFU probes offer a solution for targeted ablation in specific applications.
• Miniaturization of HIFU systems is crucial for minimally invasive procedures.

Purpose of the Study:

• To design and implement a fully integrated HIFU drive system on a chip for a 6 Fr catheter probe.
• To develop a compact and efficient driver system for intravascular ultrasound ablation.
• To evaluate the performance of the integrated HIFU system for targeted thermal therapy.

Main Methods:

• Fabrication of an 8-element capacitive micromachined ultrasound transducer (CMUT) ring array (2 mm diameter) using 0.35 μm high-voltage CMOS technology.
• Integration of eight continuous-wave (CW) high-voltage CMUT drivers, an eight-channel digital beamformer, and a phase-locked loop with an integrated VCO.
• Testing the system with the CMUT array driven by 20 Vpp CW pulses at 10 MHz in sunflower oil, monitoring focal temperature rise.

Main Results:

• The integrated chip, measuring 1.85 × 1.8 mm², successfully drove the CMUT array.
• Real-time thermal imaging showed a focal temperature rise of 16.8°C in 11 seconds.
• Finite Element Method (FEM) analysis predicted catheter surface temperature to remain below the 42°C tissue damage limit.

Conclusions:

• The developed integrated HIFU drive system on a chip is suitable for intravascular catheter probes.
• The system demonstrates effective and controlled thermal ablation capabilities for targeted therapy.
• This miniaturized HIFU system holds promise for advanced minimally invasive medical treatments.