Two-axis magnetically-driven MEMS scanning catheter for endoscopic high-speed optical coherence tomography

Area of Science:

• Biomedical Engineering
• Optical Imaging
• Microtechnology

Background:

• 3D endoscopic imaging requires precise and miniaturized scanning mechanisms.
• Spectral Domain Optical Coherence Tomography (SD-OCT) offers high-resolution cross-sectional imaging.
• Existing endoscopic OCT catheters face limitations in maneuverability and imaging speed.

Purpose of the Study:

• To develop and characterize a compact two-axis scanning catheter for 3D endoscopic SD-OCT.
• To integrate microelectromechanical systems (MEMS) for precise mirror control.
• To demonstrate in vivo 3D imaging capabilities in biological tissues.

Main Methods:

• A two-axis scanning catheter was designed using MEMS micro-mirror technology actuated by magnetic fields.
• The catheter features a 2.8 mm outer diameter and a scanning range of +/- 20 degrees.
• The system integrated a multi-functional SD-OCT for simultaneous intensity and polarization-sensitive imaging at 18.5K axial scans/s.

Main Results:

• The MEMS-based scanner achieved static and resonant frequency operation (>= 350Hz) for the fast axis.
• The catheter demonstrated a scannable length of approximately 1 mm with low operating voltages (1-3V).
• Successful in vivo 3D SD-OCT imaging of human fingertips and oral cavity tissue was achieved.

Conclusions:

• The developed two-axis scanning catheter is a viable tool for high-resolution 3D endoscopic imaging.
• MEMS technology enables miniaturization and precise control for advanced OCT applications.
• This technology holds potential for minimally invasive diagnostics and surgical guidance.