Endoscope-tip interferometer for ultrahigh resolution frequency domain optical coherence tomography in mouse colon

Area of Science:

• Biomedical Optics
• Medical Imaging Technology
• Endoscopic Imaging

Background:

• Frequency domain optical coherence tomography (FD-OCT) offers advantages in system design and handling.
• Integrating the interferometer into the endoscope tip mitigates dispersion, polarization mismatch, and beamsplitter non-uniformity issues.
• Previous endoscopic OCT systems faced challenges with complex setups and signal quality.

Purpose of the Study:

• To develop and validate a compact, high-performance FD-OCT system for endoscopic applications.
• To demonstrate in vivo imaging capabilities within a small-diameter endoscope.
• To overcome limitations of existing endoscopic OCT technologies.

Main Methods:

• A common-path FD-OCT setup was designed with the interferometer housed within the endoscope tip.
• Two reference reflection strategies were explored: one using the glass envelope and a novel beamsplitter for improved efficiency.
• A compact mode-locked Ti:Al(2)O(3) laser and a CCD-based detector were utilized for data acquisition.
• High-speed (20,000 A-lines/s) and ultrahigh axial resolution (2.4 µm) imaging were achieved.

Main Results:

• Successful in vivo tomographic imaging of mouse colon was performed using a 2 mm outer diameter endoscope.
• The integrated FD-OCT system demonstrated high-speed data acquisition.
• Ultrahigh axial resolution was achieved, enabling detailed visualization of tissue microstructure.
• The novel beamsplitter design enhanced reference light collection efficiency.

Conclusions:

• Endoscopic FD-OCT with an integrated interferometer tip is feasible and offers significant advantages.
• The developed system provides high-speed, high-resolution imaging for in vivo endoscopic applications.
• This technology has potential for advanced diagnostics and research in gastroenterology and other fields.