Endoscopic en-face optical coherence tomography and fluorescence imaging using correlation-based probe tracking.

Area of Science:

• Biomedical Optics
• Medical Imaging
• Optical Coherence Tomography

Background:

• Forward-viewing endoscopic optical coherence tomography (OCT) enables 3D *in vivo* imaging and can be combined with fluorescence imaging.
• Developing high-performance, miniaturized 2D scanning systems for OCT with a large field-of-view presents significant technical challenges.

Purpose of the Study:

• To demonstrate a method for transforming a 1D scanning OCT probe into a 2D scanning probe for volumetric imaging.
• To enable real-time 3D *en-face* OCT and fluorescence imaging by correcting for probe motion during manual scanning.

Main Methods:

• A 1D scanning probe generating cross-sectional OCT (B-scans) and 1D fluorescence T-scans is manually scanned along a second axis to create 2D scans.
• OCT volumes are reconstructed from B-scans using speckle decorrelation for out-of-plane motion estimation.
• Image registration via normalized cross-correlation corrects in-plane motion within B-scans.

Main Results:

• The system successfully generates 3D OCT volumes and fluorescence images from a manually scanned 1D probe.
• Real-time display of motion-corrected *en-face* OCT slices and fluorescence images is achieved during scanning.
• The method effectively handles out-of-plane motion up to 4 mm/s with a B-scan frame rate of 250 Hz.

Conclusions:

• Manual scanning of a 1D OCT probe provides a viable alternative to complex 2D scanning systems for 3D *in vivo* imaging.
• This approach simplifies the hardware requirements for endoscopic OCT while enabling real-time 3D visualization.
• The developed technique offers a practical solution for enhanced endoscopic imaging in biomedical applications.