High-resolution handheld rigid endomicroscope based on full-field optical coherence tomography.

Area of Science:

• Biomedical Optics
• Medical Imaging
• Optical Engineering

Background:

• Full-field optical coherence tomography (FF-OCT) enables non-destructive, in-depth, cellular-resolution structural examination of biological tissues.
• While FF-OCT shows promise for in situ cancer diagnosis and biopsy guidance, endoscopic applications have remained confined to laboratory settings.

Purpose of the Study:

• To develop and demonstrate the first handheld full-field optical coherence tomography (FF-OCT) endoscope for advanced biological tissue imaging.
• To overcome the limitations of previous lab-based endoscopic FF-OCT systems.

Main Methods:

• A novel tandem interferometry assembly with incoherent illumination was employed.
• A common-path passive imaging interferometer at the probe tip ensures robustness against environmental perturbations.
• A compact system was achieved using a low finesse Fabry-Perot processing interferometer.

Main Results:

• The handheld FF-OCT endoscope achieved a resolution of 2.7 μm transversely and 6 μm axially.
• A good signal-to-noise ratio was maintained within a 100 ms acquisition time.
• High-resolution images and video of a rat brain slice were successfully recorded ex vivo, enabling microscopic exploration up to 20 μm deep.

Conclusions:

• The developed handheld FF-OCT endoscope represents a significant advancement in endoscopic imaging technology.
• These findings open new avenues for in vivo imaging, particularly for cancer and surgical margin assessment.