Ultrathin side-viewing needle probe for optical coherence tomography.

Area of Science:

• Biomedical Engineering
• Optical Imaging
• Medical Devices

Background:

• Optical Coherence Tomography (OCT) is a valuable imaging modality for visualizing subsurface tissue microstructures.
• Existing OCT probes often lack the miniaturization required for minimally invasive in vivo applications.
• Developing smaller probes is crucial for advancing endoscopic and interstitial imaging techniques.

Purpose of the Study:

• To design, fabricate, and characterize the smallest reported side-viewing needle probe for OCT.
• To evaluate the performance of the miniaturized probe in biological tissues.
• To demonstrate the feasibility of using the probe for high-resolution 3D imaging.

Main Methods:

• A 30-gauge (0.31 mm outer diameter) all-fiber needle probe was designed and fabricated.
• An angle-polished and reflection-coated fiber tip served as the beam deflector.
• The probe was characterized optically and interfaced with an 840 nm spectral-domain OCT system.
• Biological tissue imaging was performed, including 3D OCT of lamb lungs.

Main Results:

• The needle probe achieved extreme miniaturization.
• In biological tissue, the probe exhibited a working distance of 300 μm and a depth-of-field of 550 μm.
• The OCT system with the needle probe showed a sensitivity loss of only 7 dB compared to a standard configuration.
• High-resolution 3D OCT images of lamb lungs revealed individual alveoli and bronchioles.

Conclusions:

• The developed side-viewing needle probe is the smallest reported for OCT.
• The probe enables high-resolution, minimally invasive 3D imaging of biological tissues.
• This technology holds potential for advanced diagnostic and interventional procedures.