2-photon endoscopic fluorescence probe for advanced medical imaging

Background/problem

Existing approaches to tissue imaging, particularly for early cancer detection, face several significant challenges. Techniques such as MRI and PET provide functional information but lack the cellular-level resolution needed for early diagnosis and involve contrast agents and radiation exposure. Two-photon (2P) fluorescence imaging has gained significant traction in medical applications due to its ability to provide high-resolution images of living tissues at greater depths compared to traditional imaging techniques. It leverages the absorption of two photons to excite a fluorophore, resulting in the emission of a single photon. This process confines the excitation to a small volume, enhancing spatial resolution and allowing for deeper tissue penetration.

However, current 2P technologies are far from being effective and optimal. Traditional collection devices, such as double-clad fibers and photonic bandgap fibers have low efficiency of signal collection, especially in high-scattering tissues. Also, conventional methods using optical elements to couple collected signals to fibers can introduce alignment and manufacturing complexities. Therefore, there is a pressing need for innovative imaging solutions that enhance signal collection efficiency, provide high-resolution metabolic information, and are practical for in vivo clinical applications.

Tech overview/solution

A 2-photon endoscopic fluorescence imaging probe utilizes a photonic bandgap fiber to deliver excitation pulses and multiple, angled collection fibers to gather scattered fluorescence signals. The probe features a motorized axial scanning mechanism for adjustable imaging depths (0 to 300µm) with the laser pulses focused onto the tissue via a distal tip. It enhances signal collection efficiency via slanted-cut fibers arranged around excitation optics, facilitating high-resolution, minimally invasive tissue imaging in medical applications.

Benefits/competitive advantage

Enhanced signal collection: The technology surpasses conventional single fiber approaches by using multiple, bent, slanted-cut collection fibers, significantly expanding the total collection area and efficiency.
Depth flexibility: It offers adjustable imaging depths up to 300 μm into tissue using a motor-actuated axial scanning mechanism, providing a level of flexibility and precision not found in traditional endoscopic devices.
Minimally invasive, innovative deep imaging: The compact probe design allows for deep tissue imaging in hard-to-reach areas with minimal invasion.

These features collectively contribute to the technology’s high overall transmission efficiency of 61%, improved performance in high scattering media, and potential for early cancer detection with high sensitivity and specificity. Eliminating the need for supplementary optic elements simplifies the design and reduces manufacturing challenges, making it a promising tool for endoscopic applications and other medical diagnostics.