Angle-insensitive amorphous silicon optical filter for fluorescence contact imaging.

Area of Science:

• Materials Science
• Biomedical Optics
• Cancer Imaging

Background:

• Intraoperative fluorescence imaging requires effective blocking of excitation light.
• Microscopic cancer detection necessitates high-contrast imaging.
• Oblique excitation angles pose challenges for traditional optical filters.

Purpose of the Study:

• To develop and evaluate a novel amorphous silicon absorption filter for microscopic cancer tissue detection.
• To achieve high light rejection across various incident angles for wavelengths below 700 nm.
• To enable sensitive detection of fluorescently labeled cancer cells in intraoperative settings.

Main Methods:

• Fabrication of a 15 μm thick amorphous silicon absorption filter.
• Characterization of the filter's light rejection performance at different wavelengths and incident angles.
• Demonstration of the filter's utility in a small intraoperative contact fluorescence imaging system.
• Imaging of fluorescently labeled human epidermal growth factor receptor 2+ breast cancer tissue.

Main Results:

• The filter exhibits high rejection (>5 orders of magnitude) at 633 nm for all angles of incident light.
• The filter is compatible with clinically relevant fluorophores such as IR700DX.
• Microscopic clusters of breast cancer cells were reliably detected with a 75 ms integration time.

Conclusions:

• The novel amorphous silicon filter provides excellent optical performance for intraoperative fluorescence imaging.
• This filter technology facilitates sensitive and rapid detection of microscopic cancer.
• The developed system shows promise for improving surgical guidance in breast cancer treatment.