Quantitative tumor depth determination using dual wavelength excitation fluorescence

Area of Science:

• Medical imaging
• Biophotonics
• Surgical oncology

Background:

• Accurate quantification of solid tumor margins is crucial for effective surgical resection.
• Near-infrared (NIR) fluorescence imaging offers deep tissue penetration but poses challenges in precise depth localization of fluorophores.
• Existing methods struggle to reliably delineate tumor boundaries in three dimensions.

Purpose of the Study:

• To develop and validate a novel near-infrared dual wavelength excitation fluorescence (DWEF) approach for quantifying fluorophore depth in tissues.
• To assess the accuracy of the DWEF system in determining tumor margins using a tumor-targeting fluorophore.
• To evaluate the system's performance in various experimental models, including phantoms, ex vivo tissues, and in vivo cancer models.

Main Methods:

• Development of a portable dual wavelength excitation fluorescence imaging system.
• Utilizing the wavelength-dependent attenuation of light in biological tissues to infer fluorophore depth.
• Testing the system with an NIR tumor-targeting fluorophore in tissue-mimicking phantoms, chicken tissue, and orthotopic breast cancer mouse models.

Main Results:

• The DWEF system demonstrated high accuracy in quantifying fluorophore depth across all tested models.
• The system successfully differentiated between superficial and deep fluorophore distributions.
• Experimental results validated the principle of using differential light attenuation for depth determination.

Conclusions:

• The developed NIR DWEF approach enables accurate quantification of fluorophore depth, addressing a key challenge in fluorescence-guided surgery.
• This technique enhances the visualization of tumor margins, potentially leading to more complete tumor resections.
• The system's low cost, portability, and simplicity make it suitable for widespread clinical adoption in surgical oncology.