Effect of tissue optics on wavelength optimization for quantum dot-based surface and subsurface fluorescence imaging

Area of Science:

• Biomedical Imaging
• Nanotechnology
• Optical Engineering

Background:

• Contrast-enhanced fluorescence imaging is crucial but underexplored regarding optimization.
• Minimizing contrast agent use (e.g., quantum dots - QDs) lowers cost and toxicity.
• Previous work established a quantitative approach for QD imaging optimization in liver tissue.

Purpose of the Study:

• To extend and validate a quantitative optimization approach for QD fluorescence imaging.
• To introduce and apply new performance metrics: threshold QD concentration and wavelength optimization gain.
• To assess spectral optimization across diverse tissues and QD emission wavelengths.

Main Methods:

• Experimental validation using eight different tissue types.
• Evaluation across five different QD emission wavelengths.
• Introduction and application of quantitative metrics for spectral optimization.

Main Results:

• Emission wavelength emerged as the most critical optimization parameter, improving performance up to 10,000-fold.
• Excitation wavelength and filter bandwidth offered significant, though lesser, improvements (up to 20-fold and 50%, respectively).
• Tissues with high autofluorescence and pigmentation benefit most from excitation wavelength optimization.

Conclusions:

• Spectral optimization significantly enhances QD fluorescence imaging efficiency and reduces required QD dosage.
• The developed metrics provide a quantitative framework for dosimetry in QD-based imaging.
• This research advances robust quantitative dosimetry for near-surface fluorescence imaging applications.