Fluorescence spectroscopy of normal and atheromatous human aorta. Optimum illumination wavelength

The purpose of this investigation was to determine which illumination wavelength produces the largest differences between the fluorescence emission spectra of normal and atheromatous vascular tissue. The fluorescence spectra for twelve excitation wavelengths ranging between 270 nm and 470 nm were examined and compared. The Hotelling trace, a figure of merit describing class separability, was used to compare the excitation wavelengths. Preliminary results indicate that illumination in the range from 314 nm to 334 nm consistently performed well. Wavelengths in the 364 nm to 436 nm range also showed promising performance for a limited data set. These results were found to be relatively independent of the catheter angle and distance to the tissue.