Richards-Kortum R, Mehta A, Hayes G, Cothren R, Kolubayev T, Kittrell C, Ratliff N B, Kramer J R, Feld M S
G.R. Harrison Spectroscopy Laboratory, Massachusetts Institute of Technology, Cambridge.
Am Heart J. 1989 Aug;118(2):381-91. doi: 10.1016/0002-8703(89)90199-3.
This communication demonstrates that fluorescence spectra of human aorta with good S/N ratios can be collected using an optical fiber laser catheter. The performance of this catheter is compared to a non-fiber optic collection system with an equivalent delivery/collection geometry. For a given sample, fluorescence lineshapes obtained using the two systems are identical; differences in peak fluorescence intensity are related to the different collection efficiencies of the two systems. It is shown that the fluorescence lineshape of arterial tissue depends on the delivery/collection geometry of the detection system, and that this is due to the interaction of absorption and fluorescence within the artery wall. This effect is investigated systematically using a specially designed collection system. Results are analyzed qualitatively using a simple, one-dimensional model of tissue fluorescence. With this analysis, we present design requirements for a collection system in which such geometric effects are eliminated, and show that our optical fiber laser catheter satisfies these requirements.
