<title>Characterization of human neoplastic and normal oral tissues by visible excitation and emission fluorescence spectroscopy</title>

Abstract

The steady state native fluorescence emission and excitation spectra of human normal and cancerous oral tissues are studied in the visible region. The fluorescence excitation spectrum is recorded for 600 nm emission by scanning the excitation. The excitation spectrum of normal tissues has peaks at 406, 524 and 552 nm, whereas the cancerous tissues have peaks at 406, 513 and 552 nm respectively. The fluorescence emission spectra were also recorded at 405 and 560 nm excitations. The emission spectrum of cancerous tissues has two distinct peaks at 604 and 660 nm. It is also observed that there is a distinct difference between normal and cancerous tissues at 560 nm excitation. The ratio parameter R1$ equals (I(subscript 406/I550) is introduced from the excitation spectrum for 600 nm emission and two ratio parameters R2 equals (I470/I600) and R3 equals (I470/I660) are introduced for the emission spectrum at 405 nm excitation. Among the three ratio parameters the R1 classifies the normal and cancerous tissues at a specificity and sensitivity of 83 percent and 93 percent respectively. A critical value of 1.8 is suggested for classifying the normal from cancerous tissues.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.