Table 1.

Fluorescence lifetime values for normal versus tumor epithelium

	τ1 (ps)		τ2 (ps)		a1
	Normal	Tumor	Normal	Tumor	Normal	Tumor
890 nm excitation (average shift) [n = 13]	400 (68) *	468	2269 (194) *	2464	50 (1)	51
780 nm excitation (average shift) [n = 10]	456 (90) *	546	2360 (178)	2538	47 (2)	49

Measured using two different excitation wavelengths, 890 nm and 780 nm, the two component fit of the lifetime decay showed that there is always a longer lifetime value in tumor epithelium versus normal. This was true whether or not the fluorophore, NADH or FAD, was in the free or bound state, since both τ₁ and τ₂ components were longer in duration and there was no change in the fractional contribution (a₁) from each decay component. The values in parentheses denote the average difference between normal and tumor measurements. The asterisk denotes that the tumor value is significant compared to the normal value, P < 0.05 for a Students t-test