  Laser illumination of tissue results in a characteristic fluorescence
emission spectrum whose features depend on the type of tissue, viz., healthy,
adenoma or malignant. Hence measurement of the fluorescence is potentially a
rapid and reliable diagnostic method. We have applied the technique to thyroid
tissues and found that judicious normalization of the fluorescence spectrum
reveals a close correlation between spectral shape and tissue type. Hence the
pathological state of the tissue can be unambiguously identified from the
laser-induced fluorescence spectrum. The method is rapid and portable and is
therefore eminently suitable for use during operations.
