Multicolor fluorescence imaging system for tissue diagnostics

A multicolor fluorescence imaging system for tissue diagnostics has been constructed. Examples given to illustrate the system performance are atherosclerotic plaque lesions from human artery samples and a malignant rat brain tumor model. The system simultaneously monitors fluorescence images at four different wavelengths, enabling spatial as well as spectral information to be extracted. By selection of band pass filters an artificial image of the lesion under study can be formed, based on an optimal contrast function of four fluorescence intensities. The image is constructed in a computer and displayed in false colors on a monitor. Pulsed excitation light from an N2 laser provides the possibility of using a gated detector, and in this way suppresses room light to an undectable level. Images can thus be recorded under white light illumination during visual inspection, increasing the usefulness of the system.