Laser scanning fluorescence microscopy.

Fluorescence laser scanning microscopy (LSM) offers many advantages over conventional fluorescence microscopy. Very strong excitation light can be concentrated on small spots (0.5 microm) of the specimen, enabling the detection of low concentrations of fluorescent substances. The low levels of autofluorescence generated in the microscope objective and in the immersion oil in LSM provide images of great contrast, even with weakly fluorescent specimens. Confocal LSM permits the visualization of multiple focal layers of thespecimen and 3-D image reconstructions. Combination of images stored in computer memory allow the comparison of phase contrast and fluorescence images of the same area of the specimen enabling multiparameter analysis of cells.