Confocal microscopy is a fluorescence-imaging technique that produces exquisitely sharp optical sections through biological specimens by exciting a laser over the sample and collecting emission data, point by point, to reconstruct the final image. Confocal microscopy is used in clinical and research laboratories and is especially useful in studying live cells. The three types of confocal microscopes are laser scanning microscopes, which use a sharply focused laser that scans over the sample, spinning disk microscopes, which use a disk with pinholes cut into it that are arranged in the shape of a spiral, and programmable array microscopes which use an electronically controlled spatial light modulator that produces a set of moving pinholes. Choice will depend on application- laser scanning scopes have high resolution and slow imaging frame rates, and spinning discs have high frame rates which is advantageous in live cell imaging. When selecting a system, consider the ease of training users, the ability to adapt the system to future needs, and the expense to maintain and repair the system.