Advantages of light-sheet microscopy compared to confocal microscopy. To illustrate the difference between laser scanning confocal microscopy and light-sheet microscopy, the processes of illumination and detection are split. In confocal microscopy, a tightly focused laser beam is scanned across the sample, thereby exposing the specimen to high-intensity illumination, not only in the plane of interest but also above and below. A pinhole rejects much of the excited fluorescence and confines the image to the plane of interest. In light-sheet microscopy, the sample is illuminated side-on by a thin sheet of light. As the entire fluorescence signal is collected and imaged onto a CCD camera, this method minimizes the photonic load and thus considerably limits phototoxicity.