Light efficiency vs. image acquisition time: considerations for parallel confocal microscopy applied to biological tissue observation

The concept of parallel confocal microscopy with aperture de-correlation ha s been developed in order to reduce acquisition time and to increase light efficiency over conventional scanning confocal microscopy. It consists in s imultaneously observing numerous confocal volumes of a specimen, in lieu of scanning one confocal spot over the region of interest. The cross-talk bet ween neighbouring parallel confocal systems is eliminated by capturing imag es using a sequence of linearly independent illumination and detection patt erns which permit to de-correlate the confocal from the non-confocal image. In this paper, we compare the relative efficiency of parallel and conventi onal confocal microscopy, using a simple analytical approach, and show that this depends strongly upon the illumination configuration. In particular i t is shown that despite its drawbacks in other applications, conventional c onfocal microscopy still is more efficient than parallel confocal microscop y when the dose, i.e. the total energy onto the sample, must be limited. Th is may represent a limitation to the advent of parallel confocal microscopy for the imaging of photo-sensitive tissues. (C) 2001 Elsevier Science B.V. All rights reserved.