Three-dimensional (3-D) light microscopy has been rapidly expanding for several years, both with respect to instrumentation, and biological applications. This new technology has transformed light microscopy from two-dimensional imaging of 3-D objects to a fully 3-D science. To date, qualitative analysis, reconstruction, and visualization has received far more attention compared to quantitative analysis. The motivations for 3-D image analysis are manifold, and include more accurate morphometry, separation of overlapping objects, and analysis of non-planar regions of interest and of thick specimens without the artifacts arising from physical sectioning. Furthermore, automating this analysis makes it fast, inexpensive, objective, and precise, and the results can be validated by manually confirming the analysis for any selected subset of 3-D images.
Increasingly, quantitative 3-D image analysis is emerging as an attractive technology for many applications. Studies include the testing of human-use products (shampoos, laxatives etc.), drug development, aging and development, cell loss/proliferation, fetal alcohol syndrome, and analysis of medical samples such as Pap smears, breast biopsies and a variety of cancers.