Stereology (as per Wikipedia) was originally defined as `the spatial interpretation of sections'. It is an interdisciplinary field that is largely concerned with the three-dimensional interpretation of planar sections of materials or tissues. It provides practical techniques for extracting quantitative information about a three-dimensional material from measurements made on two-dimensional planar sections of the material. Stereology is an important and efficient tool in many applications of microscopy (such as petrography, materials science, and biosciences including histology, bone and neuroanatomy).

In addition to two-dimensional plane sections, stereology also applies to three-dimensional slabs (e.g. 3D microscope images), one-dimensional probes (e.g. needle biopsy), projected images, and other kinds of `sampling'. It is especially useful when the sample has a lower spatial dimension than the original material. Hence, stereology is often defined as the science of estimating higher dimensional information from lower dimensional samples.

Stereology is based on fundamental principles of geometry (e.g. Cavalieri's principle) and statistics (mainly survey sampling inference). It is a completely different approach from computed tomography.

The system we have at USF Health is called the disector.  Disector is a 3-D geometric probe for counting numbers of objects (cells) with a probability that is unaffected by the size, shape, or orientation of the objects. In combination with Gundersen's unbiased counting rules and unbiased counting frames to avoid edge effects, the disector principle by D.C. Sterio in 1984 was the first method to allow unbiased estimates of total numbers of cells in a known volume, without assumptions, models, or correction factors.

Practical applications of the disector principle include counting objects with two physical planes (physical disector), two optical planes (optical disector), and optical planes in conjunction with the fractionator sampling scheme (optical fractionator).