Physical and optical disectors

In morphometric studies, two-dimensional histological sections are evaluated using designbased stereological methods in order to obtain three-dimensional structural information about the tissue. The stereology is a combination of geometric measurements and statistical sampling principles. The basis of stereological applications is the idea that the samples selected for analysis represent the whole structure. One of the most critical parameters in any organ or tissue is "number." Numerical data in biological structures can be obtained using the "disector" method. This provides data concerning the numerical density of particles in three-dimensional structures and yields information about the structural and functional connections of the biological tissue in question. The disector method is applied in two ways: physical disector and optical disector. The physical disector method involves the examination of two consecutive sections, while consecutive thick sections are used in the optical disector method. Both methods employ an unbiased counting frame to ensure that each particle is counted only once. This chapter provides definitions of the physical disector and optical disector methods and discusses their application to light and electron microscopic images in detail.