An optimization procedure for the alignment of marker points to assess dimensional changes.

The process of dehydration and drying associated with the preparation of tissue specimens for examination by the scanning electron microscope usually results in dimensional changes in the form of shrinkage. A new method has been devised which requires specification of the location of marker points which have been affixed in a random pattern to the surface of the specimen. A new computer programme has been developed which acquires the coordinate pairs of the marker points, optimizes the alignment between the location of the marker points for the wet (fresh or fixed) and processed (dehydration with an intermediate fluid, and/or drying) conditions of the specimen, and computes the proportional dimensional changes in two mutually-perpendicular directions, as well as along the direct path between the origin and each of the marker points. Techniques for using the programme to assess whether the shrinkage may be planar-orthotropic or planar-anisotropic are suggested.