Microtomy is a method of tissue sample preparation that is often referred to as “sectioning” or "slicing.” Microtomy has been an essential component of microscopy for over a century. Ever since human curiosity peered through the microscope, methods and tools have been developed to slice anything of interest (animals, insects, plants, etc.) and place it on the stage for viewing. Cutting sections thin enough to view with a microscope was found nearly impossible to do by hand; therefore, machines that offered precision cuts were invented and have been fine-tuned over the decades. These instruments are referred to as microtomes. Currently, there are a wide variety of microtomes that are designed for specific materials or applications. Some of these include:
- Cryostat: Used to section unprocessed, frozen tissue sections, which aid in rapid diagnosis.
- Ultramicrotome: Used to section plastic-embedded tissue samples for electron microscopy in which the cellular organelles are highlighted.
- Vibrating microtome: Often used in research settings for delicate or difficult to cut samples, such as fresh brain tissue.
- Laser microtome: Used to cut very hard materials such as bones, teeth, or ceramics.
- Rotary microtome (manual, semi-automatic, automatic): Most frequently used in a histology laboratory for sectioning paraffin-processed tissue samples between 2 and 10 microns in thickness.
The focus of this course will be on the microtomy of paraffin-processed tissue samples using a rotary microtome.