Electron microscopes do not use radiation in the traditional sense, like X-rays or gamma rays. Instead, they use a beam of electrons to illuminate the specimen.

Here's why:

* Electrons have a much shorter wavelength than light. This allows for much higher resolution, enabling us to see objects at the nanoscale level.

* Electrons interact strongly with matter. This interaction allows for the creation of images based on the scattering or absorption of electrons by the specimen.

Therefore, while electron microscopes do utilize a beam of charged particles, it's not considered "radiation" in the typical sense. However, it is important to note that electron beams can be harmful, especially at high energies, and safety precautions must be taken during operation.