To understand the types of biological effects resulting from exposure to nuclear radiation, it is important to understand how radiation interacts with the body.

Radiation is a form of energy in motion. When alpha, beta, and gamma radiation enter the body, some or all of their energy is lost in collisions with the body's atoms.

The major characteristic of these atomic interactions is the stripping away of electrons from atoms in the body. This removal of electrons is called ionization. Remember, it is for this reason, that alpha, beta, and gamma radiation are called ionizing radiation. The biological effects of radiation are caused by these ionizations and their effects on cells.