When radiation interacts with the nucleus of a cell it damages the DNA and the cell dies.

When radiation interacts with the cytoplasm (everything outside of the nucleus) the cell may reproduce before it has a chance to heal. The cell will reproduce in its mutated state and all future reproductions  will be mutated.       

Alpha Rays from a Radioactive Particle in Lung Tissue                               

         Last modified: December 20, 2007