Radiation Radiation For biologists, the most significant forms of radiation are light, heat, and ionizing radiation.
Ionizing radiation can penetrate cells and create ions in the cell contents.
The rad represents a certain dose of energy absorbed by 1 gram of tissue. It is a unit of concentration. Some forms of radiation are more efficient than others transferring their energy to the cell. X rays and gamma rays have a Q about 1, so the absorbed dose in rads is the same number in rems. Neutrons have a Q of about 5 and alpha particles have a Q of about 20.