The standard unit of radiation related to biologic hazard is the "roentgen".
In the United States, radiation absorbed dosage, measurement proportionate, and introduction are regularly estimated and expressed in the more established units called rad, rem, or roentgen (R), separately. For practical purposes with gamma and x rays, these units of measure for presentation or dosage are viewed as equivalent. This presentation can be from an outer source lighting the entire body, a limit, or other organ or tissue bringing about an outside radiation dosage. Then again, inside kept radioactive material may cause an interior radiation measurements to the entire body or other organ or tissue.