Ionizing Radiation Fact Sheet

Facts About Ionizing Radiation

  • Radiation cannot be discerned by human senses.
  • Radiation and radioactive materials are natural phenomena present in soil, water, food, plants and animals.
  • Radiation can be useful (e.g., X-rays for broken bones or nuclear medicine scans of the heart).
  • Radiation can be harmful. The probability of a harmful consequence (cancer) is related directly to how much and where radiation interacts with the body.
  • For this reason, annual LIMITS are placed on the amount of radiation dose for radiation workers.

Where Does Radiation Come From?

  • Outer space
  • Building materials
  • Soil
  • Water
  • Food
  • Human body

Radiation Protection Principles:


  • The less time spent in a radiation area, the lower the total dose.
  • You personally control the amount of time spent in a radiation field.


  • Double the distance from a radiation source to reduce the exposure rate by one quarter.
  • Most of the radiation used in laboratories causes little exposure 3 feet from the bench.


  • If it increases the time to perform an experiment, shielding is not practical.
  • Some materials can cause an increase in radiation exposure.


  • Radioactive contamination on the skin can be washed off like dirt: check the area with a survey meter after washing.
  • Prevention of internal contamination is the primary concern: no eating, drinking, using cosmetics (Chapstick@, skin creams) in the laboratory.