Three basic principles to avoid external irradiation

External irradiation can be avoided by following three basic principles, as shown in the figure: time, distance, and shielding.

• Time: the less time spent near a radioactive source, the lower the radiation dose received.
• Distance: the greater the distance from a radioactive source, the lower the radiation dose received.
• Shielding: Using adequate shielding, no radiation dose will be received. Depending on the type of radiation that the source contains, we must establisch one or the other material as shielding: