Radiation risks 2 Continued

Minimising Exposure As any exposure to ionising radiation could potentially damage cells and lead to cancer, when handling radioactive materials and in situations where workers are exposed to ionising radiation the ALARA principle should be employed. ALARA stands for As Low As Reasonably Achievable

Irradiation and Contamination What is the difference? Irradiation involves exposure to ionising EM waves (UV, X-rays, gamma rays) and alpha or beta particles. Contamination involves radioactive material (which produces ionising radiation) being physically transferred. e.g. alpha sources outside the body are harmless because our skin is a barrier to alpha particles. However, if radioactive alpha sources (like radon) are airborne they can be breathed in and then produce alpha particles in the lungs where they can do damage.

Who is this man and what is his story?

Four factors involved in exposure Distance Time Shielding Contamination Watch video of the US Army advice

The Geiger-muller tube and counter

Techniques employed when handling radioactive sources Kept in lead-lined boxes. The lead is sufficient to block alpha and beta and reduce the level of gamma rays to background levels.(shielding) Tongs with long handles are used to pick up sources. This reduces the risk of contamination (radioactive material being transferred to the hands) and the increased distance reduces the dose. e.g. alpha particles are stopped by a few cm of air, beta by around a metre of air, gamma falls off as the 1 over the distance squared.(distance) Disposable gloves.(contamination) Short handling time. It has been shown by exposing invitro cells to ionising radiation that repeat hits on a cells are more likely to lead to mutations occurring.(time)

Radiation monitoring How do you think this works?