Do you know anyone who ' d like to learn a bit more about radiation ? This pull-out sheet will help .

What is the difference between Radiation , Radioactivity and Contamination ?

Very often radiation is confused with radioactivity and radioactive contamination , so to understand the difference we need to appreciate what we mean by these terms .

Radiation is a source of energy that is emitted , either in the form of particles or packets of energy . It may be created by a material which is radioactive or generated artificially by machine , such as X-rays .

External Radiation The body can be exposed to radiation and contamination in several ways . It can be by direct exposure to radiation , where the radiation is of sufficient energy to transmit through the body , such as X-rays and gamma rays . This is called ' external ' radiation ( the source of the radiation is outside the body ).

Gamma or X-ray radiation is more penetrating and requires very dense material to shield it . The ‘ half value layer ’ is the thickness of material required to reduce the intensity of incident radiation by half .

Radioactivity is the process by which an unstable atom undergoes a transition in an attempt to become stable . This process is known as radioactive decay and results in the emission of radiation in the form of particles ( alphas , betas , neutrons and protons ), gamma rays or X-rays .

Contamination is the presence of another substance on a place or item where it is not expected to be . Radioactive contamination of surfaces may be in the form of a liquid or solid .

Internal Radiation The body can be exposed to radioactive contamination via inhalation , ingestion or injection ( such as through a wound ), or it may be absorbed through the skin . This is called ' internal radiation ' ( the source of radiation is inside the body ).

Once inside the body , radioactive material will undergo decay , causing cells to be irradiated . Depending on the type of radioactive material , processes in the body may cause it to become concentrated in different organs , or it may pass through the body and be excreted .

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36 Radiation Protection Today www . srp-rpt . uk