How to calculate a half- life : Working out the half-life allows us to calculate when a radioactive source becomes relatively safe . The diagram shows the parent atoms only . Notice that they halve after every half-life .

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If a Radioactive Source has a half-life of 30 years , how long will it take to decay to below 200kBq if the initial activity is 8,000 kBq ?

8,000kBq → 4,000kBq → 2,000kBq → 1,000kBq → 500kBq → 250kBq → 125kBq . It takes five half-lives to fall to 250kBq , and six half-lives to 125kBq nuclei . So somewhere between 5 × 30 = 150 years and 6 × 30 = 180 years .

In diagnostic imaging radioactive material is administered and can then be seen using radiation detecting equipment in order to visualise organ and tissue structure as well as function .

Q & A Why choose a source with a short half-life for diagnostic imaging ?

Because they decay quickly and minimise exposure to the body .

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From Güney İB . et al . 2017 https :// it . wikipedia . org / wiki / File : Superscan . jpg https :// creativecommons . org / licenses / by / 4.0 /

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