Physics 9702 · AS & A Level · PET scanning

PET scanning — practice question

Fluorine-18 ($^{18}_{9}\text{F}$) undergoes beta-plus ($\beta^+$) emission and has a half-life of 110 minutes.
(a(i))[1]

State the name given to the beta-plus particle.

(a(ii))[1]

Demonstrate that the decay constant for fluorine-18 is $1.05 \times 10^{-4}\,\text{s}^{-1}$.

(a(iii))[3]

Calculate the activity of $2.1 \times 10^{-12}\,\text{kg}$ of fluorine-18.

(b(i))[3]

Describe how interaction between a $\beta^+$ particle and an electron in the body makes image formation possible.

(b(ii))[2]

Suggest why 110 minutes is an appropriate half-life for a nuclide used as a tracer in medical diagnosis.

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