Medical Uses of Radiation Flashcards

All 5 cards in this deck

Why is an alpha source used inside the body to treat a tumour?

Alpha has a short range and low penetration (it is highly ionising), so it must be placed close to the tumour and damages little healthy tissue.

Why can a gamma source be used outside the body to treat a tumour?

Gamma is highly penetrating (weakly ionising), so it passes through the skin and reaches the tumour from outside.

What is a radioactive tracer used in medical diagnosis?

A radioactive substance injected or swallowed, whose radiation is detected outside the body to show how an organ is working.

What does a PET scanner detect?

Gamma rays produced when positrons emitted by the tracer annihilate with electrons in the body.

Why must an isotope used in a PET scanner, such as fluorine-18, be produced close to the hospital?

It has a short half-life, so it must be used as soon as possible after making or it decays too much during transport.