Nuclear radiation is used to see inside the body and to treat disease
- In medicine, nuclear radiation is used to explore internal organs and to control or destroy unwanted tissue.
- Each use has to be weighed against the risk that radiation can also harm healthy cells.
Exploring internal organs with a radioactive tracer
Definition
Tracer
A radioactive substance put into the body so that its path can be followed from outside using a detector.
- A patient is given a tracer, a source that emits gamma radiation.
- Gamma radiation is used because it is penetrating enough to pass out of the body to a detector outside.
- A source with a short half-life is chosen so the radioactivity does not stay in the body for long.
- Following the tracer shows doctors how well an organ is working.
Destroying unwanted tissue with radiotherapy
- A higher dose of radiation can kill living cells, so it is used to destroy cancer cells in a treatment called radiotherapy.
- The radiation is aimed carefully to limit the dose reaching healthy tissue.
Weighing the benefits against the risks
- Radiation can itself damage healthy cells and slightly raise the risk of cancer.
- Doctors weigh the benefit of a diagnosis or treatment against this risk, using data on doses and outcomes.
- For a serious illness the benefit usually outweighs the small added risk.
Common Mistake
- Do not say using radiation is completely safe: it always carries some risk, which has to be justified by the benefit to the patient.
Self review
- What are the two main medical uses of nuclear radiation?
- Why is a gamma-emitting tracer with a short half-life used to explore organs?
- How does radiotherapy treat a tumour?
- Why must the benefits of using radiation be weighed against the risks?
