Uses of Radioactivity

Medical Applications

Radiotherapy: High energy gamma rays are used to kill cancer cells in patients. This is more effective than surgery in some cases as it can target cells deep in the body.
Diagnostic Imaging: Radioactive substances (radioisotopes), such as Technetium-99m, are used to image the body. The isotopes emit gamma rays that can be detected from outside the body giving a map of where it has gone.
Sterilisation: In a medical environment, radioactive substances can be used to effectively sterilise equipment.

Archaeology and Geology

Radiocarbon dating: A technique used to date organic matter by using the relative proportions of the carbon isotopes Carbon-14 and Carbon-12, knowing that the former is radioactive and decreases over time.
Tracers: Radioactive isotopes are used in geological surveying and oil prospecting. They can be used to test soil samples for pollution or in reservoir flooding to trace water movement.

Industrial Applications

Thickness Control: Factories often use beta radiation to measure the thickness of paper, films and metals during production.
Smoke Detectors: Many smoke detectors use alpha radiation. When smoke particles disrupt this radiation, the detector sounds an alarm.
Power Generation: Nuclear power stations utilise the immense heat generated in nuclear fission of uranium or plutonium to produce electricity.

Food Irradiation

Preservation: Gamma irradiation can be used to kill bacteria, parasites and insects in foods to extend their shelf life.

Space Exploration

Power Source: Plutonium-238, a radioactive substance, is used to produce energy for spacecraft travelling in deep space, where solar energy is not available.

Each of these applications makes use of the properties of radioactive isotopes: their ability to emit energy, the unique nature of their decay, and the fact that they can be detected even in small amounts.