Uses and hazards of radiation

Carbon Dating - the determination of the age or date of organic matter from the relative proportions of the carbon isotopes carbon-12 and carbon-14 that it contains. The ratio between them changes as radioactive carbon-14 decays and is not replaced by exchange with the atmosphere.

Dating Rocks - Radiometric dating (often called radioactive dating) is a technique used to date materials such as rocks or carbon, usually based on a comparison between the observed abundance of a naturally occurring radioactive isotope and its decay products, using known decay rates.

Radiotherapy - Although ionising radiation can cause cancer, high doses can be directed at cancerous cells to kill them. This is called radiotherapy. About 40 per cent of people with cancer undergo radiotherapy as part of their treatment. It is administered in two main ways: From outsie the body using X-Rays or the radiation from radioactive cobalt/ from inside the body by putting radioactive materials into the tumour or close to it

Tracing - Doctors may use radioactive chemicals called tracers for medical imaging. Certain chemicals concentrate in different damaged or diseased parts of the body, and the radiation concentrates with it. Radiation detectors placed outside the body detect the radiation emitted and, with the aid of computers, build up an image of the inside of the body.

Radiation and living cells - When radiation collides with molecules in living cells it can damage them. This can cause a mutation. If the DNA in the nucleus of a cell is damaged, the cell may become cancerous. In this case the cell divides rapidly and causes serious health problems.

Alpha, Beta and Gamma - The degree to which each different type of radiation is most dangerous to the body depends on whether the source is outside or inside the body. If the radioactive source is inside the body, Alpha radiation is the most dangerous because it is easily absored by cells. If the radioactive source is outside the body beta and gamma are the most dangerous because they can penetrate the skin and damage the cells inside.

Nuclear waste disposal - There are different categories of nuclear waste. Low-level radioactive waste, such as contaminated gloves, can be disposed of in landfill sites. Higher level waste, which may be dangerously radioactive, is more difficult to dispose of. It can be reprocessed to extract nuclear fuel or encased in glass and left deep underground.