Radioisotopes

Radioisotopes  are widely used in medicine, industry and scientific research, and new applications for their use are constantly being developed.

What are radioisotopes?

** Before viewing this page, please note that a comprehensive brochure entitled: Radioisotopes; their role in society today can be found here.

Radioisotopes can be defined as atoms that contain an unstable combination of neutrons and protons. The combination can occur naturally, as in radium-226, or by artificially altering the atoms. In some cases, a nuclear reactor is used, in others, a cyclotron.

Atoms containing this unstable combination regain stability by shedding radioactive energy, hence the term radioisotope. The process of shedding the excess radioactive energy is called decay. The radioactive decay process of each type of radioisotope is unique and is measured with a time period called a half-life.

Radioisotopes are an essential part of radiopharmaceuticals (see below). In fact, they have been used routinely in medicine for more than 30 years. On average, every Australian can expect at some stage in his or her life to undergo a nuclear medicine procedure that uses a radioisotope for diagnostic or therapeutic purposes. Some radioisotopes used in nuclear medicine have very short half-lives, which means they decay quickly; others with longer half-lives take more time to decay, which makes them suitable for therapeutic purposes.

Industry uses radioisotopes in a variety of ways to improve productivity and gain information that cannot be obtained in any other way. Radioisotopes are commonly used in industrial radiography, which uses a gamma source to conduct stress testing or check the integrity of welds a common example is to test aeroplane jet engine turbines for structural integrity.

Radioisotopes are also used by industry for gauging (to measure levels of liquid inside containers, for example) or to measure the thickness of materials. Radioisotopes are also widely used in scientific research, and are employed in a range of applications, from tracing the flow of contaminants in biological systems, to determining metabolic processes in small Australian animals.

Medical radioisotopes

Nuclear medicine uses small amounts of radiation to provide information about a persons body and the functioning of specific organs, ongoing biological processes, or the disease state of a specific illness. In most cases, the information is used by physicians to make an accurate diagnosis of the patients illness. In certain cases radiation can be used to treat diseased organs or tumours.

Nuclear imaging

Nuclear imaging is a technique that uses radioisotopes that emit gamma rays from within the body. To make a radiopharmaceutical, a radioisotope is attached to a pharmaceutical that is taken up by a specific organ or specific diseased tissues. The radiopharmaceutical is given orally, injected or inhaled, and is detected by a gamma camera which is used to create a computer-enhanced image that can be viewed by the physician.

There is a significant difference between nuclear imaging and other medical imaging systems such as CT (computerised tomography), MRI (magnetic resonance imaging) or X-rays.