Radioactivity is something which frightens most people, with thoughts of nuclear bombs and the horrible illnesses suffered by those exposed to the resulting radiation. But in small amounts radioactivity is harmless and is part of everyday life. Being inside a tall building exposes us to tiny amounts.
In the medical specialty of nuclear medicine, radioactivity provides a useful tool in the diagnosis and treatment of many diseases.
Many different materials emit small amounts of energy in the form of radiation and this can be used to take a ‘picture’ of various parts of the body. After injection of a radioactive substance, a special camera is used to take a picture of the gamma rays which are present in the body for a short time afterwards. This process is usually called scanning.
The most common use of nuclear medicine is the bone scan, which can show up fractures (breaks) which may not be visible on normal X-rays. This test is also very useful in certain types of cancer (particularly prostate and breast cancers) to see if there has been any spread to bone. Bone scans are also useful in detecting arthritis and infection (osteomyelitis). The latter is important in children where early diagnosis is very important.
Nuclear scanning is probably the best way to detect blood clots in the lungs (emboli). This potentially lethal condition can occur after surgery and an emergency scan may be necessary to allow treatment to commence as soon as possible.
Blood flow to heart muscles can be studied through radioactive scanning and this may be very useful in suspected heart attacks and the diagnosis of chest pains.
Treatment using radioactive materials is also possible, particularly in cases of thyroid cancer, fluid in joints and also for pain from widespread deposits of cancer.
The most common question asked by patients when told they need to have a radioactive scan is: ‘will I glow in the dark?’. The answer is no. Nuclear medicine is very safe with little, if any, discomfort or side effects. The process may take a little longer than having an X-ray, but it's no more uncomfortable.
Last Reviewed: 25 June 2001