Nuclear medicine tests are a highly useful tool in the diagnosis and treatment of a range of illnesses including heart disease, bone infections, tumours and cancer progression. They are both safe and painless. Small amounts of radioactive substances known as radiotracers are injected into the patient's bloodstream, ingested or inhaled. This radiotracer travels through the bloodstream through to the area being examined then emits gamma rays that are detected using a special camera that is called a gamma camera. The images are then viewed on a computer screen and analysed.
Types of radiotracers
Radioactive tracers consist of a carrier molecule bound tightly to a radioactive atom. The carrier molecule is specific to the type of scan being carried out. For example, certain tracers bind to a specific protein or sugar in the body to give off radiation that can then be detected by a gamma camera. In the case of diagnostic nuclear medicine, the radioactive tracer is usually given to the patient via an intravenous injection. In some cases, radioactive tracers may also be directly injected into the organ of interest.
Technetium-99m is the most commonly used radioactive tracer, used in millions of medical diagnostic procedures every year. Not only is this radioactive tracer safe but it also has a relatively short half-life, allowing data to be collected rapidly whilst keeping the total radiation exposure of the patient quite low.
Common procedures utilising nuclear medicine
Heart: Nuclear medicine can be used to visualise the degree of damage done to the heart following a heart attack, detect rejection following a heart transplant, evaluate the function of the heart following chemotherapy and visualise blood flow through the intricate blood vessels of the heart.
Bones: Nuclear medicine can effectively be used to detect fractures, infections and arthritis. Additionally, it can be used to visualise the progression of bone tumours.
Brain: Neurological disorders such as dementia and Alzheimer's disease can be detected in their early stages using nuclear medicine. Furthermore, seizures, memory loss and blood flow abnormalities can also be detected.
Cancer: Nuclear medicine is widely used to determine the stage of a person's cancer including its spread and response to treatment.
Safety of radioactive tracers
Only radioactive tracers approved for safety and performance are used clinically. The nuclear medicine physician selects the tracer most appropriate for a patient's particular medical problem. Only very small amounts of tracers are used in order to minimise patients' exposure to radiation.