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Information for patients

Pairs of gamma rays are emitted in opposing directions from the radioisotope and are captured by gamma detectors arranged in formation around the patient

Pairs of gamma rays are emitted

Radiopharmaceuticals can be injected, inhaled or ingested in order for the physician to diagnose disease using imaging techniques.

Once the patient has taken the radiopharmaceutical, a detector such as a gamma camera detects the radiation coming from the radiopharmaceutical and builds up a image of the required area that can be analysed by the physician.

Reactors and cyclotrons

A cyclotron is an accelerator that accelerates charged particles to high speeds and beams them at a suitable target, producing a nuclear reaction that creates a radioisotope. ANSTO's National Medical Cyclotron is located at Prince Alfred Hospital in Sydney.

Information captured by the detectors is processed by a computer to generate a thin slice image of the organ. A series of slice images are combined to create a three dimesnional model of the organ

Creating a three dimensional image

The radioisotopes produced there are used mainly to make radiopharmaceuticals for use in diagnostic imaging.

Radioisotopes made in cyclotrons complement those made in a reactor. Atoms with extra neutrons in the nucleus are neutron-rich and are produced in a nuclear reactor. Atoms with extra protons in the nucleus are called neutron deficient and are produced in a particle accelerator such as a cyclotron. Neutron-rich and neutron deficient radioisotopes decay by different means and hence have different properties and different uses. It depends on the radioactive properties required whether a nuclear reactor or a cyclotron is used to produce the radioisotope. The most commonly used radioisotope, molybdenum 99-m (which decays into technetium 99-m) can only be produced in a research reactor, and is used in about 90 per cent of nuclear medicine treatments.