Access To The National Medical Cyclotron
About the National Medical Cyclotron
One of ANSTO's major national facilities, the National Medical Cyclotron (NMC), was opened at the Royal Prince Alfred Hospital in Camperdown in March 1992 by the Governor General, The Hon Bill Hayden A C, Governor General of Australia.
The National Medical Cyclotron and its associated facilities cost a total of $20 million.
Cyclotrons belong to a class of machine called particle accelerators. The NMC is a cyclic accelerator, creating charged particles which are accelerated to high velocities to bombard target substances.
Most homes have at least one particle accelerator in them as part of a television picture tube or computer monitor.
Some of the very short-lived cyclotron-produced radioisotopes used in PET (Positron Emission Tomography) must be administered to the patient very soon after production. Hence the cyclotron was built adjacent to the Royal Prince Alfred Hospital and connected to it by a $500,000 pneumatic rapid transfer system.
PET and SPECT (Single Photon Emission Computed Tomography) are two imaging techniques which rely on cyclotron-produced radiopharmaceuticals.
In PET, a tagged substance is injected or inhaled. This moves normally through the patient to accumulate in the targeted organ. The patient is scanned using a PET camera which translates data into computer images. Malfunctions in metabolism are immediately apparent by abnormal distribution of the tagged substance.
PET shows blood flow by imaging trace amounts of radioisotopes. It indicates decreases in blood flow to say parts of the brain indicating such diseases as Alzheimer's.
The research team working on the development of new radiopharmaceuticals has designed and built automated production systems for SPECT radiopharmaceuticals so they will be available to hospitals across Australia.
In 1995 the NMC will supply a high portion of Australia's gallium-67 and thallium-201 needs and export them to New Zealand. Gallium-67 detects soft tissue tumours and hidden infections. Gallium citrate complex is the material used, injected intravenously to assess cancers in the bronchi, lymph nodes, spleen (Hodgkin's Disease) and malignant melanoma.
It is also used to track certain solid tumours in children and to assess effectiveness of treatments.
Uses of thallium-201 in cardiology have increased dramatically in recent years. The NMC staff plan to expand production for the overseas market commencing in 1996.
Thallium-201 is used in the diagnosis of coronary artery disease, diagnosis of tissue viability (which helps the cardiologist judge the most appropriate course of therapy) and is the most powerful indicator of prospects for patient management over a broad range of coronary diseases.
The NMC is currently developing an indium-111 production system for use in SPECT for diagnosing inflammatory bowel disease. Further development in PET based pharmaecuticals include F-18 Dopa and carbon-11 labelled compounds which will be used at the PET Centre, Royal Prince Alfred Hospital.
Australian Radioisotopes, ANSTO's manufacturing arm, despatches the cyclotron-produced radiopharmaceuticals to hospitals and nuclear medicine practices across Australia.
Reactors vs cyclotrons - the research continues
One of the frequently raised issues relating to the production of radioisotopes is the possibility of replacing reactors with cyclotrons for the radioisotopes used in the nuclear medicine industry.
Both reactors and cyclotrons are needed to make these radioactive substances and ANSTO uses both - its HIFAR reactor at Lucas Heights and the $20 million National Medical Cyclotron, which it owns and operates at Sydney's Royal Prince Alfred Hospital.
Around the world there are about the same number of reactors as cyclotrons producing medical radioisotopes as a major part of their functions. Over 80% of the radioisotopes actually used in medical procedures around the world come from reactors.
To understand why both types of facilities are needed it is necessary to know a little about the differences between cyclotron-produced and reactor-produced radioisotopes.
Nuclear reactors produce radioisotopes by adding an extra neutron into the atoms of the respective elements - that is, they are neutron-rich isotopes, and it is the excess of neutrons that makes the isotopes radioactive.
Cyclotrons bombard atoms with different particles (for example protons or deuterons) to produce isotopes that are deficient in the number of their neutrons. In this case it is the neutron deficiency that makes the isotopes radioactive.
This is a fundamental difference between the two processes and it means as a general rule that reactor radioisotopes will not be made by a cyclotron, nor will cyclotron radioisotopes be made in a reactor.
The choice of which radioisotope to use in a particular application may depend on the type of radiation required, or the need of a particular chemical species.
An example of particular importance is the reactor produced radioisotope, technetium-99m, the basis for more than 80% of all nuclear medicine procedures worldwide.
Radiopharmaceuticals based on technetium-99m are used in a variety of diagnostic procedures. Researchers in a number of countries continue to work on the possibility of using a cyclotron to produce technetium-99m, but there are difficulties.
The United States Government has recently decided to use the reactor to produce the parent radioisotope of technetium-99m, but, at the same time, an alternative using a high energy accelerator is also under investigation.
As the operator of both a reactor and an accelerator for radioisotope production, ANSTO continuously monitors developments in both fields.
For a guide to ANSTO's National Medical Cyclotron, please click here