Mal Washer (Moore, Liberal Party) Share this | Hansard source

Thank you. I rise to support the motion. It is essential that the highest quality health services be provided to Australians in a timely fashion. It is critical that the best diagnostic tools be made available to Australians. There is no doubt that accurate diagnosis in the early stages of a disease is vital for effective treatment and management. I want to talk about this machine. Bear with me—I do not want to make it too technical, but I think it is important that members understand what it is.

Positron emission tomography or PET scanning, which produces a three-dimensional image of the functional processes of the body, is one of the new diagnostic tools we have—new in only the last decade or so. The system produces pairs of gamma photons—that is, light—emitted indirectly by a positron-emitting radioisotope. It is interesting to note that a positron is the antimatter counterpart of an electron, making a PET scanner one of the significant applications of quantum physics.

This radioisotope is introduced into the body, usually via the blood circulation, on a metabolically active molecule like a sugar. The common sugar they use is called fluorodeoxyglucose—for the sake of simplicity, we will call it FDG. This then concentrates in the tissues of interest, like cancer cells, which rapidly take up the glucose because their mitochondria—that is, the powerhouses of the cells that make our cells work—need the glucose to be active. In these cells there is hyperactivity, overactivity, due to their rapid growth, and so it concentrates in the tumour cells.

The positron-emitting isotope is thereby concentrated in these tissues and the positron is eventually released. When it encounters an electron—electrons are in all of the cells surrounding it—it annihilates rapidly, producing a pair of photons—bursts of light—which move in opposition directions, allowing for localisation of where the event occurred. Thereby we are able to accurately show where the metastasis—the spread of the tumour—is positioned.

PET scans are increasingly read alongside computerised tomography, or CT, scans, the combination giving both anatomic and metabolic information on the illness. Limitations to the widespread use of PET scans arise from the high cost of the cyclotrons needed to produce these radioisotopes. Also, the chemical synthesis apparatus to produce the radiopharmaceuticals necessary for the procedure is complex. As the member for Herbert said, wider use would make this more cost-effective. The PET scanner is valuable for oncology because of the cancer’s mitochondrial forms—the powerhouse forms. This is of particular value in Hodgkin’s and non-Hodgkin’s lymphoma and lung cancer. It is proving very useful with cancers like breast and prostate, particularly if disease recurrence is suspected.

Oncology scans using this sugar, or FDG, make up over 90 per cent of all PET scans in current practice. PET scanning is used in neurology to indirectly measure blood flow in the brain and, for example, it can be used to differentiate Alzheimer’s disease from other dementing processes. It may also enable an early diagnosis of Alzheimer’s with new techniques that can visualise the amyloid plaques, which are the essential part of Alzheimer’s. PET is also used for localisation of seizure focus in epilepsy, which of course is necessary if we are going to treat epilepsy by applying surgery, which is a more common means of treating epilepsy. It is proving of increasing value in cardiology, neurophysiology, psychiatry and pharmacology. I can tell the House we will hear much more about this potentially magnificent tool for medicine in the future.

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