Types of isotope dating
These are detected by a PET camera and give very precise indications of their origin.
PET's most important clinical role is in oncology, with fluorine-18 as the tracer, since it has proven to be the most accurate non-invasive method of detecting and evaluating most cancers. New procedures combine PET with computed X-ray tomography (CT) scans to give co-registration of the two images (PET-CT), enabling 30% better diagnosis than with a traditional gamma camera alone.
In Australia there are about 560,000 per year, 470,000 of these using reactor isotopes.
The use of radiopharmaceuticals in diagnosis is growing at over 10% per year.
If a series of images is taken over a period of time, an unusual pattern or rate of isotope movement could indicate malfunction in the organ.
Positioning of the radiation source within (rather than external to) the body is the fundamental difference between nuclear medicine imaging and other imaging techniques such as X-rays.
The earliest technique developed uses single photons detected by a gamma camera which can view organs from many different angles.
The camera builds up an image from the points from which radiation is emitted; this image is enhanced by a computer and viewed on a monitor for indications of abnormal conditions.
In developed countries (26% of world population) the frequency of diagnostic nuclear medicine is 1.9% per year, and the frequency of therapy with radioisotopes is about one-tenth of this.
In the USA there are over 20 million nuclear medicine procedures per year, and in Europe about 10 million.