Positron emission tomography (PET) is a medical imaging procedure that can provide information about how an organ or system in the body is working. PET scans can detect cancer in its early stages, help to monitor cancer treatment and check if the cancer is coming back. Positron emission tomography (PET) is a medical imaging procedure that provides unique information about how an organ or system in the body is working. PET scans are mainly used to assess cancers, neurological (brain) diseases and cardiovascular (heart-related) disease.
The PET scanner has a ring of detectors that surround the person. It looks similar to a CT scanner. The scan is performed by a healthcare professional called a nuclear medicine scientist, who works with a nuclear medicine specialist (doctor).
How the PET scan works
A PET scan involves the painless injection of a small amount of a ‘positron-emitting’ radioactive material (called a radiopharmaceutical). Images of the body are then taken using a PET scanner. The camera detects emissions coming from the injected radiopharmaceutical, and the computer attached to the camera creates two and three-dimensional images of the area being examined.
Areas where the injected radiopharmaceutical gathers (for example, fast-growing cancer cells) appear ‘brighter’ than normal tissues on the images.
Almost all PET scanners today are combined with a CT scanner so that the PET images can be combined or fused with the CT images. This allows the nuclear medicine specialist to combine the structural information from the CT scan with the PET’s functional information and improve the accuracy of the test. In these scanners, the person passes through both scanners on the one bed and in the same position.