PET POSITIVE EMISSION TOMOGRAPHY

WHAT IS IT? Small amounts of radionuclides (radioactive material) are injected into the body The radionuclides produce gamma rays as the brain metabolizes them Different parts of the brain will metabolize the sugar at different rates depending on how active they are. The machine then detects the gamma rays produced The signals are turned into a colorful map of brain activity It is most often used when other tests, such as MRI scan or CT scan, do not provide enough information. It can be used to detect which parts of the brain have been most affected by epilepsy or dementia

THE EQUIPMENT

THE SCANS PRODUCED

STRENGTHS Apart from intravenous injections (IV) (in the veins), procedure’s painless with very little risks or side effects. The small amount of radioactive material is not harmful and quickly excreted from the body (drinking fluids speeds up process). A small version of the PET scanner exists so that brain structures and neural activity of small animals can also be studied and compared with human functioning.

WEAKNESSES The procedure is not cost-effective because it involves radionuclides (radioactive atoms) that are short-lived and also requires a trained analyst to interpret the images produced. The technique is not recommended for claustrophobics (those with a fear of confined places) due to the confined nature of the scanner. The procedure is considerably time-consuming compared to other techniques because re-processing of data has to take place for accurate analysis. The images produced are not as clear as those produced by fMRI scans.

EXAMPLE OF STUDY Tierney et al (2001) Utilizes PET scans to investigate the cognitive process of language.