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
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.