Positron-Emission-Tomography (PET)

Author:  Gesche Tallen, MD, PhD, erstellt am 2006/12/07, Editor:  Maria Yiallouros, Reviewer:  Prof. Dr. med. Ursula Creutzig, English Translation:  Hannah McRae, Last modification:  2015/01/13

Positron emission tomography (PET) is a nuclear medical imaging procedure that is used to distinguish living from dead (tumour) tissue.

Since most tumours have a more active metabolism than healthy or dead tissue, they need more sugar. Hence, the patient receives a radioactively labeled sugar compound intravenously. The injected sugar compound (such as “2-deoxy-2-18Flouro-D-glucose,” 18F-FDG) is "swallowed" (absorbed) by the tumour cells and accumulates at the tumour site.

The radioactive substances used have a very short half-life and are used within safe limits. Neither the patient, nor the environment is harmed by radioactivity during or after this procedure.

The advantage of PET scans over different other imaging techniques is that only living tumor tissue becomes visible.

This helps determine, for example following a certain treatment phase, whether suspected residual tumour tissue found in a magnetic resonance image (please see MRI) or computed tomography (please see CT) really contains living rather than dead tumour tissue.

The results of a PET-scan are usually analysed by a paediatric radiologist. A PET-scan is generally only performed in children or teenagers (under 18 years of age) after an informed consent has been obtained by the parent or legal guardian.