Most cells in the human body use glucose as a source of energy. The same is true for the tumour cells of many cancer diseases. Compared to other cells, they have an increased metabolism and therefore consume particularly large amounts of glucose.
PET
We take advantage of this fact by injecting our patients with, for example, low-level radioactively labelled glucose (FDG = fluorodeoxyglucose). Using PET (Positron Emission Tomography), we make the low-radiating substances visible in the metabolism and can thus map biochemical and physiological functions. However, the PET procedure can hardly provide any anatomical information.
CT
This is why we combine the PET with the well-known CT (computer tomography) method. It provides us with sectional images of the desired areas, which is why it is also called "sectional x-ray".
The combination
By moving our patients in completely identical positions through the detector rings of a combined PET-CT device, we generate different images of the same areas. These images can be viewed individually or combined. In most cases, we display the image from the computer tomograph in grey scales and integrate the PET information in colour. In this way, we assign areas with an increased glucose metabolism with accurate to the millimetre.
PET-CT in cancer diagnostics
The main area of application for PET is oncology. With PET-CT we can obtain information about the presence of a malignant tumour, tumour spread (staging), the effectiveness of treatment (therapy control) or a recurrence of the tumour (recurrence, DD scar, post-therapeutic changes). An advantage of PET-CT is the full-body examination, with which the main tumour (primary tumour) as well as lymph node and distant metastases can be assessed in one examination. A PET-CT examination can also be used to plan the taking of samples (biopsy control) and to plan radiotherapy for tumours.
PET-CT for neurological and cardiological examinations
Other areas of application for PET-CT are neurology, e.g. in the case of Alzheimer's disease (differential diagnosis of dementia), cardiology, e.g. in the case of the ability of heart muscle areas with poor blood supply to recover before a bypass operation or vasodilatation (vitality diagnostics) and inflammatory medicine, e.g. in the search for inflammatory foci (focus search).
PET-CT in children
A PET-CT examination can also be performed in children of any age. From the age of four, children are usually so cooperative that no sedatives or sleeping pills need to be given. Younger children should be examined at a time when they are tired or normally sleep (late morning). After the FDG has been administered, they are given a sedative as a suppository to help them sleep. Babies can have a milk meal (bottle or breast milk) half an hour after the FDG is given, which usually helps them fall asleep on their own. You can stay with your baby during the entire preparation period and during the PET scan. You should only leave the room during the short phase of the CT scan (30 seconds).