Clinic and Polyclinic for Nuclear Medicine
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Positron emission tomography

"What is an FDG-PET/CT?"

PET/CT is a combined examination procedure consisting of positron emission tomography (PET) and computer tomography (CT) and provides information about metabolic processes taking place in the body on the one hand and, on the other, information about possible pathological changes (e.g. malignant tumors/metastases) in organs and tissue structures by generating high-resolution sectional images.

As part of the FDG PET examination, the patient is first administered a low-level radioactive tracer via a venous access. This is glucose (F-18 fluorodeoxyglucose; FDG) labeled with a radioactive fluorine isotope (fluorine-18). As most malignant tumors have a higher metabolism than healthy tissue and therefore absorb more of this radioactively labeled glucose, this procedure is suitable for differentiating between benign and malignant tumors (e.g. unclear round lung tumor), for searching for an unclear primary tumor, for staging a known tumor or for checking a response to therapy in the case of a known tumor.

"How does PET/CT work?"

The radioactive substances used for PET are positron emitters. These emit a positively charged particle, which has a very short lifespan (nanosecond range) and only has a range of a few millimeters in the body before it interacts with an electron. This produces two high-energy light quanta (photons) that are emitted in exactly opposite directions and can be recorded by a ring-shaped detector, which enables an exact spatial resolution. In combination with a computer tomography performed at the same time, the metabolic processes detected in this way can be precisely assigned anatomically in the body.

What is the "FDG-PET/CT examination procedure?"

Patients must ensure that they do not eat or drink anything, with the exception of water, for at least 6 hours before a PET/CT scan. In many cases, we perform the CT component using iodine-containing contrast agents. It must be clarified whether a hypersensitivity reaction to contrast media has occurred during a previous CT scan. It should also be clarified whether there is any kidney damage or hyperthyroidism. In the case of an outpatient examination, the patient should therefore have their creatinine and TSH levels determined by their GP in advance and bring them with them to the examination. As it takes a certain amount of time for the test substance to be distributed in the body, the examination is started approximately 60 minutes after application. The actual examination time in the PET/CT device is approx. 30 minutes. In total, you should plan to spend approx. 2-3 hours with us in the department on the day of the examination.