23 September 2026
A substance developed at Forschungszentrum Jülich, which is used to detect brain tumours has overcome an important regulatory hurdle in the US: the US Food and Drug Administration (FDA) has approved the drug 18F-fluoroethyl-L-tyrosine - FET, for short - for certain diagnostic applications for glioma. This marks another important milestone on the path from research and development at Jülich to medical application.
FET is a radiotracer. It is an artificial substance that is similar to the natural amino acid and is labelled with a small amount of radioactive fluorine. FET is more readily taken up by certain brain tumour tissue than by healthy brain tissue, which makes the tumour easier to detect. It is administered to patients as part of an examination. This is where positron emission tomography - PET, for short - comes in. PET is an imaging technique that makes it possible to see where the radiotracer has been taken up in the body. This then provides doctors with additional information on abnormal changes in the brain.
A Jülich development
FET was developed in the 1990s at Forschungszentrum Jülich and has been the subject of intensive research since the turn of the millennium under the direction of Prof. em. Dr. Karl-Josef Langen. Several institutes at Forschungszentrum Jülich were involved in this, including Cognitive Neuroscience (INM-3), Physics of Medical Imaging (INM-4), and Nuclear Chemistry (INM-5). Together with university hospitals, Jülich researchers analysed the method in numerous experimental and clinical studies.
"Our team has published the results of some 170 studies on FET-PET and examined more than 11,000 patients with brain tumours," says PD Dr. Philipp Lohmann, acting director of INM-4 and Prof. Langen's successor as head of the digital translational neuroimaging research group. "That FET has now been approved as a diagnostic drug by the FDA shows just how important this extensive interdisciplinary research is."
Application when changes are difficult to interpret
US approval is for patients who are already receiving treatment for a glioma. Following surgery, radiation, or other therapies, changes can occur in the brain that may appear similar to growing tumour tissue on magnetic resonance imaging (MRI) scans.
FET-PET can help to clarify such results. Is the change a growing or a progressing tumour? Or is it the result of a previous treatment?
Diagnostics, not treatment
It is not a drug for treating brain tumours. It does not destroy or shrink the tumour. It is only used for diagnostics. When combined with a PET scan, however, it can provide additional information - particularly on the tumour's metabolism - which assists doctors in assessing abnormal changes in the brain. FET-PET does not replace other tests or examinations, nor does it allow for a definitive diagnosis on its own.
FET-PET also used in Germany
FET-PET is already used in Germany for specific patients with malignant brain tumours. The Federal Joint Committee (GBA) stipulates for the statutory health insurance system which medical services are covered and under what conditions. It lists FET-PET as part of specialist outpatient care, including in cases where MRI results are inconclusive following treatment. The specialist outpatient care is intended for individuals with complex illnesses or diseases that are difficult to treat.
At Forschungszentrum Jülich, such studies are carried out at INM-4, which operates as a branch office of the Department of Nuclear Medicine at RWTH Aachen University Hospital. Specialists from a radius of more than 300 kilometres draw on the expertise of the Institute of Neuroscience and Medicine.
However, the regulatory status here is different from that in the US: in Germany, FET-PET is part of a specialized care programme under certain conditions. This does not mean that FET is approved as a drug here. The FDA, on the other hand, has now approved FET - under the name Pixclara® - as a drug manufactured by Telix Pharmaceuticals for a specifically defined diagnostic application.
Research on FET-PET is also ongoing at Forschungszentrum Jülich. One strand of current research, for example, is combining this method with other imaging techniques and artificial intelligence to further improve image analysis and enhance the diagnostic value.
