The TDP-43 protein plays an important role in frontotemporal dementia and ALS, among others. These TDP-43 accumulations are visible in brain examination after death of patients. Until now, we cannot demonstrate during life that the disease-causing TDP-43 protein is present in the brain. This research stimulates the further development of a TDP-43 tracer (a radioactive substance that is absorbed by the body) for PET scans. This makes it possible to make a diagnosis at an earlier stage and to monitor the effect of future medication.