Nature and extent of burden and risk associated with participation, benefit and group relatedness: Patients who will participate in this study will receive a dynamic PET/CT scan of the brain, a static total-body PET/CT scan and an MRI scan of the brain at baseline. After 4 weeks they receive a CT scan of chest and abdomen and a MRI scan of the brain. All CT and MRI scans are part of regular care. The PET/CT scan, which is a study procedure, carries a radiation burden of 4.1 mSv. This constitutes an intermediate risk, based on criteria of the International Commission on Radiological Protection. For the purpose of pharmacokinetic modeling, an arterial catheter will be placed which is an invasive procedure. Expected adverse events will be identical to that of unlabeled dabrafenib. Patients do not directly benefit from the study, but their participation helps to get more insights in the pharmacokinetics of dabrafenib and its role in the treatment of brain metastases.