Inflammation occurs in many brain diseases including Alzheimer's disease. In Alzheimer's disease, amyloid starts accumulating decades before the start of forgetfulness. Basic scientists have reported that inflammation but not amyloid is linked to forgetfulness. When people pinch a finger, it gets swollen. Similar changes occur in brain from various causes. New medications are under development to help healing and prevent permanent damages in the brain. When people pinch a finger, they can check if the injury is healing or getting worse by watching. Investigators can watch inside of the brain using a special camera called positron emission tomography (PET). It is currently possible to watch inflammation in the brain by taking pictures of a molecule called translocator protein (TSPO). But the problem is that by imaging TSPO, investigators can catch changes in more than one kind of cells. The information is not specific to each cell type. Such vague information is not useful to monitor the effect of new medications for inflammation. This proposal attempts to develop a novel method to capture changes in each of two major players in inflammation, microglia and astrocytes. To do so, investigators will take selective pictures of one cell type by using a novel imaging agent for PET. Investigators will also take PET pictures of TSPO. Investigators will process these two kinds of PET pictures using advanced mathematical methods and extract specific information on microglia and astrocytes. Our novel method will be useful to monitor new therapies to treat inflammation in brain.