Provided herein are radiolabeled compounds useful for non-invasive imaging techniques. An exemplary radiolabeled compound provided herein is useful as a radiotracer for positron emission tomography. The present application also provides unlabeled compounds useful in methods of treating diseases of the central nervous system or disease of the peripheral nervous system. Methods for preparing radiolabeled compounds, preparing unlabeled compounds, and diagnostic methods using labeled or unlabeled compounds are also provided.
