A method for positron emission tomography (PET) imaging of LRRK2 in tissue of a subject, the method comprising: administering a compound of formula I, formula II or formula III, or a pharmaceutically acceptable salt thereof to the subject, wherein the compound includes at least one C11 or F18 label thereon allowing the compound to penetrate into the tissue of the subject and collecting a PET image of the CNS or brain tissue of the subject.