RecruitingPhase 1Drug trial18F-Fluciclovine PET Amino Acid Evaluation of Brain Metastasis Treated With Stereotactic RadiosurgeryThis is a pilot imaging study in participants treated with stereotactic radiosurgery (SRS) to treat brain metastasis. The purpose of this study is to see whether 18F-Fluciclovine positron emission tomography (PET) can be used as a biomarker to measure response or progression of brain metastasis after SRS.