This issue of PET Clinics focuses on Theranostics and is edited by Drs. Ali Gholamrezanezhad and Hojjat Ahmadzadehfar. Articles will include: Good Clinical Practice for Theranostics; Theranostics in Neuroendocrine Tumors; Neuroendocrine Tumors: Imaging Perspective; Prostate Cancer Theranostics: From Target Description to Imaging; Prostate Cancer Theranostics: PSMA-targeted Therapy; Theranostics in Brain Tumors; Theranostics in Neuroblastoma; Theranostics in Thyroid Cancer; and more!