This guidance summarizes the investigational new drug application (IND) process for unapproved positron emission tomography (PET) drugs, makes recommendations on how to submit an IND, provides advice on investigational PET drug access options, and describes the process for requesting permission to charge for an investigational PET drug. This guidance does not describe all the considerations relevant to an Expanded Access submission or to an IND Request to Charge submission. For details about these processes, we encourage sponsors to review the applicable regulations and advice available on the FDA Web site.