RecruitingPhase 2Drug trialUltralow Dose PET Imaging of 18F-FDG UptakeThe goal of this clinical trial is to evaluate an investigational ultralow dose PET imaging technique for cancer detection and monitoring. The main question it aims to answer is: Can the investigators optimize the timing, scan duration, and image reconstruction to reduce the radiation dose 10-100 fold of the current clinical standard? Participants will be injected with a radioactive tracer called 18F-FDG and be imaged on a new type of high-sensitivity PET scanner for up to 3 hours.