Patients unable to lie flat comfortably for 2 hours Unable to lie flat during or tolerate PET/MRI, PET/CT or SBRT Patients must be able to lie flat for at least 60 minutes and fit on a PET-CT scanner Unable to lie flat, still or tolerate a PET scan Unable to lie flat, still or tolerate a PET scan Unable to lie flat, still or tolerate a PET scan SUB-STUDY I: Unable to lie flat during or tolerate PET/CT SUB-STUDY II: Unable to lie flat during or tolerate PET/CT SUB-STUDY III: Unable to lie flat during or tolerate PET/CT Unable to lie flat, still or tolerate a PET scan Unable to lie flat during or tolerate PET/MRI Unable to lie flat during or tolerate PET/CT Unable to lie flat, still or tolerate a PET/CT scan Unable to lie flat, still or tolerate a PET scan Patients must be willing to lie flat on their back in the PET/CT scanner for up to 2 hours to allow the imaging data to be obtained Patients must be able to lie flat for at least 60 minutes and fit on PET-CT scanner