RecruitingProcedureTargeted Therapy to Increase RAI Uptake in Metastatic DTCPapillary thyroid cancer (PTC) is a common type of differentiated thyroid cancer (DTC) in children and represents the second most common cancer in adolescent females. Recently targeted drugs that block many of the genetic drivers of DTC have become available. While Investigators know that these drugs shrink DTC tumors in many cases, the impact on radioactive iodine (RAI) avidity has not been systematically studied.