The U.S. Nuclear Regulatory Commission (NRC) is amending its regulations related to the medical use of byproduct material. The final rule will amend the NRC regulations related to the medical use of byproduct material. This rule amends the reporting and notification requirements for a medical event (ME) for permanent implant brachytherapy. This rule also amends the training and experience (T&E) requirements to remove from multiple sections the requirement to obtain a written attestation for an individual who is certified by a specialty board whose certification process has been recognized by the NRC or an Agreement State; and address a request filed in a petition for rulemaking (PRM), PRM-35-20, to exempt certain board-certified individuals from certain T&E requirements (i.e., "grandfather" these individuals). Additionally, this rule amends the requirements for measuring molybdenum contamination; adds a new requirement for the reporting of failed technetium and rubidium generators; and allows licensees to name associate radiation safety officers (ARSOs) on a medical license.