The Nuclear Regulatory Commission (NRC) is amending its regulations regarding the medical use of byproduct material. The direct final rule will clarify the definitions of authorized users, authorized medical physicists, authorized nuclear pharmacists, and radiation safety officers; clarify the notification requirements if the patient is in a medical emergency or dies; clarify the recordkeeping requirements for calibration of brachytherapy sources; correct the title for the National Institute of Standards and Technology; clarify that prior to October 24, 2004, individuals who meet the training and experience requirements in Subpart J may undertake responsibilities specified in certain sections in Subparts B and D-H; and eliminate a restriction that training for ophthalmic use of strontium-90 can only be conducted in medical institutions. These amendments are necessary to clarify certain inconsistencies within the regulations and to allow training in ophthalmic treatment to be conducted in eye clinics or private practices, in addition to medical institutions.