This work was a collaborative effort by volunteer professionals in the nuclear medicine sciences in cooperation with the staffs of the Society of Nuclear Medicine (SNM) and the Nuclear Regulatory Commission (NRC). Alan H. Maurer, MD, was among those who first proposed the need for such a volume, and it was through his organizational efforts that work on the project began. The draft was reviewed by the SNM Board of Directors, the American College of Nuclear Physicians (ACNP) Board of Regents, the Members of the ACNP/SNM Government Relations Committee, and members and staff of the American College of Radiology. NRC staff provided additional information. Of special assistance.