Accreditation: the process by which institutions or facilities (e.g. laboratories) are assessed and recognized as having met a prescribed standard.

Agreement State: a state that has entered into a compact with the Nuclear Regulatory Commission under the Atomic Energy Act Amendments of 1980 for the purpose of administering its own health and safety requirements for the use of either high-level (nuclear power plants) or low-level (medical uses) radioactive materials. States agree to require standards specified by the NRC but may also add additional requirements in many areas.

Under the new 10 CFR Part 35 rule effective April 29, 2005, training and experience requirements in Agreement States must become "compatible" with NRC requirements by April 29, 2008.

Authorized User: the status granted by either the Nuclear Regulatory Commission (NRC) in the 17 Non-Agreement states or by a state agency in the 33 Agreement States allowing physicians to use medical isotopes. Each office or facility performing nuclear cardiology procedures must have at least one Authorized User.

Certification: the voluntary process by which practice-based requirements of the profession are assessed on individual practitioners and formal recognition granted.

Credentialing: the privilege to perform, interpret, and seek professional reimbursement for nuclear cardiology services as determined at individual hospitals by the guidelines established by the Joint Commission on Accreditation of Hospitals (JCAHO). JCAHO does not determine the exact qualifications for specific privileges in nuclear cardiology, but rather that a mechanism be in place at each hospital for determining staff member privileges. Thus, each hospital establishes its own mechanism for assessing the qualifications of individual physicians and considerable variability exists between individual institutions.

Licensure: This term is somewhat confusing in that it is used both for the medical license all physicians must have from a state to practice medicine and also for the authority granted to a facility by the NRC or Agreement State to use medical isotopes. To be licensed to use nuclear materials or operate a facility that uses nuclear materials, an entity or individual submits an application to the NRC or the appropriate governmental agency within an Agreement State. The staff reviews this information, using standard review plans to ensure that the applicant's assumptions are technically correct and that the environment will not be adversely affected by a nuclear operation or facility.

Non-Agreement State: those states under the direct authority of the NRC in terms of regulation of use of byproduct material for medical isotopes and application for licensure and authorized user status.

NRC: Nuclear Regulatory Commission. NRC's primary mission is to protect the public health and safety, and the environment from the effects of radiation from nuclear reactors, materials, and waste facilities. They also regulate these nuclear materials and facilities to promote the common defense and security.