Question: If a radiologist is not an Authorized User (AU) on an NRC license at an institution, what duties may he or she perform in the nuclear medicine laboratory of that facility?

Answer: The NRC recognizes that it is frequently necessary for an AU (Authorized User) to delegate to other individuals the specific tasks associated with preparing and administering byproduct material (radiopharmaceuticals) for medical uses in patients (10 CFR 35.27). These individuals include technologists, and other physicians who may not be authorized users. If the policies and procedures of the institution holding an NRC radioactive materials license allow, the NRC regulations (10 CFR 35, subparts D* & E**) permit delegation of these duties, if the individuals performing the duties are properly instructed and supervised. The supervising AU need not be physically present for delegated use of byproduct material used under subparts D & E. Further, there is no requirement by the NRC that diagnostic studies performed using byproduct material (radiopharmaceuticals) be interpreted by an AU. Thus, the NRC regulations do not restrict who can read and interpret diagnostic scans or the results of therapeutic procedures (i.e., radiologists who are not authorized users may interpret such studies). However, it is strongly recommended that those radiologists practicing in NRC Agreement States consult the appropriate state regulatory agency to ensure that the state regulations allow for this delegation.

According to NRC regulations, only an AU can sign a written directive, including those necessary for therapeutic procedures involving unsealed byproduct material (e.g., treatment of hyperthyroidism, ablation of residual function thyroid tissue, or treatment of functioning thyroid metastases using I-131). However, administration of the therapeutic unsealed byproduct dose specified in the written directive may be delegated, if the individuals performing the administration are properly instructed in the written directive procedures and supervised accordingly.

*Subpart D- Unsealed Byproduct Material - Written Directive Not Required

**Subpart E - Unsealed Byproduct Material - Written Directive Required