Regulating alpha-emitting radioisotopes and specific considerations for actinium-225 containing actinium-227.

Although alpha-emitting radioisotopes have favorable characteristics for limiting external exposure to radiation workers, there are significant dose consequences associated with accidental internal uptake. Consequently, regulatory requirements and license restrictions are designed to limit such risks to users. This paper will review regulatory limits for decommissioning financial assurance and annual limits on intake for actinium-227, review US Nuclear Regulatory Commission guidance for alpha contamination monitoring, and discuss regulatory examples from the Wisconsin Department of Health Services.