This paper is an adaptation of the hierarchical model of the efficacy of diagnostic imaging systems by Fryback and Thornbury. The original scheme was designed to evaluate new medical imaging systems, but is less successful when applied to evaluation of new radiopharmaceuticals. The new proposed scheme is specifically directed toward the evaluation of targeted imaging agents. The six levels of the new scheme are: In-vitro characterization, In-vivo animal studies, Initial human studies, Impact on clinical care (change in management), Impact on patient outcome, and Societal efficacy. These levels, particularly the first four, implicitly define the sequence of studies that are necessary to move a new agent from the radiochemistry synthesis laboratory to the clinic. It is suggested that completion of Level Four (Impact on clinical care) should be sufficient for initial approval and reimbursement. It is hoped that these suggestions will help streamline the process and assist in bringing new, targeted radiopharmaceuticals to approval in the next few years.