Road to becoming Y-90 authorized user as an integrated vascular and interventional radiology resident (NRC alternate pathway)

Abstract

Yttrium-90 (Y-90) radioembolization, also called transarterial radioembolization (TARE), is a catheter-directed therapy for direct delivery of internal radiation to tumors in the form of microspheres. It is currently available in two forms, either as a constituent of glass microspheres called TheraSphere^® (BTG Ltd., London, UK [now Boston Scientific, Marlborough, MA, USA]) or as a biocompatible resin-based microsphere called SIR-Spheres^® (Sirtex Medical Ltd., Woburn, MA, USA). Once these microspheres are delivered to the tumor through an arterial pathway, they are embedded within the tumor microcirculation and emit β-radiation at therapeutic levels. TARE is a commonly used treatment for unresectable primary or secondary hepatic malignancies and has led to improved survival rates and increased success rates in downstaging patients before liver resection or transplantation. Immediately following the pre-treatment angiogram, each patient undergoes a nuclear medicine study, otherwise known as technetium (^99mTc) macroaggregated albumin scan, to determine the amount of radiotracer that has accumulated in the lungs (lung shunt fraction). Finally, after several calculations, the appropriate radiation dose to be delivered to the tumor is determined. While the technical aspects of radioembolization are quite complex, the collective clinical experience presented in the literature supports the use of Y-90 radioembolization for unresectable hepatic malignancies. Those ordering and administering radioembolization particles must be deemed an authorized user (AU) by the Nuclear Regulatory Commission (NRC). The NRC defines an AU as the individual responsible for ensuring that radioactive materials are handled and used safely and following NRC regulations and the terms and conditions of the NRC license. The NRC has published licensing guidance on Y-90 brachytherapy with the 10^th revision released on November 8, 2019. This guidance has outlined specific requirements for obtaining a license for the use of TheraSphere and SIR-Spheres. Following the revised licensure guidelines from the NRC on Y-90 usage, a conditional authorization has been obtained at our institution by the PGY-6 interventional radiology/diagnostic radiology (IR/DR) resident. While the full guidelines and extensive alternative requirements can be found online, we will highlight the specific guidelines applicable to and fulfilled by IR/DR residents. The traditional ABR pathway takes approximately 18 months after graduation, including passing the ABR certification examination to become an AU. With the proposed alternate pathway, trainees will potentially become AU immediately after graduation. The primary aim of this submission is to describe the process for obtaining conditional authorization for Y-90 microspheres for PGY-6 IR/DR residents.