Technical note: simultaneous ⁹⁰Y and ^99mTc-MAA injection for two-stage selective internal radiation therapy (SIRT) of liver metastases

Transarterial Radioembolization (TARE) with 90-Yttrium (⁹⁰Y) microspheres has been established in the management paradigm of a number of primary and metastatic liver neoplasms. Prior to treatment, angiographic assessment and ^99mTc-macroaggregated albumin (Tc-MAA) hepatic arterial perfusion should be performed to detect extrahepatic shunting to the gastrointestinal tract or the lungs. Wholeliver radioembolization is not desirable in subjects with compromised hepatic reserve due to the increased likelihood of RE induced liver disease. In cases with diffuse hepatic involvement, superselective segmental and/or sequential lobar TARE is often utilized to decrease the side-effect profile with intra-arterial Tc-MAA injection playing a critical role in confirming pulmonary shunt fraction and the possibility of non-targeted embolization. Given the complexities of treatment planning, and in order to improve on the efficiencies of treatment without compromising safety, the feasibility of simultaneous ⁹⁰Y RE and Tc-MAA injection into another segment/lobe for subsequent (second stage) treatment planning would be desirable to minimize additional angiography sessions. Here we present our initial experience with two patients undergoing sequential staged TARE therapy for diffuse hepatic metastases.