Yttrium-90 (90Y) radioembolization is delivered via arterial supply to the liver. Hepatic neoplasms receive greater than 80% of their perfusion from the hepatic arteries, while the normal hepatic parenchyma receives the majority of its blood supply from the portal vein. is dierential blood supply allows for the arterial delivery of relatively large radiation doses to the tumor with relative sparing of normal liver parenchyma (Welsh et al., 2006). 90Y radioembolization for primary and/or secondary neoplasms of the liver necessitates a thorough understanding of hepatic arterial anatomy to ensure safety and ecacy. e interventionalist must be aware that variations in the arterial supply to the liver are common and that these anatomic variations aect both hepatic lobes.