What is the mechanism and typical use of Y-90 radioembolization in hepatocellular carcinoma?

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Y-90 radioembolization uses tiny beads loaded with the beta-emitting isotope yttrium-90 that are injected into the hepatic artery branches feeding the tumor. Because hepatocellular carcinoma gains most of its blood supply from the hepatic artery, the beads lodge in the tumor’s microvasculature and deliver a high, localized radiation dose while sparing most normal liver tissue that relies more on the portal vein. This targeted radiotherapy causes tumor cell death with relatively limited systemic exposure.

It is typically used when the tumor is unresectable or when downstaging is desired to enable resection or liver transplantation, or when transarterial chemoembolization is unsuitable or has failed. It can also be advantageous in patients with portal vein thrombosis, where embolic therapies carry higher risk. Before the procedure, mapping angiography and a technetium-99m MAA scan assess arterial anatomy and potential shunting to non-target sites, guiding safe and effective treatment.