Tumor vasculature (Hepatic)

The target refers to the hypervascularized arterial network and capillary bed of solid tumors, most commonly within the liver. Unlike healthy hepatic tissue which receives the majority of its blood supply from the portal vein, malignant liver tumors are primarily supplied by the hepatic artery (Salem et al., 2010). This physiological difference is exploited by delivering Yttrium-90 (Y-90) microspheres via the hepatic artery, where they become physically entrapped in the small precapillary vessels of the tumor (Kennedy et al., 2007). Once lodged, the Y-90 isotope emits high-energy beta radiation with a limited tissue penetration (average 2.5 mm), allowing for the delivery of lethal radiation doses to the tumor while sparing surrounding healthy parenchyma (Goin et al., 2005). This dual approach combines micro-embolization with localized radiotherapy to induce tumor necrosis and control disease progression in patients with unresectable primary or metastatic liver cancer (Sangro et al., 2011). The entrapment is permanent, and the radiation effect occurs over several weeks as the isotope decays. Clinical efficacy is often monitored through imaging and serum tumor markers, while safety is managed by pre-treatment mapping to prevent non-target radiation delivery to the lungs or gastrointestinal tract.

Other names

Tumor microvasculatureHepatic arterial tumor bedHypervascular tumor tissueTumor capillary network

Selective internal radiation therapy (SIRT) via physical entrapment of radioactive microspheres in the tumor's precapillary bed, leading to localized high-dose beta radiation and microvascular embolization.