SIR-Spheres Y-90 resin microspheres target liver tumors with targeted radiation via the hepatic artery during Selective Internal Radiation Therapy (SIRT). Data presented at ASCO showed a 7.9 month improvement in PFS in the liver for patients with unresectable mCRC treated 1st line with SIR-Spheres Y-90 resin microspheres plus standard chemotherapy.