Background: Our goal was to study the efficacy of liver cancer embolization with magnetically targeted Yttrium-90 labeled ferromagnetic particles and establish the biodistribution profile of these particles. Materials and Methods: Of twenty rabbits, nine underwent transarterial radioembolization of implanted Vx-2 tumor with increasing 90 Y-MTC doses, three were treated with carrier particles alone, four remained untreated and four were sacrificed early to document biodistribution. At various intervals, animals were sacrificed and biodistribution, liver cancer viability and toxicity were measured. Results: There was a dose related degree of tumor necrosis, with greater than 90 Gy yielding 100% necrosis (baseline 50%). Blood radioactivity one hour post- radioembolization was less than 0.0275 ICi/g. No hematological toxicity was observed. Except for the non-targeted right liver lobe, organ radioactivity levels were within tolerance levels. Significant left (targeted) hepatic lobe necrosis was seen in subjects receiving high doses. Conclusion: Hepatic arterial radioembolization with 90 Y-MTC bolstered by external magnetic field has significant tumoricidal effect and a favorable biodistribution profile. Many loco-regional treatments, including selective internal radiation therapy (SIRT) with Yttrium-90 ( 90 Y) microsphere radioembolization, are currently available for unresectable liver neoplasms. Preliminary evidence suggests a survival benefit (1) in selected patients. A major concern however, is the risk of non-target embolization, especially lung, which can