Most of the liver tumors cannot be surgically removed because of their large size or proximity to life-threatening structures. Sometimes, the disease can cause small but many tumors to spread to the liver. In this case, surgery is both very risky and not practical. Surgical removal is not possible in two-thirds of primary liver cancer patients and more than 90 percent of patients with metastatic (secondary) liver cancer for these reasons. In patients with inoperable liver cancer, one of the treatment options is Yttrium-90 microsphere treatment.