Transcatheter chemoembolization is an interventional procedure in which chemotherapy drugs are injected into the liver to kill tumor cells. During chemoembolization, a catheter is inserted through a small nick in the skin of the groin and is then guided via x-ray image to the liver or the site of the tumor. Contrast agent or dye is injected into the blood vessels in order to highlight the arteries. The catheter is used to visualize the blood vessels that supply blood to the tumor, where chemotherapy drugs and tiny particles are injected. Once injected particles decrease blood flow and concentrate the chemotherapy drugs within the tumor in order to shrink its size.