The central vein constructed by the superior and inferior vena cava is the largest vein of the body draining all the blood from the entire body into the right atrium of the heart. Thus, this central vein is suitable for the administration of irritating drugs and long-term continuous or repeated infusions, because administered drugs are sufficiently diluted by the abundant blood flow. However, catheter placement is necessary for administering drugs directly into the central vein. Therefore, a central-venous port is well suited for situations requiring long-term central venous catheter placement for better treatment. In general, the terms “central-venous port” or “central-venous access port” refer to the entire implanted system consisting of a catheter and a port.