The findings suggest that the IP delivery of both USPIO and SPIO might be useful as a contrast agent for the study of lymph nodes in a clinical setting. The IP delivery of USPIO might also be used as a contrast agent for studying the liver. As IP delivery is not a popular injection route in clinical settings, drugs or contrast agents are currently intraperitoneally injected in limited cases of patients with cancer, peritonitis, or chronic renal failure requiring continuous ambulatory peritoneal dialysis (CAPD). 24, [28] [29] [30] Although clinical application is limited, the authors suggest, for cases of patients with ascites of unknown origin, that intraperitoneally injected iron particles may be very useful for getting Kupffer images of the liver and lymph node images to help diagnose metastases in these areas. Also, in cases of iron-deficient CAPD patients, intraperitoneally injected iron dextran has potential for filling both roles, as a route of entry in iron therapy and as a contrast agent for the liver and lymph nodes. In addition, depending on the diameter of the administered particles, it may be possible to deliver agents other than USPIO and SPIO intraperitoneally for the study of various organs.