Oily iodine compounds currently employed in myelography and lymphography are far from ideal as diagnostic contrast agents. The high viscosity of iodized oils renders the process of administration difficult and time-consuming and inflammatory responses and hypersensitivity to iodine compounds have been observed. Our laboratory has developed a new constrast agent -perfluoroctylbromide (C8F17Br). This radiopaque perfluorocarbon is extremely stable physically and chemically and is also biologically inert. The efficacy and safety of per-fluoroctylbromide in bronchography, alveolography and gastroenterography have been established in laboratory animals and are being tested in human beings. Experiments in myeleography and lymphography show that C8F17Br is well tolerated. It is much less irritating than Pantopaque to the arachnoid tissue and no convulsion or muscle spasm is encountered. Furthermore, due to perfluorocarbon's low surface tension and low viscosity, administration of this substance is easier than with other constrast media both in intrathecal and of C8F17Br in myelography and lymphography and to develop preparations and techniques for its applicantions. The biological disposition of C8F17Br will also be investigated following various routes of administration. Our utimate goal is the clinical application of perfluoroctylbromide in evaluation of the structure and function of the central nervous system and the lymphatic system.