The proposed research is a multifaceted approach to the use of radiotracers in the diagnosis and treatment of human cancer. The objective is to organize the talents and marshal the resources and facilities which are available at this institution and to focus them on the manner in which radiolabeled antibodies, trace elements, drugs, natural metabolites, and techniques of saturation analysis and radioimmunoassay may be applied to: 1) the diagnosis of the presence of a neoplastic process, 2) if present, to determine the extent and location of the disease process, and 3) the epidemiological study of cancer. In those persons who have an established diagnosis of cancer and for whom therapy has already been instituted, radiolabeled tracer studies will be used to 1) follow the results of treatment (especially the changes in the extent of the disease, changes in levels of tumor-specific antigen, as well as changes in levels of antitumor antibodies present), 2) monitor differences in uptake of drugs, normal metabolites, and tracer elements between normal and neoplastic tissue, 3) correlate the uptake of labeled drugs with the routes by which the drugs are given to determine the route resulting in greatest tumor retention (e.g., intraarterial vs. intravenous), 4) determine if tumor retention is related to therapeutic effect, and 5) determine if dose schedules can be optimized to show greatest tumor retention. This information would serve to guide existing chemotherapeutic methods which are, to a large extent, empirical. If sufficiently high uptake of any substance is shown, the use of highly radioactive substances as localized radioactive sources for treatment may be possible and may be subsequently evaluated.