Nuclear Medicine Tecnnology and Other Health Applications Extension and Project Title: L\4. Scope: Improvement of Radiographic and Diagnostic Techniques Isotopic RX-01-03-(c) (Cent'd,) derivatives will be studied for localization of ocular and, melanomas, probably, other The gonadal radiation dose to the population at large from radioisotopic procedures used in Nuclear Medicine today, though still acceptably small, has increased greatly over the past ten years, If the trend continues, the dose incurred by the population at large could become significant. Therefore, development and use of short-lived radionuclides which can provide the same or better information at a lower radiation dose is emphasized, [1-123 is an example, When used for thyroid diagnosis, the gonadal dose is 1/100 of that from I-131, Thyroid disease is common in women of child-bearing age. Studies on application wf I-123 will be extended with its replacement of I-131l and I[-125 as labels for other radiopharmaceuticals., The amino acid, tryptophan, produces ortho-amino«phenol \* (Atkins) type compounds believed to induce cancer in animal urinary bladders. In several types of cancer and in other diseases of man, the literature reports significant increases in urinary levels of some tryptophan metabolites. Carbon-14 labeled metabolites are used in animals and man to determine the normal tryptophan metabolic pathway. The labeled metabolites include anthranilic acid, kynurenine, hydroxykynurenine, and hydroxyanthranilic acid, Diseases studied include anemias, scleroderma, siderosis, malaria, pellagra, and various cancers, These studies will be reported for FY 1974 and 1975 in RX-01-03-(e). 15. (Hankes) Relationship to Other Projects: - Similar investigations involving radiopharmaceuticals and cyclotronproduced nuclides are carried out at many institutions, However, BNL is in an exceptional position due to the presence of several high energy accelerators of unusual capabilities as well as an interdisciplinary cooperative program including the Medical Department, Chemistry Department, Department of -Applied Science,and the Instrumentation Division. Particular expertise exists here which would be difficult to find in all these fields in any one other institution, (Atkins) Research projects related to the tryptophan studies are detailed Section 15 of RX-01-03-(e). in hnical Progress in FY 1973: Technetium-labeled red blood cells were evaluated for splenic imaging and showed promise for blood pool and vascular imaging. Tc-99m-DTPA is now in routine use for renal studies and is being compared to [-131 hippuran for evaluation in hypertension, (See Continuation Sheet) 147921 RX-59