Japan SUMMARY I5O-H2O2 is thought t o be a candidate o f attractive injectable tracers for the study of oxygen metabolism with PET. A simple synthetic method yielding I5O-H 0 in saline solut' n by the autoxidation of 2-ethylanthrahydroquinol with gaseous "0-0, produced by cyclotron target system is described.

SUMMARY2-1eF-phenylalanine and 3-leF-tyrosine were synthesized by direct electro hilic substitution of L-phenylalanine and Ltyrosine with PeF-acetylhypofluorite. obtained in 30 % radiochemical yield based on l$F-acetylhypofluorite within 60 min after the end of irradiation. In rat brain, 30 % of the radioactivity was fixed into acid-insoluble macromolecules and most of the free radioactivity existed as amino acids at one hour after 2-1eF-phenylalanine injection. In the case of 3-leF-tyrosine, significant amounts of radioactivity existed as organic acids. The catecholamine fraction had negligible radioactivity in both cases. These results indicate that 2-leF-phenylalanine is suitable for compartmental analysis for tissue accumulation because of its simple metabolic behavior.Both com ounds were

SUMMARYFluorination with 18F-F2 and 18F-AcOF were compared for the synthesis of 18F-fluorophenylalanines. L-phenylalanine in CF,COOH trapped 18F-AcOF more effectively than 18F-F2. The main product was ortho-18F-fluorophenylalanine when 18F-AcOF was used as a reagent. Lower radiochemical yield of 18F-fluorophenylalanines and si nificant formation of by-product were observed in the case o f feF-F,.

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