RADIOISOTOPES

α-Cyano-3-phenoxybenzyl 2, 2, 3, 3-tetramethylcyclopropanecarboxylate (fenpropathrin), a new potent synthetic pyrethroid, was labelled with carbon-14 at the cyclopropyl group for studies on its metabolism in mammals, fishes, plants and soils. Condensation of potassium cyanide-¹⁴C (2) with 1, 3-diphenyl-2-thiourea (3) in the presence of basic lead carbonate gave 1-eyano-¹⁴C-N, N'-diphenylformamidine (4) . Reduction of 4 followed by hydrolysis with barium hydroxide afforded glycine-2-¹⁴C (6) . Esterification of 6 with ethanol in the presence of anhydrous hydrogen chloride gave ethyl glycinate-2-¹⁴C hydrochloride (7) . Diazotization of 7 followed by condensation with 2, 3-dimethyl-2-butene yielded ethyl 2, 2, 3, 3-tetramethylcyclopropane-1-¹⁴C-earboxylate (8) . Hydrolysis of 8 gave 2, 2, 3, 3-tetramethylcyclopropane-1-¹⁴C-carboxylic acid (9), which was esteri feed with a-eyano-3-phenoxybenzyl bromide (10) to afford fenpropathrin- (cyelopropyl-1-¹⁴C) (1) in 13% yield from 2.

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This paper describes a control system of stockers for radioactive source in storage room at laboratory for tracer experiment. The system is composed of a personal computer, a locker controller, three card readers, a monitor TV, and a video tape recorder (VTR) . The personal computer controls other equipment with a registered user's number. When a user inserts an identification card into the card reader, the computer memorizes assigned gate number, the user's number and the time; it processes those data and prints out a document. The locker controller releases the electric key o f user's locker which is designated by the computer. The VTR records the person entering into the storage room to identity i f he uses his card. This system proved to effectively prevent intrusion into the storage room of an unregistered person or to use carelessly other user's source; in addition it can record precisely the stock of radioactive source.

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An on-line computer system for administration of the radioisotope use has been developed. This system consists of a multi-job type host computer and two sets of personal computers with identification card readers. The personal computers are employed as terminal devices for radioisotope users. By the use of an identification card, entrance and leaving times are recorded automatically. Furthermore, an easy operation of the personal computer permits users to access to the information of their resistered radioisotopes, such as nuclides, chemical forms, updated activities, storage locations, and history of usage. A recording sheet on which those data are printed is provided from the personal computer. After the use of radioisotopes, users can record their data on the recording sheets. These records are used as the input data to this system to update the data of the used radioisotopes. Owing to the concise format of the recording sheet and various sorting programs developed in present work, this system enables us to grasp the exact flow of the radioisotopes from purchase to disposal. Out-put data from high-speed kanji printer can provide many important books which are legally requested to be kept for administration of the radioisotope use.

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