title: Investigation of recoil collection method for production of high specific activity nuclear medicine isotopes.
abstract: High specific activity radiopharmaceuticals cannot readily be produced by (n, gamma) reactions in nuclear reactors, because the great abundance of parent atoms remaining have the same chemical characteristics as the produced isotope. We have investigated the effectiveness of using recoil atom collection methods for separating the produced radioisotope. Gold-198, produced from isotopically pure (natural) gold-197, was chosen for these experiments, which were run in the high flux (approximately 10(14) n/cm2 s thermal flux) of the reflector of the University of Missouri Research Reactor. Seven separate experiments were run, with a 2 mm separation between the emitter and the collector. Collection efficiencies were only a few percent of the radioisotope atoms produced in the top atomic layer of the emitter, instead of the 30% range anticipated. Furthermore, the collected radioisotope, instead of being nearly pure, contained a large quantity of the parent. Unless the reason for the "contamination" of product with the parent can be reduced by several orders of magnitude, this "surface hot atom recoil" method appears to offer no practical application for nuclear medicine isotope production.
authors.affiliation: Department of Radiological Technology, Chung-Tai Medical College of Technology, Taiwan, Republic of China.
authors.forename: K Y
authors.initials: KY
authors.lastname: Cheng
authors.forename: J F
authors.initials: JF
authors.lastname: Kunze
authors.forename: G J
authors.initials: GJ
authors.lastname: Ehrhardt
mesh_terms: D055592:Biophysical Phenomena; D001703:Biophysics; D004340:Drug Contamination; D005069:Evaluation Studies as Topic; D006046:Gold / Q000302:isolation & purification; D006050:Gold Radioisotopes / Q000302:isolation & purification; D006801:Humans; D019275:Radiopharmaceuticals / Q000302:isolation & purification*
chemical_list: D006050:Gold Radioisotopes; D019275:Radiopharmaceuticals; D006046:Gold