Reactor Production of Radionuclides for Generators

Abstract

In this review the salient aspects of reactor production of parent radionuclides which may be used for the preparation of generators for bio-medical, industrial and research applications are briefly discussed: preparation and selection of targets, optimum reactor irradiation, radiochemical processing and purification, specific activity, radionuclidic and other purity aspects, cost of production. The "Mo-" m Tc generator is only briefly considered owing to its wide coverage in the recent literature.

Radionuclides, 2. Radioactive Elements and Artificial Radionuclides

“…It is easily adsorbed by metal surfaces and extracted from aqueous solutions by, for example, benzene or CCl 4 . Strong reducing agents form At Organometallic compounds such as C 2 H 5 At or C 6 H 5 At were synthesized in tracer quantities by using iodine as nonisotopic carrier as well as, for example, astatine acetic acid (AtCH 2 COOH) or astatine-labeled radiopharmaceuticals (gglobulin, albumin, etc.).…”

“…Devices for this purpose are called charged-particle accelerators. Both sets of systems were initially developed during the 1930s and then adapted to a large scale during World War II as part of the Manhattan Project [3,4].…”

“…While the smaller (''baby'') cyclotrons are usually single-beam machines, all the others can accelerate both protons and deuterons (the latter at half-proton energy). Acceleration of 3 He and 4 He particles requires energies > 18 MeV. Higher-energy cyclotrons (> 40 MeV) are required for the production of fast-neutron and proton beams suitable for cancer chemotherapy.…”

“…Another powerful application of neutron beams takes advantage of a ''neutron generator,'' which can be utilized for the preparation of certain short-lived radionuclides, especially in laboratories without access to a reactor or a cyclotron. A neutron generator is a source of high-energy fast neutrons, and is based on a reaction between deuterium and tritium: 3 Hðd; nÞ 4 He ð9Þ…”

“…Alternatively, it is possible to achieve high activities (both total and specific) of no-carrieradded reactor-produced radionuclides through indirect (n, g) sets of reactions, e. One advantage of this approach is that the reaction yields need not be high, since high activities can be achieved by irradiating large quantities of target nuclei, followed by chemical purification of the desired radionuclide [4]. In the irradiation of 130 Te, the intermediate 131 Te (t 1/2 ¼ 25 min) decays to 131 I (t 1/2 ¼ 8 d).…”