Patent Number: 042016258
Section: summary

The present invention concerns a process for producing .sup.52 manganese by a nuclear reaction in which a target having a metal atom content is bombarded with accelerated ions of small mass, after which the .sup.52 manganese formed from the metal atoms by nuclear reaction is isolated by means of a chemical separation process. .sup.52 Manganese is of interest in the field, along others, of nuclear medicine; for example, for the diagnosis and/or therapy of blood diseases. According to the known process of production (Radioisotope Production and Quality Control, IAEA, Vienna, 1971, Technical Report No. 128, p. 805), the .sup.52 manganese isotope is produced by bombarding chromium or iron with protons or deuterons. In this process, along with the desired .sup.52 manganese, the isotope .sup.54 manganese is also produced. .sup.54 Manganese is undesired, however, because it has a substantially longer half-life (312 days) than .sup.52 manganese (5.7 days), so that on account of the higher radiation exposure of the patient, limits are imposed on its use in nuclear medicine. .sup.54 Manganese can be separated out of an isotope mixture with .sup.52 manganese only with great difficulty and at great expense. THE PRESENT INVENTION It is an object of the present invention to provide a process by which .sup.52 manganese can be obtained in a relatively simple manner. Briefly, a target containing vanadium is bombarded with .sup.3 helium ions and the .sup.52 manganese produced thereby is isolated chemically from among the target materials. .sup.52 Manganese is formed from vanadium by .sup.3 helium bombardment by the following nuclear reactions: EQU .sup.50 V(.sup.3 He,n).sup.52 Mn; Q=8,3 MeV EQU .sup.51 V(.sup.3 He,2n).sup.52 Mn; Q=-2,7 MeV .sup.50 V and .sup.51 V are contained in natural vanadium to the extent respectively of 0.25% and 99.75%. According to a particularly simple manner of carrying out the process of the invention, the target is simply constituted by a vanadium foil, which is then dissolved in acid after the .sup.3 He bombardment. The .sup.52 manganese is then chemically isolated from the solution. The nuclear reaction of vanadium with .sup.3 helium ions suited for the production of .sup.52 manganese takes place also in the presence of other substances, so that it is also possible to utilize a target in which vanadium is present in an alloy or in a chemical compound, in which case, the accompanying chemical elements should not produce any disturbing or interfering reactions upon .sup.3 helium bombardment. Since .sup.52 manganese is produced from both .sup.50 V and .sup.51 V upon .sup.3 He bombardment, it is possible to use for the production of .sup.52 manganese according to the invention, a vanadium-containing target of which the vanadium has an isotope distribution that varies from the natural isotope distribution in vanadium. Measurements of the radioactivity immediately after the .sup.3 He irradiation show the presence of short-living nuclides as .sup.52m Mn, .sup.51 Mn, .sup.49 Cr and .sup.52 V. The decay of .sup.51 Mn with a half-life of 46 minutes yields the likewise radioactive .sup.51 Cr having a half-life of 27.7 days which should be absent in the prepared .sup.52 Mn. Therefore a delay period for the substantial decay of .sup.51 Mn is preferred between the irradiation of the target and the chemical separation of manganese. After such a delay the high purity of the .sup.52 Mn can be perceived. .sup.3 He ions having an energy of about 14 MeV are preferred for the .sup.3 He bombardment of the target.