دانلود رایگان مقاله تولید رادیوایزوتوپ علوم پزشکی با پرتو ذرات آلفا

Abstract

The internal α-particle beam of the Warsaw Heavy Ion Cyclotron was used to produce research quantities of the medically interesting Sc radioisotopes from natural Ca and K and isotopically enriched 42Ca targets. The targets were made of metallic calcium, calcium carbonate and potassium chloride. New data on the production yields and impurities generated during the target irradiations are presented for the positron emitters 43Sc, 44 gSc and 44 mSc. The different paths for the production of the long lived 44 mSc/44 gSc in vivo generator, proposed by the ARRONAX team, using proton and deuteron beams as well as alpha-particle beams are discussed. Due to the larger angular momentum transfer in the formation of the compound nucleus in the case of the alpha particle induced reactions, the isomeric ratio of 44 mSc/44 gSc at a bombarding energy of 29 MeV is five times larger than previously determined for a deuteron beam and twenty times larger than for proton induced reactions on enriched CaCO3 targets. Therefore, formation of this generator via the alpha-particle route seems a very attractive way to form these isotopes. The experimental data presented here are compared with theoretical predictions made using the EMPIRE evaporation code. Reasonable agreement is generally observed.

5. Summary and conclusions

The alpha-particle beam from the cyclotron at the Heavy Ion Laboratory, University of Warsaw was used to produce quantities of medically interesting Sc isotopes sufficient for chemical and animal studies using natural and isotopically enriched Ca targets and natural K targets. The production efficiency and the generated impurities were determined for the prospective positron emitters 43Sc, 44 gSc and 44 mSc. It was demonstrated that a highly pure (purity of 4∙10−4 at EOB) 43Sc positron emitter can be produced with a natural Ca target and an extremely pure one (purity better than 10−6 at EOB) with a cheap, enriched 40Ca target. It was also demonstrated that the production of the recently proposed in vivo 44 mSc/44 gSc generator can benefit from the substantially larger angular momentum transfer with alpha particles in comparison with deuteron induced reactions. However, the large scale production of these isotopes will be only possible if a high power target device for calcium carbonate is available.