Radioisotopes developed and produced by cyclotron for nuclear medicine

Radioisotopes (RI) produced by cyclotron are becoming more and more important not only for SPECT and PET diagnoses but also for therapeutic uses in nuclear medicine. The present review describes the developing states of positron emitters and nuclides for nuclear medicine including those for therapy from the aspect of their production by cyclotron. Fundamentals of RI production by accelerators for the purpose above are cyclotrons, nuclear cross sections, target technology for high-energy beam current, chemical treatments after irradiation and yield/purity. For RI emitting photons, the author describes details of 123I and 201Tl production through respective reactions of 123Te(p, n), 124Xe(p, x)123Xe(EC/+β-decay) or 127I(p, 5n)123Xe(EC/+β-decay), and 203Tl(p, 3n)201Pb(EC-decay) as well as others like 99mTc, for gamma camera and SPECT. For RI emitting positrons, those RI used most frequently at present like 11C, 15O and 18F, new desirable nuclides to be developed, long-life RI like 64Cu, 73Se, 76Br and 124I, and alternative RI for SPECT like 94mTc are commented. For RI for therapeutic aims, a possible use of those like 64Cu, 124I, 67Ga, 111Br, 67Cu, 103Pd, 186Re and 211Re, and their production are discussed. Efforts are being made on some of RI described for their practical large-scale production. (S.I.)