Production of high purity 94mTc for positron emission tomography studies

The radioisotope (94m)Tc (T(1/2) = 52.5 min; I(beta)+ = 72%; E(beta)+ = 2.47 MeV) is of considerable interest for quantitative biodistribution studies of Tc radiopharmaceuticals using positron emission tomography. The nuclear processes (94)Mo(p,n), (93)Nb((3)He,2n), (92)Mo(alpha,pn), and (92)Mo(alpha,2n)(94)Ru --> (94)mTc are of potential interest for the production of (94m)Tc. Detailed cross section and yield measurements showed that the (94)Mo(p,n)-reaction over the energy range E(p) = 13 --> 7 MeV is most suitable: The yield of (94m)Tc is high (2 GBq/mu Ah), the impurity level is low (provided highly-enriched (94)Mo is used as target material), and a small-sized cyclotron is adequate. Using conventional targetry, sufficient quantities of the radioisotope can be produced. The chemical processing methods employed include both solvent extraction and thermochromatography. The quality of the final product is discussed. NUCL MED BIOL 27;4:323-328, 2000. (C) 2000 Elsevier Science Inc. All rights reserved.