THERMOCHROMATOGRAPHIC SEPARATION OF (99M)TC FROM ENRICHED MOLYBDENUM TARGETS AND ITS LARGE-SCALE PRODUCTION FOR NUCLEAR MEDICAL APPLICATION

The thermochromatographic behaviour of ''carrier-free'' technetium spe cies TcO(x) (x probably 3) and HTcO4 was studied in dry and moist air atmospheres. Temperatures of adsorption on quartz surfaces (T(a)) were measured to be 400+/-40-degrees-C and 300+/-30-degrees-C, respectivel y, for the two technetium species for 20 min experimental periods. Two alternative routes for fast and quantitative thermochromatographic se paration of the short-lived positron emitting technetium isotope Tc-94 m from highly enriched molybdenum targets ((MoO3))-Mo-94 were tested. The optimum conditions to separate Tc-94m within 25 min, with overall radiochemical yields of about 80-85% (non-decay-corrected 40-45%) and in high radiochemical purity of >99% as pertechnetate, were developed. The radionuclidic purity at EOB was >90%. The separation process incl uded an almost complete recovery and cyclic use of the enriched target material.