For the last 40 years 99mTc has been the workhorse of diagnosticnuclear medicine, because of its attractive physical characteristics(t1/2 6 h, g energy 140 keV), convenience of on-site supplyvia a 99Mo/99mTc generator, and the ability to image a variety oforgan systems using chelates that can be prepared quickly,efficiently, reproducibly, and safely via ‘kit’ procedures. A generatoris a closed, shielded, sterile, apyrogenic column of aluminiumoxide loaded with 99Mo (t1/2 66 h) and delivered to hospitals,generally on a weekly basis. Elution of the column with 0.9%sodium chloride yields 99mTc in a form suitable for the injection orpreparation of a range of complexes. The worldwide demand forsome 600 000 doses of 99mTc per week requires 450 TBq of 99Mo,which is produced by fission of 235U in only five nuclear reactors:NRU at Chalk River, Canada; HFR at Petten, the Netherlands; BR2 atMol, Belgium; OSIRIS at Saclay, France; and SAFARI at Pelindaba,South Africa.1,2 The OPAL reactor at Lucas Heights, Australia, hasrecently come on line and is gradually increasing its yield. Notably,there is no domestic production of 99Mo in the USA or Japan, thetwo largest markets for nuclear medicine products.
展开▼
