89Zr for antibody labeling and positron emission tomography

The use of gamma-emitting radiolabeled anti-tumor monoclonal antibodies (MAb) as potential diagnostic or therapeutic agents has yielded encouraging results. An important requirement, especially for therapy, is to measure quantitatively the time course for deposition of MAb in tissue or tumor to calculate internal radiation dosimetry. To do this with single photon emitters and conventional gamma cameras or SPECT requires elaborate calibrations using phantoms and necessitates assumptions that would not be required if a positron emitting label were available for following the pharmacokinetics of MAb. We report here the production of 89Zr, a positron emitter with half-life of 78.4 hours and its first evaluation as a protein label. (author)