Technetium 99m autoradiography of labelled white cells

The cellular uptake of technetium 99m was determined on white blood cells (WBC) by autoradiography, after 'cold' tin pyrophosphate prelabelling followed by pertechnetate labelling. The autoradiographic method gave visible tracks of 99mTc internal conversion and Auger electrons. 75 +/- 5% of the treated WBC were labelled but none of the control WBC. The number and length of tracks per cell varied greatly. This was perhaps due to imaging conditions as well as to variations in cell uptake.