A HIGH-EFFICIENCY, RAPID AND MULTIDOSE PROCEDURE FOR WHITE BLOOD-CELLLABELING WITH TC-99(M)-HMPAO

Tc-99(m)-hexamethylpropyleneamine oxime (Tc-99(m)-HMPAO) is presently recognized as an effective radio-pharmaceutical for in vitro white blo od cell (WBC) labelling in addition to its widespread utility in cereb ral blood flow imaging. While performing clinical studies in patients with a wide range of inflammatory diseases, the effect of the ligand a nd stannous ion quantify on the labelling efficiency (LE) of WBC was e xamined. A mean LE of 64 +/- 7% (n = 29) was achieved when the whole H MPAO kit was used for labelling. The LEs were 78 +/- 5% (n = 43), 83 /- 3% (n = 37) and 85 +/- 5% (n = 18) when one-half, one-third and one -fifth of the lyophilized kit was used, respectively. This is in agree ment with the reports of Sampson et al. and Lang et al., suggesting th at the optimal formulation of the Tc-99(m)-HMPAO is a fraction of the whole kit. Accordingly, fractionation of a freshly prepared Tc-99(m)-H MPAO kit into five parts for a high-efficiency WBC labelling is propos ed, encouraging the more widespread use of Tc-99(m)-HMPAO in WBC label ling.