ORIGINAL ARTICLES   

The Quarterly Journal of Nuclear Medicine and Molecular Imaging 2004 September;48(3):229-36

Copyright © 2009 EDIZIONI MINERVA MEDICA

language: English

An in vitro study to compare 99mTc-stannous colloids and 99mTc-HMPAO for labelling human leukocytes

Capriotti G. ¹, D’Alessandria C. ¹, Garin E. ², Weber E. ³, Devillers A. ², Lehmann K. ³, Corsetti F. ¹, Lecloirec J. ², Meller J. ³, Becker W. ³, Moisan A. ², Signore A. ¹

¹ Nuclear Medicine Unit, 2nd Faculty of Medicine “La Sapienza” University, Rome, Italy 2 Department of Nuclear Medicine University of Rennes, Rennes, France 3 Nuclear Medicine Unit George August University, Goettingen, Germany.

Aim. Aim of the present study was to compare in vitro the labelling efficiency (LE) and cell viability (TBE) of autologous leukocytes labelled with 99mTc-SnF2 and 99mTc-HMPAO, and to evaluate the quantity and quality of spontaneously released 99mTc (SR) from labelled cells at several time points after labelling.
Methods. A total of 14 patients with different diseases and 18 normal subjects were included in this study. A blood sample was collected from each patient; purified autologous leukocytes were divided into 2 samples and labelled with 99mTc-SnF2 and 99mTc-HMPAO. LE was evaluated at the end of labelling and TBE and SR were evaluated at 10 min and 1 h, 2 h and 4 h after labelling.
Results. LE of 99mTc-SnF2-WBC was higher than 99mTc-HMPAO-WBC (61.2±18.7% and 43.3±11.3; p<0.0001) and we found an inverse correlation between blood glucose and labelling efficiency for both methods (p=0.02). Minimal differences were also observed between 2 methods after 10 min and 1 h, as far as the cell viability is concerned. The percentage of radioactivity spontaneously released from 99mTc-SnF2-WBC was significantly higher compared to 99mTc-HMPAO-WBC at each time point. Radioactivity released from labelled cells was predominantly 99mTc-SnF2 and 99mTc-HMPAO with few free 99mTc (<20%).
Conclusion. Both radiopharmaceuticals are not toxic for WBC. Labelling with 99mTc-SnF2 give a higher LE than with 99mTc-HMPAO; however, radiolabelled colloids are more released from labelled cells over a period of 4 h. While 99mTc-HMPAO is physiological excreted into gastrointestinal tract, 99mTc-SnF2 can be re-uptaken in vivo by reticulo-endothelial cells of liver and spleen. These findings suggest that 99mTc-SnF2-WBC might be better than 99mTc-HMPAO-WBC for studying inflammatory bowel diseases.