Tc-99m HM-PAO labelled leucocyte scanning for detection of infection in orthopedic surgery

The use of labelled granulocyte scintigraphy is recognized as a reliable method for detecting osteomyelitis and other skeletal sepsis. Tc-99m hexamethyl propyleneamine oxime (Tc-99m HM-PAO), a lipophilic chelate offers the advantages of availability, lower radiation dose and higher image resolution, compared to other labelling agents. We have scanned 36 orthopedic patients with suspected infection, using autologous granulocytes labelled with Tc-99m HM-PAO. In all cases, scans were compared with clinical, microbiological and/or surgical findings. Sensitivity was 94% and specificity was 80%. We therefore believe that Tc-99m HM-PAO leucocyte scanning provides a useful method for detecting osteomyelitis and other skeletal infections.