Tc-99m HM-PAO for leukocyte labelling

Tc-99m hexamethylpropylene amine oxime d,1-diastereoisomer (HM-PAO), developed as a diffusible brain imaging agent, irreversibly labels leukocyte suspensions in saline with an efficiency above 80% when quantities of 1-20 μg are used. In dogs, the recovery and survival of reinjected cells in the bloodstream resemble what is seen with In-111 oxine-labeled cells. Images in control animals show the spleen, liver, marrow, and bladder, minimal pulmonary activity, and no gastrointestinal activity. Induced E. coli abscesses and joint inflammatory lesions in dogs are dramatically shown in 4- and 18-hour images. This complex may prove to be the agent of choice for abscess detection in humans