Ricerc@Sapienza

Background: Diagnosing diabetic foot infection is often difficult, despite several available diagnostic methods. Amongst these, several imaging modalities exist to evaluate the diabetic foot in case of a suspected osteomyelitis. Nuclear Medicine, in particular, offers a variety of radiopharmaceuticals and techniques. Nowadays the gold standard radionuclide procedure, when an osteomyelitis is suspected, is represented by the use of radiolabelled leukocytes with either99mTc-HMPAO or111In-oxine.

Nuclear medicine offers several techniques and procedures to image infection, but radiolabelled autologous white blood cells (WBCs) are still the gold standard. These cells are usually labelled with 111In or 99mTc bound to a hydrophobic chelating agent that allows these isotopes to pass through the plasma membrane and enter in the cytoplasm. The most common compound in Europe is HMPAO that efficiently chelates 99mTc. However, up to 20-40% of the complex is released from the cells in the first few hours.

The scintigraphy with radiolabelled autologous leukocytes (WBCs) is considered the gold-standard technique for imaging infections. Leukokit (R) is a commercially available, disposable, sterile kit for labelling WBCs ex vivo. In this kit, WBCs isolation from red blood cells (RBCs) was performed using poly(O-2-hydroxyethyl)starch (HES) as the RBCs sedimentation agent. Due to its poor availability, HES has been recently replaced by Gelofusine as the RBC sedimentation agent.