Physics, Techniques and Procedures

Indium leukocyte imaging

nuclear imaging technique recognized as the "gold standard" in infection imaging. In this technique, leukocytes are labelled with indium-HMPAO after centrifugation and recovery of the cells from the buffy coat. The resuspended cells are washed and then reinjected into the patient, where they join the normal granulocyte pool and participate in the standard migration of granulocytes to infected foci. Images are typically obtained after 6, 24 and optionally 48 hours and show focal accumulation in an infected site. Normal sites of accumulation are the liver, spleen and bone marrow. Therefore, infectious foci in the upper abdomen are not optimally imaged. Even better results are obtained if the granulocytes are labelled but the cleaning method is much more involved.

As the method requires a lot of laboratory preparation, simpler techniques have been introduced. The most successful so far is infection imaging with technetium-99m antigranulocyte antibodies. Other methods have also been used to identify infectious foci. Among them is gallium-67 imaging and recently, interesting results have been obtained using positron mission tomography (PET) and fluorodeoxyglucose FDG .

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