[Translated article] Guideline to radiopharmaceutical procedures for in vitro labeling of leukocytes

This guide outlines the radiopharmaceutical procedure for the in vitro labelling of leukocytes. Scintigraphy using leukocytes labeled with [^99mTc]Tc-exametazime or [¹¹¹In]In-oxine is a highly valuable diagnostic tool in infectious and inflammatory diseases due to its high sensitivity and specificity. It is based on established guidelines and consensus protocols, which incorporate the recent Spanish regulations on the extemporaneous preparation of radiopharmaceuticals, this document provides detailed and precise instructions for the safe and effective preparation and quality control of in vitro labeled leukocytes. The clinical indications for leukocyte scintigraphy are described, along with the technical requirements for both facilities and equipment. The various stages of the radiolabelling procedure are developed and substantiated, including blood sample collection, leukocyte fraction separation and isolation, incubation and subsequent radiolabelling with either [^99mTc]Tc-exametazime or [¹¹¹In]In-oxine, radiopharmaceutical conditioning for administration, and the necessary quality control procedures. The document concludes with a section describing drug interactions reported in the literature. Two annexes are included, providing example labeling protocols for both radiopharmaceuticals.