ABSTRACT

Blood cells are labeled with radionuclide and used for various indications. The most commonly used radionuclide labeled cells in nuclear medicine are leukocytes and erythrocytes. However, for some indications, platelet marking studies continue. Scintigraphy with labeled autologous leukocytes is a widely used method to detect sites of infection. Infection imaging performed by accumulation of radionuclide-labeled leukocytes at the infection focus, like leukocytes in the body, is an important step in the history of nuclear medicine. Since the isolation and labeling steps of leukocyte labeling from blood is a time-consuming and risky process that requires processing, researchers are trying to develop specific agents that bind leukocytes in vivo. Although indium-111 oxine (In-111 oxine) and Technetium-99m hexa methyl propylene amine oxime (Tc-99m HMPAO) labeled leukocyte scintigraphy was developed in the 1970s, it is still considered the gold standard method. Radionuclide-labeled platelet imaging has clinical applications for clot detection, such as pulmonary embolism, deep vein thrombosis, and cerebral venous sinus thrombosis. Although many radionuclides have been described for platelet labeling, the use of lipophilic radiopharmaceuticals Tc-99m HMPAO and In-111 oxine is common. Platelet marking is based on the separation of platelets from whole blood, as in leukocyte marking, procedures have been described in the literature.

Radiolabeled red blood cells, which have been playing an important role as diagnostic radiopharmaceuticals for decades, have been labeled with various radionuclides such as Cr-51, P-32, In-111, Tc-99m, mIn-113, mIn-114, Ga-66, Ga-67, Ga-68, Fe-52, Fe-55, Co-55, Cu-64, F-18-FDG, and used for clinical studies. According to the purpose of use, radionuclide selection, energy half-life, type of radiation emitted are taken into consideration. The main uses for labeled erythrocytes are measurement of total red blood cell volume, measurement of red blood cell survival time, determination of sites of red blood cell destruction, blood pool imaging studies including gated cardiac imaging and gastrointestinal bleeding, selective spleen with damaged red blood cells imaging studies. In vivo, in vitro and a modified in vivo method which is a combination of the two methods are used to label red blood cells. Cells are expected to show their natural behavior in the body after marking. Conditions during the marking, the substances used and their quantities, and the training of the personnel who perform the process affect the marking efficiency. Cell labeling studies include safe environmental conditions, patient and personnel safety precautions.