Granulocyte-colony-stimulating factors (G-CSF) enhance FDG uptake in which areas?

Granulocyte-colony-stimulating factors (G-CSF) are cytokines that play a crucial role in stimulating the production of granulocytes in the bone marrow. When G-CSF is administered, it leads to an increase in the number of circulating white blood cells, particularly neutrophils, which can enhance the uptake of 18F-fluorodeoxyglucose (FDG) during positron emission tomography (PET) imaging.

In the context of PET imaging, areas such as the bone marrow and spleen are particularly significant because they are sites of active hematopoiesis (blood cell formation) and immune response. The bone marrow shows increased FDG uptake due to heightened metabolic activity as the body produces more blood cells in response to G-CSF. Similarly, the spleen can exhibit increased FDG uptake due to its role in filtering blood and involvement in immune responses, often leading to activation of lymphocytes and other immune cells.

The combination of these factors in the bone marrow and spleen contributes to a notable increase in FDG uptake when G-CSF is utilized, making this option most consistent with the biological effects of G-CSF as seen on PET scans.