“…13,14 Studies comparable to the present study have been performed in the past, using a multitude of tracers, such as iron isotopes for imaging, and turnover studies of the erythropoietic precursor, Tc-99m labeled antigranulocyte antibodies for imaging of myeloid cells, 15 radiocolloids for Reticulo-endothelial system (RES) cell activity, and 111 In-chloride. [15][16][17] Compared with those methods, F-18 FLT PET has a considerably higher resolution, produces tomographic information, and allows better quantification. Moreover, it might provide more specific information about the hematopoietic bone marrow compartment than a reflection of the functional activity of the RES.…”