Radionuclide liver-spleen scan showing normalization of splenic uptake after extended hydroxyurea therapy. A 7-month-old child with markedly decreased splenic uptake at baseline (arrow in top panel) regained splenic uptake after 4 years of hydroxyurea therapy (bottom panel). The arrow in the lower panel denotes the location of splenic uptake and indicates a slightly enlarged spleen measuring 9.3 cm in length.