Elution of 111Indium from reticuloendothelial cells

Measurement of isotope accumulation in an organ is often used to assess that organ's removal of blood cells labelled with the isotope. This technique is only valid if the isotope does not elute from the organ. Elution of 111In from the liver and spleen has been investigated in 14 subjects following intravenous injection of heat-damaged erythrocytes labelled with 111In. The elution rate from the spleen was found to be low, about 2% of the initial activity per day. The liver accumulated activity with respect to its initial uptake at a rate of about 5% per day. Bone marrow was not visualised except in two patients in whom it was identifiable in the initial scan.