Alteration of the organ uptake of the Tc-99m-radiopharmaceuticals, Tc-99m-DPD, Tc-99m-DMSA, Tc-99m-tin colloid and Tc-99m-MAA, induced by the applied cytotoxic drugs methotrexate sodium and cyclophosphamide

Aim To investigate the influence of certain cytotoxic drugs on the organ uptake of the following Tc-99m-radiopharmaceuticals: Tc-99m-2,3-dicarboxypropane-1,1-diphosphonic acid (Tc-99m-DPD), Tc-99m-meso-2,3-dimercaptosuccinic acid (Tc-99m-DMSA), (TC)-T-99m-tin colloid and Tc-99m-macroaggregated albumin Tc-(99m-MAA). Methotrexate sodium and cyclophosphamide were used as models to evaluate these effects . Methods Two groups of healthy male Wistar rats were treated separately by oral application of the drugs for 7 days. On the eighth day, each of the Tc-99m-radiopharmaceuticals was applied in a separate group of treated animals. They were sacrificed at different time intervals and the radioactivity in the organs of interest was measured. The organ uptake of the Tc-99m-radiopharmaceuticals in an additional control group of animals was also studied. Results The results obtained showed an alteration in the organ uptake of (TC)-T-99m-radiopharmaceuticals in animals treated with cytotoxic drugs. In rats treated with methotrexate sodium, there was a higher uptake of Tc-99m-DMSA in the bones, stomach and intestine, a higher uptake of Tc-99m-DPD in the bones, intestine, blood and muscle, a lower uptake of (TC)-T-99m-tin colloid in the liver and a lower accumulation of Tc-99m-MAA in the lungs. Cyclophosphamide-treated animals showed enhanced uptake of Tc-99m-DMSA in the kidneys, a twofold enhanced uptake of Tc-99m-DPD in all organs except the stomach, a decreased uptake of Tc-99m-tin colloid in the lungs, spleen and kidneys and a significantly decreased uptake of Tc-99m-MAA in the lungs. Conclusion These results confirm that both methotrexate sodium and cyclophosphamide may alter the organ uptake of Tc-99m-radiopharmaceuticals in experimental animals. and COPY; 2005 Lippincott Williams and Wilkins