Altered Biodistribution of ^99mTc-DPD on Bone Scan After Intravenous Iron Supplement

We report a case with altered biodistribution of ^99mTc-dicarboxypropane diphosphonate (^99mTc-DPD) on whole body bone scan after intravenous iron supplement therapy. A 47-year-old male patient who had recently been detected with a hepatic mass suggestive of hepatocellular carcinoma underwent bone scan as staging work-up before surgery. Bone scan images at 3 h after injection of ^99mTc-DPD demonstrated unusually increased blood pool activities in the heart, liver, and spleen with usual skeletal uptakes. The patient had been treated for severe anemia from hemorrhoid with two intravenous administration of ferric hydroxide carboxymaltose complex at approximately 22 h and 2 h prior to the ^99mTc-DPD injection, which we consider as the most probable cause of altered biodistribution of ^99mTc-DPD.