Technetium-99m sestamibi scanning in multiple myeloma stem cell transplantation.

We report the use of technetium-99m sestamibi (MIBI) in a patient with multiple myeloma (MM) undergoing peripheral blood stem cell (PBSC) transplantation. MIBI is a radionuclide agent that is preferentially taken up by malignant tumors. Plain radiographs in a MM patient, taken prior to PBSC transplantation, showed a large right humeral lytic lesion that correlated with increased uptake of MIBI at the same location. MIBI uptake, demonstrating active MM bone disease, was also evident in areas which were normal on plain radiographs. Three months after PBSC transplant, the lytic lesion had healed by plain radiographs and repeat MIBI scan showed no uptake. MIBI scanning results have a positive correlation with plain radiographs, and more importantly, demonstrate active MM bone disease not yet detectable by plain radiographs. If MIBI proves more sensitive in the detection of MM bone disease than plain radiographs or bone scanning with traditional isotopes, it will have a significant role in the detection of early disease and in monitoring disease progression during and after therapy.