The use of rare-earth radionuclides and other bone-seekers in the evaluation of bone lesions in patients with multiple myeloma or solitary plasmacytoma.

Twenty-four patients with multiple myeloma and 4 with solitary plasmacytoma had total-body scans after intravenous injection of 67Ga-citrate alone (17 patients) or combined with other agents (11 patients). The latter included 99mTc-diphosphonate (99mTc-DP), 99mTc-polyphosphate (99mTc-PP), or 99mTc-sulfur colloid (99mTc-SC) given alone or combined with 171Er, 157Dy, or 167Tm as citrate. In some patients more than one agent was compared to 67Ga and radiographic bone surveys. In general, localization of the rare-earth "bone-seekers" was poor except for 157Dy, which compared well with 99mTc-PP and 99mTc-DP; 157Dy was also helpful in studies of the abdomen and pelvis because of its failure to concentrate in the gastrointestinal tract. No toxic or nonspecific effects were noted.