Several radiopharmaceuticals with a propensity to concentrate in painful metastatic bone cancer lesions are under development as a systemic radiation alternative to 32P. All are reactor produced and, when injected, have in all but 117mSn-DTPA decreased or eliminated the pain in more than three quarters of the patients, and all have caused transient myelotoxicity. Three of the four are under clinical evaluation and the generated data will be used for new drug applications for routine human use.