Delayed imaging to distinguish bone lesions from urinary tract activity

In 28/1,400 patients examined by bone imaging two hours after injection of 99mTc-polyphosphate or diphosphonate, it was found that activity in the urinary tract obscured the bony pelvis, making assessment of this region difficult or impossible. In several patients additional images were obtained 24 hours after the injection when decreased activity in the urinary tract allowed the pelvis to be more satisfactory visualized.