Cardiac Localization of99mTc-(Sn)-Pyrophosphate Following Irradiation of the Chest

Abstract
Of 70 cancer patients referred from radiotherapy for bone scans, 32% showed cardiac uptake of 99mTc-(Sn)-pyrophosphate. Only 9% of a control group showed this uptake. Of those with prior left hemithorax irradiation, 60% showed cardiac uptake. Only 12% of those with irradiation elsewhere showed this phenomenon (P < .01). The patients who had no increased uptake tended to have shorter irradiation-to-scan time intervals (< 10 mo.) than those who showed increased uptake (mean of 22 mo.).