Bone scan quality: technetium-99m HDP versus MDP

Full text: The quality of bone images obtained at 2 or 3 hours following administration of 99mTc methylene diphosphonate (MDP) was compared with that of 99mTc hydroxymethylene diphosphonate (HDP) in 108 patients. Five experienced blinded observers independently assessed the quality of paired comparable bone scintigrams which included whole body axial and extremity images matched for camera, region of interest, and age and weight of patients. Comparison of 99mTc-MDP images in 18 pairs of patients showed no difference in quality between the products of two major commercial radiopharmaceutical suppliers. Image quality was significantly better in all patients scanned at 3 hours compared with 2 hour delayed imaging. Eighteen of twenty one direct comparisons of 99mTc-MDP with 99mTc-HDP at the same imaging time showed the clear superiority of 99mTc-HDP in bone image quality (p< 0.0001 by Chi square test). In particular, blood clearance of 99mTc-HDP was substantially better than 99mTc-MDP in all comparisons. Seven patients underwent sequential studies with both 99mTc- MDP and 99mTc-HDP and in each patient the quality of the 99mTc-HDP images was unanimously judged to be superior to those obtained with 99mTc-MDP