twenty normal volunteers had measurements of 24-hr whole-body retention ( wbr ) of three structurally related tc-99m-labeled phosphonate skeletal imaging agents : ( 1-hydroxyethylidene ) diphosphonate ( hedp ) , methylene diphosphonate ( mdp ) , and hydroxymethylene diphosphonate ( hmdp ) .
C0012544
diphosphonate
C0066351
methylene diphosphonate