[Technetium polyphosphate and technetium diphosphonate. A comparative study].

99mTc-labelled phosphates are the bone seeking agents of choice. The comparison of 99mTc-polyphosphate (Poly-P) and 99mTc-ethane-1-hydroxy-1,1-diphosphonate (EHDP) shows a better in vitro stability of the latter during the first two hours after preparation. The blood clearance of EHDP is superior to Poly-P resulting in reduced background activity at scanning time. Renal excretion over a 4-hour period of urine sampling showed no significant differences between both substances. Blood activity is independent of diuresis.