Experimental Study of the Bone Scintigraphy with ^99mTc-EHDP

Abstract

Animal studies and clinical studies of ^99mTc-EHDP were done and the diagnostic efficiency of this reagent was discussed.
Organ distribution and blood clearance of ^99mTc-EHDP were studied in rats. 41.5% of administrered dose was accumulated in the skeleton at 3 hours and 46.2% at 5 hours after injection. Blood clearance of this compound was rapid, with 0.37% of retention in blood at 3 hours and 0.22% at 5 hours after injection.
Comparative study of organ distribution and blood clearance after injection of ^99mTc-EHDP, ^99mTc-pyrophosphate, and ^87mSr was done in rabbits. Blood clearance curve consisted of 2, 3 components in each of these reagents. ^99mTc-EHDP showed the most rapid clearance followed by ^99mTc-pyrophosphate, and ^87mSr showed the latest clearance. In each o f bone/blood, bone/muscle, bone/liver, bone/kidney ratio, ^99mTc-EHDP showed high ratio suggesting that bone scintigrams with this reagent are clear. In clinical study as well, blood clearance of ^99mTc-EHDP was faster than that of ^99mTc-pyrophosphate, and 29.5% of administered dose of ^99mTc-EHDP was excreted in urine at 3 hours after injection.
Scintigraphic evaluation of ^99mTc-EHDP was done in 61 patients. Scintigrams were excellent in 54 patients (89%), good in 5 patients (8.2%), and not good in 2 patients. In these 2 cases, the physical condition and renal function were severe.
For these reasons, ^99mTc-EHDP was considered to be a hopeful reagent for bone scintigraphy.