To evaluate the feasibility of 99Tcm-2-(2-ethylicimidazol-1-yl)-1-hydroxyethane-1

1-diphosphonic acid (EIDP) as a bone imaging agent

EIDP was synthesized by three-step reactions from 2-ethylicimidazol and 99Tcm-EIDP was prepared with SnCI2 in 10 min at room temperature. Normal mice were injected intravenously with 1.0 MBq 99Tcm-EIDP of 0.2 ml and sacrificed at different phase after injection. Samples of heart

liver

spleen

lung

kidney

muscle

bone and blood were taken for uptake (in %ID/g) measurement

and the bone-to-organ uptake ratios were calculated. The blood clearance kinetics was calculated

too. Bone imaging was performed in normal rabbit after intravenous injection. The total yield for the preparation of EIDP was 35.5%. Both the labeling yield and radiochemi- cal purity of 99Tcm-EIDP were over 95%. The bone uptake is up to 23.76 %ID/g at 1h after the injection. The bone-to-blood and bone-to-muscle uptake ratios were 33.94 and 95.04

respectively. The kinetics equation was: C = 1090.736e-6.982t + 84.956e-0.379t

and the initial half life and late half life were 4.76 and 105.5 min respectively. A clear bone imaging of rabbit was obtained 2h after injection. The 99Tcm-EIDP

which can be prepared conveniently

exhibited high uptake in bone and would be a potential bone imaging agent.