Abstract：Objective: To develop a method to label HYNIC-Octreotide with 99Tcm indirectly and evaluate its potential as a clinical imaging agent. Methods: SnCl2 as a reducing agent was adopted to label HYNIC-Octreotide with 99Tcm indirectly, to observe the stability of the labeled drugs; 6 rabbits, 3 healthy volunteers and 3 patients with meningioma were examined by this somatostatin receptor agent. Results: The label rate of 99Tcm-HYNIC-Octreotide was 97.8%±0.55%. The stability of the labeled drugs: ①The stability after 4 hours were above 90%. ②The replace test of cysteine: with the increase of cysteine, free 99Tcm was found to raise slowly, about 23% free 99Tcm was break away from 99Tcm-HYNIC-Octreotide when the concentration of cysteine was up to 200mmol/L. ③Plasma binding: the rate of 99Tcm-HYNIC-Octreotide combined with plasma is 17.04%±0.01% for 24 hours. ①Character of distribution with the radionuclide drug in rabbits and volunteers: Intense uptake was found in bladder and kidney, moderate uptake in liver, mild uptake in mucous membrane of nose, no obvious uptake in brain, lung and intestinal tract. ②Intense uptake was found in 3 patients with meningioma, the average value of T/NT was 5.36 after 4 hours. Conclusions: This method to label HYNIC-Octreotide with 99Tcm is promising; it has a high label rate and stability. 99Tcm-HYNIC-Octreotide has a potential as an agent imaging to meningioma.
2008, Vol. 19 
