Abstract: Objective To evaluate the vascular irritation of a 99mTc labeled radiocontrast medium, so as to make suggestions on radioprotection for personnel in the preclinical toxicological study of radiopharmaceuticals. Methods Six New Zealand rabbits were injected with technetium pentetate injection. The specific activity and radiochemical purity of the samples at the start and end of the test were analyzed, and the vascular irritation to the vein was evaluated. Dose monitoring and surface contamination monitoring were carried out during the main processes of the test. Results The maximum concentration of 555 MBq·mL-1 and the dose of 194 MBq·kg-1 (21 times of the maximum clinical dose) were intravenously administered through the ear-vein of rabbits. There wasn't drug-related vascular stimulation reactions observed in the test. The detection Results of samples' specific activity and radiochemical purity both met the test requirements. The individual highest radiation effective dose of single test of all operators was 0.01 mSv. The estimated annual total radiation effective dose is not more than 1 mSv, which is less than the limit of occupational personnel radiation effective dose (20 mSv). What's more, there was no radioactive contamination detected on surface of operators and equipments. Conclusion During the non-clinical toxicological study of radiopharmaceuticals, rational dose design and protective measures should be carried out according to the nature of nuclides and labelled substrates. It could ensure the safety and efficiency of the experimental Results. And at the same time, individual dose monitoring and pollution monitoring should be strictly carried out to ensure the radiation safety of operators.

Key words: radiocontrast medium, vascular stimulation, radiation monitoring, surface contamination, radioprotection