ObjectiveThe factors influencing residual radioactivity in ¹⁸F-FDG injection were analyzed to guide the packing of radiopharmaceuticals.

MethodsA total of 100 patients subjected to ¹⁸F-FDG PET/CT in Beijing Shijitan Hospital from October 2017 to December 2017 were analyzed. Patients were divided into different groups based on the volume and radioactivity of the radiopharmaceuticals they received. The residual radioactivity of the syringe tube, syringe needle, three-way valve, scalp needle, and background was then measured separately using a radioactivity meter. The curve of the total residual radioactivity as a function of ¹⁸F-FDG concentration was then fitted. SPSS 17.0 statistical software was used to test the normality of the data distribution, and results were analyzed by Spearman correlation.

ResultsThe residual radioactivity values of the syringe needle tube, syringe needle, three-way valve, and scalp intravenous needle were 1.59(0.93), 3.35(3.43), and 1.70(0.92) MBq, respectively. The total residual radioactivity was 7.09(4.31 MBq) and significantly related to the concentration of ¹⁸F-FDG applied(r=0.594, P < 0.01). According to the fitting curve obtained, the appropriate radioactivity concentration of ¹⁸F-FDG is less than 600 MBq/mL.

ConclusionsIn clinical work, appropriate dilution of the ¹⁸F-FDG injection volume and decreasing the radioactivity of pharmaceuticals can effectively reduce the total residual radioactivity of the procedure. Medical institutions should measure the appropriate dilution concentration of radioactive drugs according to the specifications of the syringes to increase the precision of injection and reduce the irradiation dose of the staff.