TDCR切伦科夫计数法测量223Ra的活度OA

To address the requirement for accurate activity measurement of the medical α-emitting radionuclide 223Ra in radiopharmaceutical development and clinical application,this study established a triple-to-double coincidence ratio(TDCR)Cherenkov counting method for measuring 223Ra activity.In this work,a TDCR liquid scintillation counter was used to calibrate the activity of 223Ra.The Cherenkov spectra of 223Ra and the TDCR efficiency correction curve was obtained.The Cherenkov spectra,detection efficiencies,and the effects of color quenching between 223Ra and 224Ra were compared.The results showed that Cherenkov light originating from the daughter nuclides 211Pb and 207Tl can be used for accurate activity determination of 223Ra,with a maximum detection efficiency of up to 60%and a minimum detectable activity of 0.2 Bq.A good correlation was observed between TDCR values and the detection efficiency of 223Ra,enabling efficiency correction in activity measurements.The TDCR Cherenkov counting method exhibited similar detection efficiencies for 223Ra and 224Ra,whereas color quenching affected 223Ra more significantly.This study demonstrated that TDCR Cherenkov counting offers a sensitive,accurate,and rapid approach for determining the activity of 223Ra,supporting radiopharmaceutical development and clinical applications.