The standardization of Cu-62 and experimental determinations of dose calibrator settings for generator-produced (CuPTSM)-Cu-62

The Positron Emission Tomography agent Cu-62 Pyruvaldehyde Bis(N-4-methyl)t hiosemicarbazone (PTSM) has been standardized by the National Institute of Standards and Technology (NIST) using 4 pi beta liquid scintillation counti ng with H-3-standard efficiency tracing. Using a measurement model develope d at NIST for the determination of experimental dose calibrator dial settin gs for short-lived radionuclides, the correct dial settings for (CuPTSM)-Cu -62 in a clinically useful geometry (a 35 mi plastic syringe containing 33 mi of solution) as well as the standard NIST 5 ml glass ampoule have been e lucidated. This measurement model is fully described, as is the treatment o f associated uncertainties. The correct instrument settings for the NIST Ca pintec CRC-12 re-entrant ionization chamber ('dose calibrator') were found to be `499 +/- 6' and '489 +/- 8', respectively, for the syringe and ampoul e geometries. The stated uncertainties are expanded (k = 2) uncertainties. The expanded uncertainties in the measured activity arising from these new dial settings are +/-0.8% and +/-1.4%, respectively, for the syringe and am poule. The measured activities using these settings are lower than those ob tained from the manufacture's recommended setting of '448' by 9.7% for the syringe and 7.7% for the ampoule, and underscore the need for experimental verification of the dose calibrator settings for each radionuclide and each geometry used in the clinic. Published by Elsevier Science Ltd. All rights reserved.