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

Appl Radiat Isot. 1999 Nov;51(5):515-26. doi: 10.1016/s0969-8043(99)00078-0.

Abstract

The Positron Emission Tomography agent 62Cu Pyruvaldehyde Bis(N4-methyl)thiosemicarbazone (PTSM) has been standardized by the National Institute of Standards and Technology (NIST) using 4 pi beta liquid scintillation counting with 3H-standard efficiency tracing. Using a measurement model developed at NIST for the determination of experimental dose calibrator dial settings for short-lived radionuclides, the correct dial settings for 62CuPTSM in a clinically useful geometry (a 35 ml plastic syringe containing 33 ml of solution) as well as the standard NIST 5 ml glass ampoule have been elucidated. This measurement model is fully described, as is the treatment of associated uncertainties. The correct instrument settings for the NIST Capintec CRC-12 re-entrant ionization chamber ('dose calibrator') were found to be '499 +/- 6' and '489 +/- 8', respectively, for the syringe and ampoule 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 ampoule. The measured activities using these settings are lower than those obtained 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.

MeSH terms

  • Calibration
  • Copper Radioisotopes / analysis*
  • Copper Radioisotopes / standards*
  • Organometallic Compounds / analysis*
  • Radiopharmaceuticals / analysis*
  • Reference Standards
  • Scintillation Counting / methods
  • Scintillation Counting / standards*
  • Thiosemicarbazones / analysis*
  • Tomography, Emission-Computed / methods
  • Tritium

Substances

  • Copper Radioisotopes
  • Organometallic Compounds
  • Radiopharmaceuticals
  • Thiosemicarbazones
  • Tritium
  • copper pyruvaldehyde bis(N(4)-methylthiosemicarbazone) complex