Impact of Recent Change in the National Institute of Standards and Technology Standard for 18F on the Relative Response of 68Ge-Based Mock Syringe Dose Calibrator Standards

Article Figures & Data

TABLE 1

Comparison of K_VIC Values for Ampoule and Mock Syringe Geometries for ¹⁸F and ⁶⁸Ge

↵* On the basis of the reported value of 10.12(3) pA·MBq⁻¹ and corrected for differences in measurement geometry.
↵† Adjusted unpublished value by −4% to reflect change in ¹⁸F.
Data are as measured in present study and as reported in Fitzgerald et al. (1) (for ¹⁸F) and Zimmerman and Cessna (3) (for ⁶⁸Ge, denoted SSIC in that reference). Value of K_VIC for ¹⁸F mock syringe was previously determined during experiments reported in Zimmerman and Cessna but was not included in the paper. Uncertainties are quoted as combined standard (k = 1) uncertainties. Details of uncertainty analysis are given in text (for present studies) or in appropriate reference.

TABLE 2

Measured Dial Settings for ¹⁸F and ⁶⁸Ge Mock Syringes in Several NIST-Maintained Activity Calibrators

Uncertainties (k = 1) are given in parentheses and are expressed as uncertainty in last digit of dial setting. % activity column gives uncertainty in measured activity value arising from uncertainty in dial setting. Values for previous dial settings for ¹⁸F and ⁶⁸Ge are from Cessna et al. (11) and Zimmerman and Cessna (3), respectively.