Related Experiment Video
Updated: Mar 29, 2026
Absolute Quantification of Aβ1-42 in CSF Using a Mass Spectrometric Reference Measurement Procedure
Published on: March 21, 2017
(Mis)use of (133)Ba as a calibration surrogate for (131)I in clinical activity calibrators
1Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899-8462, USA.
Abstract:
Using NIST-calibrated solutions of (131)Ba and (131)I in the 5mL NIST ampoule geometry, measurements were made in three NIST-maintained Capintec activity calibrators and the NIST Vinten 671 ionization chamber to evaluate the suitability of using (133)Ba as a calibration surrogate for (131)I. For the Capintec calibrators, the (133)Ba response was a factor of about 300% higher than that of the same amount of (131)I. For the Vinten 671, the Ba-133 response was about 7% higher than that of (131)I. These results demonstrate that (133)Ba is a poor surrogate for (131)I. New calibration factors for these radionuclides in the ampoule geometry for the Vinten 671 and Capintec activity calibrators were also determined.
Related Concept Videos
01:12Instrument Calibration
Analytical Balance Calibration
An analytical balance measures mass and requires regular calibration to...
01:20Calibration Curves: Linear Least Squares
For data that follow a straight line, the standard method for fitting is the linear...
01:11Glassware Calibration
Volumetric flasks: Volumetric flasks are designed to prepare aqueous solutions of precise volumes accurately with a calibration line on the neck. To calibrate a volumetric flask, it is important to fill it with distilled...