Successive measurements of 99mTc and 18F sources experimentally showed that, according to the time, temporal variation in their activities was consequentially linked to the radioactive disintegration process. All experimental measurements and their respective ratios are presented in Tables 1 and 2, and the different trends for obtained values, in Figures 1 and 3.
Swerves correspond to deviation between the value of the experimental activities acquired with the dose calibrator, and that theoretically and simultaneously expected for the source, at the time of measurement.