Specific Activity Calculator

The Specific Activity Calculator accepts an input volume, activity, specific activity for a given isotope and calculates the amount of isotope present in the sample both in moles and moles/volume.

Getting There

The Specific Activity Calculator is available in the Tools Menu.


The Specific Activity Calculator requires several values to make its calculations. An activity, volume, isotope, and specific activity are used to calculate the number of excited molecules and molarity of a given sample.


Value Units Description
Activity MBq, kBq, mCi, or μCi and measurement time Amount of isotope as measured in a dosimeter or with the NanoSPECT.
Volume cm3, mm3, ml, μl The volume containing the activity.
Isotope Hours The isotope of interest and its associated half-life. Several pre-defined options are available.
Specific Activity MBq/pmol, kBq/pmol and measurement time The specific activity of the isotope being used as measured by a specific activity calibration. Specific activity describes the number of excited atoms out of the total atoms present in a given sample, i.e., the amount of the activity that has not yet decayed to a ground state.
Amount pmol, nmol, or # The calculated amount, or number, of excited molecules in the sample.
Molarity pmol/ml, nmol/ml The calculated molarity, or concentration, of excited molecules in a sample of activity.