Assignment 2: Monthly QC

In the same line as the daily quality control. There is a short test that should be performed at least monthly. Although there are centers where it is performed weekly and, in an automatic system, it is not very time consuming to do it daily.


Have a look at the instruction video:

In this video the test is performed that is written down below.

The test is performed on a not very user friendly meter. Therefore, in practice, the test will be, in most cases, less time consuming.


Energy respons

This test gives us an idea of the stability of the meter for the different isotope settings.


  • Use the tab-sheet ‘monthly test’ in the Excel-file.

  • Give in date, time and tester information.

  • Put the reference source in the meter, using the source holder.

  • First make a measurement using the correct isotope setting for the source.

  • Note the reading in the Excel sheet.

  • Repeat the measurement using the isotope settings of three other most used isotopes at the department.

  • Note the readings in the Excel sheet. (Mark that you may change the isotopes in the heading of the tabel).


The table ‘stability’ gives you the proportion between the reading of the reference source with the setting of another isotope. These proportions should be stable in time. The last table ‘relative difference’ gives you the deviation of the results in time.  This differences should be smaller then 5%.



  • Do you, in routine, perform a test like this?

  • On a daily, weekly, monthly basis?

  • Are there differences in the way you perform the test, or calculate the results?

  • In what way?

  • Did you encounter all ready instability of your meter?

  • If yes, what did you do?

  • Do you think this is a useful test?


Please put your answers on the forum of this lesson, so we can have a discussion on QC.


Last modified: Wednesday, 20 February 2019, 6:10 PM