#27 Question on bar pattern MTF

[Don]

Hi,

I am trying to determine a MTF from bar patterns in a Catphan CTP 528 phantom. I created rectangular ROIs around some of the significant bar patterns and ran a bar pattern MTF analysis. I adjust the frequency in regard to the slected ROIs (6-9 lp/mm).
The resulting MTF plots are empty. Maybe I just entered the wrong unit for the frequency. Do you have any advice on this or is there any manual available that I have missed?

Thank you very much,
Don