III.A.21.     The exposure output of an x-ray tube can be changed without changing the spectrum by adjusting the:

    a.     KV.    No

    b.     MAS.    Yes

    c.     Filter.    No

    d.     Focal-spot size.    No

   Discussion:    If either the KV or filter is changed it will have an effect on the spectrum.   Changing focal spot size does not change exposure output.

   Reference:    Physical Principles of Medical Imaging, 2nd Edition. p. 108