I.A.3.     Which of the following modalities does not use a form of ionizing radiation:

    a.     Radiography.     No

    b.     Computed tomography.     No

    c.     Sonography.     Yes

    d.     Positron emission tomography.     No

    e.     Magnetic resonance imaging.     Yes

   Discussion:    This is an example of a question in a negative form (“does not“) which requires attention when selecting the appropriate answers. All electromagnetic radiation is not ionizing. It is only the radiation with high-energy photons.

   Reference:    Physical Principles of Medical Imaging, 2nd Edition. p. 25