Pitch and Roll Coordinate Systems of the Table Top are not defined in IEC 61217. These angles are defined in the DICOM standard in a way compatible with the current notion of IEC by introducing them as rotations of the IEC Table Top System as indicated below.

The Table Top Pitch Angle is defined as the rotation of the coordinate axes Yt, Zt about axis Xt by an angle (t; see Figure C.8.8.25-3. An increase in the value of angle (t corresponds to the clockwise rotation of the Table Top as viewed from the Table Top coordinate system origin along the positive Xt axis.

The Table Top Roll Angle is defined as the rotation of the coordinate axes Xt, Zt about axis Yt by an angle (t; see Figure C.8.8.25-4. An increase in the value of angle (t corresponds to the clockwise rotation of the Table Top as viewed from the Table Top coordinate system origin along the positive Yt axis.

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Figure C.8.8.25-3 Table Top Pitch Angle
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Figure C.8.8.25-4 Table Top Roll Angle