| Tag | (0018,1521) |
|---|---|
| Type | Conditionally Required, Empty if Unknown (2C) |
| Keyword | PositionerSecondaryAngleIncrement |
| Value Multiplicity | 1-n |
| Value Representation | Decimal String (DS) |
Incremental change in secondary positioner angle for each frame.
See Section C.8.7.5.1.3.
Required if Positioner Motion (0018,1500) equals DYNAMIC.
If the positioner angles change during acquisition of a multi-frame image, the Positioner Angle Increment Attributes describe the angular change per frame.
If the change in positioner angle is nominally constant for each frame, these fields may contain a single value of the average angular change per frame. Alternatively, the fields may contain a vector of offsets from the (initial) Positioner Angle Attributes, with one value for each frame in the multi-frame image. The number of values in the Positioner Angle Increment Attributes must be one, or must be equal to Number of Frames (0028,0008) in the Multi-frame Module (see Section C.7.6.6).
It is permissible to generate a vector of the absolute positioner angles in the Positioner Angle Increment Attributes, and set the Positioner Primary and Secondary Angle Attributes to value 0.