DICOM PS3.3 2019a - Information Object Definitions
C. CT Additional X-Ray Source Macro

Table C.8-126b specifies the Attributes of the CT Additional X-Ray Source Macro. This Sequence may be multi-valued, depending on the number of additional active X-Ray sources. It defines the X-Ray source parameters beyond the basic system.

Table C.8-126b. CT Additional X-Ray Source Macro Attributes

Attribute Name



Attribute Description

CT Additional X-Ray Source Sequence



Contains the Attributes defining the data acquisition in a multiple X-Ray source system beyond the primary source. The primary X-Ray source is specified in the CT X-Ray Details Sequence.

One or more Items shall be included in this Sequence.




Peak kilo voltage output of the X-Ray generator used.

>X-Ray Tube Current in mA



Nominal X-Ray tube current in milliamperes.

>Data Collection Diameter



The diameter in mm of the region over which data were collected.

>Focal Spot(s)



Used nominal size of the focal spot in mm.

>Filter Type



Type of filter(s) inserted into the X-Ray beam. See Section C.

>Filter Material



The X-Ray absorbing material used in the filter.

>Exposure in mAs



The exposure expressed in milliampere seconds, for example calculated from exposure time and X-Ray tube current.

>Energy Weighting Factor



The weighting factor of the data from this additional source in a multiple energy composition image. This factor incorporates the effects of

  • the specific X-Ray source and kV value

  • examination specific characteristics.

Required if Required if Frame Type (0008,9007) Value 4 of this frame is ENERGY_PROP_WT. May be present otherwise.

DICOM PS3.3 2019a - Information Object Definitions