DICOM PS3.3 2020b - Information Object Definitions
C.8.2.2.2 Multi-energy CT X-Ray Detector Macro

Attributes for the CT X-Ray Detector(s).

Table C.8.2.2-3. Multi-energy CT X-Ray Detector Macro Attributes

Attribute Name

Tag

Type

Attribute Description

Multi-energy CT X-Ray Detector Sequence

(0018,936F)

1

X-Ray Detector (see Section C.8.2.2.1.1) information.

One or more Items shall be included in this Sequence.

>X-Ray Detector Index

(0018,9370)

1

Identification number of this item in the Multi-energy CT X-Ray Detector Sequence.

The number shall be 1 for the first Item and increase by 1 for each subsequent Item.

>X-Ray Detector ID

(0018,9371)

1

Identifier of the physical X-Ray detector. This might be the serial number.

When a single detector discriminates different energies, the X-Ray Detector ID (0018,9371) will have the same value in different Items of Multi-energy CT X-Ray Detector Sequence (0018,936F).

>Multi-energy Detector Type

(0018,9372)

1

Technology used to detect multiple energies.

Defined Terms:

INTEGRATING

physical detector integrates the full X-Ray spectrum.

MULTILAYER

physical detector layers absorb different parts of the X-Ray spectrum

PHOTON_COUNTING

physical detector counts photons with energy discrimination capability

>X-Ray Detector Label

(0018,9373)

3

Label of this item in the Multi-energy CT X-Ray Detector Sequence.

Note

The label might be High, Low or some nominal bin energy.

>Nominal Max Energy

(0018,9374)

1C

Nominal maximum energy in keV of photons that are integrated/counted by the detector (see Section C.8.2.2.1.1). Due to energy resolution limits of the detector, some photons above the nominal maximum may be counted.

Required if Multi-energy Detector Type (0018,9372) is PHOTON_COUNTING. May be present otherwise.

>Nominal Min Energy

(0018,9375)

1C

Nominal minimum energy in keV of photons that are integrated/counted by the detector (see Section C.8.2.2.1.1). Due to energy resolution limits of the detector, some photons below the nominal minimum may be counted.

Required if Multi-energy Detector Type (0018,9372) is PHOTON_COUNTING. May be present otherwise.

>Effective Bin Energy

(0018,936E)

3

Energy of the heterogeneous (polychromatic) photon beam represented by this detector (see Section C.8.2.2.1.1) calculated as if it were monochromatic.

Note

E.g., this can be calculated based on the beam spectrum or derived from the attenuation of phantom measurement.


C.8.2.2.2.1 Multi-energy X-Ray Detector Description

Each item in the Multi-energy CT X-Ray Detector Sequence (0018,936F) might describe either an integrating detector or one output corresponding to a specific spectrum of a physical detector like:

  • One layer of a multi-layer detector.

  • One energy bin of a photon counting detector.

  • One energy threshold of a photon counting detector.

The sequence attribute descriptions will refer to a detector, meaning one item in the Multi-energy CT X-Ray Detector Sequence (0018,936F). The attributes use the phrase "physical detector" when it is necessary to refer to the actual device rather than the current item.

DICOM PS3.3 2020b - Information Object Definitions