DICOM PS3.3 2020b - Information Object Definitions

C.8.11.4 DX Detector Module (Current)
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#### C.8.11.4 DX Detector Module

Table C.8-71 contains IOD Attributes that describe a DX detector.

Table C.8-71. DX Detector Module Attributes

Attribute Name | Tag | Type | Attribute Description
--- | --- | --- | ---
Include Table C.8-71b “Digital X-Ray Detector Macro Attributes” |
Detector Active Time | (0018,7014) | 3 | Time in mSec that the detector is active during acquisition of this image. ### Note This activation window overlaps the time of the X-Ray exposure as defined by Exposure Time (0018,1150) and Detector Activation Offset From Exposure (0018,7016).
Detector Activation Offset From Exposure | (0018,7016) | 3 | Offset time in mSec that the detector becomes active after the X-Ray beam is turned on during acquisition of this image. May be negative.
Field of View Shape | (0018,1147) | 3 | Shape of the Field of View, that is the image pixels stored in Pixel Data (7FE0,0010). Enumerated Values: RECTANGLE ROUND HEXAGONAL
Field of View Dimension(s) | (0018,1149) | 3 | Dimensions in mm of the Field of View, that is the image pixels stored in Pixel Data (7FE0,0010). If Field of View Shape (0018,1147) is: RECTANGLE: row dimension followed by column. ROUND: diameter. HEXAGONAL: diameter of a circumscribed circle.
Field of View Origin | (0018,7030) | 1C | Offset of the TLHC of a rectangle circumscribing the Field of View, that is the image pixels stored in Pixel Data (7FE0,0010), before rotation or flipping, from the TLHC of the physical detector area measured in physical detector pixels as a row offset followed by a column offset. Required if Field of View Rotation (0018,7032) or Field of View Horizontal Flip (0018,7034) is present. See Section C.8.11.4.1.1 for further explanation.
Field of View Rotation | (0018,7032) | 1C | Clockwise rotation in degrees of Field of View, that is the image pixels stored in Pixel Data (7FE0,0010), relative to the physical detector. Enumerated Values: 270 180 90 0 Required if Field of View Horizontal Flip (0018,7034) is present. See Section C.8.11.4.1.1 for further explanation.
Field of View Horizontal Flip | (0018,7034) | 1C | Whether or not a horizontal flip has been applied to the Field of View, that is the image pixels stored in Pixel Data (7FE0,0010), after rotation relative to the physical detector as described in Field of View Rotation (0018,7032). Enumerated Values: YES NO Required if Field of View Rotation (0018,7032) is present. See Section C.8.11.4.1.1 for further explanation.
Imager Pixel Spacing | (0018,1164) | 1 | Physical distance measured at the front plane of the detector housing between the center of each image pixel specified by a numeric pair - row spacing value(delimiter) column spacing value in mm. See Section 10.7.1.3 for further explanation of the value order. The value of this Attribute shall never be adjusted to account for correction for the effect of geometric magnification or calibration against an object of known size; Pixel Spacing (0028,0030) is specified for that purpose.
Include Table 10-10 “Basic Pixel Spacing Calibration Macro Attributes” |
Cassette ID | (0018,1007) | 3 | Identifier of the cassette that contains the photostimulable phosphor plate, for CR acquisitions.
Plate ID | (0018,1004) | 3 | Identifier of the photostimulable phosphor plate, for CR acquisitions.

Table C.8-71b contains common Attributes that describe digital X-Ray detector.

Table C.8-71b. Digital X-Ray Detector Macro Attributes

Attribute Name | Tag | Type | Attribute Description
--- | --- | --- | ---
Detector Type | (0018,7004) | 2 | The type of detector used to acquire this image. Defined Terms: DIRECT X-Ray photoconductor SCINTILLATOR Phosphor used STORAGE Storage phosphor FILM Scanned film/screen
Detector Configuration | (0018,7005) | 3 | The physical configuration of the detector. Defined Terms: AREA single or tiled detector SLOT scanned slot, slit or spot
Detector Description | (0018,7006) | 3 | Free text description of detector.
Detector Mode | (0018,7008) | 3 | Text description of operating mode of detector (implementation specific).
Detector ID | (0018,700A) | 3 | The ID or serial number of the detector used to acquire this image.
Date of Last Detector Calibration | (0018,700C) | 3 | The date on which the detector used to acquire this image as identified in Detector ID (0018,700A) was last calibrated.
Time of Last Detector Calibration | (0018,700E) | 3 | The time at which the detector used to acquire this image as identified in Detector ID (0018,700A) was last calibrated.
Exposures on Detector Since Last Calibration | (0018,7010) | 3 | Total number of X-Ray exposures that have been made on the detector used to acquire this image as identified in Detector ID (0018,700A) since it was calibrated.
Exposures on Detector Since Manufactured | (0018,7011) | 3 | Total number of X-Ray exposures that have been made on the detector used to acquire this image as identified in Detector ID (0018,700A) since it was manufactured.
Detector Time Since Last Exposure | (0018,7012) | 3 | Time in Seconds since an exposure was last made on this detector prior to the acquisition of this image.
Detector Binning | (0018,701A) | 3 | Number of active detectors used to generate a single pixel. Specified as number of row detectors per pixel then column.
Detector Manufacturer Name | (0018,702A) | 3 | Name of the manufacturer of the detector component of the acquisition system
Detector Manufacturer's Model Name | (0018,702B) | 3 | Model name of the detector component of the acquisition system
Detector Conditions Nominal Flag | (0018,7000) | 3 | Whether or not the detector is operating within normal tolerances during this image acquisition. Enumerated Values: YES NO ### Note This flag is intended to indicate whether or not there may have been some compromise of the diagnostic quality of the image due to some condition such as over-temperature, etc.
Detector Temperature | (0018,7001) | 3 | Detector temperature during exposure in degrees Celsius.
Sensitivity | (0018,6000) | 3 | Detector sensitivity in manufacturer specific units. ### Note This value is intended to provide a single location where manufacturer specific information can be found for annotation on a display or film, that has meaning to a knowledgeable observer. This value is manufacturer-specific. DICOM specifies Standard Attributes in Table 10-23 'Exposure Index Macro', which are recommended.
Detector Element Physical Size | (0018,7020) | 3 | Physical dimensions of each detector element that comprises the detector matrix, in mm. Expressed as row dimension followed by column. ### Note This may not be the same as Detector Element Spacing (0018,7022) due to the presence of spacing material between detector elements.
Detector Element Spacing | (0018,7022) | 3 | Physical distance between the center of each detector element, specified by a numeric pair - row spacing value(delimiter) column spacing value in mm. See Section 10.7.1.3 for further explanation of the value order. ### Note This may not be the same as the Imager Pixel Spacing (0018,1164), and should not be assumed to describe the stored image.
Detector Active Shape | (0018,7024) | 3 | Shape of the active area. Enumerated Values: RECTANGLE ROUND HEXAGONAL ### Note This may be different from the Field of View Shape (0018,1147), and should not be assumed to describe the stored image.
Detector Active Dimension(s) | (0018,7026) | 3 | Dimensions in mm of the active area. If Detector Active Shape (0018,7024) is: RECTANGLE: row dimension followed by column. ROUND: diameter. HEXAGONAL: diameter of a circumscribed circle. ### Note This may be different from the Field of View Dimensions (0018,1149), and should not be assumed to describe the stored image.
Detector Active Origin | (0018,7028) | 3 | Offset of the TLHC of a rectangle circumscribing the active detector area from the TLHC of a rectangle circumscribing the physical detector area, measured in physical detector pixels as a row offset followed by a column offset. See Section C.8.11.4.1.1 for further explanation.
Include Table 10-23 “Exposure Index Macro Attributes” |

##### C.8.11.4.1 DX Detector Attribute Descriptions

###### C.8.11.4.1.1 Physical, Active, Field of View, Exposed and Displayed Areas

The relationship between the Physical Detector Area, the Active Detector Area, the Field of View (what is stored in Pixel Data (7FE0,0010)), the Exposed Area (after X-Ray Collimation) and the Displayed Area is illustrated in the following diagrams.

### Note

Some of these Attributes relate the image data to manufacturer specific characteristics of the detector that may be used for quality control purposes, e.g., correlation of image artifacts with a detector defect map, analysis of noise performance, etc.

The Displayed Area is defined in pixel coordinates relative to the stored image pixel values by the Attributes of the Display Shutter Module (see Section C.7.6.11). If this Module is not present or supported, then the Displayed Area is equal to the Field of View.

The Exposed Area is defined in pixel coordinates relative to the stored image pixel values by the Attributes of the X-Ray Collimator Module (see Section C.8.7.3).

For the Digital X-Ray IODs, the Field of View is usually rectangular in shape and usually has the same size as the stored Pixel Data (7FE0,0010). The shape and size of the Field of View and the spacing of the pixels are defined by the following Attributes:

- Field of View Shape (0018,1147),

- Field of View Dimensions (0018,1149),

- Imager Pixel Spacing (0018,1164),

- Rows (0028,0010),

- Columns (0028,0011).

In the case where the Field of View has the same size as the stored Pixel Data (7FE0,0010) the following relationships are verified:

If the Field of View Shape (0018,1147) Attribute equals RECTANGLE:

- Field of View Dimensionsrow dimension = Imager Pixel Spacingrow spacing * Rows

- Field of View Dimensionscolumn dimension = Imager Pixel Spacingcolumn spacing * Columns

If the Field of View Shape (0018,1147) Attribute equals ROUND or HEXAGONAL:

- Field of View Dimensionsdiameter = Imager Pixel Spacingrow spacing * Rows

- Field of View Dimensionsdiameter = Imager Pixel Spacingcolumn spacing * Columns

The following Attributes define the relationship of the Field of View to the Physical Detector Area:

- Field of View Origin (0018,7030),

- Field of View Rotation (0018,7032),

- Field of View Horizontal Flip (0018,7034).

For the Digital X-Ray IODs, the Active Area, i.e., that part of the detector matrix that was activated for this exposure, is usually rectangular in shape. The shape and size of the Active Area and the size and spacing of the detectors are defined by the following Attributes:

- Detector Active Shape (0018,7024),

- Detector Active Dimensions (0018,7026),

- Detector Element Physical Size (0018,7020),

- Detector Element Spacing (0018,7022).

### Note

1. The Detector Element Physical Size (0018,7020) and Detector Element Spacing (0018,7022) may be different if there are insensitive regions between each detector.

2. This model of description is not able to accurately describe multiple matrices of detectors that are "tiled" to produce a single image.

The following optional Attribute defines the relationship of the Active Area to the Physical Detector Area:

- Detector Active Origin (0018,7028).

In the case where the Field of View has the same size as the stored Pixel Data (7FE0,0010), the relationship between detectors and stored image pixels is defined by Detector Binning (0018,701A), which specifies how many detectors, in each of the row and column directions, contribute to (are pooled or averaged to form) a single stored image pixel.

### Note

1. Detector Binning (0018,701A) may have values less than one if sub-sampling is used to derive an image with higher spatial resolution than the detector matrix.

2. The detector binning results in the size of a stored image pixel being different from the contributing physical detector pixels. In this case it is important to notice that the Field Of View Origin (0018,7030) is defined with respect to the center of the detector element located at the TLHC of the Field of View.

3. For images where the Field of View describes an area not equal to the size (rows and columns) of the stored Pixel Data (7FE0,0010), Detector Binning (0018,701A) does not fully specify the relationship between the contributing physical detector pixels and the stored image pixels.

Figure C.8-14. Explanation of Digital Detector Attributes

Figure C.8-15. Explanation of Digital Detector Attributes

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DICOM PS3.3 2020b - Information Object Definitions