DICOM PS3.3 2021d - Information Object Definitions

C.8.11.5 DX Positioning Module (Current)
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#### C.8.11.5 DX Positioning Module

Table C.8-72 contains IOD Attributes that describe the positioning used in acquiring Digital X-Ray Images.

Table C.8-72. DX Positioning Module Attributes

Attribute Name | Tag | Type | Attribute Description
--- | --- | --- | ---
Projection Eponymous Name Code Sequence | (0018,5104) | 3 | A Sequence that describes the radiographic method of patient, tube and detector positioning to achieve a well described projection or view. Only a single Item is permitted in this Sequence. Shall be consistent with the other Attributes in this Module, if present, but may more specifically describe the image acquisition.
>Include Table 8.8-1 “Code Sequence Macro Attributes” . | BCID 4012 “Projection Eponymous Name”.
Patient Position | (0018,5100) | 3 | Description of imaging subject's position relative to the equipment. See Section C.7.3.1.1.2 for Defined Terms and further explanation. If present, shall be consistent with Patient Gantry Relationship Code Sequence (0054,0414) and Patient Orientation Modifier Code Sequence (0054,0412).
View Position | (0018,5101) | 3 | Radiographic view of the image relative to the imaging subject's orientation. Shall be consistent with View Code Sequence (0054,0220). See Section C.8.11.5.1.1 for further explanation.
View Code Sequence | (0054,0220) | 3 | Sequence that describes the projection of the anatomic region of interest on the image receptor. ### Note It is strongly recommended that this Attribute be present, in order to ensure that images may be positioned correctly relative to one another for display. Shall be consistent with View Position (0018,5101). See Section C.8.11.5.1.1 for further explanation. Only a single Item is permitted in this Sequence.
>Include Table 8.8-1 “Code Sequence Macro Attributes” . | BCID 4010 “DX View”.
>View Modifier Code Sequence | (0054,0222) | 3 | View modifier. One or more Items are permitted in this Sequence.
>>Include Table 8.8-1 “Code Sequence Macro Attributes” | BCID 4011 “DX View Modifier”.
Patient Orientation Code Sequence | (0054,0410) | 3 | Sequence that describes the orientation of the patient with respect to gravity. See Section C.8.11.5.1.2 for further explanation. Only a single Item is permitted in this Sequence.
>Include Table 8.8-1 “Code Sequence Macro Attributes” . | BCID 19 “Patient Orientation”.
>Patient Orientation Modifier Code Sequence | (0054,0412) | 3 | Patient Orientation Modifier. Required if needed to fully specify the orientation of the patient with respect to gravity. Only a single Item is permitted in this Sequence.
>>Include Table 8.8-1 “Code Sequence Macro Attributes” | BCID 20 “Patient Orientation Modifier”.
Patient Gantry Relationship Code Sequence | (0054,0414) | 3 | Sequence that describes the orientation of the patient with respect to the gantry. Only a single Item is permitted in this Sequence.
>Include Table 8.8-1 “Code Sequence Macro Attributes” . | BCID 21 “Patient Equipment Relationship”.
Distance Source to Patient | (0018,1111) | 3 | Distance in mm from source to the table, support or bucky side that is closest to the Imaging Subject, as measured along the central ray of the X-Ray beam. ### Note This definition is less useful in terms of estimating geometric magnification than a measurement to a defined point within the Imaging Subject, but accounts for what is realistically measurable in an automated fashion in a clinical setting. This measurement does not take into account any air gap between the Imaging Subject and the "front" of the table or bucky. If the detector is not mounted in a table or bucky, then the actual position relative to the patient is implementation or operator defined. This value is traditionally referred to as Source Object Distance (SOD). See Section C.8.11.7 for explanation if Positioner Type (0018,1508) is MAMMOGRAPHIC.
Distance Source to Detector | (0018,1110) | 3 | Distance in mm from source to detector center. ### Note This value is traditionally referred to as Source Image Receptor Distance (SID). See Section C.8.11.7 for explanation if Positioner Type (0018,1508) is MAMMOGRAPHIC.
Estimated Radiographic Magnification Factor | (0018,1114) | 3 | Ratio of Source Image Receptor Distance (SID) over Source Object Distance (SOD).
Positioner Type | (0018,1508) | 2 | Defined Terms: CARM COLUMN MAMMOGRAPHIC PANORAMIC CEPHALOSTAT RIGID NONE ### Note The term CARM can apply to any positioner with 2 degrees of freedom of rotation of the X-Ray beam about the Imaging Subject. The term COLUMN can apply to any positioner with 1 degree of freedom of rotation of the X-Ray beam about the Imaging Subject.
Positioner Primary Angle | (0018,1510) | 3 | Position of the X-Ray beam about the patient from the RAO to LAO direction where movement from RAO to vertical is positive, if Positioner Type (0018,1508) is CARM. See Section C.8.7.5 for further explanation if Positioner Type (0018,1508) is CARM. See Section C.8.11.7 for explanation if Positioner Type (0018,1508) is MAMMOGRAPHIC.
Positioner Secondary Angle | (0018,1511) | 3 | Position of the X-Ray beam about the patient from the CAU to CRA direction where movement from CAU to vertical is positive, if Positioner Type (0018,1508) is CARM. See Section C.8.7.5 for further explanation if Positioner Type (0018,1508) is CARM. See Section C.8.11.7 for explanation if Positioner Type (0018,1508) is MAMMOGRAPHIC.
Detector Primary Angle | (0018,1530) | 3 | Angle of the X-Ray beam in the row direction in degrees relative to the normal to the detector plane. Positive values indicate that the X-Ray beam is tilted toward higher numbered columns. Negative values indicate that the X-Ray beam is tilted toward lower numbered columns. See Section C.8.7.5 for further explanation. See Section C.8.11.7 for explanation if Positioner Type (0018,1508) is MAMMOGRAPHIC.
Detector Secondary Angle | (0018,1531) | 3 | Angle of the X-Ray beam in the column direction in degrees relative to the normal to the detector plane. Positive values indicate that the X-Ray beam is tilted toward lower numbered rows. Negative values indicate that the X-Ray beam is tilted toward higher numbered rows. See Section C.8.7.5 for further explanation. See Section C.8.11.7 for explanation if Positioner Type (0018,1508) is MAMMOGRAPHIC.
Column Angulation | (0018,1450) | 3 | Angle of the X-Ray beam in degree relative to an orthogonal axis to the detector plane. Positive values indicate that the tilt is toward the head of the table. ### Note The detector plane is assumed to be parallel to the table plane. Only meaningful if Positioner Type (0018,1508) is COLUMN.
Table Type | (0018,113A) | 3 | Defined Terms: FIXED TILTING NONE
Table Angle | (0018,1138) | 3 | Angle of table plane in degrees relative to horizontal plane [Gravity plane]. Positive values indicate that the head of the table is upward. Only meaningful if Table Type (0018,113A) is TILTING.
Body Part Thickness | (0018,11A0) | 3 | The average thickness in mm of the body part examined when compressed, if compression has been applied during exposure.
Compression Force | (0018,11A2) | 3 | The compression force applied to the body part during exposure, measured in Newtons.
Compression Pressure | (0018,11A3) | 3 | The average compression pressure applied to the body part during exposure, calculated in kPa.
Compression Contact Area | (0018,11A5) | 3 | The area of the body part to which compression has been applied during exposure, measured in mm2. ### Note Area information is useful in addition to the Compression Pressure (0018,11A3) and Compression Force (0018,11A2) in the event that unusual values are encountered.
Paddle Description | (0018,11A4) | 3 | Description of the compression paddle, if compression was applied to the body part during exposure.

##### C.8.11.5.1 DX Positioning Attribute Descriptions

###### C.8.11.5.1.1 View Code Sequence

View Code Sequence (0054,0220) replaces the function of View Position (0018,5101), and describes the radiographic view of the image relative to the real-world patient orientation as described in Annex A “Explanation of Patient Orientation (Normative)” in PS3.17.

###### C.8.11.5.1.2 Patient Orientation Code Sequence

This Attribute is not related to Patient Orientation (0020,0020) and conveys a different concept entirely.

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DICOM PS3.3 2021d - Information Object Definitions