DICOM PS3.16 2021e - Content Mapping Resource

TID 10050 X-Ray Source Reference Coordinate System

This template describes the transformation between the X-Ray-source-related coordinate positions and the RDSR reference coordinate system.

Type:

Extensible

Order:

Non-Significant

Root:

No

Table TID 10050. X-Ray Source Reference Coordinate System

NL

Rel with Parent

VT

Concept Name

VM

Req Type

Condition

Value Set Constraint

1

CONTAINER

EV (130519, DCM, "X-Ray Source Reference Coordinate System")

1

M

2

>

CONTAINS

DATETIME

DT (111526, DCM, "DateTime Started")

1

M

3

>

CONTAINS

DATETIME

DT (111527, DCM, "DateTime Ended")

1

M

4

>

CONTAINS

TEXT

EV (113832, DCM, "Identification of the X-Ray Source")

1

M

5

>

CONTAINS

TABLE

EV (130520, DCM, "Transformation Matrix")

1

M

NCOLUMNS = 4

NROWS= 4

CELL VR = FD

6

>

CONTAINS

SCOORD3D

EV (130521, DCM, "Center of Rotation")

1

MC

IFF Row 8 is present

GRAPHIC TYPE = {POINT}

7

>

CONTAINS

SCOORD3D

EV (130522, DCM, "Rotation Plane Normal Point")

1

MC

IFF Row 8 is present

GRAPHIC TYPE = {POINT}

8

>

CONTAINS

TABLE

EV (130523, DCM, "Rotation Angle")

1

U

NCOLUMNS = 2

COLUMN 1 = EV (111526, DCM, "DateTime Started")

COLUMN 2 = EV (130523, DCM, "Rotation Angle")

COLUMN 2 UNITS = EV (deg, UCUM, "deg")

COLUMN 1 VR = DT

COLUMN 2 VR = FD


Content Item Descriptions

Row 2

The DateTime of the beginning of the time period over which the content items are applicable.

Row 3

The DateTime of the end of the time period over which the content items are applicable.

Row 4

Identification the X-Ray source. This designation shall not change for a given source throughout the entire RDSR. For systems with multiple X-Ray sources, each source shall be described with a separate instance of this template.

Row 5

A 4-by-4 matrix of dimensionless numbers of the form defined in Section C.20.2.1.1 “Frame of Reference Transformation Matrix” in PS3.3 . The matrix describes the rigid transformation matrix (including translation and rotation) that transforms the X-Ray source reference coordinate system to the RDSR reference coordinate system. The translation described by this matrix indicates the position and orientation of the X-Ray source within the RDSR reference coordinate system. Like the RDSR RCS, the X-Ray source reference coordinate system shall be a right-handed Cartesian coordinate system.

In the specific case of a source rotating about a fixed point within a plane, Row 6-8 may be specified to describe the rotation of a moving source without the need to encode multiple transformation matrices. For an RDSR that describes only a rotating source in a single plane, the source transformation matrix may be described only once, with all subsequent movements described by the values in Row 6-8. If Row 6-8 are used, the transformation matrix described in Row 5 corresponds to the position and orientation of the source at the beginning of the rotation.

Row 6

Position of the center of rotation of the X-Ray source in the X-Ray source reference coordinate system. Since the X-Ray source RCS uses the source as the origin, this value defines the vector from the source to the center of rotation.

Its value shall be assumed to be the position at the initial angle of rotation. Zero degrees in Row 8 is the angle of the source about the center of rotation at its initial position.

Row 7

Row 6 is combined with Row 7 to define the normal vector to the rotational plane. The Center of Rotation SCOORD3D value from Row 6 defines the origin of the vector. Row 7 defines the distal end of the vector. The orientation of the vector assumes the same x, y, and z axis orientations as the X-Ray source reference coordinate system. The positive rotation angle is clockwise as viewed from the center of rotation along this normal vector. This vector may or may not be a unit vector.

Row 8

Two-column table specifying DateTime values and X-Ray source rotation angles. This table shall only be populated in the specific case when the X-Ray source is rotating about a fixed center of rotation within a plane. It allows encoding of a single value, i.e., angle, of a source in a specific motion (rotating around a fixed point), along with an accompanying DateTime value. The position of the source at the beginning of the rotation is defined as zero degrees.

The first DateTime value shall not be before the start DateTime value in Row 2 of the template, and the final DateTime value shall not be after the end DateTime value specified in Row 3.

DICOM PS3.16 2021e - Content Mapping Resource