Материал: part03

Note​

X-Ray images generally use PRIMARY value for images captured from patient exposure.​

•​Value 2 shall identify the Patient Examination Characteristics in accordance with Section C.7.6.1.1.2​

Enumerated Values:​

PRIMARY​

SECONDARY​

•​Value 3 shall identify the image set in terms of the imaging planes.​

Enumerated Values:​

SINGLEPLANE​Image is a single plane acquisition​

BIPLANE A​ Image is the first plane (e.g., Frontal) of a Bi-plane acquisition​

BIPLANE B​ Image is the second plane (e.g., Lateral) of a Bi-plane acquisition​

•​Other Values are implementation specific (optional).​

C.8.7.1.1.2 Pixel Intensity Relationship​

Pixel Intensity Relationship (0028,1040) shall identify the relationship of the pixel values to the X-Ray beam intensity.​

Defined Terms:​

LIN​ Approximately proportional to X-Ray beam intensity;​

LOG​ Non-linear "Log Function"; A Modality LUT shall be included with the image to allow it to be scaled back to its proportional​ value to X-Ray beam intensity;​

DISP​Ready to be displayed; A Modality LUT may be included with the image to allow it to be scaled back to its proportional value​ to X-Ray beam intensity. The Attribute Acquisition Device Processing Description may be used to provide some indication on​ the pre-processing performed to create the ready to be displayed image.​

C.8.7.1.1.3 Acquisition Device Processing Description​

Acquisition Device Processing Description (0018,1400) provides some indication in human readable text of the digital processing on​ theimagesbeforeexchange.Examplesofthisprocessingare:edgeenhanced,subtracted,timefiltered,gammacorrected,convolved​ (spatially filtered).​

C.8.7.1.1.4 Scan Options​

The Scan Options Attribute identifies any acquisition technique that was used during the acquisition of the image.​

Defined Terms:​

EKG​ EKG Event Trigger​

PHY​ Physiological Event Trigger​

TOMO​Tomography​

CHASE​Bolus Chasing​

ROTA​ Rotation​

C.8.7.1.1.5 Derivation Description​

If an Image is identified to be a Derived image (see Section C.8.7.1.1.1), Derivation Description (0008,2111) is an optional and imple-​ mentation specific text description of the way the image was derived from an original image. As applied to X-Ray images, it may be​ usedtodescribederivationoperationssuchasedgeenhancement,temporalfiltering,digitalsubtraction,orotherlinearandnon-linear​ transformations.​

C.8.7.1.1.6 Bits Allocated​

Enumerated Values:​

8​

16​

- Standard -​

C.8.7.1.1.7 Bits Stored​

Enumerated Values:​

8​

10​

12​

16​

C.8.7.1.1.8 High Bit​

For X-Ray Images, High Bit (0028,0102) shall be one less than the value in Bit Stored.​

C.8.7.1.1.9 Synchronization of Frame and Waveform Times​

The synchronization of a multi-frame X-Ray image with a waveform (e.g., ECG, pressure, or respiration) encoded in a different SOP​ Instance is managed through the Attributes of the Synchronization Module (see Section C.7.4.2) of the Frame of Reference IE.​

Note​

The use of a Curve IE within the X-Ray IODs was previously defined in DICOM (see PS3.3-2004). That use has been retired​ in favor of encoding waveform data in a separate IOD.​

C.8.7.1.1.12 Frame Dimension Pointer​

Frame Dimension Pointer (0028,000A) identifies Attributes that vary or increment with each frame, and are clinically significant for​ viewing or processing the image. This is intended for SOP Instances whose preferred clinical presentation is dependent on frame​ relationships other than simply time.​

Defined Terms for multi-frame cine from the Cine Module (see Section C.7.6.5) are:​

00181063H​ Frame Time (0018,1063)​

00181065H​ Frame Time Vector (0018,1065)​

Defined Terms for rotational acquisition from the XA Positioner Module (see Section C.8.7.5) are:​

00181520H​ Positioner Primary Angle Increment (0018,1520)​

00181521H​ Positioner Secondary Angle Increment (0018,1521)​

Defined Terms for stepped acquisition from the X-Ray Table Module (see Section C.8.7.4) are:​

00181135H​ Table Vertical Increment (0018,1135)​

00181137H​ Table Longitudinal Increment (0018,1137)​

00181136H​ Table Lateral Increment (0018,1136)​

Defined Terms for an arbitrary labeled increment:​

00182002H​ Frame Label Vector (0018,2002)​

Note​

1.​PreviouseditionsoftheStandarddidnotincludetheoptionalFrameDimensionPointer(0028,000A),butinsteaddepended​ entirely on the mandatory Frame Increment Pointer (0028,0009), and envisaged that only time and no other dimension​ would relate frames. Image creators that add the Frame Dimension Pointer (0028,000A) must anticipate that many im-​ plementations will ignore or discard this Attribute when displaying or storing images and continue to assume that frames​ are temporally related.​

2.​Frame Time (0018,1063) or Frame Time Vector (0018,1065) will also be present and will contain appropriate values​ consistent with the times of acquisition of the frames.​

C.8.7.1.1.13 Referenced Image Sequence​

When Image Type (0008,0008) Value 3 is BIPLANE A or BIPLANE B, Referenced Image Sequence (0008,1140) shall be used to​ identify the corresponding SOP Instance of the Biplane acquisition. In this case, either:​

•​only a single Item shall be present, or​

- Standard -​

•​multiple Items may be present, each with the Purpose of Reference Code Sequence (0040,A170) present, and only the first Item​ having the Purpose of Reference value (121314, DCM, "Other image of biplane pair").​

TheReferencedFrameNumber(0008,1160)AttributeshallnotbepresentintheItemthatreferencesthecorrespondingSOPInstance​ of the Biplane acquisition.​

C.8.7.2 X-Ray Acquisition Module​

Table C.8-27. X-Ray Acquisition Module Attributes​

ROUND​

RECTANGLE​

- Standard -​

Note​

The sum of the area dose product of all images of a Series​ or a Study may not result in the total area dose product to​ which the patient was exposed.​

C.8.7.2.1 X-Ray Acquisition Attribute Descriptions​

C.8.7.2.1.1 Exposure Time​

Exposure time is the cumulative time the patient received X-Ray exposure during this image (Multi-frame image acquisition). Calcu-​ lation is pulse width * number of frames.​

C.8.7.2.1.2 Field of View​

The Field of View Attribute describes the shape and dimensions of the Image Receptor Field of View, applicable to both Image Intens-​ ifier and Digital Detector. This could be further restricted by the Collimator. See Section C.8.7.3.​

C.8.7.3 X-Ray Collimator Module​

An X-Ray Collimator is a device placed close to the X-Ray Source to restrict the span of the X-Ray beam. It is often made of lead​ shutters. Figure C.8-9 presents in a graphical form its relationship with the Field Of View Dimensions (0018,1149).​

Geometry of the collimator is specified with respect to a row and column coordinate system where the origin is the upper left hand​ pixel. This origin is specified by the values 1,1 for row/column. A row coordinate represent a number of raw spacing (vertical) and a​ column coordinate represents a column spacing (horizontal). Up to three different collimator shapes may be used and superimposed.​

- Standard -​

X-Ray Source

Collimator

Field of View

Exposure

Area

Detector

Figure C.8-9. Relationships of X-Ray Collimator​

Table C.8-28. X-Ray Collimator Module Attributes​

Include Table C.8-28b “X-Ray Collimator Dimensions Macro Attributes”​

Table C.8-28b. X-Ray Collimator Dimensions Macro Attributes​

- Standard -​