Pixel Spacing Attribute
| Tag | (0028,0030) |
|---|---|
| Type | Conditionally Required (1C) |
| Keyword | PixelSpacing |
| Value Multiplicity | 2 |
| Value Representation | Decimal String (DS) |
| Example Values |
|
Physical distance in the Patient between the center of each pixel, specified by a numeric pair - adjacent row spacing (delimiter) adjacent column spacing in mm. See Section 10.7.1.1 and Section 10.7.1.3. Required if the image has been calibrated. May be present otherwise.
Section 10.7.1.1
10.7.1.1 Pixel Spacing
Pixel Spacing (0028,0030) specifies the physical distance in the Patient between the center of each pixel.
If Pixel Spacing (0028,0030) is present and the image has not been calibrated to correct for the effect of geometric magnification, the values of this Attribute shall be the same as in Imager Pixel Spacing (0018,1164) or Nominal Scanned Pixel Spacing (0018,2010), if either of those Attributes are present.
If Pixel Spacing (0028,0030) is present and the values are different from those in Imager Pixel Spacing (0018,1164) or Nominal Scanned Pixel Spacing (0018,2010), then the image has been corrected for known or assumed geometric magnification or calibrated with respect to some object of known size at known depth within the Patient.
If Pixel Spacing Calibration Type (0028,0A02) and Imager Pixel Spacing (0018,1164) and Nominal Scanned Pixel Spacing (0018,2010) are absent, then it cannot be determined whether or not correction or calibration have been performed.
Note
-
Imager Pixel Spacing (0018,1164) is a required Attribute in DX family IODs.
-
Nominal Scanned Pixel Spacing (0018,2010) is a required Attribute in Multi-frame SC family IODs
Section 10.7.1.3
10.7.1.3 Pixel Spacing Value Order and Valid Values
All pixel spacing related Attributes are encoded as the physical distance between the centers of each two-dimensional pixel, specified by two numeric values.
The first value is the row spacing in mm, that is the spacing between the centers of adjacent rows, or vertical spacing.
The second value is the column spacing in mm, that is the spacing between the centers of adjacent columns, or horizontal spacing.
To illustrate, consider the example shown in Figure 10.7.1.3-1.
Figure 10.7.1.3-1. Example of Pixel Spacing Value Order
Pixel Spacing = Row Spacing \ Column Spacing = 0.30\0.25.
All pixel spacing related Attributes shall have positive non-zero values, except when there is only a single row or column or pixel of data present, in which case the corresponding value may be zero.
Note
A single row or column or "pixel" may occur in MR Spectroscopy Instances.
This description applies to:
-
Pixel Spacing (0028,0030)
-
Imager Pixel Spacing (0018,1164)
-
Nominal Scanned Pixel Spacing (0018,2010)
-
Image Plane Pixel Spacing (3002,0011)
-
Compensator Pixel Spacing (300A,00E9)
-
Detector Element Spacing (0018,7022)
-
Presentation Pixel Spacing (0070,0101)
-
Printer Pixel Spacing (2010,0376)
-
Object Pixel Spacing in Center of Beam (0018,9404)