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InterFile 3.3

The only format with a header in plain ASCII text, so you do not need a special utility to fiddle with the header keys. It supports several study types ... however not with a one to one relationship to for example DICOM or even PET studies.
scaling factors / quantitation:
The official format doesn't specify a quantitation value but it supports any kind of pixeltype from 1bit up to doubles and ASCII. Quantified images will be saved as floats but you can use the options [-b16 or -b8] to force the writing of integer pixel values (with a non-standard global slope/intercept added to the header).
patient/slice orientations:
Only defined in tomographic InterFile studies. Note however that you can specify the patient orientation (for tomographic studies) but it does not specify how the images where actually stored in the file. In fact, only DICOM does.
extra notes:
- static and dynamic studies: slice thickness and patient orientation are lost. We mostly split up the time frames of a dynamic (PET) study into separate tomographic studies in order to preserve the parameters (on the other hand: now your time relation will get lost :)
- the "slice thickness" & "centre-centre slice separation" keys must be specified in pixel units. However, there is no key that specifies the pixel size in the Z-dimension. Therefore, (X)MedCon uses the average of the pixel sizes in X,Y-dimensions (which are mostly the same). In other words:
   [slice_thickness_pixels] = [slice_thickness_mm] / ( [pixel_xsize_mm + pixel_ysize_mm] / 2 )
- Support added for gated and gated spect studies based on this proposal. Some more information can be found at the library notes.
Format: InterFile 3.3  
Color Mapgrayscale-
File Endianlittle & big-
Pixel Types1-bit, all integers, float, double, ASCII-
Scaling Factorsquantify & calibrate factors / image are NOT supported
Dimensions / Imagedifferent dimensions for each image are supported
Pixel Types / Imagedifferent pixeltypes for each image are supported

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Page last modified on January 30, 2007, at 12:14 AM