<div dir="ltr"><div>Hi Greg,</div><div>- rtk can convert these files in any ITK file format. Run</div><div><span style="font-family:monospace">rtkprojections -p DIRECTORY -r FILENAME -o test.mha --nolineint</span></div><div>- They are not already dark and flood corrected. See the converting class</div><div><a href="https://github.com/RTKConsortium/RTK/blob/main/include/rtkVarianObiRawImageFilter.h#L35-L38">https://github.com/RTKConsortium/RTK/blob/main/include/rtkVarianObiRawImageFilter.h#L35-L38</a></div><div>- The FDK output are in 1/length unit. The length unit are a user choice, so if you set all ditances (spacings in image meta information and lengths in RTK geometry) in mm, then you reconstruct in 1/mm.</div><div>- Conversion to HU requires a linear conversion after calibrating the value for air and water. We don't do that usually but I believe there is an ITK filter for this conversion.</div><div>- If you want to use a subset of projections, you can use our tool rtksubselect :</div><div><span style="font-family:monospace">srit@srit-Precision-5480:~$ rtksubselect -h<br>RTK 2.7.0, git hash 5e5929a510fc5940dccba9a96eec70aa6597f2fc<br><br>Subselects a few projections from a list of projection files and a geometry <br>file.<br><br>Usage: RTK [OPTIONS]... [FILES]...<br><br> -h, --help Print help and exit<br> -V, --version Print version and exit<br> -v, --verbose Verbose execution (default=off)<br> -g, --geometry=STRING XML geometry file name<br> --out_geometry=STRING Output geometry file name<br> --out_proj=STRING Output projections stack file name<br> -f, --first=INT First projection index (default=`0')<br> -l, --last=INT Last projection index<br> -s, --step=INT Step between projections (default=`1')<br> --list=INT List of projection indices to keep (0-based)<br></span></div><div><br></div><div>Good luck with all this,</div><div>Simon</div><div><br></div><div><br></div></div><br><div class="gmail_quote gmail_quote_container"><div dir="ltr" class="gmail_attr">On Mon, Mar 16, 2026 at 7:51 PM Sharp, Gregory C. <<a href="mailto:gcsharp@mgb.org">gcsharp@mgb.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">Hi all, I have a few questions:<br>
<br>
Is there any viewer for these files and/or can I convert them into mha?<br>
<br>
Are the xim files already dark and flood corrected?<br>
<br>
What are the units for the fdk output? Can they be scaled into something like HU?<br>
<br>
Is there a way to specify subsets of gantry angles to be used in the fdk recon?<br>
<br>
Thank you,<br>
Greg<br>
<br>
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