RadiAnt DICOM Viewer - Discussion Forum
off-topic: tools to compress DICOM files

sorry but I need some help.
we recently installed a breast tomosynthesis machine.

the images are very nice but the amount of data which is generated in a single exam is very large and doesn't fit inside a CD-ROM

we had to burn 3 to 6 CDs per patient and this become unconfortable for the referring physicians that cannot open a single study with a single CD.

DVD burning is not an option since our burning Robot doesn't supports very well DVDs (we tried but the burning time is extremely long... more than 40 minutes per patients, while burning multiple CDs takes considerably less time)

so I'm wondering if anybody of you knows some compressing tool to reduce the size of DICOMs (or converts them to another format) in order to make them fit inside a CD to make image review easier

Mar 11, 2016 05:21 AM
by Tommy
Tommy, there is a free Tool in Dicom Toolkit called dcmcjpeg that can be used to convert Dicom files to lossless Jpeg Transfer Syntax.


You will need to run this on each file in the directory. This can be achieved by

for /r %i in (*) do dcmcjpeg %i %i

You need to test if Radiant supports the Transfer Syntax, not all viewers do. But I think Radiant does.

If perfect quality is not a concern, you can go for lossy compression for even smaller size. The mileage may vary.

Mar 16, 2016 10:48 PM
by Aaaaaaaaa
Tommy, I have posted an answer to your question, but with links, so it has to be moderated. Look for dcmcjpeg on google.


Mar 18, 2016 12:07 PM
by aaaaaaaaa
I've downloaded the DCMTK but I need some step by step instruction how to use is since this seems commandline based and I'm not very expert with it...

let's say the DCMTK folder is C:\DCMTK\
and the DICOM folder to process is C:\DICOM\

what should I exactly do to use the code you suggested before to do the compression?

Mar 24, 2016 02:13 AM
by Tommy
for /r %i in (*) do c:\dcmtk\dcmcjpeg %i %i

Backup your directory first.
Make sure dcmcjpeg is in dcmtk and not in dcmtk\bin

Compare size of files afterwards (with your backup).
Try if files are displayable by radiant.


Mar 28, 2016 09:31 PM
by aaaaa
Sorry should be cd \DICOM


Mar 28, 2016 09:32 PM
by aaaaa
thanks it works!!!
and RadiAnt reads the images with no issues!!!

Mar 31, 2016 04:04 AM
by Tommy
just to be sure... is that code doing a "lossless" JPEG compression ?

I'd prefer using lossless rather than lossy

Mar 31, 2016 05:30 AM
by Tommy
just curious to know one thing...
once a DICOM-JPEG-lossless case archived into the PACS is downloaded and viewed in RadiAnt what happens to the images?

do they remain compressed or uncompressed?

I compressed a 715 MB case with DCTK that shrinked down to 445 MB in the PACS archive folder.

when I retrieved it using RadiAnt I saw that the whole "tmp" DICOM folder is not 445 MB but again 715.

so it seems the compression is removed while viewing, is that correct?

Mar 31, 2016 12:14 PM
by Tommy27
Default should be lossless.

Your PACS probably changes the transfer syntax. I dont think radiant would do that.

Mar 31, 2016 10:09 PM
by aaaaaaa
so do you assume that images are decompressed upon sending, not while receiving?

Apr 1, 2016 03:45 AM
by Tommy
You can set the preferred transfer syntax in RadiAnt (there is no guarantee that the server will respect it, however):

Apr 2, 2016 06:46 PM
by RadiAnt
Preferably change the transfer syntax setting on your PACS if you need the PACS to outpu compressed files.

Apr 2, 2016 10:06 PM
by Aaaaaa
thanks to both of you

so this confirms my observations... as said before those DICOM cases are already stored in JPEG lossless syntax but are sent out uncompressed by the PACS into RadiAnt...

I'll try to modify the RadiAnt receiving syntax as Maciej suggested and see it's enough to solve the issue, otherwise I'll check the settings of my PACS which is a ClearCanvas system

Apr 3, 2016 06:17 AM
by Tommy
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