I use MIPAV[1] which can run on Linux (or any OS with a new enough Java Runtime Environment). I don’t have a lot of experience with other DICOM viewers and have somewhat limited use cases for it, but it seems to have a good number of features.

It’s completely free, but accessing the download (or the source) requires (free) registration.[2] Filling out the form should take you straight to the download links (i.e. you should not have to wait for a manual approval to download).

[1] https://mipav.cit.nih.gov/ [2] https://mipav.cit.nih.gov/clickwrap.php

Ginkgo CADx evolved quickly for a while some years ago (while it was partly funded by the Spanish government and developed by a private company), but that project and company closed. The code was released as open source and it gets some commits every once in a while by volunteers.

It has a weird UX/UI, but it might be enough for you.

Also, it's packaged on most distributions.

https://github.com/gerddie/ginkgocadx

Aeskulap was the best one, I used it successfully a couple of years ago, despite the home page making it look like abandonware.

http://www.nongnu.org/aeskulap/

Unfortunately it seems it's no longer available in Fedora repositories.