Hi,

GDCM was added back in 2022 by the commit 15caeb745c5d77b69905d38d43b4d09742bc71b6.

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15caeb745c5d77b69905d38d43b4d09742bc71b6
Author:     Antero Mejr <antero@mailbox.org>
AuthorDate: Wed Jun 15 15:39:53 2022 +0000
Commit:     Ludovic Courtès <ludo@gnu.org>
CommitDate: Sun Jan 8 16:11:45 2023 +0100

gnu: Add gdcm.

* gnu/packages/bioinformatics.scm (gdcm): New variable.
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And it's on the 3.0.20.

Closing as already availale.

Thanks,
Oleg