gh-144217: Add dicom support (medical imaging) to mimetypes (GH-144218)

benediktjohannes · blurb-it[bot] · ZeroIntensity · web-flow · commit 76d3ae71bab2 · 2026-01-25T22:22:43.000Z
Co-authored-by: blurb-it[bot] &lt;43283697+blurb-it[bot]@users.noreply.github.com&gt;
Co-authored-by: Peter Bierma &lt;zintensitydev@gmail.com&gt;
diff --git a/Doc/whatsnew/3.15.rst b/Doc/whatsnew/3.15.rst
@@ -603,6 +603,7 @@ math
 mimetypes
 ---------
 
+* Add ``application/dicom`` MIME type for ``.dcm`` extension. (Contributed by Benedikt Johannes in :gh:`144217`.)
 * Add ``application/node`` MIME type for ``.cjs`` extension. (Contributed by John Franey in :gh:`140937`.)
 * Add ``application/toml``. (Contributed by Gil Forcada in :gh:`139959`.)
 * Rename ``application/x-texinfo`` to ``application/texinfo``.
diff --git a/Lib/mimetypes.py b/Lib/mimetypes.py
@@ -477,6 +477,7 @@ def _default_mime_types():
     types_map = _types_map_default = {
         '.js'     : 'text/javascript',
         '.mjs'    : 'text/javascript',
+        '.dcm'    : 'application/dicom',
         '.epub'   : 'application/epub+zip',
         '.gz'     : 'application/gzip',
         '.json'   : 'application/json',
diff --git a/Lib/test/test_mimetypes.py b/Lib/test/test_mimetypes.py
@@ -226,6 +226,7 @@ def check_extensions():
             for mime_type, ext in (
                 ("application/epub+zip", ".epub"),
                 ("application/octet-stream", ".bin"),
+                ("application/dicom", ".dcm"),
                 ("application/gzip", ".gz"),
                 ("application/ogg", ".ogx"),
                 ("application/pdf", ".pdf"),
diff --git a/Misc/NEWS.d/next/Library/2026-01-25-03-23-20.gh-issue-144217.E1wVXH.rst b/Misc/NEWS.d/next/Library/2026-01-25-03-23-20.gh-issue-144217.E1wVXH.rst
@@ -0,0 +1 @@
+:mod:`mimetypes`: Add support for DICOM files (for medical imaging) with the official MIME type ``application/dicom``. Patch by Benedikt Johannes.

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1 @@`
	`1`	+:mod:`mimetypes`: Add support for DICOM files (for medical imaging) with the official MIME type ``application/dicom``. Patch by Benedikt Johannes.