diff --git a/heudiconv/dicoms.py b/heudiconv/dicoms.py
index b9734d7f..1526ef28 100644
--- a/heudiconv/dicoms.py
+++ b/heudiconv/dicoms.py
@@ -9,7 +9,6 @@
 from pathlib import Path
 import sys
 import tarfile
-from typing_extensions import Protocol
 from typing import TYPE_CHECKING, Any, Dict, Hashable, List, NamedTuple, Optional, Union, overload
 from unittest.mock import patch
 import warnings
@@ -27,9 +26,13 @@
 
 if TYPE_CHECKING:
     if sys.version_info >= (3, 8):
-        from typing import Literal
+        from typing import Literal, Protocol
     else:
-        from typing_extensions import Literal
+        from typing_extensions import Literal, Protocol
+if sys.version_info >= (3, 8):
+    from typing import Protocol
+else:
+    from typing_extensions import Protocol
 
 with warnings.catch_warnings():
     warnings.simplefilter("ignore")