diff --git a/pypet2bids/pypet2bids/helper_functions.py b/pypet2bids/pypet2bids/helper_functions.py
index d010a34..4889bfc 100644
--- a/pypet2bids/pypet2bids/helper_functions.py
+++ b/pypet2bids/pypet2bids/helper_functions.py
@@ -135,7 +135,7 @@ def single_spreadsheet_reader(
 ) -> dict:
 
     spreadsheet_metadata = {}
-    metadata_fields = pet2bids_metadata.PET_metadata
+    metadata_fields = pet2bids_metadata
 
     if type(path_to_spreadsheet) is str:
         path_to_spreadsheet = pathlib.Path(path_to_spreadsheet)