diff --git a/atlas/views.py b/atlas/views.py
index 4ad213d1..df53b08c 100755
--- a/atlas/views.py
+++ b/atlas/views.py
@@ -4333,15 +4333,12 @@ def collection_case_dicom_json_review(request, exam_id, case_id):
 
 def collection_case_dicom_json(request, exam_id, case_number, review=False):
     # Support either case_number (index) or case_id (case PK)
+    collection = get_object_or_404(CaseCollection, pk=exam_id)
     try:
-        casedetail = CaseDetail.objects.get(case=case_id, collection=exam_id)
+        case_obj = collection.get_case_by_index(int(case_number))
+        casedetail = CaseDetail.objects.get(case=case_obj, collection=collection)
     except Exception:
-        collection = get_object_or_404(CaseCollection, pk=exam_id)
-        try:
-            case_obj = collection.get_case_by_index(int(case_id))
-            casedetail = CaseDetail.objects.get(case=case_obj, collection=collection)
-        except Exception:
-            raise Http404("Case not found in collection")
+        raise Http404("Case not found in collection")
 
     if review:
         priors = casedetail.caseprior_set.exclude(prior_visibility="NO")