diff --git a/platform/core/src/services/HangingProtocolService/HangingProtocolService.ts b/platform/core/src/services/HangingProtocolService/HangingProtocolService.ts
index fd85749ac..67de64e57 100644
--- a/platform/core/src/services/HangingProtocolService/HangingProtocolService.ts
+++ b/platform/core/src/services/HangingProtocolService/HangingProtocolService.ts
@@ -11,6 +11,7 @@ import { isDisplaySetFromUrl, sopInstanceLocation } from './custom-attribute/isD
 import numberOfDisplaySetsWithImages from './custom-attribute/numberOfDisplaySetsWithImages';
 import seriesDescriptionsFromDisplaySets from './custom-attribute/seriesDescriptionsFromDisplaySets';
 import uuidv4 from '../../utils/uuidv4';
+import { getUniqueAttributeFromList } from './lib/getUniqueAttributeFromList';
 
 type Protocol = HangingProtocol.Protocol | HangingProtocol.ProtocolGenerator;
 
@@ -77,15 +78,15 @@ export default class HangingProtocolService extends PubSubService {
     },
     ModalitiesInStudy: {
       name: 'Gets the array of the modalities for the series',
-      callback: metadata =>
-        metadata.ModalitiesInStudy ??
-        (metadata.series || []).reduce((prev, curr) => {
-          const { Modality } = curr;
-          if (Modality && prev.indexOf(Modality) == -1) {
-            prev.push(Modality);
-          }
-          return prev;
-        }, []),
+      callback: metadata => {
+        if (metadata.ModalitiesInStudy?.length > 0) {
+          return metadata.ModalitiesInStudy;
+        }
+        if (Array.isArray(metadata.series)) {
+          return getUniqueAttributeFromList(metadata.series, 'Modality');
+        }
+        return [];
+      },
     },
     isReconstructable: {
       name: 'Checks if the display set is reconstructable',
diff --git a/platform/core/src/services/HangingProtocolService/lib/getUniqueAttributeFromList.ts b/platform/core/src/services/HangingProtocolService/lib/getUniqueAttributeFromList.ts
new file mode 100644
index 000000000..4ea3af867
--- /dev/null
+++ b/platform/core/src/services/HangingProtocolService/lib/getUniqueAttributeFromList.ts
@@ -0,0 +1,19 @@
+/**
+ * Returns an array of unique values for the given attribute from a series array.
+ * If the attribute is not present on the series, attempts to get it from the first instance.
+ * @param {Array} series - The series array to extract attributes from.
+ * @param {string} attribute - The attribute name to extract.
+ * @returns {Array} Array of unique attribute values.
+ */
+export function getUniqueAttributeFromList(series, attribute) {
+  return series.reduce((prev, curr) => {
+    let value = curr[attribute];
+    if (!value && curr.instances && curr.instances[0]) {
+      value = curr.instances[0][attribute];
+    }
+    if (value && prev.indexOf(value) === -1) {
+      prev.push(value);
+    }
+    return prev;
+  }, []);
+}