diff --git a/extensions/default/src/DicomWebProxyDataSource/index.js b/extensions/default/src/DicomWebProxyDataSource/index.js
index cf016c825b..e873237dde 100644
--- a/extensions/default/src/DicomWebProxyDataSource/index.js
+++ b/extensions/default/src/DicomWebProxyDataSource/index.js
@@ -27,7 +27,7 @@ function createDicomWebProxyApi(
         throw new Error(`No studyInstanceUids in request for '${name}'`);
       }
 
-      let url = query.get('url');
+      const url = query.get('url');
 
       if (!url) {
         throw new Error(`No url for '${name}'`);