diff --git a/script/sim/utils.py b/script/sim/utils.py
index 76c7214..cfcac51 100644
--- a/script/sim/utils.py
+++ b/script/sim/utils.py
@@ -14,7 +14,7 @@ def integrate_roi(source, x,y, w, h):
     if source.data is None:
         source.update()
     roi = source.data.getRoi(Rectangle(x,y, w, h))
-    return sum(roi.integrateHorizontally(False))
+    return roi.integrate(False)