diff --git a/src/src/UI/Widget/dicomimageview.cpp b/src/src/UI/Widget/dicomimageview.cpp
index 822f8e2..6ed0d4c 100644
--- a/src/src/UI/Widget/dicomimageview.cpp
+++ b/src/src/UI/Widget/dicomimageview.cpp
@@ -720,7 +720,13 @@ bool DicomImageView::checkFusion(DicomImageView *base, DicomImageView *overlap)
         return false;
     //same series
     if (baseSeries->GetSeriesNumber() == overlapSeries->GetSeriesNumber()) return false;
-    return baseSeries->IntersectWorldBounds(overlapSeries);
+    // not enough slice
+    if (baseSeries->GetProperty()->GetSliceCount() < 20 ||
+        overlapSeries->GetProperty()->GetSliceCount() < 20) return false;
+    // check intersect
+    if(!baseSeries->IntersectWorldBounds(overlapSeries)) return false;
+    // check current slice orientation
+    return base->CompareWorldSliceOrientation(overlap);
 }
 
 bool DicomImageView::checkFusion(DicomImageView *overlap) {