diff --git a/Library/Airways/PTKComputeRadiusForBranch.m b/Library/Airways/PTKComputeRadiusForBranch.m
index c2bd445ac..5454c42df 100644
--- a/Library/Airways/PTKComputeRadiusForBranch.m
+++ b/Library/Airways/PTKComputeRadiusForBranch.m
@@ -181,8 +181,14 @@
     % tissue
     min_hu = -1024;
     max_hu = 0;
-    min_intensity = lung_image_as_double.HounsfieldToGreyscale(min_hu);
-    max_intensity = lung_image_as_double.HounsfieldToGreyscale(max_hu);
+    try
+        min_intensity = lung_image_as_double.HounsfieldToGreyscale(min_hu);
+        max_intensity = lung_image_as_double.HounsfieldToGreyscale(max_hu);
+    catch
+        imgV = lung_image_as_double.RawImage(:);
+        min_intensity = max(min_hu,min(imgV));
+        max_intensity = min(max_hu,max(imgV));
+    end    
     interp_image = max(double(min_intensity), interp_image);
     interp_image = min(double(max_intensity), interp_image);
     midpoint = ceil(size(interp_image, 1)/2);
diff --git a/Library/Airways/PTKReallocateAirwaysByLobe.m b/Library/Airways/PTKReallocateAirwaysByLobe.m
index dad23ea8d..37f840f29 100644
--- a/Library/Airways/PTKReallocateAirwaysByLobe.m
+++ b/Library/Airways/PTKReallocateAirwaysByLobe.m
@@ -12,6 +12,9 @@
     
     uncertain_bronchi = start_branches.LeftUncertain;
     for bonchus = uncertain_bronchi
+        if ~isfield(bonchus(1).GetCentrelineTree,'GlobalIndex')
+            continue;
+        end
         indices = GetVoxelsForTheseBranches(bonchus, lobes);
         lobe_values = lobes.RawImage(indices);
         lobe_values = setdiff(lobe_values, 0);
diff --git a/Library/Lungs/PTKSeparateAndLabelLungs.m b/Library/Lungs/PTKSeparateAndLabelLungs.m
index 037b2e045..67810e336 100644
--- a/Library/Lungs/PTKSeparateAndLabelLungs.m
+++ b/Library/Lungs/PTKSeparateAndLabelLungs.m
@@ -89,8 +89,10 @@
     num_pixels = cellfun(@numel, CC.PixelIdxList);
     total_num_pixels = sum(num_pixels);
     [largest_area_numpixels, largest_areas_indices] = sort(num_pixels, 'descend');
-
-    if ~isempty(trachea_top_local)
+        
+    if ~isempty(trachea_top_local) && ...
+            length(trachea_top_local) > 1 && ...
+            length(size(both_lungs.RawImage)) > 2
         left_region = both_lungs.RawImage(:, 1:trachea_top_local(2), :);
         right_region = both_lungs.RawImage(:, trachea_top_local(2) + 1:end, :);
         left_sum = sum(left_region(:));