Blocking out pages that have permissions

I have a scenario where I'm making pages not public. If you try opening the pages (when logged out) the pages are not served. Great.
I have the following code that gets the pages but I'm not sure how to determine if the user viewing the node has permission. I've applied permissions to pages so I'd like to determine how to not display a node if the user does not have permission

 

 

try

 

 

 

RadPanelItem item = e.Item;

 

 

 

PageSiteNode dataItem = (PageSiteNode)e.Item.DataItem;

 

 

 

if (!dataItem.ShowInNavigation)

 

 

 

if (item.Level > 0)

 

 

 

RadPanelItem pi = (RadPanelItem)item.Parent;

 

pi.Items.Remove(item);

 

 

else

 

 

 

this.PanelBar.Items.Remove(item);

 

 

 

return;