How do you account for artifact due to hardware, or what measures do you take, to optimize planning in the setting of a post-operative spine SBRT treatment?  

The most difficult issue from artifact from hardware is adequately seeing the spinal cord for proper delineation.  In order to properly see the cord in cases where artifact from MRI obscures the cord, we typically obtain a CT myelogram and fuse that with our simulation CT to allow us to draw ou...

If feasible, discuss the case with the surgeon prior to surgery, and ask that no screws or crosslinks be placed at the level of the tumor...  CT myelogram simulation is the best option, if that is not available, you can do MRI fusion, try thin slice T2 and carefully review the fusion in ax...