|Target volume||Definition||MSKCC Standard Approach|
|GTV||Gross tumor in the bone, including soft tissue extension||
Consider fusing diagnostic imaging including PET. MRI is recommended for spinal metastases.|
Consider reviewing diagnostic and/or simulation imaging with a diagnostic radiologist.
|CTV||Margin for microscopic extension of tumor||
GTV + 5 mm but not extending beyond the bone unless direct extension with adjacent tissue invasion is present.|
NOTE: For lesions in the spine undergoing SBRT, published guidelines will be followed 
|PTV||Margin for setup error (patient positioning and treatment delivery)||CTV + 3 mm (if using daily CBCT)|