Table 5.

Summary of contouring guidelines for GTV, CTV, and PTV in spinal stereotactic radiosurgery.

Target volume	Guidelines
GTV	Contour gross tumor using all available imaging
	Include epidural and paraspinal components of the tumor
CTV	Include abnormal marrow signal suspicious for microscopic invasion
	Include bony CTV expansion to account for subclinical spread
	Should contain GTV
	Circumferential CTVs encirclincg the cord should be avoided except in rare instances were the vertebral body, bilateral pedicles/lamina, and spinous processes are all involved or when there is extensive metastatic disease along the circumference of the epidural space without spinal cord compression
PTV	Uniform expansion around the CTV
	CTV to PTV margins <3 mm
	Modified dural margin adjacent critical structures to allow spacing at discretion of the treating physician unless GTV compromised
	Never overlaps with cord
	Should contain entire GTV and CTV

CTV, clinical target volume; GTV, gross tumor volume; PTV, planning target volume. From Cox et al. (62).