Preventive Effect of Hippocampal Sparing on Cognitive Dysfunction of Patients Undergoing Whole-Brain Radiotherapy and Imaging Assessment of Hippocampal Volume Changes

Table 1

Technical methods of irradiation for both groups.

	Group with hippocampal sparing	Group without hippocampal sparing
Hippocampus	Contouring	Without contouring
Illumination area	Whole-brain radiotherapy+hippocampal sparing	Whole-brain radiotherapy
Illumination technique	Tomotherapy	IMRT
Illumination volume	2500 cGy/10f (PCI) or 3000 cGy/10f (WBRT)±local dosing	2500 cGy/10f (PCI) or 3000 cGy/10f (WBRT)±local dosing
CTV	Whole brain (fully including the dura)	Whole brain (fully including the dura)
PTV	0.5 cm CTV expansion	0.5 cm CTV expansion
Hippocampus PRV	0.5 cm expansion	None
Hippocampal PRV dose limitation	Gy,  Gy,  Gy	None
OAR	Hippocampus, eye, lens, optic nerve	Eye, lens, optic nerve
OAR dose limitation	Dmax of  Gy, Dmax of  Gy, Dmax of optic  Gy	Dmax of  Gy, Dmax of  Gy, Dmax of optic  Gy