What dose and fractionation scheme do you prefer for retreatment of meningiomas in close proximity to the optic structures?

This is a common problem. If the patient has never received prior radiation therapy and the meningioma is within a few millimeters of the optic chiasm, I discuss two options. The first option is to do standard radiation therapy, ie 5040 cGy in 180 cGy fractions, planned so that the maximum optic chi...