Preservation of visual fields after Peri-Sellar gamma-knife radiosurgery

Radiosurgical treatment of pituitary and peri-sellar tumors has become an i ncreasingly utilized modality as an alternative to conventional radiotherap y and surgery. Such radiosurgery results in a relatively high dose of radia tion to the optic chiasm. The clinical data establishing safe single-fracti on doses to the chiasm is immature, although taken together previous litera ture suggests a recommended maximal dose of 8 Gy, Optic neuropathy, when it occurs, tends to take place within 2 years of treatment, We evaluated the visual fields of 20 sequential patients that received significant doses to the optic chiasm by Gamma-knife radiosurgery, There were 17 cases of pituit ary adenoma and 3 cases of meningioma, and two patients refused follow-up t esting. Preoperative visual field and cranial nerve examinations were done prior to radiosurgery and in follow-up, with a median follow-up of 24 month s. There were no cases of quantitative visual field deficit induced by trea tment, No patients developed symptomatic visual deterioration. Radiat. Onco l. Invest. 90:343-350, 2000. 2000 Wiley-Liss, Inc.