THE ROLE OF GAMMA KNIFE IN NEUROSURGERY

Abstract

The initial gamma knife unit design was intended for lesion generation in functional neurosurgical procedures. The first major modification in gamma unit design provided a more spherical dose profile for treatment of brain lesions. Further years of experience allowed not only the development of sophisticated neuroimaging and computer software, but also widespread recognition of the safety and efficacy ofthe gamma knife. In the field of cerebral AVMs, it is now used for lesions less than 3cm in diameter, in deep and critical areas of the brain and other sites in medically unfit patients. Subtotal obliteration of the AVM was found to be of no benefit and a latency period between treatment and total occlusion was found to be up to 2 years. Control of neoplastic growth of pituitary tumours by the gamma knife is a reasonably reliable treatment while control of endocrinopathies is possible, provided that an optimal localization and dose are used. The technique"applies best to smaller tumours generally associated with Cushing's disease. GH-producing tumours and prolactinomas are larger than ACTH-producing tumours. This limits the applicability of