STEREOTAXIC GAMMA-RADIOSURGERY OF CRANIOPHARYNGIOMAS

Ten cases of solid craniopharyngioma have been treated safely and effe ctively by gamma knife for a mean follow-up time of 13.9 months. Gamma radiosurgery was done as an initial radiotherapy to the residual or r ecurrent tumor after surgery in 8 cases. One recurrent tumor from surg ery and conventional radiotherapy, and another tumor without previous treatment, have also been treated. Dose planning and dosimetry were pe rformed using both axial and coronal MRIs. The tumor had a mean diamet er of 21.1 mm and volume of 6.14 cm(3). The tumor was treated with a m ean maximum and marginal dose of 27.6 and 14.2 Gy respectively. The do se to the optic pathways is critical and was kept as low as possible w hich was calculated to be <13.0 Gy on average. As a result, marked shr inkage of the tumor in 7 and central necrosis in 3 tumors have been ob tained without significant side effects.