Linac Based Radiosurgery (X-knife) for Brain Metastases

Abstract

Linac based stereotactic radiosurgery by X-knife, technique that permits the precise delivery of a high dose of radiation from 6 MV linear accelerator to intracranial target(s) while sparing the normal tissue, has been used as an alternative treatment for brain metastasis. Five patients with 9 metastatic lesions were treated with this technique. The radiation dose was 15-25 Gy with the 75-80 per cent isodose line encompassing the enhancing tumor according to the tumor volume, site and previous treatment. All metastatic lesions were evaluated at 4 weeks after treatment, there were 2 CR, 4 PR and 3 remained unchanged. The result showed a very distinct clear radiation effect margin between the target and normal tissue. The patient could tolerate the treatment procedure well without any complications inherent to the technique. All patients with neurological symptoms had a satisfactory recuperation. Radiosurgery with X-knife is an effective and safe therapy for brain metastases. It can be applied as a primary treatment, as a booster in combination with whole brain irradiation, or as treatment for patients with relapse in a previous irradiated area.