GammaTile is fda approved for newly diagnosed as well as recurrent malignant brain tumors, both primary and metastatic. They are a form of brachytherapy - an implant positioned in the tumor bed after the tumor is removed to start radiation therapy immediately and to where it is needed the most. This article talks about the experiances using it on 10 patients with fast growing brain mets. None of them had a local recurrence.with a median follow up time of 6 months. There were no adverse radiation effects.