Interstitial intracranial radiotherapy implants, or brachytherapy, is an adjuvant option for treatment of recurrent high-grade meningiomas after resection. The implants are placed in the resection cavity following tumor resection. The most commonly used isotope is Iodine-125 (I-125). While there are no controlled studies comparing treatment of meningiomas with or without brachytherapy, several case series report good long-term survival, suggesting that this may be a useful adjuvant for recurrent high-grade tumors. Complications can occur including radiation necrosis, impaired wound healing, hydrocephalus and infection. In the future, new isotopes are being explored that may have fewer complications and better safety profiles.