Sometimes, a biopsy is done with a needle. The surgeon makes a small hole in the skull and then guides a needle to the tumor. It is often used to destroy tumor tissue that cannot be removed with surgery or to kill cancer cells that may remain after surgery. Radiation therapy is also used when surgery is not possible. Radiation therapy may be given in two ways.
External radiation comes from a large machine.
Generally, external radiation treatments are given 5 days a week for several weeks. The treatment schedule depends on the type and size of the tumor and the age of the patient. Giving the total dose of radiation over an extended period helps to protect healthy tissue in the area of the tumor. Depending on the material used, the implant may be left in the brain for a short time or permanently. Implants lose a little radioactivity each day.