Brain edema

After 10 months , 30 days full brain radiation ,as well as, Gama knife , i still have swelling on the brain ,, steroids help ( Dexamethasone ) but i just had a severe seizure in the last couple days , had another MRI and the tumor is still there ,, im kinda freaking bout the edema , it don't seem to be going away , any suggestions ?
KEN