Kathy,
I did some reasearch on "vasogenic edema" to see what that is.. This is what I found out:
Definition
Edema is a condition of abnormally large fluid volume in the circulatory system or in tissues between the body's cells (interstitial spaces).
Description
Normally the body maintains a balance of fluid in tissues by ensuring that the same of amount of water entering the body also leaves it. The circulatory system transports fluid within the body via its network of blood vessels. The fluid, which contains oxygen and nutrients needed by the cells, moves from the walls of the blood vessels into the body's tissues. After its nutrients are used up, fluid moves back into the blood vessels and returns to the heart. The lymphatic system (a network of channels in the body that carry lymph, a colorless fluid containing white blood cells to fight infection) also absorbs and transports this fluid. In edema, either too much fluid moves from the blood vessels into the tissues, or not enough fluid moves from the tissues back into the blood vessels. This fluid imbalance can cause mild to severe swelling in one or more parts of the body.
So, I'd say it's a medical way of saying that some fluid has built up around where the tumor is/was. My last visit with my surgeon, he said that I had something similar (altho he didn't use that medical terminology with me). He wanted to keep an eye on it to make sure the fluid didn't solidify/calcify or get bigger, but he didn't seem to concerned with it. I wouldn't worry about it too much.
I can't speak to headaches after radiation, but I presume they'll get better with time as well.
Regards,
Brian