This is very common and does freak people out.
I wish I could find the study for you... There is one somewhere on pubmed...
www.pubmed.comThe study found that visible necrosis has no bearing on the eventual outcome of radiation treatment...
First of all the "Necrosis" may not be "Necrosis" at all.... Its just how the tumour lights up with the gadolinium dye.
which relates to how the blood with the dye is flowing through the tumour.. It says little about the health of the cells within the tumour itself.
If you are treated with Cyberknife, you are usually treated to the 80% isodose line..
That means the center of the tumour gets 25% more radiation.... Radiation does damage blood vessels which can lead to the "Necrosis" look... and as the tumour gets more radiation in the middle it is more likely to go dark..
Radiation gives you just enough radiation to stop the cells from replicating... It doesn't actually kill the cells immediately.
Its actually bad to kill the cells immediately. You would end up with a rotting piece of meat in your head... no good....
The cells will eventually die from old age but that takes years
So dont panic, its very common for the 6 month MRI to show a darkened center and for it to fill again..
Just remember the study... that I can't find....... Necrosis has no bearing on the eventual outcome