skull radiotherapy

Hello ladies, Has anyone any experience of radiotherapy to the skull, wich I am having as a last ditch resort for mets in the meninges. I wasn’t too worried, until I had my first treatment today!
I experienced what I can only describe as a ‘light being switched on’ as the therapy started, which stopped as the beam stopped. This happened on each side–yet the operators didn’t know what I meant.
I know this is rare, but has anyone come accross this treatment?
Love to all, caramelbunny