Definition: Preventative radiation therapy to the head to kill cells that may have already spread there, but are unable to be seen yet with scans.
Pronunciation: pro-ful-ak-tik kray-ne-ul ir-fay-dee-ay-shun
Also Known As: PCI
Examples:
Sam was given prophylactic cranial irradiation to kill any lung cancer cells that may have spread to his brain, but were to small to be seen on his brain CT scan.
