Ironically, radiation can cause and destroy cancer. Health workers administer radiation in several different ways. Sometimes, they inject it into the bloodstream, where it circulates throughout the body, finding the cancer and destroying it. In other cases, they implant radioactive capsules directly into the tumor. The most common form of radiation therapy is machine radiation, which focuses a small beam of radiation directly at the tumor.
Radiation kills all the cancer cells in the beam's focus.
The radiation beam goes through the body and the tumor, without killing all the cells along its path. To kill only the tumor, health workers control the machine so the radiation beam rotates. As the beam rotates, it remains focused on the tumorous area long enough to be lethal. The surrounding healthy cells receive some radiation, but not enough to kill them. Side effects of radiation therapy include radiation sickness, which are nausea and skin redness in the tumor area.