How Does Radiation Therapy Work?

Radiation therapy, also known as radiotherapy, uses a focused beam of energy to damage cancerous cells while minimizing exposure to healthy tissue. Radiation damages the DNA in cancer cells, which interrupts their ability to reproduce, causing them to die and the tumor to shrink. Normal cells can recover from radiation more easily.

Treatment is delivered to the target site with a machine called a linear accelerator, or linac. The linac generates a high-energy beam, which is delivered from many different angles, to target each part of the tumor and deliver the prescribed amount of radiation. Typically, treatment is delivered five days a week over several weeks.

When designing your treatment plan, your medical team relies on one or more types of 3-D scans of your body. These can include a CT scan, an MRI, and/or a PET scan. By looking at these scans and other test results, the radiation oncologist and his or her treatment team determine which treatment technique is best suited for your particular case.