How Does Radiosurgery Work?


Radiosurgery works by using highly focused beams of powerful radiation to overwhelm cancer cells. Radiation damages the DNA in cancer cells, interrupting their ability to reproduce. When the damaged cancer cells attempt to divide, the tumor shrinks or dies. Normal cells, however, can recover from radiation more easily.

Similar to external beam radiation therapy, radiosurgery is performed with a linear accelerator, or linac. The linac generates a high-energy radiation beam focused precisely on the tumor. The beam is delivered from many different angles to target each part of the tumor and deliver the prescribed amount of radiation.

While a radiotherapy routine may include up to 40 treatments (5 days a week for several weeks), radiosurgery is performed in five sessions or less over a period of two weeks. Although the total number of radiosurgery treatments is fewer, each session usually takes more time than a typical radiotherapy treatment in order to make sure the patient is accurately positioned in relation to the linac.

Stabilization devices are often used to ensure proper positioning. When designing your treatment plan, your clinical 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, with his or her team, determines which radiation technique is best suited for your particular case.