UnityPoint Health - John Stoddard Cancer Center

Stereotactic Radiosurgery (SRS)

The John Stoddard Cancer Center was the first to offer Stereotactic Radiosurgery (SRS) in central Iowa. SRS treats complex cancers with a precise delivery of a single, high dose of radiation in a one-day session.

Radiosurgery (one-session treatment) has such a dramatic effect in the target zone that the changes are considered "surgical." Through the use of three-dimensional computer-aided planning and the high degree of immobilization, the treatment can minimize the amount of radiation that passes through healthy tissue. Stereotactic radiosurgery is routinely used to treat brain tumors and lesions. It may be the primary treatment, used when a tumor is inaccessible by surgical means; or as a boost to other treatments for a recurring or malignant tumor. Using the TrueBeam STx, we are also able to treat cancers in the brain, lung, liver, pancreas and spine.

Stereotactic radiosurgery works the same as all other forms of radiation treatment. It does not remove the tumor or lesion, but it distorts the DNA of the tumor cells. The cells then lose their ability to reproduce and retain fluids. The tumor reduction occurs at the rate of normal growth for the specific tumor cell. In lesions such as AVMs (a tangle of blood vessels in the brain), radiosurgery causes the blood vessels to thicken and close off. The shrinking of a tumor or closing off of a vessel occurs over a period of time.

Radiosurgery versus Radiotherapy

Radiosurgery is one version of radiotherapy. Both deliver radiation but use different means and doses to minimize the risk of radiation damage to healthy tissue. Standard radiotherapy delivers small daily doses of radiation in multiple treatment sessions over several weeks. Radiosurgery delivers radiation in single high doses that conform closely to the tumor shape, and fall off sharply at the edge of the tumor. Whether a patient receives standard radiotherapy or a form of radiosurgery depends on the type of tumor and its location.