Externally delivered radiation therapy uses a stream of high-energy particles, or waves, to destroy the ability of cancer cells to divide and multiply. A machine called a linear accelerator delivers the beams. Most often, this treatment is given on an outpatient basis. Certain kinds of cancer may benefit from a more specialized form of external beam radiation therapy such as stereotactic radiosurgery and intraoperative radiotherapy.

Stereotactic Radiosurgery

Rapid City Regional Hospital's Cancer Care Institute offers stereotactic radiosurgery for treating brain tumors. Brain tumors can start in the brain (primary) or spread to the brain from other parts of the body (metastatic). Treatment typically includes surgery, radiation and, often, chemotherapy. Stereotactic radiosurgery is a treatment that precisely focuses radiation beams to the tumor in either a single dose or multiple doses. For many brain tumors, the results are as promising as surgery.

Treating brain tumors is made easier by precisely locating the tumor and pinpointing where to deliver the radiation. At the Cancer Care Institute, radiosurgery consists of four steps.

The first step is a minor surgical procedure where three gold markers are implanted just inside the surface of the skull. This is usually an outpatient procedure with little discomfort. The second step is an imaging study involving CT (computerized tomography, often called a "Cat" scan) and MRI (magnetic resonance imaging). These images provide detailed information on the size and location of the lesion. The third step is to plan the radiation treatment using the gold markers and the imaging studies to precisely locate the tumor. Powerful computers are used to merge the CT with MRI images and create a 3-D image of the patient. The final step is to treat the patient with beams of radiation from a linear accelerator. A number of small radiation arcs intersect at the tumor giving it a high dose of radiation while the surrounding healthy brain tissues receive a much lower dose.

In comparison to other stereotactic radiosurgery, the Cancer Care Institute's system enhances patient comfort and convenience. Many systems use a bulky, uncomfortable, metal frame attached to the patient's skull that requires the radiation treatment to be given the same day. By comparison, the implanted gold markers are permanent. The radiation treatment can be scheduled for a different day and the patient's outward appearance is unchanged.

Stereotactic Radiosurgery Patient Education