Stereotactic Radiosurgery

Stereotactic Body Radiotherapy in the Spine

Radiosurgery Plan for Spine Treatment

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Spine SBRT typically is used to treat metastatic tumors that have spread to the spine. Metastatic tumors result from cancer that started elsewhere in the body and spread to the bones of the spine. Most metastatic spine tumors result from cancers of the lung, prostate, kidney or breast, but almost any tumor can spread to the spine. Treatment for metastatic tumors of the spine can involve combinations of surgery, radiation and chemotherapy depending on the patient's age, general health, and tumor size and number. The medical team takes all these factors into account when determining the most appropriate treatment for the patient.

Before Treatment

Several steps are involved in preparing for stereotactic spine radiosurgery. First, the team fashions an immobilization device that keeps the patient in the proper position during the planning and treatment. Motion must be limited when delivering high-precision radiosurgery to ensure that the treatment is effective and reduce the possibility of damage to tissues around the tumor. The type of immobilization device used depends on the location of the tumor.

After the immobilization device has been made, the patient has a computed tomography (CT) scan to help pinpoint the target for the treatment. In addition, an MRI scan of the spine is often obtained to more accurately define the tumor. Some patients may receive permanent "markers" implanted into the surrounding bone or nearby tissues. The markers are implanted during an outpatient procedure in a radiology suite or an operating room, and typically are implanted before the immobilization device is designed. The markers are made of materials such as gold, and are tracked during SBRT to precisely determine treatment position. This process reduces the amount of radiation given to nearby tissues while more accurately delivering radiation to the tumor. The patient's medical team will decide if placement of markers is necessary for the patient.

After creation of the immobilization device and marker placement, the radiation oncologist and medical professionals such as physicists and dosimetrists plan the radiosurgery treatment. The team uses complex treatment planning systems to direct the radiation to the tumors and minimize the radiation to normal tissues, tailoring the plan to each patient's needs. During this planning, patients do not need to remain at the clinic, and many return home until their first day of treatment. Some patients may be asked to come back one day prior to the actual treatment for a practice session to ensure that the planned treatment is setting up perfectly.

Treatment

First, the patient lies on the treatment table in the immobilization device. Several measurements that involve the use of complex robotics and/or imaging are taken to ensure accuracy, and adjustments are made as needed. A radiation oncologist and physicist then verify the accuracy of the positioning, and the treatment begins. Treatment typically lasts from 30 to 60 minutes. The treatment itself is not painful, although there may be a risk of side effects. The radiation oncologist will discuss potential side effects with the patient before the treatment. Patients may require up to five treatments in an SBRT program which may last one to two and one-half weeks.

After Treatment

After treatment the patient is free to go. Follow-up exams are determined based on each patient's need. Typically, patients undergo follow-up radiographic scans 8 to 16 weeks after treatment.