Stereotactic Radiosurgery

Stereotactic Body Radiotherapy on the Liver

Treatment Plan for Liver Treatment

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Liver radiosurgery is a form of stereotactic body radiotherapy. Radiosurgery to the liver is quite similar to lung SBRT except that it typically is used to treat tumors that have spread to the liver, or liver or bile duct tumors that cannot be removed with surgery. Some patients are not candidates for surgery or other ablative techniques due to medical conditions, liver function problems such as cirrhosis or hepatitis, or age. The medical team takes these and other factors (general health, and size, number and location of tumors) into consideration when determining the treatment plan that is most beneficial for the patient.

The patient's normal breathing pattern is an important factor when treating liver tumors because of the movement of the diaphragm and abdomen.

Before Treatment

Several steps occur before treatment. Simulating the treatment is an important part of planning. First, an immobilization device is fashioned to help keep the patient in the proper position during treatment, since body motion must be limited during radiosurgery. The patient lies in a plastic bag on beanbag-like material, and then a vacuum sucks out the air to create a comfortable, stable and precise mold of the patient's body. After the immobilization device is created, the patient has a four-dimensional computed tomography (CT) scan to help pinpoint the target for the radiosurgery treatment. In liver radiosurgery, physicians take into account a patient's normal breathing pattern, which may be less important when treating tumors that do not move. A four-dimensional CT scan also captures the respiratory motion. Some patients have a compression or clamp-like device placed over their stomach during treatment to assist in limiting the motion of tumors. Before the fitting of the immobilization device, some patients are assessed to decide whether audio and visual coaching techniques will help them breathe regularly.

In addition, some patients are considered for placement of markers into the tumor or nearby tissues before the simulation. The markers typically are implanted in an outpatient procedure. The markers are made of materials such as gold, and are tracked during treatment by imaging devices to precisely determine the patient's position. This process reduces the amount of radiation given to the surrounding body tissues while more accurately delivering radiation to the tumor.

After these steps, the radiation oncologist and a team of medical professionals such as physicists and dosimetrists plan the radiosurgery treatment. Treatment planning is detailed and can take several days. Complex treatment planning systems help the team to direct the radiation to the tumors and minimize the dose of radiation to healthy tissues, tailoring the plan to each patient's needs. During 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 undergo a practice session to ensure that the planned treatment is physically achievable. If so, this may be done the day the immobilization device is created or the day prior to the planned start of treatment.

Treatment

During treatment, the patient lies in the custom immobilization device. The patient is asked to use the same breathing or breath-hold techniques used during the initial simulation. Using robotics or imaging, several measurements are taken to ensure the accuracy of the treatment. Adjustments are made as needed and verified by the radiation oncologist and physicist before the treatment begins. The treatment typically lasts 60 to 90 minutes. The treatments are not painful, though some side effects may occur from the treatment. The radiation oncologist will explain possible side effects before the treatment.

After Treatment

After SBRT, the patient may leave the treatment area. Up to 5 treatments may be given over eight to 14 days. Follow-up exams are determined based on the patient's need. Typically, patients undergo follow-up scans 4-6 weeks after treatment.