Radiation therapy uses high-energy radiation to shrink tumors and kill cancer cells. When treating cancer with radiation, the treatment dose can be delivered through X-rays, gamma rays or charged particles. Cancer treatments with radiation may be delivered by a machine outside the body (external-beam radiation therapy), or by placing radioactive material internally, near the site impacted by cancer cells (internal radiation therapy, also called brachytherapy). While not all cancer patients will require radiation therapy, about half of all cancer diagnoses can benefit from some type of radiation therapy during the course of their treatment.
External Beam Therapy
Singing River Health System Regional Cancer Center utilizes the Trilogy® System with RapidArc and gating technology to treat patients needing external beam radiation. This state-of-the-art technology allows the radiation oncology team to plan and treat the cancer site with the highest possible dose and as accurately as possible, many times, with fewer treatments than other radiation therapy technology.
The Trilogy Linear Accelerator from Varian Medical Systems offers a variety of benefits to patients at the Singing River Health System Regional Cancer Center.
Through more precise targeting of the beam, dosage levels can be increased and target volumes (the three and four-dimensional areas to receive treatment) can be reduced, so tumors get a higher dose of radiation and healthy surrounding tissues get very little. Because of this, radiotherapy can be more effective at treating disease while simultaneously reducing treatment times and side effects of the treatment.
Due to the increased accuracy and power, smaller lesions can be treated more quickly, easily and effectively.
State-of-the-art motion management techniques allow doctors to coordinate treatment with a patient’s breathing patterns. During these treatments, patients can continue to breathe naturally, reducing stress and increasing comfort.
Radiotherapy can be used to treat more different types of cancer, which means that patients may be spared the invasive techniques of surgery and/or chemotherapy.
How It Works
The Trilogy system is built around an advanced medical linear accelerator, a machine that rotates 360 degrees around the patient to deliver radiotherapy treatments from many angles. The Trilogy system has been enhanced for stereotactic applications that involve delivering higher doses of radiation to smaller areas over a shorter period of time.
The Trilogy system incorporates sophisticated technologies for shaping the radiation beam so that the dose of radiation is limited to the region of abnormality. By changing the beam shape over time while delivering the radiation, doctors achieve very fine control over how and where the radiation is administered.
The Trilogy Stereotactic System also incorporates a number of technologies for positioning patients accurately, including:
- A special X-ray imager that is used to check the patient’s position prior to treatment and to monitor the position of the targeted area during treatment.
- An optical guidance system with infrared cameras that continuously monitor the patient’s position to provide therapists with real-time feedback about any changes in a patient’s position.
The Regional Cancer Center utilizes Gated RapidArc radiotherapy for applicable patients. This technology makes it possible to monitor patient breathing and compensate for tumor motion while quickly delivering dose during a continuous rotation around the patient. Gating enables the use of RapidArc to target lung tumors with greater precision by “gating” the beam, turning it on and off, in response to tumor motion. Gated RapidArc makes it possible to deliver highly targeted treatments to many types of tumors, including lung tumors that are moving.
Internal Radiation Therapy
Internal radiation therapy (brachytherapy) is radiation delivered from radiation sources (radioactive materials) placed inside or on the body. Several brachytherapy techniques are used in cancer treatment. Interstitial brachytherapy uses a radiation source placed within tumor tissue, such as within a prostate tumor. Intracavitary brachytherapy uses a source placed within a surgical cavity or a body cavity, such as the chest cavity, near a tumor. Episcleral brachytherapy, which is used to treat melanoma inside the eye, uses a source that is attached to the eye.
In brachytherapy, radioactive isotopes are sealed in tiny pellets or “seeds.” These seeds are placed in patients using delivery devices, such as needles, catheters, or some other type of carrier. As the isotopes decay naturally, they give off radiation that damages nearby cancer cells. If left in place, after a few weeks or months, the isotopes decay completely and no longer give off radiation. The seeds will not cause harm if they are left in the body.
Brachytherapy may be able to deliver higher doses of radiation to some cancers than external-beam radiation therapy while causing less damage to normal tissue.