Saint John’s Cancer Center is installing a state-of-the-art Trilogy® system from Varian Medical Systems for treating cancer with image-guided radiotherapy and radiosurgery.The Trilogy system is a powerful, precise and versatile treatment machine that can be used to deliver advanced forms of radiotherapy, including accurate stereotactic approaches for treating very small lesions quickly and accurately.
“This state-of-the-art system is proven technology that will enable us to offer advanced image-guided radiotherapy for a broad spectrum of cancer patients,” said Sandy Crawley, Saint John’s Cancer Center director. “It provides us with tremendous versatility and precision for customizing treatments and for choosing an appropriate delivery approach based on the specifics of each patient’s case.”
At the core of the Trilogy system is Varian’s high-powered medical linear accelerator, a machine that rotates around the patient to deliver radiotherapy treatments from virtually any angle. The system is able to concentrate radiation doses on the tumor while minimizing exposure of surrounding healthy tissue.
Trilogy also incorporates an X-ray imager that can generate 2-D, 3-D and moving images of the tumor and surrounding anatomy. For accurate tumor targeting, the patient’s position is adjusted based on these real-time images prior to treatment. A beam-shaping device called a multileaf collimator continually shapes and reshapes the radiation beam to match the three-dimensional shape of the tumor as the machine rotates around the patient during treatment.
The Trilogy system can be used for RapidArc and Gated RapidArc® radiotherapy treatments. RapidArc delivers fast, precise image-guided treatments during a continuous rotation around the patient, with many treatments delivered in two minutes or less. Gated RapidArc compensates for tumor motion due to respiration during a RapidArc treatment. “With Gated RapidArc, the beam is automatically switched on and off as the tumor moves in and out of range,” explained Dr. Alexander Yeh, a specialist in radiation oncology at Saint John’s. “This is important when we are treating lung and other tumors in areas of the body that move when the patient breathes.”
The Trilogy linear accelerator is capable of stereotactic applications that involve delivering high doses of radiation to small areas over short periods of time.
“Stereotactic approaches are generally most appropriate for small lesions and early metastases,” said Dr. Yeh. “Better diagnostic tools are making it possible for us to see tumors much earlier, when they’re still very small, so stereotactic radiotherapies are likely to play a much larger role in the future of cancer care.”
“Radiotherapy is an integral component in the treatment of cancer,” said Dr. Yeh. “Using the image guidance, beam shaping and motion management tools available with the Trilogy system, we can do a better job of protecting healthy tissue while delivering more powerful doses to tumors.”