Trilogy Stereotactic System





The Trilogy Stereotactic System from Varian Medical Systems is the most advanced, sophisticated machine of its type in the world.  As the leading image-guided radiotherapy (IGRT) system, Trilogy marks the beginning of a new generation of cancer care.  The versatile Trilogy system can be used to deliver the widest range of external beam radiotherapy:  3D conformal radiotherapy, IMRT, stereotactic radiosurgery, fractionated stereotactic radiation therapy and intensity-modulated radiosurgery for cancer and neurosurgical treatments.  Advanced imaging capabilities built into the system allow therapists to position patients for treatment with sub-millimeter accuracy, making sure the tumor is lined up precisely with the treatment beam before the beam is turned on.  A respiratory gating system takes into account the tumor movement that can occur as a patient breathes, turning the beam on and off, so that treatment is delivered only when the tumor is stationary.


At the core of the Trilogy systems is Varians Clinac, the linear accelerator that has been enhanced for stereotactic applications that involve delivering higher doses of radiation to smaller areas over a shorter period of time.  The system features an ultra-precise multi-leaf collimator (MLC), and the tightest isocenter, or beam focal point, currently available.

Prior to treatment, images of a patients tumor and the surrounding anatomy are generated (using MRI, CT or PET scanning), and clinicians use this information, along with sophisticated analytical software programs, to prepare a detailed treatment plan.  The treatment plan specifies the exact dose to be delivered to the tumor, as well as how the technology can best deliver that dose, given the three-dimensional geometry of the target and surrounding tissues.  When the patient arrives for treatment, clinicians use Trilogys advanced imaging system to confirm the exact tumor position relative the radiation beam, and make any needed adjustments before treatment begins.  Some treatments, primarily for small lesions and metastases, can be accomplished in a single session, while other treatments require multiple sessions.

This combination of precision and power allows Trilogy to reduce both treatment times and side effects.






Through more precise targeting of the beam, radiotherapy may become more effective at treating disease while simultaneously reducing side effects of the treatment.

Due to the increased accuracy and power, smaller lesions can be treated more easily and effectively.

Radiotherapy can be used to treat more different types of cancer, which means that more patients can be spared the invasive techniques of surgery and/or chemotherapy.


The Trilogy Stereotactic System is the first linear accelerator that can deliver all advanced forms of external-beam radiation therapy.  By allowing veterinarians to choose the most appropriate treatment modality for treating cancer--whether in the body or the brain--Trilogy ushers in a new generation of cancer care, in which veterinarians can provide the most appropriate therapy for a specific patients case, rather than being limited by technology.  With Trilogy, veterinarians have the option to treat small lesions using stereotactic radiosurgery, which is delivered in a single treatment; or stereotactic radiotherapy, which is delivered over a few days; or more traditional forms of radiotherapy, which are delivered in smaller doses over several weeks.

The Trilogy system incorporates the ability to position the patient precisely, using images of the tumor and surrounding anatomy taken just prior to each treatment.  The images are used to verify tumor position immediately before treatment. This care applied to treatment accuracy maximizes the dose to the tumor, and minimizes the dose to surrounding healthy tissue.

The respiratory gating system automatically turns the beam on and off to compensate for breathing motion during treatment. With respiratory gating, the beam is switched on only when the tumor is within a known location.   This keeps the radiation beam focused on the tumor, and further protects normal healthy tissues.

The Trilogy system and its accessories can shape a beam very precisely, with sub-millimeter accuracy.  In addition to the precision of its beam, Trilogy offers the highest dose rates available, to deliver a potent punch of radiation in a short amount of time.