Providence Sacred Heart Medical Center & Children's Hospital's says a new radiation treatment machine it recently installed, along with some optional features that will be installed later, will enable the hospital to improve its accuracy in irradiating cancerous tumors, and thus minimize damage to nearby healthy tissue.

The new device, called a linear accelerator, replaces a 15-year-old machine here and will cost the hospital about $4 million, including the optional equipment Sacred Heart plans to install on it in coming months, says Dr. J. Lance Griffiths, a radiation oncologist at the hospital. Griffiths says Sacred Heart has been using linear accelerators for tumor irradiation for 20 years and has one other older model that it will continue to use.

The new device, called a Trilogy, was manufactured by Varian Medical Systems Inc., of Palo Alto, Calif. Using the Trilogy and its added options, radiation therapists at the hospital will be able to reduce the area of a patient's body that receives radiation treatment, and also will be able to speed up the treatment process, which can be uncomfortable for patients, Griffiths says.

One major improvement the Trilogy boasts over previous models is that it will have a computed tomography (CT) scanner and digital X-ray equipment built into the machine, he says. That imaging equipment will be added to the device in June.

Traditionally, radiation therapists have used CT or X-ray images, often taken once a week during the treatment-planning phase, to determine where on a patient's body radiation treatment will be targeted and how large the treatment area will be, Griffiths says.

Using that information, therapists make markings with pen on the patient's skin and use those markings to line up the linear accelerator's radiation beam.

That's made more difficult because bodies aren't static—the exact location of a tumor can shift from day to day, and breathing patterns and excess weight can alter a tumor's position, he says.

Because the Trilogy will have imaging equipment on board, those pre-treatment images now can be made when a patient is positioned on the treatment table for radiation therapy, providing a more accurate assessment of the tumor's location. The beam is then adjusted to the targeted area more quickly than otherwise would be the case, which is beneficial to patients, who often must wear uncomfortable restraints to help keep them in position during radiation treatments.

During treatments, radiation therapists strive to target a tumor as tightly as possible to minimize the delivery of radiation to surrounding tissue and organs, which can damage them and lead to unpleasant side effects, such as bladder irritation or rectal bleeding after prostate cancer treatments, he says.

Griffiths says the new equipment, though more expensive to use because of the ability to do a lot more imaging, will be useful for a lot of the center's patients. Reducing side effects on healthy organs also can help improve patients' quality of life substantially, he says.

Sacred Heart radiation physicist Ray Luse says other options Sacred Heart has chosen to add to the machine also will improve treatments for patients.

One such option is a software program called SmartArc, made by Royal Philips Electronics, of the Netherlands.

That software will enable therapists to automate use of the Trilogy's volumetric arc therapy, in which the device moves the radiation beam around the patient in up to a complete, 360 degree rotation, says Luse.

In the process it employs a radiation dosing technique called intensity modulated radiation therapy, or IMRT, which is used to treat irregularly shaped tumors. While in the past therapists had to reposition the patient and modify the beam before each blast of radiation, the software will adjust the intensity of the beam as it automatically moves around the patient, in 2-degree increments, administering a varying intensity of radiation based on the three-dimensional treatment model that has been programmed.

The patient doesn't have to move during the process, and the software will reduce greatly the time it takes to do a treatment. The new software should be installed by September, Luse says.

Also later in the year, Sacred Heart will add a stereotactic radiosurgery component to the Trilogy. The component, called Novalis Tx and developed by a German company named BrainLAB AG, will allow a procedure similar to the well-known gamma knife radiosurgery to be done on the Trilogy. Gamma knife is used to destroy cancerous brain tumors with high doses of gamma radiation.

The procedure is done collaboratively by a radiation oncologist and a neurosurgeon. To perform the radiosurgery, CT or MRI images of the patient's head are loaded into a computer, which creates a three-dimensional reference frame and triangulates the location of the tumor. The Trilogy then employs the IMRT dosing technique, thereby increasing accuracy of the treatment area to within 1 millimeter, compared with accuracy of between 3 millimeters and 5 millimeters using a linear accelerator that doesn't have the stereotactic equipment, Luse says.

The main difference between the gamma knife and the new stereotactic add-on is that the new machine moves around the patient's head, while the gamma knife treatment is administered through a helmet that delivers the radiation to a fixed area. Gamma knife technology currently is in use at Deaconess Medical Center here.

The Novalis Tx also will allow the stereotactic radiosurgery technique to be used more readily on tumors near the base of the head and upper neck, Luse says.

A final add-on for the new Trilogy device will be what's called a respiratory gaiting system, which can reduce the size of the treatment area needed to treat tumors in areas of the body that move extensively, primarily in the lungs, as a person breathes.

The system uses imaging to map the location of a tumor throughout a person's breathing pattern.

The machine then is programmed to deliver the radiation dose at a certain point in the patient's breathing process, and to turn off during the rest of the breathing cycle, reducing the size of the area that must be irradiated, thus reducing damage to surrounding lung tissue, says Griffiths.