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UC Davis Health System

UC Davis Health System

Fighting cancer with tomotherapy

Photo of the installation of the tomotherapy equipment
Since first reaching the market in 2002, seven tomotherapy systems have been acquired on the West Coast, UC Davis has the only unit in Northern California.

The field of radiation oncology has witnessed rapid progress in recent decades, as technological advances have made it possible for physicians to deliver increasingly targeted and powerful doses of radiation to treat cancers.

Tomotherapy is at the cutting edge of this trend. UC Davis Cancer Center is the first facility in Northern California to offer tomotherapy technology to treat patients with cancer. Only 55 of the machines are in use nationwide.

Reduced margin of error

Tomotherapy addresses a shortcoming inherent in conventional radiation treatment. Traditionally, a physician obtains images of a tumor days or weeks before radiation therapy starts, and uses these images to plan treatment. But by the time treatment starts, the cancer may have grown or changed shape, or the patient's weight may have changed, causing a shift in tumor position.

"This uncertainty about the tumor's exact position has always meant calculating a 'margin of error' and treating a zone around the tumor that is likely to include some healthy tissue. To avoid applying excessive radiation doses to this surrounding tissue, radiation oncologists have had to use lower-than-desired doses to treat the tumor," said Srinivasan Vijayakumar, professor and chair of radiation oncology.

More effective doses

Tomotherapy solves this problem by marrying a high-resolution CT scanner to a sophisticated linear accelerator, allowing doctors to visualize a tumor and apply radiation at the same time, with pinpoint accuracy. This enhanced precision enables doctors to use tighter margins and higher, more effective radiation doses.

In addition, tomotherapy employs a linear accelerator that rotates in a 360-degree spiral around the patient, delivering radiation to the tumor from all directions. Traditional linear accelerators deliver radiation beams from just a handful of angles.

Photo of tomotherapy imaging
Tomotherapy allows doctors to visualize a tumor and apply radiation at the same time.

Since the technology first reached the market in 2002, six other tomotherapy systems have been acquired on the West Coast: one in Bellingham, Wash., and five in Southern California. UC Davis has the only tomotherapy unit in California north of Los Angeles County.

The investment in new technology makes UC Davis Cancer Center's Radiation Oncology Clinic the best-equipped facility in Northern California and among the most sophisticated in the country.

"We can offer our patients more treatment options than any other cancer center in our region," said Vijayakumar.

More than 2,000 children and adults are diagnosed with cancer at UC Davis Cancer Center each year, and thousands more come to the center for treatment. About half of all cancer patients require radiation therapy.

UC Davis Cancer Center is the only National Cancer Institute-designated cancer center serving the Central Valley and inland Northern California, a region of more than 6 million people