Doctors in select Canadian hospitals are testing robotic radiation technology that allows them to deliver larger-than-usual radiation doses on tumours that otherwise would have been considered inoperable.

Despite its name, the "cyberknife" doesn't involve cutting. Instead it is a non-invasive, non-surgical approach that delivers focused radiation on patients at much larger doses than usual.

The cyberknife system has a robotic arm which moves around the patient to deliver focused radiation from any direction. The device also has a camera which helps track the tumours, which move while the patient breathes.

Because it is non-invasive, it is a viable option for patients who have tumours that are considered inoperable or surgically complex, including brain, lung and prostate tumours.

Also, because the radiation doses are larger than usual, patients require fewer treatment sessions.

Dr. Shawn Malone from the Ottawa Hospital described to CTV News how the cyberknife works, using the example of kidney cancer.

"The robotic arm will be actually moving continuously up and down with the kidney cancer, that way we can deliver extremely high doses of radiation to the tumour to ablate it while protecting the healthy normal tissue," he said.

A recent study published by the Ottawa hospital suggested that for kidney cancer, the cyberknife works as well as surgery in cases that would have otherwise been considered hopeless.

"We treated about five or six patients already to date, and to date we have been able to eradicate all of the tumours in the patients we treated," Malone said. More studies are underway.

Cancer patient Olga Maxine Wright has a dangerous tumour in her right kidney, but she also has other health problems that make surgery too risky for her. As a result, doctors are treating her tumour with the cyberknife.

Wright said she was happy to know there was another option.

"I was willing to try anything. I thought it was a good idea, especially when I knew that I couldn't have surgery," she said.

Wright's treatment has consisted of three two-hour sessions, which she says are painless.

"There is absolutely no pain, you lie there and you listen to the nice music and you think of how lucky you are," she said.

Because the technology can treat tumours in fewer sessions, with fewer side effects, doctors are now testing it on inoperable cancers in the brain, spine, lung and prostate.

With a report from CTV medical specialist Avis Favaro and producer Elizabeth St. Philip