NASHVILLE, Tenn. -

Bryce Greenwell is no stranger to tests or hospitals. He has leukemia and will undergo treatments for the next three years or more.

"I don't know how he does it, you know. He's amazing," said Jenny Greenwell, Bryce's mother.

A little pup named Swoosh is making Bryce's hospital visits much more bearable.

"It gives us something to talk about. He gets excited to come see Swoosh," Greenwell said.

Bryce and Swoosh are participating in a study to determine if dogs can help pediatric cancer patients.

Mary Jo Gilmer, director of palliative care research at the Vanderbilt University School of Nursing, understands the impact the disease has on lives and is excited to see how the dogs can help.

"We know that the disease takes a terrible emotional toll on families," Gilmer said. "It’s very obvious to me, just anecdotally, that those dogs are making a difference; that interaction is making a difference."

Studies in adult patients have shown interaction with man's best friend can lower blood pressure, reduce anxiety and improve lung function. This is the first pilot study to test animal therapy in kids with cancer.

The dogs spend about 15 minutes with patients before treatments. The kids have their pulse and blood pressure checked before and after, along with a questionnaire.

The dogs even have their saliva checked to determine if they experience stress, but Swoosh's owner, Michelle Thompson, said she doesn't think that's the case.

"He loves to work. He loves to get his vest on, and he's excited to go," Thompson said.

It's therapy any kid would love.

Researchers at five sites across the country will enroll a total of 120 families for the study. They are still collecting data and cannot report on results, but Gilmer said they have noticed children who interact with the dogs require less anti-anxiety medications than they did before the pet therapy.

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