"They don’t call it “brain surgery" for nothing. Removing a tumor from the brain is one of the most challenging operations surgeons can perform.

Typically, they rely on MRI images to guide them to the right spot, but now there’s a new way to light up cancer.

Keaton Wrenn reads at a fifth grade level, but his mom, Lisa Owen Wrenn, said this third grader’s movements aren’t as developed as most kids his age.

"His walking was always pretty really wobbly," Wrenn said.

When Keaton was just 16-months-old, doctors found a golf ball-sized tumor in his brain. Oncologist Jim Olson said removing a tumor like Keaton's is tricky because normal tissue looks just like cancerous tissue.

"You can end up leaving big chunks of cancer behind," said Dr. Jim Olson, an oncologist with Fred Hutchinson Cancer Research Center.

Olson developed a tumor paint to help surgeons see cancer while they operate. The paint is made from re-engineered scorpion venom. It's injected into the bloodstream a day before surgery. Surgeons use a special instrument to see the paint in real-time.

"It brings a light molecule to the cancer, so the cancer cells light up," Olson explained.

The tumor paint has been used in mice and dogs and is a thousand times more sensitive than MRI scans.

Wrenn said the research is exciting. Keaton had the traditional surgery, and today is cancer-free.

"He's been through so much, and he just takes it all in stride," Wrenn said.

In the preclinical trials, the tumor paint also lit up prostate, colon and breast cancers. Doctors said it may also be used to detect various forms of skin cancer. Olson said he expects human trials to begin in early 2014.

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