The surgeon carefully maneuvered the miniature tools on the surgical robot into position, aiming to remove the tumor in his patient’s kidney. He was experienced and in familiar territory — but now the surgeon had the help of some innovative new technology.

City of Hope surgeons recently became the first in California to perform a new image-guided surgical procedure. Only six others worldwide have used the method.

City of Hope surgeons are among the first to use a new imaging technology to improve robotic-assisted surgeries to remove kidney tumors. (Photo by p.cunningham)

The technique, developed by the maker of the da Vinci surgical robots in use at City of Hope, involves a dye called indocyanine green.

Physicians infuse the dye into the cancer patient’s blood. From there, it spreads throughout the body. Then, the surgeon shines a special type of light called near-infrared on the area of the tumor.

Under the near-infrared light, the dye makes healthy tissue glow a fluorescent green color. But tumors don’t take up the dye as much as normal tissue, so they remain more dull and gray. The contrast makes it easier to see and remove the tumor while avoiding healthy tissue and blood vessels.

In complex organs like the kidney, this clarity can be crucial.

“The kidneys have a lot of blood vessels, and nicking any of them could cause life-threatening blood loss,” said surgeon Mark Kawachi, M.D., clinical associate professor of surgery in the Division of Urology and Urologic Oncology.

So, before beginning the process of removing a kidney tumor, the surgeon flips a switch. The normal kidney tissue and the blood vessels that feed it suddenly glow bright green. The tumor, on the other hand, shows much less color.

“Flipping back and forth from normal light to near-infrared lets us see the blood vessels that feed the kidney, so we can isolate the main one that runs to the tumor,” Kawachi said. This allows the surgeon to precisely remove the tumor without restricting needed blood flow to the remainder of the kidney, avoiding any long-term damage to the healthy tissue, he explained.

The fluorescence imaging system currently has approval from the U.S. Food and Drug Administration for use in kidney surgery, but City of Hope is helping to expand the technique.

“We’re looking into using the system in prostate cancer surgery and to improve our ability to see lymph nodes in patients with invasive bladder cancers,” Kawachi said.