David Josephson, M.D., carefully maneuvered the miniature tools on the da Vinci surgical robot into position, aiming to remove the tumor in his patient’s kidney. As the codirector of City of Hope’s Kidney Cancer Program, he was in familiar territory — but with new technology.

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)

Josephson recently became the first surgeon in California to use a new image-guided surgical procedure. Only six other surgeons worldwide have used the method.

The technique, developed by the manufacturer of the da Vinci surgical robots in use at City of Hope, uses a dye called indocyanine green. Physicians infuse the dye into the cancer patient’s blood, which spreads the dye throughout the body. Then, using a special attachment on the surgical robot, the surgeon shines a 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; however, tumors do not take up the dye as much as normal tissue, so they remain more dull and gray. The contrast makes seeing and removing the tumor, while avoiding healthy tissue and blood vessels, easier. In complex organs like the kidney, this clarity can be crucial.

“There are two main renal arteries, one for each kidney, that branch out into smaller blood vessels to feed different parts of the organs,” said Josephson, director of the Urology & Urologic Oncology Fellowship program and an assistant professor of surgery in the Division of Urology and Urologic Oncology. Nicking any of those blood vessels could cause life-threatening blood loss.

“Clamping off the main artery to a kidney seems like the easy option, but then the entire kidney sustains damage from the lack of blood flow,” he explained.

So, before he began removing the tumor, Josephson quickly flipped a switch. The normal kidney tissue as well as the blood vessels that fed it suddenly glowed bright green. The tumor showed much less color.

“The fluorescent imaging allows for real-time identification of the blood vessels feeding the kidney, and we are able to clamp off only a segmental artery to the kidney tumor,” said Josephson. “This allows us to perform a meticulous and precise dissection of the tumor without restricting blood flow to the kidney, so we avoid any long-term damage to the healthy tissue.”

Josephson believes the new technique will greatly benefit patients.

“The imaging system allows us to have greater confidence that we are minimizing any potential blood loss during the procedure, and that we’re not leaving any tumor mass behind,” he said. “And the better the job of dissecting the tumor with minimal damage to healthy tissue, the better our possible outcomes for preserving good kidney function.”

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

“We are exploring its utility in improving the precision of prostate cancer surgeries and also identifying lymph nodes in patients undergoing surgery for invasive bladder cancers,” he said.