In the tangle of tissue surrounding a tumor, a surgeon seeking to excise the growth can struggle to know where the malignancy ends and the healthy tissue begins.

As a result, a lot of operating time goes into specimen-taking and analysis to ensure a safe margin around the tumor has been removed.

To combat that problem, a special fluorescent dye currently in phase 1 clinical trials could literally light up the tumor in a specific color so it’s precisely outlined for removal. Along the same lines, another fluorescent dye is under development to light up any nearby nerves, no matter how thin or obscured, in a different color, to help keep them from being cut and preserving the functions they control, says Quyen Nguyen, M.D., a head and neck surgeon and researcher at University of California, San Diego.

The dye allows surgeons to work with much more certainty, reducing surgery time by reducing the need to test the areas of removal, she says.

The highest hope for the tumor/nerve marker combination is in prostate surgery, in which nerve-sparing techniques now still carry a 40 percent to 80 percent risk of erectile dysfunction and incontinence.

“The reason is not because surgeons are no good, it’s just that the nerves are too difficult to see,” says Nguyen. With fluorescent definition, “they will stand out like a lightbulb in the dark,” she says.

More Marvels:

Shining even more light on the body

The benefit of ultrasound is limited by a lack of contrast, but researchers are souping up a strained spinach mixture to help see the gastrointestinal tract better, according to the University at Buffalo–State University of New York. The key ingredient is a chlorophyll extract that illuminates the gut. It works in fluorescence imaging, too.

Sweating the details

A temporary tattoo has been shown to accurately measure blood-alcohol levels in perspiration, without the finger stick of current blood tests or the false positives of a Breathalyzer, IEEE Spectrum has reported.