Scientists have developed a handheld “cancer pen” that can detect tumors within seconds, giving surgeons the ability to more accurately remove them.

Researchers at the University of Texas at Austin who developed the probe said works in real time, and is as accurate as removing a tissue sample and sending it to a pathologist, NBC News reports.

The pen uses a little drop of water to make the analysis and doesn’t require any cutting of tissue, the team reported in the journal Science Translational Medicine.

"If you talk to cancer patients after surgery, one of the first things many will say is 'I hope the surgeon got all the cancer out,' " Livia Schiavinato Eberlin, an assistant professor of chemistry who led the work, said in a statement.

"It's just heartbreaking when that's not the case. But our technology could vastly improve the odds that surgeons really do remove every last trace of cancer during surgery."

To gauge the pen’s accuracy, the team programmed a mass spectrometer device — which measures chemical signatures — to detect compounds that make lung, thyroid, ovary, and breast tumors different from healthy tissue.

The study showed that the probe, called the MasSpec Pen, was accurate 96 percent of the time.