A new technology for cancer detection that eliminates the need for drawing blood has been developed by Purdue University researchers.

By shining a laser on surface veins, such as those on the wrist and inside the cheek, researchers are able to reveal and count circulating tumor cells. In addition to being less invasive, the new detection method is able to evaluate a much larger volume of blood than what can be drawn from a patient for analysis.

By directly labeling tumor cells while they are in the bloodstream, some of the costs and problems associated with testing drawn blood samples can be avoided.

The technique uses a fluorescent tumor-specific probe that labels tumor cells in circulation. When hit by a laser, which scans across the diameter of the blood vessel 1,000 times per second, the tumor cells glow and become visible. The in vivo flow detection was performed on a two-photon fluorescence microscope in Cheng’s lab. The researchers compared several methods and found two-photon fluorescence provides the best signal to background ratio.