Omar Bustamante/Fusion

Detecting cancer can be difficult. Sometimes, the diagnosis comes too late to be life-saving. But now, scientists at Carnegie Mellon University and Penn State University say they've developed a system that can quickly and accurately detect traces of cancer in blood using sound waves.

If it works out, this new method could give clinicians a new powerful way to diagnose and study cancer, according to a new study published in this week's issue of the journal Proceedings of the National Academy of Sciences. The method would "enable not only a more accurate, comprehensive analysis of [cancer tumor cells] but also offer the potential for better cancer treatment options, such as noninvasive testing of drug susceptibility of cancer patients over the course of chemotherapy, and possible early detection," the authors wrote in the study.


To detect cancerous cells, the new method uses something called tilted-angle standing surface acoustic waves. Think of it as a tiny cellular luge running down the center of two transducers that emit sound waves. When the sound waves bump up against cells coursing down the cellular luge, they deflect them just a tiny bit. The amount of deflection depends on the cell's size, density and compressibility.

Malignant cells will deflect differently than normal white blood cells, and the luge is designed in such a way that it routes cancerous cells down one side of a split track, while healthy cells slide down the other side. This sorting process is shown in the image below.

Using sound waves to separate out different types of cells is useful because it doesn't warp the cells' structure or internal chemistry, which leaves them as close as possible to their natural state for scientists to study them. Using an antibody, for instance, may perturb the cell's structure. Plus, developing antibodies that select out specific types of cells can take years and lots of money. Using sound waves allows scientists to potentially catch more types of cells on the cheap.


Scientists have used sound to separate out cancerous from normal cells before with good results in the lab, but the process had been slow. The new method is faster and up to 20 times better at separating cancer cells from white blood cells than previous acoustic devices, according to the study. It's also minimally invasive—doctors can draw blood as part of their usual workup, and then use some of the sample to isolate the cancerous cells floating around in patients' blood. The researchers also showed for the first time that the method works not just on lab samples, but in blood from real patients.

If this system, for which the scientists are seeking a patent, ultimately gets clearance from the U.S. Food and Drug Administration, it could turn into a powerful diagnostic. Scientists could use sound waves in the lab to study how cancer changes in realtime. And we'd have an unconventional new weapon in the battle against cancer.

Daniela Hernandez is a senior writer at Fusion. She likes science, robots, pugs, and coffee.