Finding cancer cells in the blood can be nearly impossible. Just 1 milliliter of blood contains about 5 billion red blood cells, and only about one to 10 cancer cells. But detecting these circulating tumor cells (CTCs) is critical, so that doctors can determine whether someone has cancer, what stage it's at, and if a treatment is working effectively.
In the future, doctors hope that by sequencing the genomes of these CTCs, they'll be able to prescribe treatments that are individually tailored to target each patient's cancer. Now, a new device that uses sound waves to separate CTCs from the rest of the blood could help.