Quantum physics may soon help physicians track whether a cancer has spread. In experiments in mice and pigs, a team of chemists and surgeons has used quantum dots—nanometer-scale crystals that emit light—to refine lymph node biopsies.
The first lymph node into which fluids from a tumor drain is called the sentinel node. If the cancer is spreading, it typically moves to this node before reaching other organs. In an increasingly popular diagnostic procedure for breast cancer and melanoma patients, surgeons remove sentinel nodes in search of cancer cells.