A miniaturized fiber optic probe has been invented that can simultaneously measure body temperature and take images deep inside the body. The single-fiber-based image and sensing probe uses an OCT lens fabricated at the distal end of a double-clad fiber. The fiber has a thin layer of rare-earth-doped tellurite glass to enable temperature measurements. The high refractive index of the tellurite glass enables a common-path interferometer configuration for OCT, allowing easy exchange of probes for biomedical applications. The tiny imaging and sensing probe is as thin as a single strand of human hair. Courtesy of University of Adelaide. The miniaturized imaging and sensing probe was developed to help study drug-induced hyperthermia. “Using some drugs such as ecstasy can make certain brain regions overheat and then become damaged. Using the probe’s imaging function during experiments, our medical collaborators would be able to see deep inside the brain of a living organism and guide the placement of the probe to the right brain region. Then, they can use the probe’s built-in thermometer to monitor any changes to the local temperature of that region,” said researcher Jiawen Li at the University of Adelaide. Li said that the probe has a diameter of just 130 μm. “This means it can be delivered deep inside the body in a minimally invasive way. It also allows us to see and record physiological data in real time that we weren’t able to access before,” she said. The probe could help researchers better understand how hypothermia develops and find treatments to prevent drug-induced overheating of the brain. It could also help researchers refine thermal treatment of cancers. The first generation of the probe can both take OCT images and measure body temperature, but Li hopes that future generations will be able to take other measurements, such as pH values, oxygen saturation, and accumulation of fat in arteries. The research was published in Optics Letters, a publication of OSA, The Optical Society (doi:10.1364/OL.43.001682).