A new imaging technique called photoencephalography could someday harness UPE signals as a diagnostic tool to supplement PET scans and MRIs. As a team of researchers—led by Haley Casey from Algoma University in Ontario, Canada—found out, the human brain can actually luminesce. They also were trying to prove that UPE signals from the brain could be distinguished from background photon noise. Subjects wore an EEG cap that had electrodes attached, along with photomultiplier tubes, to monitor brain activity. As a result, passive measurement of brain activity is undisturbed and allows for detection of electromagnetic stimuli in the surrounding environment.