Researchers tested 671 nm and 808 nm 1 mW/cm^2 laser photon delivery in a severed cadaver head. They compared sinus (transsphenoidal), oral, and head (transcranial) light delivery at both wavelengths. 808 delivered more energy than 671 to a 40 mm target inside the brain tissue. They found that sinus delivery delivered 20 times more photons than transcranial delivery. Comparing oral, sinus and head delivery, and comparing 671 nm to 808 nm delivered at the same power density, the 808 nm diode transferred the largest quantity of photons to the farthest parts of the brain.