Low level light therapy (LLLT) has been clinically utilized for many indications in medicine requiring protection
from cell/tissue death, stimulation of healing and repair of injuries, pain reduction, swelling and inflammation.
Presently, use of LLLT to treat stroke, traumatic brain injury, and cognitive dysfunction is attracting growing
interest. Near-infrared light can penetrate into the brain tissue, allowing noninvasive treatment to be carried out
with few treatment-related adverse events. Optimization of LLLT treatment effect is one key issue of the field;
however, only a few experimental tests on mice for wavelength selection have been reported. We addressed this
issue by low-cost, straightforward and quantitative comparisons on light dosage distribution in Visible Chinese
human head with Monte Carlo modeling of light propagation. Optimized selection in wavelength, beam type and
size were given based on comparisons among frequently-used setups (i.e., wavelengths: 660 nm, 810 nm, 980 nm;
beam type: Gaussian and flat beam; beam diameter: 2 cm, 4 cm, 6cm).This study provided an efficient way to
guide optimization of LLLT setup and selection on wavelength, beam type and size for clinical brain LLLT.