Effects of power densities, continuous and pulse frequencies, and number of sessions of low-level laser therapy on intact rat brain.

Objective: The aim of the present study was to investigate the possible short- and long-term adverse neurological effects of low-level laser therapy (LLLT) given at different power densities, frequencies, and modalities on the intact rat brain.

Background Data: LLLT has been shown to modulate biological processes depending on power density, wavelength, and frequency. To date, few well-controlled safety studies on LLLT are available.