Laser therapy is also known as photo-biostimulation. It works by stimulating cells with light. It is fast, painless and sometimes effective. The photons (light as it travels in bundles) from the laser device penetrates deep into tissue, about 3 inches, without causing heat or tissue damage. Laser therapy heals at a cellular level. Although it is not considered as effective as ultrasound, it can be a useful backup plan if the patient isn’t a good candidate for ultrasound therapy.