PHOTOBIOMODULATION DOSING A drug-free, surgery-free, non-invasive pain treatment alternative PBM dosing - the k ey to results Dosimetry in photobiomodulation (PBM) therapy is highly complicated - no single “dose” will work for all possible PBM therapies, and in some cases, different dosimetries can be equally effective. Safe and effective PBM dosimetry must consider multiple treatment parameters including: wavelength, irradiance (often called power density or brightness), and irradiation time . 28 Furthermore, it is important to recognize that PBM is challenged by energy loss that occurs as light enters the skin and travels from superficial to deeper tissues. At the skin’s surface this is primarily due to reflection and below the surface by absorption from different tissues competing for different wavelengths of light. Proper configuration of the laser is a key factor in getting sufficient energy to target tissues.
Factors that impact dose delivery at depth • Wavelength • Irradiance (power & beam area)
Laser classes - what do they mean? Lasers are classified by the FDA according to their output power. In the field of photobiomodulation therapy, there are two common laser classifications:
• Class IIIb, Maximum power output of 0.5 watts • Class IV, Maximum power output of over 0.5 watts
• Mechanism of delivery (contact vs. non-contact) • Treatment time • Size of treatment area • Type of tissue
Both Class IIIb and Class IV lasers require that safety eye protection be worn during emission.
The impact of power on treatment time Power is a key factor when delivering a therapeutic dose to deep target tissues. Not only do LightForce® lasers have higher output powers, but they also have larger beam areas, making them more capable of delivering a therapeutic dose to larger treatment areas. For example, to effectively treat a 300 cm 2 thoracic spine at 10 J/cm 2 , 3,000 joules of energy are required at the surface of the skin to deliver a therapeutic dose at depth. How long would that treatment take with a Class IIIb laser vs. a Class IV laser?
Class IIIb 3,000 J at 0.5 W = 100 min
Class IV 3,000 J at 15 W = 3.3 min
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