Photobiomodulation Therapy: Survey and Principal Study Leading to Design Rules for Implants

Area of Science:

• Biomedical Engineering
• Photomedicine
• Regenerative Medicine

Background:

• Photobiomodulation (PBM) therapy utilizes red and near-infrared light for regenerative effects on cellular functions and health applications.
• Power density is a critical parameter influencing PBM treatment outcomes.
• Transcutaneous light delivery to deeper tissues is limited by power attenuation, hindering internal organ regeneration applications.

Purpose of the Study:

• Investigate the cellular mechanisms of red light in PBM therapy.
• Review and classify existing light therapy research, analyzing effects of power density and exposure time.
• Propose design rules for implantable PBM devices targeting internal organs.

Main Methods:

• Literature review and classification of PBM studies.
• Experimental correlation of LED input power with generated power density at varying distances.
• Analysis of power delivery requirements for achieving therapeutic light levels in deep tissues.

Main Results:

• Identified positive and negative effects of light power density and exposure time in PBM.
• Determined that 18 mW input power to an LED yields 100 mW/cm2 power density over 1 cm2.
• Established that safe wireless power delivery (<1.6 W/kg SAR) is feasible for deep-tissue PBM.

Conclusions:

• PBM therapy holds promise for internal organ regeneration.
• This work provides a design rule and approach for developing safe and efficient implantable PBM devices.
• Extends the application scope of light therapy for internal health regeneration.