Transcutaneous light penetration of simultaneous superpulsed and multiple wavelength photobiomodulation therapy in living dog tissue

Abstract

Photobiomodulation therapy (PBMT) is used as an adjunctive therapy for wound healing, pain relief and rehabilitation. The penetration of light to the target tissue is the crucial factor. The aim of this study was to investigate the potential penetration of simultaneous superpulsed and multiple wavelength (SPMW) PBMT on living tissue in dogs. Twenty client-owned dogs were anesthetized and underwent abdominal surgery. The PMBT device was set at 50 Hz and delivered light for 60 sec at different distances; at 0 cm (contact) and 1 cm tissue-device distance (non-contact). The power meter was placed and measured the mean output power (MOP) under the skin tissue only and the combination of skin and muscle tissue. The average thickness of skin was 2.97 mm (ranging from 1.7 to 4.3 mm) and the combination of skin and muscle tissue thickness was 15.87 mm (ranging from 10.0 to 30.0 mm). For skin tissue, MOP was found to be at 13.00±4.99 mW and 3.47±1.79 mW using the skin contact and non-contact mode, respectively. For the combination of skin and muscle tissue, MOP was found to be at 1.46±1.11 mW and 0.35±0.51 mW using the skin contact and non-contact mode, respectively. The MOP of skin contact was significantly greater than the non-contact both on skin tissue only and the combination of skin and muscle tissue (P<0.05). Based on these results, transcutaneous SPMW PBMT with a preset parameter of 50 Hz has been proven to be appropriate for target tissue thickness up to approximately 30.0 mm.