Penetration depth study of 830 nm low-intensity laser therapy on living dog tissue

Abstract

Background and Aim: Recent studies have shown that low-intensity laser therapy (LILT) enhances chronic wound healing, reduces pain, reduces inflammation, and improves post-operative rehabilitation. However, clinical outcomes in the veterinary use of LILT vary between different experimental studies. This is explained by improper laser parameter settings and limits of its penetration depth. This study aimed to investigate the penetration depth of 830 nm LILT on living dog tissue in different operating modes. This entailed continuous wave (CW) versus pulse wave (PW) and with contact versus non-contact techniques of the laser probe at different tissue-laser probe distances. The results can be applied for use in clinical practice. Materials and Methods: Twenty-four dogs that had undergone abdominal surgery were included in this study. The laser parameters were set at 200 mW, fluence of 4 J/cm2 and the laser power output denoted as mean output power (MOP) was measured by a power meter. Results: The MOP of the 830 nm CW laser was significantly higher than the PW laser (p<0.05). The MOP of the contact technique was significantly greater than that of the non-contact technique in both CW and PW modes (p<0.05). The MOP through the skin tissue was between 16.09 and 18.60 mW (8.05-9.30%) for the contact technique and 8.73 and 19.36 mW (4.37-9.68%) for the non-contact technique. In the muscle-skin layer, the MOP was between 0.50 and 1.56 mW (0.25-0.78%) and the MOP was not detected using the non-contact technique with a 5 cm tissue-laser probe distance. Conclusion: Our study indicates that 830 nm LILT (with laser parameter setting at 200 mW, fluence of 4 J/cm2 for both contact and non-contact techniques, and tissue-laser probe distance up to 5 cm) was appropriate for treatments within 14 mm of depth. However, the use of 830 nm LILT for an application in which the target tissue is deeper than 14 mm may limit its positive effect.

Assessment of wound area reduction on chronic wounds in dogs with photobiomodulation therapy: A randomized controlled clinical trial

“…Moreover, treatment with a single wavelength of 830 nm PBMT with a fluence of 4 J/cm 2 , power of 200 mW, and frequency of 50 Hz, and simultaneous SPMW-PBMT with a preset of 1-250 Hz showed significant improvement of the wound healing process on the basis of wound size reduction compared with a non-PBMT treatment from days 7 to 13 after treatment. This finding supports a previous PBMT parameter study using an 830 nm light with a dose of 4 J/cm 2 that would be appropriate for superficial wound treatment in dogs [26]. In addition, our result is related to the findings of the previous studies, which noted an improvement in mice wound healing with the use of a single 830 nm PBMT with a fluence of 3-4.2 J/cm 2 [32,33].…”

“…The two PBMT groups (L1 and L2) were treated with irrigated saline without topical medication together with the different PBMTs every 2 nd day for 2 weeks (Table-2). The wound in the L1 group was radiated with a single wavelength of 830 nm PBMT (BTL-5800 SL Combi, BTL Industries Ltd., London, UK) with the dose setting recommended by Millis and Saunders [25] and based on our previous study [26]. The wound in the L2 group was Radiance Medical, Solon, OH, USA) with a preset program for tissue repairing protocol from the manufacturer's recommendations.…”

Proposed Canadian Consensus Guidelines on Osteoarthritis Treatment Based on OA-COAST Stages 1–4

“…Photobiomodulation (Laser) treatments can potentially be beneficial for some patients, using appropriate settings for specific tissues or conditions. There have been significant knowledge gains in the field of laser therapy over the last 10 years and it is important to understand the technicalities to assure that the targeted tissue depth is reached, as it will vary depending on tissue ( 168 , 169 ). The mechanism of action of Laser (light amplification by stimulated emission of radiation) is on a cellular level via photobiomodulation.…”

Photobiomodulation in 3D tissue engineering

“… 87 Following the tissue architecture and light source parameters, light penetration can be restricted to 10 to 50 mm. 88 , 89 …”