More than Ninety Percent of the Light Energy Emitted by Near-Infrared Laser Therapy Devices Used to Treat Musculoskeletal Disorders Is Absorbed within the First Ten Millimeters of Biological Tissue

Abstract

There is increasing interest in the application of near-infrared (NIR) laser light for the treatment of various musculoskeletal disorders. The present study thoroughly examined the physical characteristics of laser beams from two different laser therapy devices that are commercially available for the treatment of musculoskeletal disorders. Then, these laser beams were used to measure the penetration depth in various biological tissues from different animal species. The key result of the present study was the finding that for all investigated tissues, most of the initial light energy was lost in the first one to two millimeters, more than 90% of the light energy was absorbed within the first ten millimeters, and there was hardly any light energy left after 15–20 mm of tissue. Furthermore, the investigated laser therapy devices fundamentally differed in several laser beam parameters that can have an influence on how light is transmitted through tissue. Overall, the present study showed that a laser therapy device that is supposed to reach deep layers of tissue for treatments of musculoskeletal disorders should operate with a wavelength between 800 nm and 905 nm, a top-hat beam profile, and it should emit very short pulses with a large peak power.

Neuron Foundry Mach 8: A Concept of Multi-modal Neuro-supportive Energy Therapy Device for Treating Neurodegenerative Disorders

“…The study conducted by [163] Overall, the study's findings support the potential advantages of multi-modal neurosupportive energy therapy as a complementary treatment for people with neurodegenerative diseases. To better understand the therapeutic potential of these interventions, Neuron Foundry Mach 8 needs to be completed and tested.…”

“…The study conducted by [163] shares similarities with the Neuron Foundry Mach 8 concept in its focus on the therapeutic application of light, although there are notable differences in methodology and target outcomes. Both studies leverage light as a therapeutic tool, showcasing the versatility of light-based therapies in addressing various medical conditions, depending on the specific wavelengths and applications.…”

Photothermal Effects of High-Energy Photobiomodulation Therapies: An In Vitro Investigation

“…In the authors’ opinion, the reasons for the mixed research outcomes reported in the literature when small optic probes are employed is related to the issue of achieving radiant exposure (J/cm 2 ) adequate for targeting tissues over larger areas, particularly in the case of some sub-surface conditions, where the treatment area may extend to several cm 2 or more. Attenuation of the applied beam, in view of optical scatter in the red to NIR wavelength regions, reduces photon delivery at a depth of 5–10 mm to approximately 5–10% of the dose applied to the surface [ 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 ]. To compensate for this energy loss, it is therefore necessary to increase the dose delivered to the surface by at least 10-fold in order to achieve the desired value at a depth of 10 mm [ 4 , 38 , 39 , 40 ].…”

“…Attenuation of the applied beam, in view of optical scatter in the red to NIR wavelength regions, reduces photon delivery at a depth of 5–10 mm to approximately 5–10% of the dose applied to the surface [ 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 ]. To compensate for this energy loss, it is therefore necessary to increase the dose delivered to the surface by at least 10-fold in order to achieve the desired value at a depth of 10 mm [ 4 , 38 , 39 , 40 ].…”

“…Optical transport in the red to NIR wavelengths is primarily forwards, with significant energy losses to depth, consequent to scatter and remission, a process resulting in a concentration of photons within the immediate boundary of the epidermis to the dermis [ 34 , 35 , 36 , 37 , 40 ]. Optical scatter predominates over absorption, permitting the delivery of photons to sub-surface tissues.…”