Can a 1,072 nanometer wavelength penetrate the human skull and what are its effects on human tissues?

Can 1,072 nm Wavelength Penetrate the Human Skull?

Yes, a 1,072 nm wavelength can theoretically penetrate the human skull, though with significant attenuation, and there is emerging but limited research on its tissue effects.

Evidence for Near-Infrared Penetration Through Skull

The near-infrared (NIR) spectrum, which includes 1,072 nm, demonstrates superior tissue penetration compared to visible light wavelengths. Computational modeling using Monte Carlo simulations and visible human phantoms has shown that wavelengths in the 660-1,064 nm range can penetrate into cerebral tissue, with 660 nm and 810 nm performing optimally 1. While 1,064 nm showed less effective penetration than 660 nm or 810 nm in these models, it still demonstrated measurable photon fluence distribution within cerebral cortex 1.

The 1,072 nm wavelength falls within the NIR portion ranging from 700-1,440 nm, which has physical properties allowing increased depth penetration compared to shorter wavelengths 2. This wavelength can reach cells throughout both the epidermis and dermis, penetrating to greater depths than traditional phototherapy wavelengths 2.

Specific Research on 1,072 nm Wavelength

Direct research on 1,072 nm is notably sparse. The only documented clinical applications of 1,072 nm NIR light therapy to date have been limited to infection treatments and photorejuvenation in female patients 2. The theoretical basis for its deeper penetration relates to its position in the electromagnetic spectrum, where longer NIR wavelengths can traverse increased tissue density and thickness 2.

Skull Penetration Considerations

Physical Properties

• The skull presents a significant barrier due to its calcium content and density, which increases photon absorption 3
• Bone tissue has greater capacity to absorb electromagnetic energy compared to soft tissue 3
• The specific absorption characteristics at 1,072 nm through human skull bone have not been directly quantified in published literature

Comparative Wavelength Data

• Near-infrared laser therapy at 808 nm has been studied for transcranial application in acute ischemic stroke, with the postulated mechanism being photobiostimulation through skull penetration 3
• The 808 nm wavelength was selected based on evidence that near-infrared radiation could be absorbed by mitochondrial chromophores after passing through the skull 3
• Computational models suggest that 1,064 nm (close to 1,072 nm) has measurable but reduced penetration effectiveness compared to 660 nm and 810 nm 1

Tissue Effects and Safety Profile

Documented Effects

• 1,072 nm NIR light therapy has demonstrated cutaneous effects, with the ability to reach more cells throughout epidermis and dermis compared to traditional phototherapy wavelengths 2
• The mechanism involves photobiomodulation, where NIR radiation is absorbed by mitochondrial chromophores, accelerating enzymatic activity and increasing ATP production 3

Safety Considerations

• The wavelength falls well outside the ionizing radiation spectrum (x-rays, gamma rays) that causes tissue reactions and stochastic effects like cancer 3
• Non-ionizing electromagnetic radiation at these wavelengths does not cause the DNA damage, tissue necrosis, or deterministic effects associated with ionizing radiation 3
• Radiofrequency and NIR wavelengths do not produce the threshold-dose tissue reactions (skin injury, bone necrosis, cataracts) seen with ionizing radiation 3, 4

Critical Knowledge Gaps

There are no published studies specifically examining 1,072 nm wavelength penetration through human skull or its effects on deeper brain tissues. The available evidence consists of:

• Extrapolation from nearby wavelengths (808 nm, 1,064 nm) 3, 1
• Computational modeling rather than direct human measurements 1
• Cutaneous studies that do not address transcranial applications 2

Clinical Implications

• Any transcranial application would require careful dosimetry to account for skull attenuation
• The optimal fluence at the skull surface needed to achieve therapeutic levels in brain tissue remains undefined for this specific wavelength
• Individual variations in skull thickness, density, and composition would significantly affect penetration 1

Practical Considerations

If considering transcranial application of 1,072 nm:

• Expect significant energy attenuation through skull bone (exact percentage unknown)
• Account for increased absorption by calcium-rich bone tissue 3
• Consider that efficacy may be substantially lower than the better-studied 808 nm wavelength 3, 1
• Recognize that surface heating effects would occur before achieving therapeutic brain tissue doses
• No established safety or efficacy data exists for this specific application

The theoretical possibility of skull penetration exists based on the physical properties of NIR light in this range, but the clinical utility and safety profile for transcranial applications remain completely uncharacterized in the medical literature.