What Is The Purpose Of 405Nm-940Nm Multispectral Imaging? Unlock 3D Skin Analysis Today

The primary purpose of integrating multiple wavebands from 405 nm to 940 nm in an MSI system is to achieve comprehensive, depth-resolved imaging of skin tissue. By utilizing the varying penetration capabilities of different wavelengths, the system can simultaneously visualize superficial structures and deep dermal layers to construct a three-dimensional analysis of the skin.

Core Takeaway Light interacts with skin differently depending on its wavelength; short waves stop at the surface, while long waves travel deeper. By combining specific bands (405, 525, 660, and 940 nm), an MSI system effectively "slices" through the tissue optically, mapping the spatial distribution of melanin and hemoglobin to accurately calculate the thickness and volume of a lesion.

The Physics of Optical Penetration

Wavelength-Dependent Depth

The fundamental principle driving this integration is that the depth of light penetration is directly related to its wavelength.

Short wavelengths possess higher energy but are scattered and absorbed more quickly by biological tissue. Conversely, longer wavelengths encounter less scattering, allowing them to travel further into the tissue before returning to the sensor.

Layer-by-Layer Visualization

This variance allows the LED ring light to act as a non-invasive depth gauge.

For instance, 525 nm green light is a short wavelength that captures data primarily from superficial tissues and the epidermis. In contrast, 940 nm infrared light bypasses the upper layers to retrieve information from the deep dermis.

The Role of 405 nm and 660 nm

The system utilizes 405 nm light specifically to trigger and capture autofluorescence, which reveals surface-level biological activity.

Intermediate wavelengths, such as 660 nm (red light), bridge the gap between the surface and the deep dermis, ensuring a continuous profile of the skin structure.

Creating a 3D Biological Map

Tracking Chromophores

The ultimate goal of using these specific bands is to map the distribution of chromophores—specifically melanin and hemoglobin.

These compounds absorb light at specific signatures. By analyzing how much light returns at each waveband, the system determines the concentration and location of these chromophores.

Evaluating Lesion Thickness

Because the system captures data from the surface (405/525 nm) down to the deep dermis (940 nm), it moves beyond 2D photography.

It reconstructs the three-dimensional spatial distribution of the lesion. This capability is critical for evaluating lesion thickness, a key metric in assessing the severity and progression of skin conditions.

Understanding the Trade-offs

Dependence on Specific Chromophores

This method relies heavily on the presence of melanin and hemoglobin to generate contrast and depth data.

If a lesion or skin anomaly does not contain significant amounts of these specific chromophores, the derived "thickness" and 3D structure may be less accurate or harder to define compared to highly pigmented lesions.

Resolution vs. Depth

There is an inherent optical trade-off between the depth of penetration and the resolution of surface features.

While 940 nm light reaches deep tissues, it often provides lower resolution detail compared to the sharp, surface-level imaging of 525 nm light. A composite image is required to balance structural depth with surface clarity.

Making the Right Choice for Your Goal

When configuring or utilizing MSI systems for medical imaging, consider the specific clinical objective:

If your primary focus is surface topology and biological activity: Prioritize the analysis of the 405 nm (autofluorescence) and 525 nm bands to inspect superficial irregularities.
If your primary focus is determining tumor invasion or lesion volume: Rely heavily on the data from the 940 nm band to visualize the deep dermis and assess the vertical thickness of the tissue.

By synthesizing these multiple spectral views, you transform a standard visual inspection into a volumetric medical assessment.

Summary Table:

Wavelength	Spectrum	Penetration Depth	Key Clinical Focus
405 nm	Violet/UV	Superficial	Autofluorescence & surface biological activity
525 nm	Green	Epidermis	Superficial tissue & epidermal irregularities
660 nm	Red	Mid-Dermis	Intermediate structures & hemoglobin mapping
940 nm	Infrared	Deep Dermis	Lesion thickness, volume & deep dermal invasion

Elevate Your Clinic with Precision Skin Diagnostics

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By integrating our professional skin analysis technology, you can:

Provide clients with scientific, 3D biological mapping of skin health.
Enhance treatment results for body sculpting (EMSlim, Cryolipolysis) and hair removal through precise data.
Build trust with detailed thickness and chromophore distribution reports.

Ready to upgrade your diagnostic capabilities? Contact us today to discover how BELIS equipment can transform your practice.

References

Noémi Nóra Varga, Norbert Kiss. Optically Guided High-Frequency Ultrasound Shows Superior Efficacy for Preoperative Estimation of Breslow Thickness in Comparison with Multispectral Imaging: A Single-Center Prospective Validation Study. DOI: 10.3390/cancers16010157

This article is also based on technical information from Belislaser Knowledge Base .