Relevance and utility of the in-vivo and ex-vivo optical properties of the skin reported in the literature: a review [Invited]

May combine two claims.

Overall, variability is highest for ex-vivo absorption measurements, with differences of up to 77-fold compared with 9.6-fold for the in-vivo absorption case.

“Overall, variability is highest for ex-vivo absorption measurements with differences of up to 77-fold compared with 9.6-fold for the in-vivo absorption case.”

May combine two claims.

Several authors using integrating sphere techniques to determine ex-vivo skin optical properties present data that all differ markedly, with 2-10-fold differences between absorption coefficients across a range of wavelengths and 2-3-fold variation in scattering coefficients.

“Several authors have used integrating sphere techniques to determine the optical properties of the skin ex-vivo [15,21,49–54]. However, the data that they present all differ markedly, with 2–10-fold differences between absorption coefficients across a range of wavelengths and 2–3-fold variation in scattering coefficients.”

May combine two claims.

Numerous authors have measured optical properties of skin on the forearm using DRS and absorption coefficients vary 9-fold amongst publications from 0.01 mm-1 to 0.09 mm-1 at 700 nm.

“Numerous authors have measured the optical properties of skin on the forearm using DRS and the absorption coefficients vary 9-fold amongst the publications from 0.01 mm-1 - 0.09 mm-1 at 700 nm [37,46,55,57,60].”

• cites [37] Torricelli, 2001, Phys. Med. Biol. sourceNot checked yet

  Not checked in the free run.

• cites [46] Zonios, 2006, Opt. Express sourceNot checked yet

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• cites [55] Tseng, 2009, Opt. Express sourceNot checked yet

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• cites [57] Doornbos, 1999, Phys. Med. Biol. sourceNot checked yet

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• cites [60] Hung, 2015, Biomed. Opt. Express sourceNot checked yet

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May combine two claims.

The wavelength range for ex-vivo data was greater than for in-vivo data, ranging from 400 nm - 2200 nm and 390 nm - 1600 nm respectively.

“The wavelength range for ex-vivo data was greater than for in-vivo data, ranging from 400 nm - 2200 nm and 390 nm - 1600 nm respectively.”

The quote only partly states this claim.

By averaging the ex-vivo published data, the 640 nm peak became more apparent.

“By averaging the ex-vivo published data, this peak became more apparent.”

May combine two claims.

For both data sets, a large scattering peak is observed at 640 nm; this is the most significant peak amongst the in-vivo data.

“For both data sets, a large scattering peak is observed at 640 nm. This is the most significant peak amongst the in-vivo data.”

May combine two claims.

Between 1300 nm and 1500 nm, ex-vivo transmission decreased from ∼85% to ∼72% through the epidermis and from ∼4.5% to ∼0.2% beyond the dermis.

“A corresponding peak in transmission is not observed for ex-vivo skin, in fact between 1300 nm and 1500 nm transmission decreased from ∼85% to ∼7 2% transmission trough the epidermis and ∼4.5% to ∼0.2% transmission beyond the dermis.”

May combine two claims.

Published data available for skin in the in-vivo situation are variable and incomplete.

“It is clear that the published data available for skin in the in-vivo situation are variable and incomplete and a comprehensive dataset covering a broad set of wavelength measurements is required for optimising skin treatments and imaging.”

May combine two claims.

This 640 nm peak does not tend to be seen in the published data when taken individually; reduced scattering coefficients generally reduce linearly with increasing wavelength.

“This does not tend to be seen in the published data when taken individually; reduced scattering coefficients generally reduce linearly with increasing wavelength.”

May combine two claims.

At 1700 nm, TMFP is at its greatest and scattering and absorption troughs are coincident.

“At this point TMFP is at its greatest and scattering and absorption troughs are coincident suggesting that this wavelength range might have the potential to provide deeper imaging and better resolution than at shorter wavelengths.”

May combine two claims.

At 1400 nm, ∼93% of light into the epidermis is transmitted beyond it and ∼24% of this light is transmitted beyond the dermis.

“Transmission through in-vivo skin peaks at 1400 nm, with ∼93% of the light into the epidermis being transmitted beyond it and ∼24% of this light being transmitted beyond the dermis.”

May combine two claims.

Both in-vivo and ex-vivo absorption and reduced scattering data display multiple peaks, some being true resonant peaks whilst other represent the noise amongst the data.

“Both in-vivo and ex-vivo absorption and reduced scattering data display multiple peaks, some being true resonant peaks whilst other represent the noise amongst the data.”

May combine two claims.

At 1400 nm, using in-vivo data, light is expected to travel 1.38 mm into the skin before becoming diffuse, compared with 0.6 mm using ex-vivo data.

“However, if one uses the in-vivo data recorded at 1400 nm, light would be expected to travel 1.38 mm in to the skin before it became diffuse compared to 0.6 mm for the same wavelength using the ex-vivo data.”

Probably not a substantial claim: may not pass S3 (load-bearing).

NIR II and III have been exploited for deep-tissue high-resolution optical imaging in other tissues.

“Similar has been shown to be true for other tissues, and NIR II and III have also been exploited for deep-tissue high-resolution optical imaging [27,31–36].”

• cites [27] Sordillo, 2014, J. Biomed. Opt. sourceNot checked yet

  Not checked in the free run.

• cites [31] Smith, 2009, Nat. Nanotechnol. sourceNot checked yet

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• cites [32] Poelman, 2020, J. Appl. Phys. sourceNot checked yet

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• cites [33] Hemmer, 2016, Nanoscale Horiz. sourceNot checked yet

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• cites [34] Shaw, 2022, Front. Chem. sourceNot checked yet

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• cites [35] Kenry, 2018, Adv. Mater. sourceNot checked yet

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• cites [36] Zhao, 2018, J. Mater. Chem. B sourceNot checked yet

  Not checked in the free run.

Probably not a substantial claim: may not pass S3 (load-bearing).

More than 200 papers describing the optical properties of tissues both in-vivo and ex-vivo from multiple animal sources but not focussed on the skin have been published annually since 2011.

“There has been a recent surge in publications describing the optical properties of tissues both in-vivo and ex-vivo from multiple animal sources but not focussed on the skin, with more than 200 papers being published annually since 2011 [1,2].”

• cites [1] Bashkatov, 2018, J. Biomed. Opt. sourceNot checked yet

  Not checked in the free run.

• cites [2] Martins, 2023, Biomed. Opt. Express sourceNot checked yet

  Not checked in the free run.

May combine two claims.

Technologies currently available for imaging the layers of the skin are limited in depth, and therefore for skin diseases like skin cancer, biopsies are still required for reliable diagnosis.

“Technologies currently available for imaging the layers of the skin, are limited in depth and therefore for skin diseases, like skin cancer, biopsies are still required for reliable diagnosis [3].”

• cites [3] Li, 2021, JID Innov. sourceNot checked yet

  Not checked in the free run.

Probably not a substantial claim: may not pass S3 (load-bearing).

Human skin is made up of approximately 65% water and 9% lipid.

“In general terms, human skin is made up of approximately 65% water and 9% lipid [37].”

• cites [37] Torricelli, 2001, Phys. Med. Biol. sourceNot checked yet

  Not checked in the free run.

May combine two claims.

Between 600 nm and 700 nm, absorption decreases and scattering becomes dominated by collagen and elastin bundles in the dermis.

“Between 600 nm and 700 nm absorption decreases and scattering becomes dominated by collagen and elastin bundles in the dermis [16].”

• cites [16] Gajinov, 2010, Serbian J. Dermatol. Venereol. sourceNot checked yet

  Not checked in the free run.

May combine two claims.

For visible and near infra-red wavelengths, scattering dominates over absorption in skin, being 100-1000 times stronger (and reduced scattering being 10-100 times stronger).

“For visible and near infra-red (NIR) wavelengths, scattering dominates over absorption in skin, being 100 - 1000 times stronger (and reduced scattering being 10 - 100 times stronger) [10].”

• cites [10] Cheong, 1990, IEEE J. Quantum Electron. sourceNot checked yet

  Not checked in the free run.

May combine two claims.

In skin, chromophores such as melanin in the epidermis and haemoglobin in the dermis are the major absorbers of light, and the absorption spectra depend on the amount of these chromophores present.

“In the skin, chromophores such as melanin in the epidermis and haemoglobin in the dermis are the major absorbers of light and the absorption spectra will depend on the amount of these chromophores present [16].”

• cites [16] Gajinov, 2010, Serbian J. Dermatol. Venereol. sourceNot checked yet

  Not checked in the free run.

May combine two claims.

At visible wavelengths, light is absorbed by melanin and haemoglobin, whereas structures such as cell components and melanosomes of less than 300 μm give rise to scatter.

“At visible wavelengths, light is absorbed by melanin and haemoglobin; whereas structures, such as cell components and melanosomes of less than 300 µm, give rise to scatter [10].”

• cites [10] Cheong, 1990, IEEE J. Quantum Electron. sourceNot checked yet

  Not checked in the free run.

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

Age and obesity affect skin composition, with a doubling of lipid content reported in abdominal subcutaneous fat content with high levels of obesity.

“However, factors such as age and obesity affect the composition with a doubling of the lipid content being reported in the abdominal subcutaneous fat content with high levels of obesity [38].”

• cites [38] Rodriguez, 2022, J. Biomed. Opt. sourceNot checked yet

  Not checked in the free run.

Probably not a substantial claim: may not pass S3 (load-bearing).

The skin is generally considered to be stacked layers of epidermis, dermis, and subcutaneous tissue, each with varying thickness and different optical characteristics.

“The skin is generally considered to be stacked layers of epidermis, dermis, and subcutaneous tissue each with varying thickness and different optical characteristics associated within each layer [8] (Fig. 1).”

• cites [8] Mignon, 2018, Biomed. Opt. Express sourceNot checked yet

  Not checked in the free run.

May combine two claims.

NIR I has been well characterised for imaging human tissue, and NIR II, III and IV have been shown to offer increased penetration and optical transparency over NIR I in a range of ex-vivo and in-vivo tissue including normal and malignant breast and prostate tissue, human aorta, pig and mouse brain and chicken and rat tissue.

“NIR I has been well characterised for imaging human tissue [12,18,20–25], and NIR II, III and IV have been shown to offer increased penetration and optical transparency over NIR I in a range of ex-vivo and in-vivo tissue including normal and malignant breast and prostate tissue, human aorta, pig and mouse brain and chicken and rat tissue [18,26–28].”

• cites [18] Wilson, 2015, J. Biomed. Opt. sourceNot checked yet

  Not checked in the free run.

• cites [26] Sordillo, 2015, J. Biomed. Opt. sourceNot checked yet

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• cites [27] Sordillo, 2014, J. Biomed. Opt. sourceNot checked yet

  Not checked in the free run.

• cites [28] Hong, 2014, Nat. Photonics sourceNot checked yet

  Not checked in the free run.

May combine two claims.

For skin, the anisotropy factor g tends to be between 0.8 and 0.95, i.e. scattering occurs mostly in the forward direction.

“For skin, g tends to be between 0.8-0.95, i.e. scattering occurs mostly in the forward direction.”

• cites [10] Cheong, 1990, IEEE J. Quantum Electron. sourceNot checked yet

  Not checked in the free run.

May combine two claims.

In general, the scattering coefficient is much higher at shorter wavelengths and changes relatively smoothly with wavelength.

“In general, this leads to a much higher scattering coefficient at the shorter wavelengths and, overall, a scattering coefficient that changes relatively smoothly with wavelength.”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

In the Rayleigh regime the scattering intensity is proportional to λ-4, whereas in the Mie regime the relationship is typically λ-1.

“In the Rayleigh regime the scattering intensity is proportional to λ-4, whereas in the Mie regime the relationship is more complex but is typically λ-1.”

May combine two claims.

At NIR wavelengths, scattering of photons in skin tends to decrease and these wavelengths are able to penetrate deepest into the skin.

“At NIR wavelengths, scattering of photons in skin tends to decrease and these wavelengths are able to penetrate deepest into the skin.”

May combine two claims.

Melanosomes affect scattering in the 600 nm to 700 nm range, and due to their high refractive index, their scattering coefficient is at least one order of magnitude higher than their absorption coefficient at 650 nm, even though melanin is a strong absorber.

“Melanosomes also effect scattering in the 600 nm to 700 nm range and, due to their high refractive index in comparison to their surroundings, their scattering coefficient is at least one order of magnitude higher than their absorption coefficient at 650 nm, even though melanin is a strong absorber [17].”

• cites [17] Song, 2017, Biomed. Opt. Express sourceNot checked yet

  Not checked in the free run.

May combine two claims.

Lipid absorption peaks at 900 nm, with minor absorption peaks at 1040 nm, 1210 nm, 1400 nm, 1730 nm and 1760 nm.

“Lipid absorption, which greatly affect the subcutaneous skin layer, peaks at 900 nm, but it also has minor absorption peaks at 1040 nm, 1210 nm, 1400 nm, 1730nm and 1760nm [18,43].”

• cites [18] Wilson, 2015, J. Biomed. Opt. sourceNot checked yet

  Not checked in the free run.

• cites [43] van Veen, 2005, J. Biomed. Opt. sourceNot checked yet

  Not checked in the free run.

May combine two claims.

Two absorption peaks were observed at 1460 nm and 1950 nm with absorption being 2.2 mm-1 at 2050 nm.

“Two absorption peaks were observed at 1460 nm and 1950nm with absorption being 2.2 mm-1 at 2050nm.”

• cites [54] Troy, 2001, J. Biomed. Opt. sourceNot checked yet

  Not checked in the free run.

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

Absorption in the epidermis was greater than in the dermis and subcutaneous tissue and decreased with wavelength except for a peak at 1450 nm corresponding with water absorption.

“Similarly, these authors described absorption in the epidermis being greater than in the dermis and subcutaneous tissue and that this decreased with wavelength except for a peak at 1450 nm corresponding with water absorption.”

• cites [52] Salomatina, 2006, J. Biomed. Opt. sourceNot checked yet

  Not checked in the free run.

Probably not a substantial claim: may not pass S3 (load-bearing).

In the visible spectrum, water absorption is negligible.

“In the visible spectrum water absorption is negligible.”

Probably not a substantial claim: may not pass S3 (load-bearing).

Prahl suggested that the optical depth was quite sensitive to (bloodless) tissue coagulation, which changes in the first 50-75 seconds of exposure to light.

“Prahl suggested that the optical depth was quite sensitive to (bloodless) tissue coagulation, which changes in the first 50 - 75 seconds of exposure to light [15].”

• cites [15] Prahl, 1998Not checked yet

  Not checked in the free run.

May combine two claims.

Between 1000 nm and 2200 nm, scattering remained between 0.8 mm-1 and 1.3 mm-1 and tended to decrease with increasing wavelength.

“Between 1000 nm and 2200 nm scattering remained between 0.8 mm-1 and 1.3 mm-1 and tended to decrease with increasing wavelength.”

• cites [54] Troy, 2001, J. Biomed. Opt. sourceNot checked yet

  Not checked in the free run.

May combine two claims.

Although haemoglobin is a strong absorber, its total effect on skin absorption is modest because blood makes up only a few percent of total skin volume and melanin is confined to the thin epidermal layer.

“For example, although melanin absorbs strongly at visible wavelengths, it is only located in the very thin epidermal layer of the skin. Blood only makes up a few percent of the total skin volume, and is different depending upon the layer in question, therefore, although haemoglobin is a strong absorber, its total effect is modest [41].”

• cites [41] Campolmi, 2016, Med. Princ. Pract. sourceNot checked yet

  Not checked in the free run.

May combine two claims.

Oxyhaemoglobin has absorption peaks at 418 nm, 542 nm and 577 nm, while deoxyhaemoglobin has peak absorption at 430 nm and 555 nm.

“Oxyhaemoglobin has peaks at 418 nm, 542 nm and 577 nm, while deoxyhaemoglobin has peak absorption at 430 nm and 555 nm [41,42].”

• cites [41] Campolmi, 2016, Med. Princ. Pract. sourceNot checked yet

  Not checked in the free run.

• cites [42]Not checked yet

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May combine two claims.

Water has multiple absorption peaks with increasing wavelength, with minor peaks at 740 nm and 835 nm and major peaks at 970 nm, 1180 nm, 1430 nm, 1650 nm, 1930 nm and 1975 nm.

“Water has multiple peaks with increasing wavelength, with minor peaks at 740 nm and 835 nm and major peaks at 970 nm, 1180 nm, 1430 nm, 1650 nm, 1930nm and 1975nm [25,44].”

• cites [25] Taroni, 2003, Photochem. Photobiol. Sci. sourceNot checked yet

  Not checked in the free run.

• cites [44] Hale, 1973, Appl. Opt. sourceNot checked yet

  Not checked in the free run.

May combine two claims.

Overall, compression was shown to increase absorption and scattering coefficients by up to ∼75%, however it didn't follow a monotonic trend.

“Overall, compression was shown to increase absorption and scattering coefficients by up to ∼75%, however it didn’t follow a monotonic trend.”

• cites [49] Chan, 1997, IEEE J. Select. Topics Quantum Electron. sourceNot checked yet

  Not checked in the free run.

May combine two claims.

The optical properties for the epidermal and dermal skin section were 2.5-18.5-fold greater than those of the subcutaneous layer; e.g., at 633 nm the mean absorption coefficient for the epidermal/dermal layer ranged from 0.033 mm−1 to 0.241 mm−1 compared to 0.013 mm−1 for the subcutaneous layer.

“The optical properties for the epidermal and dermal skin section were 2.5 - 18.5-fold greater than those of the subcutaneous layer e.g., at 633 nm the mean absorption coefficient for the epidermal/dermal layer ranged from 0.033 mm−1 to 0.241 mm−1 compared to 0.013 mm−1 for the subcutaneous layer.”

• cites [50] Simpson, 1998, Phys. Med. Biol. sourceNot checked yet

  Not checked in the free run.

May combine two claims.

Troy et al.'s data corroborates Simpson et al., whose data showed that absorption may increase beyond 1000 nm.

“This corroborates Simpson et al., whose data showed that absorption may increase beyond 1000 nm [50].”

• cites [50] Simpson, 1998, Phys. Med. Biol. sourceNot checked yet

  Not checked in the free run.

May combine two claims.

Single and double integrating sphere methods are potentially limited by sample thickness, and this should be a consideration when choosing a method for measuring optical properties of samples.

“This potentially suggests that single and double integrating sphere methods are limited by sample thickness and this should therefore be a consideration when choosing a method for measuring the optical properties of samples.”

May combine two claims.

With no applied pressure, the absorption coefficient ranged from 0.34 mm-1 to 0.59 mm-1, with a 2-fold difference in measurements within samples from one donor.

“With no applied pressure the absorption coefficient ranged from 0.34 mm-1 - 0.59 mm-1, with a 2-fold difference in measurements within samples from one donor.”

• cites [49] Chan, 1997, IEEE J. Select. Topics Quantum Electron. sourceNot checked yet

  Not checked in the free run.

May combine two claims.

At 1000 nm, absorption was recorded as an average of ∼0.1 mm-1, tending to increase slowly across the measured spectrum of 1000 nm-2200 nm.

“At 1000 nm absorption was recorded as an average of ∼ 0.1 mm-1, tending to increase slowly across the measured spectrum of 1000 nm - 2200 nm.”

• cites [54] Troy, 2001, J. Biomed. Opt. sourceNot checked yet

  Not checked in the free run.

Probably not a substantial claim: may not pass S3 (load-bearing).

From 1700 nm, absorption starts to increase again with increasing wavelength.

“From 1700nm absorption starts to increase again with increasing wavelength.”

• cites [49] Chan, 1997, IEEE J. Select. Topics Quantum Electron. sourceNot checked yet

  Not checked in the free run.

Probably not a substantial claim: may not pass S3 (load-bearing).

Beyond the NIR, water also has an absorption peak at 3400 nm.

“Beyond the NIR, water also has an absorption peak at 3400 nm [44].”

• cites [44] Hale, 1973, Appl. Opt. sourceNot checked yet

  Not checked in the free run.

May combine two claims.

Error in Simpson et al.'s data was large and attributed to differences in reflectance from imaging back to front and vice versa.

“Error in the data was large and attributed to differences in reflectance from imaging back to front and vice versa.”

• cites [50] Simpson, 1998, Phys. Med. Biol. sourceNot checked yet

  Not checked in the free run.

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

A linear increase in anisotropy corresponded with tissue dehydration and thinning, which was proposed to reduce the distance between scatterers and increase their effective size.

“A linear increase in anisotropy was shown to correspond with tissue dehydration and thinning which was proposed to reduce the distance between scatterers and increase their effective size.”

• cites [15] Prahl, 1998Not checked yet

  Not checked in the free run.

May combine two claims.

Chan et al. showed that absorption decreased rapidly from 1.4 mm-1 at 400 nm to 0.2 mm-1 at 1250 nm and peaked at 1450 nm to 2.1 mm-1, corresponding with maximal water absorption, with a sharp decrease thereafter.

“Absorption was shown to decrease rapidly from 1.4 mm-1 at 400 nm to 0.2 mm-1 at 1250 nm and to peak at 1450 nm to 2.1 mm-1, corresponding with maximal water absorption, with a sharp decrease in absorption thereafter.”

• cites [49] Chan, 1997, IEEE J. Select. Topics Quantum Electron. sourceNot checked yet

  Not checked in the free run.

May combine two claims.

In the NIR spectrum (750-1400 nm), oxyhaemoglobin absorption has maximal absorption at 900 nm and deoxyhaemoglobin absorption peaks at 960 nm.

“In the NIR spectrum (750 nm – 1400 nm) oxyhaemoglobin absorption has maximal absorption at 900 nm and deoxyhaemoglobin absorption peaks at 960 nm.”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

Melanin absorption peaks at 335 nm but reduces steadily with increasing wavelength.

“Melanin absorption peaks at 335 nm but this reduces steadily with increasing wavelength.”

May combine two claims.

In agreement with Doornbos et al., the forehead was the location of greatest scattering amongst the subjects and the arm the least.

“In agreement with Doornbos et al., the forehead was the location of greatest scattering amongst the subjects and the arm the least [57].”

• cites [57] Doornbos, 1999, Phys. Med. Biol. sourceNot checked yet

  Not checked in the free run.

May combine two claims.

Peak absorption and scattering coefficients for all skin layers was at 405 nm, steadily reducing with increasing wavelength, with the greatest absorption and scattering coefficients being in the epidermis.

“Peak absorption and scattering coefficients for all skin layers was at 405 nm steadily reducing with increasing wavelength with the greatest absorption and scattering coefficients being in the epidermis.”

• cites [53] Shimojo, 2020, J. Biomed. Opt. sourceNot checked yet

  Not checked in the free run.

Classified as probably not a substantial claim.

Because of the change of penetration depth associated with wavelength, different wavelengths could be used to determine the optical properties of different skin layers.

“Because of the change of penetration depth associated with wavelength, it was suggested that different wavelengths could be used to determine the optical properties of different skin layers.”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

The greater scattering in the forehead may be due to 1 cm - 2 cm tissue depth being probed by photons, the skin being thinnest at the forehead and photons being scattered by the skull beneath.

“This may have been due to 1 cm - 2 cm tissue depth being probed by photons, the skin being thinnest at the forehead and photons being scattered by the skull beneath.”

May combine two claims.

Absorption in the epidermis, dermis and subcutaneous layer ranged from ∼1.5 mm-1, ∼1 mm-1 and ∼1.8 mm-1 at ∼400 nm to 0.8 mm-1, ∼0.8 mm-1 and ∼0.4 mm-1 at 1600 nm respectively; on average a reduction of ∼2-fold for the absorption coefficient at 1600 nm compared to 400 nm.

“Absorption in the epidermis, dermis and subcutaneous layer ranged from ∼1.5 mm-1, ∼1 mm-1 and ∼1.8 mm-1 at ∼400 nm to 0.8 mm-1, ∼0.8 mm-1 and ∼0.4 mm-1 at 1600 nm respectively; on average a reduction of ∼2-fold for the absorption coefficient at 1600 nm compared to 400 nm.”

• cites [52] Salomatina, 2006, J. Biomed. Opt. sourceNot checked yet

  Not checked in the free run.

May combine two claims.

At the wavelength spectrum of 405 nm-1064 nm, absorption ranged from 3.32 mm-1 to 0.13 mm-1 and reduced scattering ranged from 9.95 mm-1 to 2.85 mm-1 in the epidermis (standard deviations for both coefficients tended to reduce with increasing wavelength).

“At the wavelength spectrum of 405 nm - 1064 nm, absorption ranged from 3.32 mm-1 - 0.13 mm-1 and reduced scattering ranged from 9.95 mm-1 - 2.85 mm-1 in the epidermis (standard deviations for both coefficients tended to reduce with increasing wavelength).”

• cites [53] Shimojo, 2020, J. Biomed. Opt. sourceNot checked yet

  Not checked in the free run.

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

Salomatina et al. suggested that scattering properties were dependent upon location and that collagen-elastin networks in fat from the scalp were thicker and denser than those in the subcutaneous adipose tissue of skin taken from the back.

“Salomatina et al., suggested that scattering properties were dependent upon location and that collagen-elastin networks in fat from the scalp were thicker and denser than those in the subcutaneous adipose tissue of skin taken from the back [52].”

• cites [52] Salomatina, 2006, J. Biomed. Opt. sourceNot checked yet

  Not checked in the free run.

May combine two claims.

In Doornbos et al., at 630 nm absorption was greatest in the forehead compared to the sole of the foot and the arm; at 660 nm it was greatest in the sole of the foot; at 700 nm the arm had greatest absorption.

“Wavelength measurements were limited to 630 nm, 660 nm and 700 nm and at 630 nm absorption was greatest in the forehead compared to the sole of the foot and the arm. At 660 nm it was greatest in the sole of the foot, and at 700 nm the arm had greatest absorption.”

• cites [57] Doornbos, 1999, Phys. Med. Biol. sourceNot checked yet

  Not checked in the free run.

May combine two claims.

Torricelli et al. found that scattering decreased progressively with increasing wavelength, while absorption showed features of water, haemoglobin, and lipid, with average spectral peaks at ∼600 nm, 760 nm, and 950 nm of approximately 0.017 mm-1, 0.013 mm-1, and 0.027 mm-1 respectively.

“Again, scattering decreased progressively with increasing wavelength, while the absorption showed the features of absorption by water, haemoglobin, and lipid, with average spectral peaks at ∼600 nm, 760 nm and 950 nm of approximately 0.017 mm-1, 0.013 mm-1 and 0.027 mm-1 respectively.”

• cites [37] Torricelli, 2001, Phys. Med. Biol. sourceNot checked yet

  Not checked in the free run.

May combine two claims.

Kono et al. found that average absorption coefficients amongst all data showed spectral peaks at 600 nm, 1000 nm, 1200 nm and 1450 nm corresponding with absorbers in the skin, with main differences between locations being observed in the visible spectrum.

“Across the subjects the average absorption coefficients amongst all data showed spectral peaks at 600 nm, 1000 nm, 1200 nm and 1450 nm corresponding with absorbers in the skin, with main differences between locations being observed in the visible spectrum.”

• cites [63] Kono, 2019, Int. J. Thermophys. sourceNot checked yet

  Not checked in the free run.

Probably not a substantial claim: may not pass S3 (load-bearing).

Kono et al. found scattering ranged from 12 mm-1 down to 3.7 mm-1 between 450 nm and 1400 nm.

“Scattering ranged from 12 mm-1 down to 3.7 mm-1 between 450 nm and 1400 nm.”

• cites [63] Kono, 2019, Int. J. Thermophys. sourceNot checked yet

  Not checked in the free run.

May combine two claims.

The amount of absorption associated with each skin constituent depended upon skin location and the most absorbing locations varied amongst subjects.

“The amount of absorption associated with each of these skin constituents depended upon skin location and the most absorbing locations varied amongst subjects.”

• cites [37] Torricelli, 2001, Phys. Med. Biol. sourceNot checked yet

  Not checked in the free run.

May combine two claims.

Hung et al. data showed a downward trend in optical scattering across the spectrum from 2.45 mm-1 to 1.15 mm-1; standard deviations for measurements above 1000 nm are large suggesting no significant differences between scattering coefficients beyond 1000 nm.

“Their data showed a downward trend in optical scattering across the spectrum from 2.45 mm-1 to 1.15 mm-1; however, the standard deviations for measurements taken above 1000 nm are large suggesting no significant differences between the scattering coefficients beyond 1000 nm.”

• cites [60] Hung, 2015, Biomed. Opt. Express sourceNot checked yet

  Not checked in the free run.

May combine two claims.

Jonasson et al. found a significant difference between men and women; measured reduced scattering coefficients were greater in men than women across the spectrum measured.

“there was a significant difference between men and women; measured reduced scattering coefficients were greater in men than women across the spectrum measured.”

• cites [61] Jonasson, 2018, J. Biomed. Opt. sourceNot checked yet

  Not checked in the free run.

Probably not a substantial claim: may not pass S3 (load-bearing).

The decrease in reduced scattering with age may be due to decreasing collagen concentrations in skin with age.

“potentially due to decreasing collagen concentrations in skin with age.”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

Between 1200 nm and ∼1275 nm the absorbance declined rapidly and then increased sharply beyond this wavelength.

“Between 1200 nm and ∼1275 nm the absorbance declined rapidly and then increased sharply beyond this wavelength.”

• cites [60] Hung, 2015, Biomed. Opt. Express sourceNot checked yet

  Not checked in the free run.

May combine two claims.

Tseng and Hsu's scattering and absorption profiles followed a similar pattern to other authors, with absorption greatest between 500 nm and 600 nm, declining with increasing wavelength except for a small peak at ∼970 nm.

“However, their scattering and absorption profiles followed a similar pattern to the other authors’ with absorption being greatest between 500 nm and 600 nm beyond which it declines steadily with increasing wavelength except for a small peak observed at ∼970 nm.”

• cites [55] Tseng, 2009, Opt. Express sourceNot checked yet

  Not checked in the free run.

• cites [56] Hsu, 2015, Biomed. Opt. Express sourceNot checked yet

  Not checked in the free run.

Probably not a substantial claim: may not pass S3 (load-bearing).

This resulted in increased scattering coefficients compared to the back where connective tissue was thin.

“This resulted in increased scattering coefficients compared to the back where connective tissue was thin.”

May combine two claims.

A new SFD model reduced the median relative error by 10% for μs' and 64% for μa compared to previously used models.

“This model reduced the median relative error by 10% for µs’ and 64% for µa compared to previously used models.”

• cites [69] Post, 2023, J. Biomed. Opt. sourceNot checked yet

  Not checked in the free run.

May combine two claims.

The 1700 nm wavelength range might have the potential to provide deeper imaging and better resolution than at shorter wavelengths.

“At this point TMFP is at its greatest and scattering and absorption troughs are coincident suggesting that this wavelength range might have the potential to provide deeper imaging and better resolution than at shorter wavelengths.”

May combine two claims.

Like Saager et al., Phan et al. showed that skin pigmentation affected measured coefficients and that inter-subject variation for both absorption and scattering decreased amongst all locations measured with increasing wavelength.

“Like Saager et al., these authors showed that skin pigmentation affected the measured coefficients and that inter-subject variation for both absorption and scattering was found to decrease amongst all locations measured with increasing wavelength [64,65].”

• cites [64] Saager, 2015, J. Biomed. Opt. sourceNot checked yet

  Not checked in the free run.

• cites [65] Phan, 2021, J. Biomed. Opt. sourceNot checked yet

  Not checked in the free run.

May combine two claims.

Phan et al. found not enough measurements across the spectrum to observe absorption peaks associated with skin components, although the general trend was for a reduction in absorption with increasing wavelength.

“There were not enough measurements made across the spectrum to observe absorption peaks associated with the components of the skin, although the general trend was for a reduction in absorption with increasing wavelength.”

• cites [65] Phan, 2021, J. Biomed. Opt. sourceNot checked yet

  Not checked in the free run.

Probably not a substantial claim: may not pass S3 (load-bearing).

The 640 nm peak in Hsu et al. data potentially represents scattering due to collagen bundles in the skin.

“potentially representing scattering due to collagen bundles in the skin [56].”

• cites [56] Hsu, 2015, Biomed. Opt. Express sourceNot checked yet

  Not checked in the free run.

May combine two claims.

Aguénounon et al. improved SFD imaging by using Single Snapshot imaging of Optical Properties (SSOP), reducing image acquisitions to one and applying machine learning to improve accuracy, reduce edge artifacts, improve resolution and increase imaging speed.

“Improvements to SFD imaging have been made by Aguénounon et al., to enable its use in surgical settings, by using Single Snapshot imaging of Optical Properties (SSOP). This reduces the number of image acquisitions to one and applies machine learning approaches to improve accuracy, reduce edge artifacts, improve resolution and increase imaging speed.”

May combine two claims.

At 900 nm both absorbance and reduced scattering in the skin of all subjects was similar, however at shorter wavelengths variability between measurements was greater.

“At 900 nm both the absorbance and reduced scattering in the skin of all subjects was similar, however at shorter wavelengths variability between measurements was greater.”

• cites [64] Saager, 2015, J. Biomed. Opt. sourceNot checked yet

  Not checked in the free run.

May combine two claims.

Saager et al. data followed the same general trends as other authors, but optical properties were only measured up to 900 nm so water peaks beyond this were not observed.

“Although their data followed the same general trends as that of other authors, the optical properties were only measured up to 900 nm so peaks associated with the water beyond this were not observed.”

• cites [64] Saager, 2015, J. Biomed. Opt. sourceNot checked yet

  Not checked in the free run.

Probably not a substantial claim: may not pass S3 (load-bearing).

The epidermis and dermis thicknesses used were taken from Meglinski et al. as an example of average skin layer depths.

“The thickness of the epidermis and dermis used were taken from Meglinski et al., and used as an example of average skin layer depths [58].”

• cites [58] Meglinski, 2002, Physiol. Meas. sourceNot checked yet

  Not checked in the free run.

May combine two claims.

SFD imaging is limited due to slow and sequential acquisitions of light patterns and edge artifacts and is therefore difficult to apply to clinical applications that require real-time feedback such as surgery.

“SFD imaging, discussed here, is limited due to slow and sequential acquisitions of light patterns and edge artifacts and is therefore difficult to apply to clinical applications that require real-time feedback such as surgery [68].”

• cites [68] Aguénounon, 2020, Biomed. Opt. Express sourceNot checked yet

  Not checked in the free run.

Probably not a substantial claim: may not pass S3 (load-bearing).

Melanin has been shown to depolarise light.

“For example, melanin has been shown to depolarise light [93].”

• cites [93] Baumann, 2012, Biomed. Opt. Express sourceNot checked yet

  Not checked in the free run.

May combine two claims.

The degree of depolarisation has allowed differentiation between cancerous and benign lesions, showing importance for detecting skin cancers.

“This has been shown to be of importance for detecting skin cancers where the degree of depolarisation has allowed differentiation between cancerous and benign lesions [90,91].”

• cites [90] Louie, 2018, J. Biomed. Opt. sourceNot checked yet

  Not checked in the free run.

• cites [91] Tchvialeva, 2013, J. Biomed. Opt. sourceNot checked yet

  Not checked in the free run.