Mie and Rayleigh modeling of visible-light scattering in neonatal skin

Saidi, Iyad S.; Jacques, Steven L.; Tittel, Frank K.

doi:10.1364/ao.34.007410

Cited by 260 publications

(185 citation statements)

References 16 publications

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“…Accounting for both light backscatter and melanin as a transmission filter in our model is well founded (9,12,14). Open to discussion is the assumption that all the light transmitted into the dermis and not scattered back out is absorbed by Hb and bilirubin in the dermis and not much further into subdermal tissue.…”

Section: Model Justificationmentioning

confidence: 94%

“…Because light within the skin is diffuse, it is also valid, for the present purpose, to model the distribution of blood and bilirubin in the skin as homogeneous (9,12). Demonstrated by fluorescence studies, the distribution of bilirubin with respect to Hb in blood can also be considered homogeneous (18).…”

Section: Model Justificationmentioning

confidence: 99%

“…There is much evidence that until the bilirubin exceeds its binding sites on albumin, most of the bilirubin remains bound to albumin (19). That this is valid in vivo is indicated by the measurement of bilirubin in the skin by transcutaneous reflectometry, which tracks the serum bilirubin level in the blood (12,17,20,21). There is no evidence that extravascular bilirubin binds to other skin components (17).…”

Section: Model Justificationmentioning

confidence: 99%

“…Enabled by advances in physical optics and electronics, the optical properties of human skin have become well described (1,2,(9)(10)(11)(12)(13)(14). This has resulted in a model of skin optics that has led to improvements in devices such as transcutaneous bilirubinometers (2,9,14,21,37).…”

Section: Model and Calculationsmentioning

confidence: 99%

“…To try to help explain these observations, we applied semiempirical calculations based on a modern and well-accepted model of skin optics (1,2,(9)(10)(11)(12)(13)(14), known spectral data, and data on the blood and bilirubin levels in the skin, to show that Hct may, in fact, significantly affect phototherapy efficacy. In addition, the calculations allowed us to predict that a narrow wavelength-band emitting light source, such as light-emitting diodes (LEDs), at 476 nm would be the most efficient for phototherapy and would also minimize heating of the neonate by absorbed light.…”

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confidence: 99%

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The effect of hematocrit on the efficacy of phototherapy for neonatal jaundice

et al. 2013

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Background:The therapeutic phototherapy action spectrum ranges from 420 to 500 nm. However, a recent report of improved efficacy of fluorescent "turquoise" light (~490 nm) as compared with blue light (~450 nm) underscores the need to define an optimal action spectrum for precision-targeted phototherapy using very narrow wavelength ranges. Methods: We used a current semi-empirical model of the optical properties of skin for robust calculations of the fraction of light absorbed by bilirubin at various wavelengths that could be confounded by hemoglobin (Hb), melanin, and skin thickness. Applying assumptions regarding the wavelength dependence of bilirubin photochemistry, "action spectra" were assembled from the calculated values. results: All the calculated action spectra displayed a peak between 472 and 480 nm (most at 476 nm), which is a significant shift from the well-reported 460 nm absorption peak of bilirubin. Of note, the relative amplitudes of the action spectra showed an inverse relationship with hematocrit (Hct). conclusion: We speculate that a narrow range of light at 476 nm would be 60% more effective than blue (broadband) fluorescent lamps. Because Hb serves as a major competitor of bilirubin for light absorption, the calculations also predict that the efficacy of phototherapy is dependent on the Hct. A high Hct could reduce therapeutic efficiency. a n in vivo model to better define the optimal wavelength range for precision-targeted phototherapy has been elusive. Advances in understanding of skin optical properties have provided an optical model of neonatal skin in the therapeutic range (400-520 nm) that allows facile calculation of the influences of skin structure, melanin pigmentation, and cutaneous hemoglobin (Hb) on the action spectrum for phototherapy. Of these, Hb absorbs most of the visible light in the skin (1,2). As a result, competition from Hb with bilirubin for light should strongly affect the wavelength region of light that is most effective for phototherapy of neonatal jaundice. Although Hb competition has been recognized and used, in part, to predict the action spectrum for phototherapy (3,4), explicit reference to Hb competition appears to be absent from the recent literature. The reports of clinical studies showing that blue-green or green light may be more effective than blue light (5,6) generally rationalize these observations on the general notion that the longer wavelengths "penetrate deeper into the skin" without specific reference to Hb absorbance.Furthermore, significant competition for light by skin Hb also implies that the hematocrit (Hct) may in turn affect the efficacy of phototherapy. This possibility was recognized in 1974 by Lucey and Hewitt (7), who conjectured that the Hct "may be a contributing factor to the differences in response of serum bilirubin to light that one observes in different infants. " They observed in in vitro irradiation studies that changes in the Hct affect diazo-reactive bilirubin disappearance in blood. Almost a decade elapsed before a clinical st...

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Section: Model Justificationmentioning

confidence: 94%

Section: Model Justificationmentioning

confidence: 99%

Section: Model Justificationmentioning

confidence: 99%

Section: Model and Calculationsmentioning

confidence: 99%

mentioning

confidence: 99%

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The effect of hematocrit on the efficacy of phototherapy for neonatal jaundice

et al. 2013

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Light–Tissue Interaction at Optical Clearing

Genina¹,

Bashkatov²,

Larin³

et al. 2010

Laser Imaging and Manipulation in Cell Biology

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Wireless Electrical Power Delivery Using Light through Soft Skin Tissues under Misalignment and Deformation

Seo

Kim

Jeong

et al. 2022

Adv Materials Inter

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Among these, wireless power transfer via RF inductive coupling has the advantage of providing relatively high power. [31,32] However, RF wireless power transfer may have limited efficiency when the transceiver is miniaturized [16,33,34] or misaligned. [28,31] The technology using photovoltaics can also provide adequate electrical power to implants by capturing ambient light [24,36] or capturing light from an external light source. [37,38] While these technological advancements are encouraging, the characteristics of electrical performance when using devices under deformation or misalignment caused by opaque soft skin tissues have not yet been reported. The electrical performance characteristics are essentials in integrating reliable power systems to various electronic implants Herein, we report the electrical performance characteristics of a PV implant and external light source patch depending on misalignment, implantation depth, and deformation, which may occur in practical applications. Our experimental studies included ex vivo trials with a PV implant under an animal skin whose surface was covered by an attachable light source patch. We varied the lateral misalignment distance, implantation depth, and bending radius and direction. These results should be useful in the design and application of wireless power transfer using light for implantable medical electronic devices.

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Mie and Rayleigh modeling of visible-light scattering in neonatal skin

Cited by 260 publications

References 16 publications

The effect of hematocrit on the efficacy of phototherapy for neonatal jaundice

The effect of hematocrit on the efficacy of phototherapy for neonatal jaundice

Light–Tissue Interaction at Optical Clearing

Wireless Electrical Power Delivery Using Light through Soft Skin Tissues under Misalignment and Deformation

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