The Radiation of Heat From the Human Body. Iv. The Emission, Reflection, and Transmission of Infra-Red Radiation by the Human Skin

Hardy, James D.; Muschenheim, Carl

doi:10.1172/jci100624

Cited by 113 publications

(66 citation statements)

References 11 publications

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“…The amount of the reflected light increases with increasing the incidence angle, with that the least reflection occurs when the laser beam is directed perpendicular to the skin [6]. If the incidence angle is 20˚, the percentage of the reflectance at 800 nm is about 22~29% [7]. As the thickness of the skin increases from 0.43 mm to 1.6 mm, the percentage of the reflectance at 800 nm also increases from 19% to 32% [8].…”

Section: Introductionmentioning

confidence: 99%

A new design of light illumination scheme for deep tissue photoacoustic imaging

Wang¹,

Ha²,

Kim³

2012

Opt. Express

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Abstract:A new light illumination scheme to increase imaging depth in photoacoustic (PA) imaging was designed and evaluated by in silico simulations and tested by in vitro experiments. A relatively large portion of the light energy shining into the body of a human reflects off the skin surfaces. Collecting the reflected light and redirecting it onto skin surfaces will increase the effective input energy, resulting in an increase of light penetration depth for the same light source. Its performance in PA imaging was evaluated using a finite element (FE)-based numerical simulation model composed of four modules. In the in vitro experiments with the light catcher, PA image of multiple targets at different locations exhibited an enhancement both in uniformity and in depth of the light illumination.

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Section: Introductionmentioning

confidence: 99%

A new design of light illumination scheme for deep tissue photoacoustic imaging

Wang¹,

Ha²,

Kim³

2012

Opt. Express

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“…while the direct transmission alone amounts to only about 1 Figure 4 is given the transmission curve of fact the curve is an exceptionally good example of the water spectrum. The curve is corrected for scattering but no correction is needed beyond 7.6 t From Figure 2 it is obvious that the magnitude of the scattering factor is very much less for such thin epidermal pieces than it is for the thick specimens.…”

Section: Resultsmentioning

confidence: 94%

“…In 1934 the authors (1) reported the results of spectroscopic observations on the emission, reflection and transmission of infra-red radiation by the human skin. The experiments were undertaken with the primary purpose of determining -whether the emissive and absorptive properties of the skin were those of black-body radiator within the spectral range in which the human body radiates heat.…”

mentioning

confidence: 99%

Radiation of Heat From the Human Body. V. The Transmission of Infra-Red Radiation Through Skin

Hardy¹,

Muschenheim²

1936

J. Clin. Invest.

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In 1934 the authors (1) reported the results of spectroscopic observations on the emission, reflection and transmission of infra-red radiation by the human skin. The experiments were undertaken with the primary purpose of determining -whether the emissive and absorptive properties of the skin were those of black-body radiator within the spectral range in which the human body radiates heat. The results of the experiments, carried out by the use of a reflecting infra-red spectrometer equipped with a rock salt prism, confirmed previously accumulated evidence (2,3,4) as to the truth of this assumption, and thus seemed to establish beyond all doubt the validity of the radiometric method of skin temperature measurement. Recently published results of Christiansen and Larsen (11), using questionable technique, would lead one to the dubious conclusions that the white human skin has a radiating power only about 78 per cent that of a black body and that the skin is quite transparent to the infra-red radiation in the region of the radiation emission from the human body. This new evidence is in direct contradiction to that of the combined work of nearly all other workers on this problem; it will be briefly discussed below. During the course of our previous transmission experiments it was noted that: (1) the penetrability of skin for the near infrared region of 0.75 ,u to 3 u, which is not included in the range of black-body emission above alluded to, was considerably lower as found by us than as reported by the majority of previous observers (5,6,7,8,9,10) and (2) the transmission spectrum of the thinnest layers of skin showed an apparently characteristic fine structure which resembled that of the infra-red spectrum of many organic compounds, and its most prominent bands were thought to be due to the C-H, N-H and 0-H linkages in the organic substances composing the skin.The present report is of further experiments concerned principally with these two findings of the former investigation. Since nearly all observers agree that it is only within the near infrared range than any appreciable penetration of the skin occurs, it is this portion of the spectrum, if any, which is effective in the deep penetration of radiant heat. As the present use of infra-red therapy is based partially on the supposition that the infra-red radiation penetrates in effective amounts, it was thought desirable to repeat the observations on living skin as well as on dead skin, on which alone our previous observations had been made. To determine more exactly the amount of scattered transmitted radiation, thus determining accurately the total amount of transmitted radiation, is also of importance. This range of wave lengths also includes those effective in infra-red photography, and the question of how far and in what quantities the radiation penetrates is of importance in determining the limitations of this method of photographing subcutaneous structures.As regards the second of the findings, i.e. the presence of characteristic absorption bands in the tra...

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“…Each media involved five sets of measurements and yielded the mean densities presented below density of skin -1.03 g/cm3 (6) density of-fat -0.98 g/cm (7) density of muscle -1.01 g/cm 3 (8) "Here one must recognize that the density for skin represents a mean value for the entire skin which consists predominantly of dermal tissues.…”

Section: Thermal Properties Of Skinmentioning

confidence: 99%