Infra-red Transmission of the Flesh

Cartwright, C. Hawley

doi:10.1364/josa.20.000081

Cited by 42 publications

(8 citation statements)

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“…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.…”

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confidence: 48%

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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confidence: 48%

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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“…Moreover, in the near future, they will be able to operate remotely, implying that they will be totally unobtrusive. Following the pioneering work of Cartwright [10], Haxthausen [11], Matthes [12] and Molitor et al [13], Alrick B. Hertzman (physiologist at St. Louis University School of Medicine, USA), discovered in 1938 a relationship between the intensity of backscattered polychromatic light and blood volume in the skin. His instruments consisted of three essential components still found in modern systems: a light source, a light detector ( Fig.…”

Section: Customization In Healthcare and Biomedical Engineeringmentioning

confidence: 99%

“…The basic principle behind the measurement of blood volume changes in the skin by means of PPG is the simple fact that hemoglobin in the blood absorbs infrared light many times more strongly than the remaining skin tissue [6][7][8][9][10]. For example, as blood pressure in the skin vessels decreases, the surface area of the vessels is reduced.…”

Section: Customization In Healthcare and Biomedical Engineeringmentioning

confidence: 99%

Customized optoelectronic in-ear sensor approaches for unobtrusive continuous monitoring of cardiorespiratory vital signs

Blažek¹,

Venema²,

Leonhardt³

et al. 2018

IJIEM

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Customization of diagnostic and therapeutic pathways in medicine and personalization of medical devices are currently major trends in biomedical engineering together with miniaturization, digitalization and increasingly ambient and unobtrusive sensor strategies. This article presents a novel optoelectronic sensor: its concept is based on simple, easy-to-use classical photoplethysmography technology, but is attached to the ear. Via the ear channel or the inner tragus, the sensor detects diagnostically relevant parameters from peripheral arterial and venous blood volume movement (including heart rate, heart rate variability, respiratory activity, blood oxygen saturation and other subdermal blood phenomena). The diagnostic system consists of customizable i) sensor forms, ii) biodata mining, and iii) communication protocols sent to the medical control center. This article describes novel possibilities for cardiorespiratory monitoring with these sensors characterized by enhanced customization features. In contrast to established art sensor applications on fingers or toes, this optical in-ear sensor technology offers additional physiological and technological advantages by mining vital signs in the ear channel. Since the optical in-ear sensor is comfortable, noninvasive and unobtrusive, it is recommended not only for patients at high cardiovascular risk but also (potentially) for homecare application and the monitoring of physical activities, e.g. during high altitude climbing. Preliminary results demonstrate that vital signs can be assessed with sufficient robustness and accuracy and that, due to the customized sensor application, patient comfort is higher compared with the classical wearable (non-customized) sensors.

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“…Photoplethysmography. Photoplethysmography (PPG) was originally described for the assessment of the arterial system [116]. In the venous system, the principle of photoplethysmography depends on the variation in the light absorption of the skin caused by hemoglobin in the dermal venous plexuses.…”

Section: Plethysmographymentioning

confidence: 99%