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The influence of cosmetics and ointments on the spectral emissivity of skin (skin temperature measurement)
This content has been downloaded from IOPscience. Please scroll down to see the full text. 1976 Phys. Med. Biol. 21 920 (http://iopscience.iop.org/0031-9155/21/6/002) View the table of contents for this issue, or go to the journal homepage for more
Download details: IP Address: 149.171.67.164 This content was downloaded on 05/09/2015 at 23:33
Please note that terms and conditions apply.
PHYS. MED. BIOL.,
1976, VOL. 21,
NO.
6,920-930.
@
1976
The Influence of Cosmetics and Ointments on the Spectral Emissivity of Skin J. STEKETEE Department of Biological and Medical Physics, Erasmus University Rotterdam, P.O. Box 1738, Rotterdam, The Netherlands
Received 25 March 1976, i n f l n a l form 28 M a y 1976 ABSTRACT. Measurements of the spectral emissivity, &(X), of human skin described in a previous paper were performed with a modifled monochromator by comparing the radiation from the skin with blackbody radiation in the wavelength range between 2 and 14 pm. Using the same equipment the spectral emissivity has been measured of skin which had been covered with different cosmetics and ointments. From these data it is possible to predict theoretically the apparent temperaturedifference as seen by an infrared scanner or radiometer with a detector of which the spectral detectivity, D*(X),is known. These values are compared with the readings of a Bofors Thermograph with an InSb detector. When talcum venetum has been applied to theskin, 8 greater apparent temperature difference must be expected for thermographiccamerasequipped with a HgCdTe detector than for cameras with InSb detectors.
1. Introduction
The emissivity, E , of human skin has acquired considerable importance because of the increasing medical use of infrared scanners and radiometers to measure skin temperature. I n a previous paper (Steketee 1 9 7 3 ~a) method was described for measuring the spectral emissivity by comparing skin radiation with blackbody radiation, in the wavelength range between 2 and 14 pm. Fujimasa, Sakurai and Atsumi(1973) pointed out the difference in emissivity when the skin is covered with tinctures or paints. These emissivity differences can lead to misinterpretation of the temperature readings of radiometers and infraredscanners.Wethereforemeasured,with the sameequipmentas described in the previous paper, the spectral emissivity, &(h),of skin covered withdifferent cosmetics and ointments. I n thesemeasurementsonly the emissivity a t normal incidence was measured. 2. Methodsandmaterials 2.1. Selection of cosmetics and ointments
As it was impossible to investigate all the materials which are used by patients, a selection had to be made. I n consultation with dermatologists a list of ointments and basic materials was compiled, complete with some cosmetics and sprays which could be presumed to affect skin radiation measurements. Samples of these materials were applied to the frontof a celleron plate which could be heated from the back by warm water from a thermostat. The celleron plate was coatedwithablack paint (NextalB Brand; 3M Company), the
ln$uence of Cosmetics on 8peccfral Bmissivit?y of Skin,
92 1
emissivity of which is nearly the same as that of the skin (see section 4, fig. 6 ) . That) the temperature distribution of this surface was sufficiently uniform is shown i n fig. I , n.here a thermogram is reproduced, macle with a Bofors .\Iark 11.1
k'ic. I .
'I'~I(,I.II!O~I,;!III ol'tl1(, II(YII(YI
S ! I I ~ ~ I Cbefore C
lixirlc t l r t .
1 1 1 : 1 t ( ~ r i ; 1 I(sI ~ ~ I '; III )I ( I
;Il.t1.1.
I!)
I1
(ripllt ).
Thermograph. The picture is made with the highest possible contrast, which means that the difference betn.een black and white is about 0.2 K. Special attention was given to the fact t,hatseveral materials are volatile and therefore produce temperature differences on the surface by evaporation.Forthis reason the definitive thermogram (and from that t,he definitive selection) was made about 20 h after fixation. The radiation difference between the coated surface (spot) and theuncoated surface surrounding this spot was measured with the Bofors in the isotherm mode. Thercsnltsare given in table 1. It must be emphasized thatthe differences are probably due only to emissivity differences and not to temperature cliffcrcnces. For this reason, in table I , AT is called theapparent temperature differencc. 2.2. T m p e r n t w e qradien,t A radiation difference can also be caused by a temperature gradicnt across the layer.Tomeasurethese temperaturegradientsdirectly is extremely difficult because of the verythinlayer(thickness, d, less than 0-05 mm). Severtheless, to obt,ain some estimate of the value of this temperature gradient, the radiation was measured as a function of the thickness, x, of the laycr. For this purposefour layers of a well defined thickness were formecl by attaching four rings to the surface The thicknesses of theserings were
J . Steketee
9-32
1.0, 2.0, 4.0 and 6.0 mm respectively. These rings werefilled up with the material and theracliationwas measured by theRofors (fig.3 ) . To avoid the effects of transmission the surface of t,he layer was covered with soot (see section 2.3).
Table 1 . 3Tcasured values of the apparent tcmprraturedifference in I< betn.een base and material. Adeps lanae hydroaus ;\tleps srlillus Alcohol crtylicrls
< 0.0.5 < 0.2 0.2-0.4
Amylrlm oryznc 0.rP0.7 =\ftersrln cream 0.25 I3ismuthi srlhgallns (Dermatol c ) 0.5 Celcstotlcrm-Y R 0.2 Cera Inncttc < 0.2 Cctaccnm
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My IOPscience
The influence of cosmetics and ointments on the spectral emissivity of skin (skin temperature measurement)
This content has been downloaded from IOPscience. Please scroll down to see the full text. 1976 Phys. Med. Biol. 21 920 (http://iopscience.iop.org/0031-9155/21/6/002) View the table of contents for this issue, or go to the journal homepage for more
Download details: IP Address: 149.171.67.164 This content was downloaded on 05/09/2015 at 23:33
Please note that terms and conditions apply.
PHYS. MED. BIOL.,
1976, VOL. 21,
NO.
6,920-930.
@
1976
The Influence of Cosmetics and Ointments on the Spectral Emissivity of Skin J. STEKETEE Department of Biological and Medical Physics, Erasmus University Rotterdam, P.O. Box 1738, Rotterdam, The Netherlands
Received 25 March 1976, i n f l n a l form 28 M a y 1976 ABSTRACT. Measurements of the spectral emissivity, &(X), of human skin described in a previous paper were performed with a modifled monochromator by comparing the radiation from the skin with blackbody radiation in the wavelength range between 2 and 14 pm. Using the same equipment the spectral emissivity has been measured of skin which had been covered with different cosmetics and ointments. From these data it is possible to predict theoretically the apparent temperaturedifference as seen by an infrared scanner or radiometer with a detector of which the spectral detectivity, D*(X),is known. These values are compared with the readings of a Bofors Thermograph with an InSb detector. When talcum venetum has been applied to theskin, 8 greater apparent temperature difference must be expected for thermographiccamerasequipped with a HgCdTe detector than for cameras with InSb detectors.
1. Introduction
The emissivity, E , of human skin has acquired considerable importance because of the increasing medical use of infrared scanners and radiometers to measure skin temperature. I n a previous paper (Steketee 1 9 7 3 ~a) method was described for measuring the spectral emissivity by comparing skin radiation with blackbody radiation, in the wavelength range between 2 and 14 pm. Fujimasa, Sakurai and Atsumi(1973) pointed out the difference in emissivity when the skin is covered with tinctures or paints. These emissivity differences can lead to misinterpretation of the temperature readings of radiometers and infraredscanners.Wethereforemeasured,with the sameequipmentas described in the previous paper, the spectral emissivity, &(h),of skin covered withdifferent cosmetics and ointments. I n thesemeasurementsonly the emissivity a t normal incidence was measured. 2. Methodsandmaterials 2.1. Selection of cosmetics and ointments
As it was impossible to investigate all the materials which are used by patients, a selection had to be made. I n consultation with dermatologists a list of ointments and basic materials was compiled, complete with some cosmetics and sprays which could be presumed to affect skin radiation measurements. Samples of these materials were applied to the frontof a celleron plate which could be heated from the back by warm water from a thermostat. The celleron plate was coatedwithablack paint (NextalB Brand; 3M Company), the
ln$uence of Cosmetics on 8peccfral Bmissivit?y of Skin,
92 1
emissivity of which is nearly the same as that of the skin (see section 4, fig. 6 ) . That) the temperature distribution of this surface was sufficiently uniform is shown i n fig. I , n.here a thermogram is reproduced, macle with a Bofors .\Iark 11.1
k'ic. I .
'I'~I(,I.II!O~I,;!III ol'tl1(, II(YII(YI
S ! I I ~ ~ I Cbefore C
lixirlc t l r t .
1 1 1 : 1 t ( ~ r i ; 1 I(sI ~ ~ I '; III )I ( I
;Il.t1.1.
I!)
I1
(ripllt ).
Thermograph. The picture is made with the highest possible contrast, which means that the difference betn.een black and white is about 0.2 K. Special attention was given to the fact t,hatseveral materials are volatile and therefore produce temperature differences on the surface by evaporation.Forthis reason the definitive thermogram (and from that t,he definitive selection) was made about 20 h after fixation. The radiation difference between the coated surface (spot) and theuncoated surface surrounding this spot was measured with the Bofors in the isotherm mode. Thercsnltsare given in table 1. It must be emphasized thatthe differences are probably due only to emissivity differences and not to temperature cliffcrcnces. For this reason, in table I , AT is called theapparent temperature differencc. 2.2. T m p e r n t w e qradien,t A radiation difference can also be caused by a temperature gradicnt across the layer.Tomeasurethese temperaturegradientsdirectly is extremely difficult because of the verythinlayer(thickness, d, less than 0-05 mm). Severtheless, to obt,ain some estimate of the value of this temperature gradient, the radiation was measured as a function of the thickness, x, of the laycr. For this purposefour layers of a well defined thickness were formecl by attaching four rings to the surface The thicknesses of theserings were
J . Steketee
9-32
1.0, 2.0, 4.0 and 6.0 mm respectively. These rings werefilled up with the material and theracliationwas measured by theRofors (fig.3 ) . To avoid the effects of transmission the surface of t,he layer was covered with soot (see section 2.3).
Table 1 . 3Tcasured values of the apparent tcmprraturedifference in I< betn.een base and material. Adeps lanae hydroaus ;\tleps srlillus Alcohol crtylicrls
< 0.0.5 < 0.2 0.2-0.4
Amylrlm oryznc 0.rP0.7 =\ftersrln cream 0.25 I3ismuthi srlhgallns (Dermatol c ) 0.5 Celcstotlcrm-Y R 0.2 Cera Inncttc < 0.2 Cctaccnm
