Background of the Invention Thermography methods are effectively utilized for the early detection of breast cancer. These methods are based on scanning the body's infrared radiation, and constructing a thermal image of the scanned organs. The thermographical image can then be utilized to inspect and to detect groups of abnormal cells of different types in live tissue, such as tumors. This detection is based on detection and analysis of temperature gradients derived from thermal image, which are usually related to angiogenesis phenomenon (formation of a blood vasculature directed to cancerous cells).

Digital Infrared Imaging (DII) tests are particularly attractive, since these are noninvasive procedures which do not require radiation, compression, contact, or intravenous injection, as other tests commonly used today (e. g., mammography, biopsies, etc. ) do. In most cases, and particularly in breasts cancer test, a thermal camera is utilized to obtain a thermal image of the inspected organ. It is therefore a noninvasive test which does not risk the patient's health, and which enables detection of cancer at its earliest stage, or, alternatively eliminates the need for surgical biopsies by determining if a breast abnormality is malignant or benign. Sensitive infrared cameras and sophisticated computer programs are utilized in DII tests to detect and analyze temperature variations between normal and infected tissue. In the breast cancer test particularly, the thermal images obtained from both breasts are usually compared to obtain a better indication, and sophisticated computer programs are utilized to determine whether the tissue is malignant or benign. However, those sophisticated means require skills, proper training and experience from medical staff, as well as utilization of strict protocols. Moreover, women breasts are usually not completely symmetrical, and thus an analysis obtained by comparing the thermal images of both breasts may be less reliable.

Not all tumors can be detected by utilizing thermal imaging, since not all tumors are associated with blood vessel activity (e. g. , angiogenesis). Other types of tests (e. g. , mammography) are efficient for the detection of some types of tumors, and of course not all of them, particularly in cases of smaller tumors in younger patients and in the cases of dense breast tissues.

Infrared imaging for early detection of tissue abnormalities, especially of cancerous tumors, has been studied and researched thoroughly. Because there is no certain method for breast cancer prevention, effective techniques for early detection are of main importance. Most of the thermographical methods which are commonly used for tests are based on detection of thermal differences of body tissues, which can be effective for the detection of tissue abnormalities to some extent. However, such thermographical methods still suffer from inaccuracy, particularly when early detection is extremely important for providing an efficient medical treatment. In addition, thermographical methods are not sufficiently accurate whenever diagnosis of the type of abnormality is required, as well as of the stage of abnormality.

Other conventional diagnosis methods are based on pyrometric (temperature based) measurements, which are sensitive to the degree of roughness of the tested skin area, and should be performed when the temperature detectors are located essentially in perpendicular position with respect to the tested skin area. These cumbersome limitations result is an inaccurate analysis.

It is therefore an object of the present invention to provide a method and apparatus for accurate detection and analysis of abnormal live tissues.

It is another object of the present invention to provide a method and apparatus for the early detection of live tissue abnormalities such as cancerous tumors and inflammations.

It is still another object of the present invention to provide a method and apparatus for the detection and diagnostics of different types and stages cancerous tumors.

It is yet another object of the present invention to provide a method and apparatus for instant and reliable detection of abnormalities of live tissues.

It is a further object of the present invention to provide method and apparatus for accurate detection and analysis of abnormal live tissues, which are not sensitive to the position or to the roughness of the tested body area.

Other objects and advantages of the invention will become apparent as the description proceeds.

Summary of the Invention The following terms are defined for clarity: Thermography: measurement of the regional temperature of the body or an organ by infrared receivers, based on self-emanating infrared radiation. A diagnostic technique in which an infrared camera is used to measure temperature variations on the surface of the body, producing images that reveal sites of abnormal tissue growth.

The present invention is directed to a method for measuring the temperature and the emissivity factor of an inspected body. An optical receiver that comprises an active receiving area and has at least one pair of output contacts is provided. The optical receiver is capable of outputting a first electric signal that represents the optical energy received on the receiving area. At least a portion of the optical energy emitted from the body is received by the optical receiver. The first electrical signal and the first value of the temperature of the receiving area are measured and the temperature of the receiving area is changed to a second value by applying a second electrical signal that represents a different level of optical energy to the pair and the temperature of the body, and the emissivity factor are calculated using the first and second values and the first and second signals, such that the effects of changes in the relative position between the optical receiver and the body, and of deviations of the optical properties of the body from those of a black-body are essentially canceled.

The present invention is also directed to a method for the accurate detection of abnormal cells in an inspected live tissue. An optical receiver that comprises an active receiving area, such as a thermocouple, and has at least one pair of output contacts is provided. The optical receiver is capable of outputting a first electric signal that represents the optical energy received on the receiving area. at least a portion of the optical energy emitted from a surface being subjacent to the inspected live tissue and characterized by its emissivity factor, is received. The first electrical signal and the first value of the temperature of the receiving area are measured and the temperature of the receiving area is changed to a second value by applying a second electrical signal, representing a different level of optical energy to the pair. The temperature of the inspected live tissue and the emissivity factor are calculated using the first and second values and the first and second signals. The value of a third electrical signal, representing the actual value of the optical energy distributed within predetermined wavelength range, that corresponds to the calculated temperature, is measured by using the calculated temperature and the emissivity factor, and that value is compared to an expected value for the range and the calculated temperature. Indications regarding the presence of abnormal cells are obtained whenever the measured value of the third electrical signal essentially differs from the expected value.

The type of abnormality is determined according to the value of difference between the measured and the expected value of the third electrical signal, within a predetermined range. The wavelength range is predetermined by a set of optical filters, each of which having a different cutoff wavelength, operating in combination with an optical receiver. The value of the third electrical signal may be measured by an optical receiver, operating in combination with a set of optical filters, each of which having a characteristic cutoff wavelength, for determining the required wavelength, or by a set of optical receivers, each of which operating in combination with a corresponding optical filter having a characteristic cutoff wavelength, for determining the required wavelength.

Preferably, the type and/or the stage of abnormalities are determined, by obtaining for each range, the distribution of the energy represented by the third electrical signal, within the range, whenever a difference between the measured and the expected value of the third electrical signal is detected. peaks representing emission of optical energy and/or dips representing absorption of optical energy are identified in the distribution and a type and/or a stage of abnormality is assigned to each peak/dip, according to the wavelength at which the peak/dip is detected and to the magnitude of the peak/dip. Preferably, the second electrical signal is a periodic pulse comprising, in each cycle after reaching a first thermal equilibrium around the first value of the temperature of the receiving area, a first portion, during which the temperature is changed in one direction until reaching second thermal equilibrium around another value, and a second portion after reaching the second thermal equilibrium, during which the temperature of the receiving area is changed in the opposite direction until returning to the first thermal equilibrium.

The optical beam that comprises the energy that is emitted from the surface may be shaped by positioning a diaphragm having a limiting, essentially conical, window and/or focusing lenses, between the surface and the active area.

The present invention is also directed to an apparatus for measuring the temperature and the emissivity factor of an inspected body, that comprises: a first optical receiver comprising an active receiving area for receiving at least a portion of the optical energy emitted from the body and having at least one pair of output contacts; circuitry for outputting through the contacts, a first electric signal representing the optical energy received on the receiving area; a signal generator for applying a second electrical signal, representing a different level of optical energy to the pair changing the temperature of the receiving area to a second value; and processing means for measuring the first electrical signal and the first value of the temperature of the receiving area and for calculating the temperature of the body, and the emissivity factor using the first and second values and the first and second signals.

In one aspect, the invention is directed to an apparatus for the accurate detection of abnormal cells in an inspected live tissue, that comprises : a first optical receiver comprising an active receiving area for receiving at least a portion of the optical energy emitted from the live tissue and having at least one pair of output contacts; circuitry for outputting through the contacts, a first electric signal representing the optical energy received on the receiving area; a signal generator for applying a second electrical signal, representing a different level of optical energy to the pair changing the temperature of the receiving area to a second value; one or more optical filters for filtering the optical energy at a predetermined wavelength range that corresponds to the calculated temperature; processing means for measuring the first electrical signal and the first value of the temperature of the receiving area and for calculating the temperature of the live tissue and the emissivity factor, using the first and second values and the first and second signals; processing means for measuring the value of a third electrical signal, representing the actual value of the optical energy distributed within the predetermined wavelength range; comparison means for comparing the actual value to an expected value for the range and the calculated temperature; and means for providing indication regarding the presence of abnormal cells whenever the measured value of the third electrical signal essentially differs from the expected value.

The apparatus may further comprise a set of optical filters, each of which having a different cutoff wavelength and operating in combination with an optical receiver, for determining the wavelength range, or an optical receiver, operating in combination with a set of optical filters, each of which having a characteristic cutoff wavelength, for measuring the value of the third electrical signal. The apparatus may further comprise a set of optical receivers, each of which operating in combination with a corresponding optical filter having a characteristic cutoff wavelength, for measuring the value of the third electrical signal.

The second electrical signal, generated by the signal generator, may be a periodic pulse comprising, in each cycle after reaching a first thermal equilibrium around the first value of the temperature of the receiving area, a first portion, during which the temperature is changed in one direction until reaching second thermal equilibrium around another value, and a second portion after reaching the second thermal equilibrium, during which the temperature of the receiving area is changed in the opposite direction until returning to the first thermal equilibrium.

The apparatus may further comprise a diaphragm having a limiting, essentially conical, window and/or focusing lenses, positioned between the surface and the active area for shaping the optical beam that comprises the energy that is emitted from the surface.

Brief Description of the Drawings In the drawings: Fig. 1 schematically illustrates black-body power distribution at different temperatures; Fig. 2A schematically illustrates a setup for obtaining parameters required for the measurement of optical radiation emitted by an area of a live tissue, according to a preferred embodiment of the invention; Fig. 2B schematically illustrates the geometrical shaping of the optical radiation emitted from live tissues being subjacent to the skin ; Figs. 3A schematically illustrates the structure of an optical receiver; Figs. 3B schematically illustrates the vaveform of current applied to externally vary the temperature of the thermoelectric optical receiver; - Figs. 4A-4C schematically illustrate distribution of the energy of the radiation emitted from an inspected surface, with reference to the radiation of a black-body after filtering, according to a preferred embodiment of the invention; Fig. 5 schematically illustrates a setup for the measurement of optical radiation emitted by an area of a live tissue, according to a preferred embodiment of the invention; and Fig. 6 schematically illustrates deviations from the expected optical radiation values in the distribution of optical energy, obtained from the setup of Fig. 5, according to a preferred embodiment of the invention.

Detailed Description of Preferred Embodiments The present invention is directed to detection and diagnostics of live tissue abnormalities, based on inspection of the optical radiation spectrum emitted by the tissue. The diagnosis method proposed by the present invention is based on the detection of deviations of the optical energy distribution of the radiation of a tested live tissue from an expected value. As will be explained hereinafter, the presence of an abnormal tissue alters the distribution of the optical energy (mainly in the IR wavelengths) radiated from infected organs. This deviation is measured and analyzed with reference to the optical radiation expected from a determined area of a live tissue.

One of the reasons which alters the energy radiated from cell tissue in a live organ is due to a phenomenon, in which glucose exploitation manner is changed. In this mutation of the cells, the cells change from an oxidative respiration cycle to a fermentative respiration cycle. Namely, the mutated cells start to use glucose (adenosine triphosphate, (ATP)), instead of oxygen, in order to produce energy. The mutated cells grow in an uncontrolled manner may originate cancer, as was shown by the study of Pro£ Otto Warburg, Nobel Lecture, December 10, 1931).

The normal Oxygen respiration is replaced by a fermentative respiration mechanism. The mutated cells become anaerobic, namely, they start fermenting glucose, instead of the normal oxidation, in order to produce the energy that they require. The optical energy radiated by the anaerobic cells introduces deviations in the expected value of optical energy distribution to be radiated from a tissue containing healthy cells. The detection of these deviations of the optical energy distribution can be utilized (if detected) to identify formation of cancerous tumors in their earlier stages.

Acquiring a spectral scan of live tissues is a challenging task. Some of the difficulties that should be considered are the determination of the Emissivity factors and temperatures, which are different for different parts of the body (variations in the Emissivity of the skin), and obtaining spectral diagnostics of particular portions of the radiated spectrum (also referred to herein as the "power distribution"). More difficulties are present due to the curvature and the roughness of live organs (i. e. , different areas of the body surface are observed from different angles by the optical receiver), and variations of the Emissivity.

One way to understand the deviations of energy distribution emitted from the inspected live tissue is to represent the tissue as a set of energy emitters.

Thus, the energy spectrum of a healthy tissue (i. e. , not possessing ill and/or mutated cells) may be represented as a collection of emitters having constant emission rate and power. The presence of ill and/or mutated cells within the inspected tissue may be illustrated in this presentation in the presence of energy emitters which emit more energy than the expected, in a healthy tissue, or in a phenomenon in which some of the emitters becomes receptors of energy, and instead of emitting energy they absorb it.

Therefore the presence of ill and or mutated cells in the inspected tissue is characterized in deviations of the energy distribution, from the distribution expected from a healthy tissue. Those deviations can be observed, and will typically appear as excess, or as a lacking, of emitted energy in parts of energy spectrum.

The optical energy radiated from a body is given by the Stefan-Boltzmann law E = ##S###T4, where # is the Stefan-Boltzmann constant, S is the radiating area, and T is the object temperature expressed on the absolute temperature Kelvin scale [0°K =-273°c]). The power of the radiated optical energy increases as temperature of the body increases (Fig. 1). This optical radiation is distributed over a wide range of wavelengths, and can be examined conveniently with reference to the power spectrum of an ideal black-body (A black-body is a theoretical object that absorbs 100% of the radiation that is received on its surface. Therefore, it reflects no radiation and appears perfectly black. At a particular temperature, the black-body would emit the maximum amount of energy possible for that temperature. This value is known as the black-body radiation. It would emit at every wavelength of light, as it must be able to absorb every wavelength to ensure absorbing all incoming radiation. It also emits a definite amount of energy at each wavelength for a particular temperature).

The power of radiation in any given wavelength A and temperature T, can be computed by Planck's equation: where cl and c2 are constants.

All the optical energy that strikes a black-body is completely absorbed by it, i. e. , having Emissivity factor £ of unity (s=l). However, this is not the case with real radiating objects, which usually absorb only portions of the radiation (energy) that is received on their surface (6 < 1). The optical energy (per area unit) exchanged between two black bodies, having temperatures Ta and Tb, respectively, can be obtained utilizing Stefan-Boltzmann law- (I) E=o-. (y-r) When the objects are not ideal black-bodies, (e. g., gray-bodies) the object geometric and physical characteristics are also considered. Namely, the radiating/absorbing areas of each object Sa and Sb respectively, L the distance between the objects, the Emissivity of the objects (£a and c,), and since they are usually not completely flat, a loss factor k, should be introduced into the equation, thus obtaining- (II) E = ###a##B#(Tb4-Ta4)#Sa#Sb#k/L2 This relation (II) is particularly convenient for expressing the radiation energy falling on a radiation optical receiver, as will be discussed hereinbelow.

Fig. 2A schematically illustrates a setup for obtaining parameters required for the measurement of optical radiation emitted by an area of a live tissue, according to a preferred embodiment of the invention. The optical receiver 100 is preferably a broad band infrared optical receiver with broad spectral response (e. g. , a film thermoelectric optical receiver), which produces an electrical signal (voltage drop) that is proportional to the optical energy received on its active area (an exemplary optical receiver is illustrated in "High-responsive thermoelectric radiation receivers", V. V. Razinkov et al, Jaournal of Thermoelectricity, No. 1, Oct. 1993, pages 62-66). The active surface 110, of the optical receiver 100, is exposed to optical radiation, and characterized by a receiving area Sb and Emissivity £b. The optical radiation falling on the optical receiver surface 110 (also referred herein as the receiving area, Sb) is radiated from the observed body subjacent to area Sa of the inspected object 105 (in this example, a skin area covering a portion of a human body, which form a non-ideal black-bodies), which is of Emissivity Ea and temperature Ta. The optical receiver 100 is positioned at distance L from the inspected object 105. The optical beam that comprises the energy that is emitted by the body subjacent to area Sa is shaped by positioning a diaphragm 101, which functions as a limiting"window", resulting in an essentially conical shaped radiation pattern (dotted line), connecting between area Sa and the active area of optical receiver 100, Sb. The geometrical limitations induced by diaphragm 101 are illustrated in Fig. 2B. Each point on area Sa is"mapped"to a corresponding point on area Sa, thus, determining the portion of the optical energy, emitted from the body subjacent to area Sa, that is actually obtained on area Sb. The optical receiver 100 outputs a voltage that represents the temperature of the body subjacent to area Sa, which increases in response to optical energy received thereon.

The optical receiver 100 collects the optical energy radiated from the body subjacent to the observed area Sa of the inspected object through diaphragm 101. The radiated power is inversely proportional to the squared distance (I72) i. e. , radiation intensity declines as the distance L increase. However, in practice, the same radiation intensity is obtained on area Sb for different values of the distance L, since the conical pattern formed by diaphragm 101 causes the effective area Sa to become larger if the distance L increases, and smaller if the distance L decreases. Thus changes in the optical energy received at area Sb in response to variations in the distance L are compensated by corresponding changes in the effective area Sa. Area Sb is selected to have optical properties, which are of to be close to those of a blach- body.

The energy exchanged between the optical receiver surface Sb 110 (characterized by Emissivity £b and temperature Tb), and the surface of the inspected body Sa (characterized by Emissivity £a and temperature Ta), which are located in distance L from each other, is characterized by equation II. Equation II includes the factor of the geometric location (L 2) and a factor k introduced due to a tilt angle a, of the inspected surface, relative to the optical receiver surface 110. The factor k is constant in a given measurement setup, and it expresses the distribution of radiation intensity (proportional to the cosine of the tilt angle cosa) introduced due to the relative location and orientation of surfaces Sa and Sb.

As mentioned hereinbefore, the inspected bodies, especially when dealing with live tissues, are not flat, and since they do not behave as ideal black bodies, the factor k is introduced in the radiation power exchange equation (II).

Accordingly, the power of radiation E1 that is measured in this case is- (II. 1) E1 = ###a##b#(Tb4-Ta4)#Sa#Sb#k/L2 In such measurement, the optical receiver active surface Sb receives the optical radiation emitted from the body subjacent to area Sa of the inspected object 105. As a result, the temperature of area Sb is raised until thermal equilibrium is reached at temperature Tb, which can be obtained by measuring changes in the voltage drop across the output port of optical receiver 100. For example, if the temperature of the area of the inspected object is Ta=37°c (body temperature), and the temperature of the optical receiver active area Sb is 25°c (room temperature), optical energy that is emitted from the body subjacent to area Sa, is received at area Sb, and thermal equilibrium may be reached, for example, when the temperature Tb of area Sb reaches 27°C.

Returning to equation (II. 1), it should be understood that most of its components are known for a given measurement setup. The area Sb and the Emissivity £b, of the optical receiver receiving surface 110, are fixed and known for a given optical receiver, and its temperature Tb can be measured.

Therefore, since the radiation power EI is measured by the optical receiver 100, the inspected object Emissivity £a and the surface temperature Ta are the only variables left unknown in equation (II. 1). As will be explained hereinbelow, these variables are of particular importance for practical implementation.

To obtain these unknowns, the object temperature (Ta) and Emissivity (£a), a second measurement is carried out for the same inspected object (i. e. , for the same surface Sa of Emissivity £a, positioned in distance L, and tilt angle a).

In this second measurement, the temperature of the area of the optical receiver is artificially increased or decreased (by applying a corresponding known voltage to the thermoelectric optical receiver) to a new temperature Tb' (Tb'=Tb+AT). So the measurement of the radiated energy E2 carried out for the object new temperature ? %'should correspond to- (11. 2) E2 = #(Ta4-Tb'4)#Sa#Sb#k/L2 To simplify equations (II.1) and (II.2), the parameter #=###b#Sb#k#Sa/L2 is introduced to represent the contribution of all constants, and thereby the following set of equations, of two unknown variables, is obtained- The temperature Ta of the body subjacent to area Sa may be computed by- and once the temperature Ta in computed, the value of 77 can be obtained, and the inspected object Emissivity can be easily obtained from: E1<BR> <BR> (II.4) #a=<BR> <BR> <BR> <BR> ##(Tb4-Ta4) It should be noted that additional factors should be introduced into equations (II. 1) and (II. 2) according to the properties of the optical receiver, and whenever lenses, filters, and/or other optical elements are utilized. However, this elements are still constant for in a given measurement setup, and thus the same computation of Ta and £a can be carried out only by modifying the parameter 77 accordingly. By doing so, the effects of changes in the relative position between said optical receiver and said body, and of deviations of the optical properties of said body from those of a black-body are essentially canceled. Hence, the measurement becomes accurate, regardless spatial parameters, such as the angle of measurement, the roughness of the skin, the presence of objects or organs that deteriorate the smoothness of the skin. This feature proposed by the present invention allows emulating the properties of a black-body, for the tissue being subjacent to each inspected area.

Increasing or decreasing the temperature optical receiver should be carried out such that only the temperature of the active receiving area Sb is changed, while the temperature of all other parts of the optical receiver remain unchanged.

Figs. 3A and 3B schematically illustrates a method for externally controlling the temperature of the optical receiver surface Sb according to a preferred embodiment of the invention. The method is illustrated herein for types of thermoelectric optical receivers, its structure in principal being depicted in Fig.

3A.

These types of optical receivers are based on the Seebeck Effect (The Seebeck effect, refers to the appearance of a thermo-electromotive force in an electric circuit composed of (High-responsive thermoelectric) conductors, which contacts have different temperatures. The conductors are connected in series.

The temperature difference causes current to flow in the conductors, which is directed from the hot end to the cold one. In the point of the conductors' contact, a potential difference occurs. The magnitude of thermo-electromotive force depends on the material of the conducts, contact temperature and does not depend on the temperature distribution along the conductors) where a voltage is obtained, in the presence of a temperature differences ATj = Tb-Ts between the terminals of two types of conductors, P and N, containing free charge carriers. The area where the conductors are in contact is called junction, and each pair of PN (or NP) conductors forming a junction is also known as a thermocouple. A plurality of thermocouples connected in series 300, as shown in Fig. 3A, construct a thermopile.

Such connectivity of thermocouples is also typical for types of thermoelectric batteries. The voltage V measured between the terminals of such connectivity structure of thermocouples is proportional to the number of thermocouples, to the temperature differences ATj = Tb-Ts between the temperature Tb of the optical receiver receiving surface Sb to the temperature of the optical receiver packaging Ts (IToTj Ov).

In a preferred embodiment, the temperature Ts of the optical receiver packaging, is measured. The temperature Tb of the receiver is changed according to the power of the optical radiation falling on the optical receiver surface. It therefore possible to obtain the temperature of the PN junctions, according to the measured voltage V (ATj). More particularly, each voltage obtained on the optical receiver terminals is associated with a certain temperature difference #Tj, and since the surrounding temperature Tb'is measured, the junctions temperatures is simply Tb = Ts + #Tj.

In the second measurement, the temperature of the receiving surface Sb is increased/decreased to Tb'= Ar, by the externally applying electric current through the thermocouple structure 300. The flow of electric current through the thermocouple structure 300 results in emitting or absorbing heat energy at the thermocouple junctions. Emission or absorption of heat energy depends on the direction of the current flowing (Peltier Effect). The amount of heat emitted/absorbed by the thermocouples is proportional to the current magnitude I, and can be computed by equation (III): (III) Q = +HI +I 2R where I is the electric current magnitude, R is the electrical resistance of the thermocouple structure 300, and n the Peltier constant.

A current of magnitude I1 applied over a pre-calculated time interval cl can be utilized to raise the temperature of the optical receiving area Sb to a desired new temperature Tb' (as shown in Fig. 3B). After the current pulse I1 is applied the thermoelectric receiving film Sb, the temperature Tb'is maintained for some time interval tl, after which it will start to drop, as illustrated in Fig. 3B. During the time interval tl, the second measurement is carried out, according to which E2 is obtained. The temperature of the optical receiving area Sb will continue to drop, however, it may take a considerably long time until it falls back to the starting temperature Tb. In a typical scenario, sequences of measurements are performed continuously, which requires accelerating the rate at which the temperature falls back to the starting temperature, Tb, which will then allow taking more frequent measurements.

In order to accelerate the rate at which the junction temperature falls back to the initial temperature Tb, current of magnitude I2 (in the opposite direction then the direction of I1) is applied during a time interval r2. This current pulse will accelerate the rate of temperature change (Peltier Effect), and after a relatively short time, the initial temperature Tb is reached and a new measurement may be started wherein EI is obtained in the measurement performed in the time interval to.

A single measurement cycle ts comprises heating and cooling intervals (Tl and r2 respectively), and measurements of the radiated energies EI and E2 (during time intervals t, and t2 respectively). It is of course possible to take more measurements in single measurement cycle. For example, it may be preferred to take n (n=1, 2, 3,...) different measurements of energies E2 E2(2),E2(3),...,E2(n) for a corresponding set of temperatures Tb'(1),Tb'(2),Tb'(3),...,Tb'(n). In addition, one may choose to carry out measurements in which the thermoelectric receiving film Sb is cooled first and then heated back to its original temperature. It is also possible to use a low profile thermoelectric array, in which current is forced to flow. The obtained data can be processed by a computer, so as to obtain visual representation.

Once the Emissivity £a and temperature Ta of the inspected surface Sa are determined, inspection of the power distribution of the measured body can be carried out by relating the power distribution radiated from a black-body of temperature Ta°, given in equation (IV) : This power distribution 121 is utilized as a reference for further examination of the power radiated from the inspected object.

The energy radiated from the inspected body is analyzed utilizing the energy distribution of a blach-body of temperature Ta° as a reference. This analysis may be carried out utilizing sets of narrow band-pass optical filters, diffraction networks, such as diffraction gratings (used as optical filters), and similar techniques. According to a preferred embodiment of the invention, the distribution of the radiated energy is analyzed by utilizing at least three optical (long wave edge) filters. Those filters can be used to analyze the radiation spectrum utilizing a single radiation optical receiver, by way of addition. Alternatively, the method proposed by the invention may be implemented utilizing three identical radiation optical receivers, each of which receives its radiation from one optical channel (delivering the radiation from the inspected surface Sa), utilizing a different filter from said at least three filters.

The method for analyzing the energy of the radiation emitted from an inspected surface Sa, with reference to the radiation of a black-body of temperature Ta°, according to a preferred embodiment of the invention, is schematically illustrated in Figs. 4A-4C. The energy flux density from surface Sa at temperature Ta°, received through the first filter, according to Planck's law, is given by: where Cl = 3, 7418 l0-l6W M2 is a first constant and C2 = 1,4388#10-2#M#K is the second constant if Planck's law, and cD) is the wave length response of the optical filter, as illustrated in Fig. 4A.

Similarly, for the second and third filters, zip (i) and Cg (A) respectively, the energy flux densities according to Planck's law are given by: respectively, as illustrated in Figs. 4B and 4C.

Therefore, for each of the spectral wave length bandwidths, which are obtained utilizing said filters, the corresponding energy is obtained: F6#Sa = [#(Ta0)4-F5]#Sa=EA, (F5-F1)Sa = EB, (F1-F3)Sa = EC, and F3Sa = ED.

The difference in the voltage signals measured by the optical receiver in each case is proportional to the differences in the energy in the corresponding wave length band. Therefore, the voltage signal difference V3-V1 should be proportional to the energy in the wave length band of EB, where V3 and V1 are the voltage signals obtained by the optical receiver utilizing filters Og (. ) and (which passes radiation above and/ wave lengths) respectively.

Similarly, the voltage signal difference V1-V2 should be proportional to the energy in the wave length band of Ec, where V2 is the voltage signal obtained by the optical receiver utilizing filter (D2 (2) (which passes radiation above 22 wave lengths).

The spectral analysis of the radiated energy is obtained by comparing the ratio of the voltage signals differences (V3-V1), corresponding to the wavelength V1-V2 bands of Es and Ec, with the ratio of the computed energy (ex), that c corresponds to the same wavelength bands for a black-body being at temperature Ta0. By doing so, the deviation of the properties of the inspected body subjacent to area Sa from those of a black-body are compensated, and the measurement are results are analyzed like the radiating body subjacent to area Sa is of a black-body. Of course, other methods for processing the collected data may be used.

V3-V1 EB<BR> Therefore, if the comparison results indicate that >, then it is<BR> <BR> <BR> V1-V2 EC possible that the inspected surface Sa comprise an additional source of radiation, which radiates in the wave length band between and , or alternatively, it may be that the inspected surface Sa comprise a radiation absorber, which absorbs radiation in the wave length band between 8 and 4.

In cases where V3-V1 < EB, the possible determinations are vice versa.

VI-V2 EC Namely the inspected surface may comprise a source of radiation, which radiates in the wavelength band between #1 and/1,, or a absorber of radiation, which absorbs radiation in the wave length band between 4 and 8.

A determination if an absorber or a source of radiation is present in the inspected surface, is obtained by an additional comparison, which is carried out between the wavelength bands of EC and ED (Figs. 4A-4C). More particularly, the ratio of the voltage signals V2/V1 is compasred with the ratio of ED the energies , in the respective wave length bands.

ED + EC It is of course possible to obtain such determinations utilizing other methods for processing the data that comes out from the measured signals. The presence of ill cells, the stage of the illness, and different pathologic mutations, can be diagnosed via spectral analysis of the measured signals, upon determination of the wavelength bands in which excess, or less than the expected, energy is radiated energy.

Fig. 5 schematically illustrates a setup for the measurement of optical radiation emitted by an area of a live tissue, according to a preferred embodiment of the invention. The setup 200 consists of a first optical receiver 100 that is used for obtaining the parameters required for accurately calculating the temperature Ta and the Emissivaty Ea of the observed body subjacent to area Sa (as described hereinabove with respect to Figs. 2A, 3A and 3B) and a second optical receiver 100' (which can be identical to the first optical receiver 100, or any conventional optical receiver being capable of outputting an electric signal representing the optical energy received thereon) that operates in combination with an array of optical filters 203, which are used for obtaining the energy levels EA to ED (as described hereinabove with respect to Figs. 4A to 4C). The output port of the first optical receiver 100 is connected to a processor 201, which receives the electrical signal (voltage drop) that is proportional to the optical energy received on the active area Sb of optical receiver 100. A signal (pulsed) generator 202 is also connected to this output port, in order to apply a current pulse train for controlling the temperature on the active area Sb (as described hereinabove with respect to Figs. 3B), so as to obtain the parameters required for calculating Ta and £a.

The second optical receiver 100'is also connected to processor 201 (or to a different processor-not shown), which receives the electrical signal (voltage drop) that is proportional to the optical energy received on the active area Sb', and concurrently outputs an electric signal representing the optical energy received thereon, for each filter selected from array 203. The processor 201 calculates the energy levels EA to ED, and compares them with the expected (theoretical) values that correspond to each region (in Figs 4A to 4D), calculated after Ta and Ea have been calculated. Of course, it is possible to use separate optical receivers, each of which operates in combination with a single optical filter that corresponds to a specific region in Fig 4C.

Fig. 6 schematically illustrates deviations from the expected optical radiation values in the distribution of optical energy (or power), obtained from the setup of Fig. 5, according to a preferred embodiment of the invention. The expected power distribution for the calculated temperature TaO is illustrated by a dashed line. Therefore, the expected energy value EBO for the region defined by the wavelength range between and/ is calculated by integrating the expected power distribution (performed by processor 201) curve between points and ,,. As shown, the actual energy value EB for the region defined by the wavelength range between and , results from the measurement (performed by the setup of Fig. 5) for that range, and compared to the reference value EBO. In this example, EB < Eso. Therefore, is assumed that groups of cells being subjacent to area Sa act like absorbers of optical energy, which means that they are infected cells. The actual power distribution (processed and displayed by processor 201) for that region and for the calculated temperature TaO, is illustrated by a solid curve. This curve shows a local minimum, located at the region between #3 and . If the cells being subjacent to the inspected area Sa are healthy cells, the curve will be essentially similar to the expected curve for that region. The total energy for TaO (defined by the area below the solid curve, which is obtained by integrating the power distribution curve along the wavelength A) is constant for any change in the power distribution. Consequently, (in this example), the actual energy in the region defined by the wavelength range between and Ais higher than expected, i. e., Ec > Eco, which means that other groups of cells being subjacent to area Sa act like emitters of optical energy and may contain a malignant tumor. The relations between the actual and the expacted values of energy in each region, as well as changes in these relations may be used for obtaining inferences regarding the presence of unhaealthy cells within the body subjacent to area Sa.

Of course, more than three filters can be used in order to examine the optical energy distribution (or changes in that distribution) in each region in higher resolution, if required. The properties of these changes and their location within each region are used to obtain inferences regarding the medical and biological state of these groups of cells (e. g. , tumors, inflammatory cells, etc.), as well as the stage of infection.

The above examples and description have of course been provided only for the purpose of illustration, and are not intended to limit the invention in any way. As will be appreciated by the skilled person, the invention can be carried out in a great variety of ways, employing techniques different from those described above, all without exceeding the scope of the invention.