MXPA99006493A - Spatially resolved optical measurements - Google Patents

Abstract

Methods and apparatus are provided for determining a characteristic of a sample of a material by the interaction of electromagnetic radiation with the sample. The apparatus includes a source of electromagnetic radiation, an optical assembly and a detector. The optical assembly sequentially illuminates a plurality of volume elements in the sample with an intensity distribution in the sample that drops off substantially monotonically from a first region in a first optical path and collects electromagnetic radiation emanating from each of the volume elements. The optical assembly collects the electromagnetic radiation emanating from each of the volume elements with a collected distribution that drops off substantially monotonically from a second region in a second optical path. The first and second regions at least partially overlap in each of the volume elements. The detector detects the collected electromagnetic radiation emanating from each of the sequentially illuminated volume elements to produce responses representative of the characteristic in each of the volume elements.

Description

"OPTICAL MEASUREMENTS RESOLVED SPATIALLY" FIELD OF THE INVENTION The present invention provides apparatuses and methods for deriving spatially differentiated analytical information from an exposed surface, analyzing the results of the interaction of the electromagnetic relationship with elements of discrete volume of the sample. This is accomplished by spatially limiting the sounding beam to a small volume element and limiting the detected accepted response of the same volume element only, by scanning the sample at various depths along the axis of the optical array formed by the beam to determine the interaction of the volume elements at the different depths and collect this data from a plurality of points in a plane usually perpendicular to the sounding beam.

BACKGROUND OF THE INVENTION There is an important requirement for an instrument that will provide rapid and automatic diagnostic information, for example, of cancerous tissue and otherwise diseased tissue. In particular, there is a need for an instrument that could map the grade and stage of cancerous tissue without having to cut a large number of tissue samples for subsequent biopsies. In the current technique, the medical profession generally depends on visual analysis and biopsies to determine specific pathologies and abnormalities. Various forms of biochemical images are used as well. The singular optical responses of several pathologies are exploding in attempts to characterize also the biological tissue. These techniques of the previous branch, however, contain a serious inconvenience, as documented in the co-pending applications Serial Nos. 08 / 510,041 filed on August 1, 1995 and 08 / 510,043 filed on August 1, 1995, which are incorporated in the present by reference. For example, when carrying out a tissue biopsy and analyzing the tissue removed in the laboratory, it requires a large amount of time. In addition, tissue biopsies can only characterize the tissue based on the representative samples taken from the tissue. This results in a large number of resections that are carried out routinely to collect a selection of tissue capable of accurately representing the sample. In addition, tissue biopsies are subject to sampling and interpretation errors. Magnetic resonance imaging is a satisfactory tool, but it is expensive and has serious limitations to detect pathologies that are very dim in their early stages of development. One technique used in the medical field for tissue analysis is induced fluorescence. Laser-induced fluorescence uses a laser tuned to a specific wavelength to excite the tissue and cause the tissue to fluoresce in a set of secondary wavelengths that can then be analyzed to infer tissue characteristics. Fluorescence may originate from molecules found normally within the tissue or from molecules that have been introduced into the body to serve as marker molecules. Although the mechanisms involved in the fluorescence response in biological tissue to the excitation of ultraviolet radiation have not been clearly defined, the fluorescence signature of the neoplasm appears to reflect both biochemical and morphological changes. The changes observed in the spectra are similar for many cancers, which suggest that similar mechanisms are working. For example, useful auto-fluorescence spectral markers can - - reflect biochemical changes in mitochondria, e.g., in the relative concentration of nicotinamide adenine dinucleotide (NADH) and flavins. Mucosal thickening and changes in capillary profusion are structural effects that have been interpreted as causing some typical changes in the spectroscopic record. The main molecules in the biological tissue that contribute to fluorescence emission under the ultraviolet light situation of almost 337 nm, have been identified as tryptophan (emission of 390 nm), chromophores in elastin (410 nm) and collagen (300 nm), NADH (470 nm), flavins (520 nm) and melanin (540 nm). However, it should be noted that in the tissue, there is some peak displacement and changes in the total shape relative to the pure compounds. Accordingly, the sample can be illuminated with a sufficiently short wavelength of ultraviolet radiation and records the responses of the wavelengths of light listed above in order to determine the presence of each of the previously identified contributions to tissue types. It has further been shown that hemoglobin has an absorption peak of between 400 and 540 nm, while both oxyhemoglobin and hemoglobin have intense light absorption at more than 600 nm. The distribution - Blood can also influence the emission aspects observed from the corner, collagen, NAD and NADH. Additional compounds present in the tissue that can absorb the emitted light and change the shape of the emitted spectra include migglobin, porphyrins and dinucleotide co-enzymes. A general belief is that the neoplasm has high levels of NADH because its metabolic path is mainly anaerobic. The inability of the cells to raise their "NAD +: NADH" ratio during confluence is a characteristic of the transformed cells related to their control of defective growth.The NADH +: NADH ratio is an indicator of the metabolic capacity of the cell, For example, its capacity for glycolysis versus gluconeogenesis, superficial fluorescence has been used to measure the relative level of NADH in both in vitro and in vivo tissues, and the emission aspects obtained from the individual myocyte produce residual green fluorescence, probably originating from the mitochondrite flavine proteins, and the blue fluorescein is compatible with NADH of a mitochondrial origin.The collagen, NADH, and the flavin adenine dinucleotide are believed to be the main fluorophores in the colonic tissue and were used to spectrally decompose the fluorescence spectra.The residuals between the settings and the data resemble the spectrum s absorption of a mixture of oxy- and deoxy-hemoglobin; therefore, the residuals can be attributed to the presence of blood. Alfano, in U.S. Patent No. 4,930,516 discloses the use of luminescence to distinguish cancerous tissue from normal tissue when the shape of the visible luminescence spectra of normal and cancerous tissue are considerably different, and in particular, when the cancerous tissue exhibits a shift to blue with different intensity crests. For example, Alfano reveals that a distinction between known healthy tissue and suspect tissue can be made by comparing spectra of suspect tissue with healthy tissue. According to Alfano, tissue spectra can be generated by exciting the tissue with essentially monochromatic radiation and comparing the fluorescence induced by at least two wavelengths. Alfano, in US Patent Number 5,042,494, discloses a technique for distinguishing cancer from normal tissue by identifying how the shape of the visible luminescence spectra of normal and cancerous tissue are considerably different.

Alfano further discloses in US Patent Number 5,131,398 the use of luminescence to distinguish cancer from normal or benign tissue by using monochromatic or near monochromatic excitation wavelengths (a) less than 315 nm, and, in particular, between 260 and 315 nm, and, specifically, at 300 nm, and (b) comparing the resulting luminescence at two wavelengths of approximately 340 and 440 nm. Alfano, however, fails to disclose a method capable of distinguishing between normal, malignant, benign, tumorous, dysplastic, hyperplastic, inflamed or infected tissue. The failure to define these subtle distinctions in diagnosis makes the appropriate treatment choices almost impossible. Even though the simple relationship, difference and comparative analysis of Alfano and others has shown that they are useful tools in cancer research and provocative indicators of the current state of tissue, these have not yet allowed a method or provided means that are as sufficiently accurate and robust to make clinically acceptable for cancer diagnosis. It is quite evident from the foregoing that the current spectra obtained from biological tissues are extremely complex and, therefore, difficult to solve by normal peak matching programs, spectral convolutions or spectral comparison analysis. further, the spectral shift further complicates these attempts during the spectral analysis. Finally, laser fluorescence and other tissue optical responses typically fail to achieve deep resolution because either the optical or electronic instruments commonly used for these techniques involve integrating the signal emitted by the excited tissue across the entire volume of the illuminated tissue. Rosenthal, in the North American Patent Number 4,017,192 discloses a technique for the automatic detection of abnormalities including cancer, in multicellular bulk bio-medical specimens that overcome the problems associated with the complex spectral responses of biological tissues. Rosenthal discloses the determination of optical response data (transmission or reflection) of biological tissue through a large number of wavelengths for numerous samples and then the correlation of these optical responses to conventional clinical results to select the lengths Test wave and a series of constants to form a correlation equation. The correlation equation is then used together with the optical responses to the selected wavelengths that are taken in an uncharacterized tissue to predict the current state of that tissue.

However, to obtain good and solid correlations, Rosenthal cuts the tissues and essentially obtains a homogeneous sample in which the optical responses do not include the optical signatures of the underlying tissues. The Rosenthal methods, therefore, can not be used in in vivo applications as proposed in the present invention. In the studies carried out at the Ellman Laboratories of Photomedicine, using a single-fiber depth integration probe, Schomacker has shown that the auto-fluorescence of the human colon polyp signature in vivo is an indicator of normality , benign, pre-cancerous and malignant hyperplasia. See from Schomacker et al., Lasers Surgery and Medicine, 12, 63-78 (1992) and Gastroenterology 102, 1155-1160 (1992). Schomacker also discloses the use of multivariate linear regression analysis of the data to distinguish neoplastic from non-neoplastic polyps. However, using the Schomacker techniques, the observation of mucosal abnormalities was prevented by the submucosa signal, since the 87 percent fluorescence observed in normal colonic tissue can be attributed to submucosa collagen. Accordingly, there is a need for a more effective and accurate device in order to characterize the specimens and particularly, the in vivo specimens that will obtain the responses of the well-defined volume elements within the specimen, and automatically present data from a relatively large area comprising a plurality of volume elements. In addition, there is a need for methods in order to automatically interpret this data in terms of simple diagnostic information and volume elements. In the above-mentioned applications, serial numbers 08 / 510,041 and 08 / 510,043, Modell, DeBaryshe and Hed disclosed the general principles for obtaining valuable analytical data of a volume element in a target sample using spatial filters with dimensions that generally they are greater than the diffraction limits for the wavelengths of the sounding radiation. This spatial filtering is obtained by means of an optical device that includes an illumination and a detection system containing both field limiters and the field limiters being conjugated with respect to each other through the volume element to be analyzed, essentially providing a microprobe of non-image-forming volume. Even though the family of devices described in the aforementioned application are very useful in the analysis of a plurality of points within a - - sample of white, there is a need to easily and automatically obtain this data in a complete array of points in order to convert this data into an artificial image of the analytical discoveries through a large area of the sample. This is particularly important when examining heterogeneous samples such as biological samples with the non-image forming volume microprobe. For example, when examining tissues to determine the presence or absence of oncological pathologies or other pathologiesIn some cases, visual techniques are followed by resection of the biopsy specimen. These techniques are naturally limited since the doctor's eye can only evaluate the visual appearance of potential pathologies and the number of biopsies taken is necessarily very limited. The appearance of pathological tissues does not provide information on the depth of the pathologies and can not provide a positive diagnosis of the pathology. In addition, since the biopsies are carried out ex vivo, a time lag between the taking of the biopsy and the obtaining of its results can not be avoided. It would be very useful for physicians to have a device capable of carrying out these in vivo diagnostic tasks and obtain differential diagnoses (between healthy and pathological tissues) while the examination is being carried out. This - - It is particularly important when carrying out exploratory surgical procedures, but it can be very useful when examining also the most accessible tissues. A number of devices related particularly to confocal microscopy have been described in the prior art where lighting and detection arrangements are provided. For example, a confocal scanning microscope where mechanical scanning of transmitted (or reflected) light beams is avoided is described in U.S. Patent No. 5,065,008. A light shutter assembly is used to provide synchronous detection of a scanned light beam without the need to move a photodetector to track the scanning beam, and each of the shutters is serving, in essence, as a field limitation in the Confocal microscope In other embodiments, two overlapping sets of liquid crystals are used as optical shutter assemblies to try to effect the reduction in the size of the field constraints. It is well known in the technique of confocal microscopy, that in order to obtain the desired resolution provided by this technique, the dimensions of the field limitations need to be small in relation to the diffraction limit of the optical beam used in the system. Other embodiments also provide means for two sets of field limiters, conjugated within the sample, one set for the illumination beam and one set for the reflected transmitted beam. Although this patent discloses the use of electronic scanning of light and response beams, the intensity of illumination and the intensity of the response signal are drastically limited due to the use of double liquid crystal optical shutters required to achieve the effect of a confocal scanning microscope. Another confocal imaging device is disclosed in U.S. Patent No. 5,028,802 wherein a microlaser assembly provides a moving light spot source in a confocal configuration. Similarly, U.S. Patent No. 5,239,178 provides means for a lighting grid for essentially the same purpose, with the exception that the light emitting diodes are used for the light sources of the grid. These approaches, however, are limited to monochromatic illumination and are capable of being used only at relatively long wavelengths where solid-state laser diodes and therefore, micro-laser arrays or diode arrays in light emission become available.

None of these devices provides a set for volume non-image forming microprobes. Accordingly, there is a need for a device comprising a set of non-image forming volume microprobes wherein a plurality of volume elements in a sample can be quickly scanned in order to obtain diagnosis or analytical information through a relatively large area of the sample, without integrating the data of all the volume elements sampled.

COMPENDIUM OF THE INVENTION In the present invention, the principles disclosed in the aforementioned application are applied to automatically obtain optical responses from a three-dimensional set of these volume elements, providing a plurality of non-image-forming, non-image-forming microprobes that automatically displays the projection of the map information of the diagnostic information sought, in a plane generally parallel to the surface of the specimen (the xy plane) and in the z direction, which is usually perpendicular to the xy plane.

- - The optical responses of all the volume elements are further analyzed to visually provide (namely on a monitor) information that can not be easily obtained by direct examination of the specimen. This is achieved, in essence, providing an artificial three-dimensional biochemical map composed of the optical responses, or more accurately the derivatives of this response of each individual volume element examined in a set and also converting these biochemical data into an artificial pathological image that delineates the serious nature and depth of the observed pathologies. This is achieved by creating an artificial pathological scale for each pathology of interest, training the instrument to recognize specific pathologies. Specifically, a specimen training game in which optical responses were collected with a non-image-forming microprobe is subjected to a risky laboratory determination of the pathological status of each of its specimens and a value is assigned to each specimen. on the artificial pathological scale. A set of linear equations related to the answers (or functions of the answers) for each specimen towards pathological states, is constructed and solutions are searched for the optimum for the correlation coefficients. These - - Correlation coefficients are then used to transform the responses obtained into unknown specimens in order to obtain the pathological status of these unknown specimens. The objects of the present invention are achieved by providing an array of optical assemblies each consisting of two conjugate or partially conjugate optical assemblies. In each of these sets, the first optical assembly is designed to selectively image ones transmitted from a light source, or other radiation source, within a plurality of selected volume elements of a sample in a sequence manner. The second optical assembly is designed to collect light or radiation emanating from the volume elements in the same manner in sequence and transmit the collected light or radiation to a detector for further analysis of the interaction of the first transmitted beam with the elements of volume. The first optical assembly includes a first field limiter for achieving selective illumination of a selected volume element, and the second optical assembly includes a second field limiter for restricting the acceptance of radiation or light emanating from the collection optics, essentially, only from the selected volume element. In addition, a controller is provided to adjust the depth of the selected volume elements relative to the sample surface, by controlling the respective focus points of two optical assemblies while maintaining the same conjugates and having the volume element as a Common conjugation point for both optical sets. The sequential illumination of several volume elements in a set is desirable to ensure that only the responses of a given volume element are picked up by the optical set associated with the volume element at any given time. The sequential illumination of a plurality of volume elements can be carried out with a variety of devices. In some embodiments of the invention, a set of optical shutters is interposed between the light source and the sample, each shutter serving either as a field limiter or an aperture limiter for a specific optical assembly. In some embodiments, a single set of optical shutters is provided while in other embodiments two sets of optical shutters are provided. In still another embodiment of the invention, a set of micromirrors is used to control the illumination in sequence and the collection of the response of the different volume elements in the - - sample. In still another embodiment of the invention, a bundle arranged of optical fibers is used to sequentially illuminate a set of volume elements in the sample and to collect in sequence the responses of the volume elements. Appropriate movement of the optics is provided to probe various depths of the sample. The optical responses of the selected volume elements carry important information about the volume elements such as chemistry, morphology and in general, the physiological nature of the volume elements. When the sample is spectrally simple, these optical responses are analyzed by classical spectral techniques of peak matching, deconvolution or intensity termination at selected wavelengths. One of these systems would be the determination of the degree of homogeneity of a mixture or a solution of a plurality of compounds. However, when the samples are complex biological specimens, as mentioned above, the spectral complexity is often too great to obtain a meaningful diagnosis. When analyzing these biological specimens for subtle characteristics, we find surprisingly that the application of correlation transformations to spatially filtered optical responses obtained from a set of discrete volume elements, or the use of these transformations together with the data obtained through non-image forming microscopy, yields diagnostically significant results. Specifically, we first select a training sample of a specific target pathology. This sample of preference will have at least ten specimens. Optical responses are first collected from well-defined volume elements in the specimens and recorded. These optical samples can be taken with a microprobe array or with a single volume microprobe device, as described in the copending application mentioned above. The same volume elements that have been sampled with the non-imaging volume microprobe are cut and biopsies are performed (namely, the cytological analysis of the cut volume elements) in a classical pathological laboratory whose specimens are classified on a scale. arbitrary that is related to the degree of the pathology that is being characterized, C (for example, a specific cancer). These scores Cj, where Cj is the value of the score assigned to the specimen j within the training game, should be as accurate as possible and therefore, an average of a number of pathologist scores (which can be used) can be used. determine in the same elements of volume, j). We now create a game - - of equations Sa-¡_CF (I_j_j) = Cj, where i designates a relatively narrow spectral window (usually between 5 and 50 nM) and therefore F (Ij_j) is a function specific to the intensity of the response or other characteristics of the spectral response in the window i for the volume element j. The F function is sometimes the intensity of the same response in that window, namely, F (I-¡j) = I_j_j, or F (Ij_j) = (dlj_j) / d?) Ij_j, where? is the median wavelength in the window i, or other functions. The factors a_j_c, the coefficients of the correlation transform for pathology C, are now found in the set of equations created above by means well known in the prior art, such as multivariate linear regression analysis or univariate linear regression analysis . In this analysis, the number of windows and the wavelength required to obtain faithful correlations between the optical responses and the pathological derivations of the Cj values is minimized and the correlation coefficient set a -__, - is found. , for the pathology. When we now record the answers (I?]) (Which is a vector in the space of the optical windows i, now reduced to the minimum up to a limited number of discrete elements) in a sample outside the training game and we apply the operator of the transform (aj_c) into the vector FÍI-j ^), namely, we obtain the sum? aicF ^ ik) = ck 'we obtain - automatically the score for pathology C of white for the volume element sampled. It should be understood that other statistical tools could also be used, such as the regression analysis of principal components for the optical responses. One can consider the use in the correlation transformations, instead of the functions of the optical responses to specific wavelengths, the Fourier transform of the total spectral responses. In addition, even when the spectral responses of the specific volume elements are taken, these responses can be treated optically through either a spatial Fouries transform generator (such as a Sagnac interferometer) or a temporary Fourier transform generator (such as an interferometer). Michelson) and then, the data can be obtained to create the desired correlation matrices to train the system for data acquisition and additional image generation of the distribution of possible pathologies. The instruments encompassing the invention are considered useful for obtaining artificial images of some characteristics of the turbid materials, such as biological tissue, plastics, coatings and chemical reaction processes, and may offer specific benefits in the analysis of biological tissue, both in - - vitro as in vivo. To provide internal analysis, the invention is adapted to work with endoscopes, laparoscopes and existing arthroscopes.

DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic and generalized functional diagram of the main elements of the present invention. Figure 2 is a functional diagram of an embodiment of the invention with a set of light valves wherein each light valve acts as a steerable field limiter for the illumination and detection beams. Figure 3 illustrates an embodiment wherein a set of lenses of the same periodicity as the set of light valves acts as a target lens assembly for both light and detection beams. Figure 4 and Figure 4A illustrate embodiments of the invention wherein separate light and light detection valve assemblies create sets of aperture limiters each in conjunction with lens assemblies that serve as targets for illumination and detection optics . In Figure 4A, the detection lens assembly is replaced with a single lens.

- Figure 5 illustrates a embodiment of the invention in which a set of flat (deformable) micromirrors is used as the field limiters and the sequence selection of the micromirrors serves to illuminate in sequence the volume elements in a sample. Figures 6 and 6A show embodiments of the invention wherein a set of off-axis parabolic mirrors (deformable) serve to select the objects to sequentially apply the excitation beams to the different volume elements and collect the responses of the elements of volume. Figure 7 shows an embodiment of the invention in which the light-sealing assembly is replaced with a fiber switching device to illuminate in sequence (and obtain the responses of) a set of volume elements in a target sample. Figure 8 illustrates a modality that has two optical assemblies each coupled with their own bundles of fiber (excitations and detection) where the illumination in sequence of the fibers (and detection) is carried out to obtain the data of a set of volume elements. Figures 9 and 10 illustrate the embodiments of the invention wherein the light shutter assemblies are coupled with fiber optic bundles.

- - Figure 11 is a schematic representation of one of the embodiments of the invention, including a functional diagram of the control and data processing elements of the system. Figure 12 is a functional diagram illustrating the method for using volume probe assemblies of the invention, particularly in the diagnosis of different pathologies. Figures 13a and 13b are bottom and top views respectively of a partial segment of a PVDF based on an optical shutter arrangement. Figure 14 shows another embodiment of a PVDF based on the optical shutter assembly. Figure 15 is a top view of a microlaboured optical shutter arrangement. Figure 16 shows another embodiment of a microlaboured optical shutter arrangement.

DETAILED DESCRIPTION OF THE INVENTION In Figure 1 we show a generalized schematic volume probe array 10, whose function is to collect data from a plurality of points in a target sample. The system usually includes an appropriate light source 11 whose light output is - conditioning and can be multiplexed in block 12 to create a plurality of light sources that are to be transferred to a set 13 of light valves. These light valves can act as lighting field limiters and aperture field limiters and only one valve is open at a given time thereby providing the sequential illumination of the volume elements in the sample 19. The light that emanates from each light valve then is directed towards a reference volume element in the sample 19 with an appropriate lighting object 14. In some modalities, a single object lens is used, while in other modalities we incorporate an array of objective microlenses that have the same periodicity as that of the light valve assembly. The responses of each reference volume element in the form of light emanating from the volume elements is collected through an optical collection object (which in some embodiments may be the same as the illumination object and a set of microlenses), and through a set 16 of light valves (which can also be a set equal to that used for lighting). The responses are then directed to one or more detectors 17 to determine the optical and spectral characteristics.

- - It should be emphasized that both the lighting optics and the collection optics each contain a field limiter that has dimensions that are relatively large relative to the average wavelength of the illumination radiation and also these field limiters combine with the other through the volume element examined. As a result, a well-defined volume element is illuminated at one time and the optical response of the element collected through the field limiter and the collection optics is essentially limited to the responses emanating from the volume element. A controller 18 is provided to control the sequence of scanned volume elements (in the x, y plane, the plane of the sample) and to control the depth of the examined volume elements (in the z direction). In Figure 2, a single example of a microprobe system 20 of the array is shown. The system includes a light source 21. The light from the light source is condensed with a lens 22 towards a set of light shutters 24 through a beam splitter 25. In this embodiment, each element 28 in the light shutter arrangement is light serves as a field limiter that is being formed in an image through an objective lens 26 in a sample 27. The dimensions and shape of the shutters determines the morphology of the volume elements sampled in the manner discussed in detail in the Copending Applications Serial Numbers 08 / 510,041 and 08 / 510,043. In essence, the average dimension, d, of each obturator is selected to be larger than the wavelength divided by the numerical aperture NA of the objective or d »? / NA. Therefore, the image of the field limiter in the plane of the sample is larger than the solution limited by diffraction for the wavelength. As a result, a very large proportion of the light passes through a given field limiter and the image in the sample is formed by remaining within the well-defined volume element of the sample. Similarly, even when the total response to illumination is distributed across a very large spatial angle (essentially 4p steradians), only the responses emanating within the same volume element are formed in an image back towards the limiter of field and arrive at the detector 29, being reflected in the beam splitter 25 towards a connector lens 23 which concentrates the response towards the detector 29. This results from the fact that the respective field limiter of the lighting and detection systems conjugate one with respect to another through the white volume element. In the modality shown in Figure 2, both - Field limiters are encompassed within the same aperture (an optical shutter or a light valve 28 within the optical shutter assembly). In some embodiments, the beam splitter 25 can be a dichroic mirror, particularly when the light source is a short wavelength (UV) excitation light source and the responses are fluorescence responses. In other embodiments, the beam splitter 25 may be a silvered mirror means that separates the optical path of the sample responses from the optical path of the excitation beam, for example, when the excitation beam is provided with a light source of broad spectrum and the responses involve backscattering and reflections of the sample (and therefore, mostly the degree of absorption of the excitation beam in which the selected target volume element is examined). The set of light valves or optical shutters can be implemented in a number of different ways. Liquid crystal sandwiched between two groups of electrodes (deposited as in the prior art on transparent plastic glass sheets in the form of transparent electrodes made of Indium Tin Oxide (ITO) or Tin Oxide (TO)) can be used, usually adulterated with fluorine to provide a good - - air conductivity). PDLC films (liquid crystals dispersed in polymer) that could be easier to handle and have lower production costs can also be used. Another modality proposed when the required exploration is particularly rapid, is a set of ferroelectric elements each acting as a light valve. Yet another embodiment of the light valves may involve a set of bimorphs of PVDF (polyvinyl difluoride) each coated to be a reflector (or opaque on both sides) on the side facing the light source designed to disperse out of the path luminous in order to create a light valve. The typical dimensions of the light valve scale from as low as about 20 microns to as much as 1000 microns. The size is determined mainly by the application, the nature of the sample analyzed and the specific design of the microprobe of specific volume used. When the overall design of Figure 2 is used, with a single large objective lens serving as a common objective for all common limitations in the assembly, the space between the adjacent light valves is usually kept as small as possible for provide volume elements that are explored and separated as closely as possible. It should be understood, however, that in some modalities, the separation remains relatively large (as large as the field limitation itself) when it is more appropriate to an image of the pathology consisting of discrete and well-spaced points. During operation, the controller 18 keeps one of the light valves open and adjusts the position of the device to form an image of the field limiter as the desired volume element in the sample 27. Once the position has been optimized In general terms, the controller causes the specimen surface to be scanned in the xy direction (the plane of the specimen) by sequentially closing an open light valve and opening an adjacent light valve. The time interval of each light valve in the open position is an intense function from the intensity of the light source and the efficiency of collecting the responses from each volume element. In some modalities, this time interval may be shorter than 1 millisecond while in other modalities tens and hundreds of milliseconds are required. The controller 18 also controls the position of the volume elements within the sample and the z-direction, generally an axis perpendicular to the plane of the samples. This can be achieved in a number of ways. For example, the entire optical assembly can move back and forth in the z direction. In some embodiments, this movement of the image plane of the field limiters in the sample can be achieved by moving the objective alone or the set of light valves or both of these elements simultaneously. The specific design depends on the specific modality of the device. It should be appreciated that since the intensity of the illumination is higher within the volume element probed by the excitation beam (relative to the areas surrounding the volume element) and that the response detected by the sensor 29 is mainly the same Volume element (and contains little illumination emanating from the areas surrounding the volume element), that changing the position of the volume element within the sample in the z direction will provide responses with various depths of the sample. This, in essence, allows the in vivo analysis of tissues at various depths as long as the total absorption of the illumination beam by the tissue and the responses to the beam are not excessive. In Figure 3, a slightly different modality of a microprobe 30 of overall volume of the present invention is shown. The system includes a light source 31 with appropriate optics (not shown) for projecting a common field limiter 41 through a condenser lens 32 toward a steerable obturator assembly 34. Each element in the steerable obturator assembly can be considered an aperture limiter which serves to further limit the spatial distribution of the light incident on a sample 37. Instead of using a large singular objective (as used in the embodiment described in FIG. Figure 2) to form the image of the field limiter in each volume element in the sample 37, a lens array 36 is interposed between the obturator arrangement and the sample. The lens assembly 36 consists of a plurality of microlenses 42. The periodicity of the lens assembly is exactly the same as that of the shutter assembly and each lens 42 within the lens assembly 36 corresponds to a light valve 38 within the assembly 34 of the lens assembly. light shutter. In most embodiments, the light incident on the obturator assembly would collimate from the obturator assembly would be fixed in position with rotation to the lens assembly. The probed volume element would remain at the focus point of the objective lens within the microlens array, and the movement of the shutter combination and the lens assembly in the z direction can be used to - probing different layers within the sample, as explained above when describing a bulk volume microprobe of Figure 2. However, other arrangements can be conceived wherein the lens assembly and the shutter assembly are capable to move independently and the probing of the sample in the z direction is achieved by moving in the z-direction of the lens assembly alone. The light responses to the excitation radiation from the light source 31 from each of the volume elements sampled are collected through the same objective elements through which the illumination is effected. The light responses are separated from the illumination beam by the beam splitter 35. These responses are then formed in an image through the collection lens 33 towards a collection field limiter 43 which restricts the responses received by a sensor 39 to be essentially only from the volume element probed. During operation, the controller 18 opens a particular shutter and allows the illumination of a single volume element. Also, the same light shutter allows the optical responses to the excitation to be recorded by the detector 39. This is followed by the closing of the light valve and the opening of another light valve so that the volume elements - - discrete in sequence within the sample are scanned to obtain the optical responses of them, you can explore all the desired volume elements in the set in a x, y determined plane and then re-explore the set at a different depth (in the z-axis) in order to obtain the three-dimensional information in the target sample. It may also be selected that the set volume microprobe be operated in such a manner that for each pixel, the respective light valve 38 is kept open while the controller causes the shutter assembly together with the lens assembly to move in the z direction, thereby probing the same location volume elements x, and at various depths of the specimen. In yet another embodiment of the bulk volume microprobe, the illumination and detection optics are each provided with their own set of optical shutters. In Figure 4, this mode is shown schematically. Specifically, the set volume microprobe 50 includes a light source 51, a first field limiter 52, a collimation lens 53, a first shutter assembly 54, a first set 55 of the objective lens, a dividing means 56 of beam, and a second objective lens assembly 58, a second optical shutter assembly 59, a second collimation lens 60, a second field limiter 61, and a detector 62. The appropriate means for forming the same are not shown in Figure 4. the image of the light source 51 and the detector 62 to their respective field limiters 52 and 61. In operation, the light source 51 is imaged to the field limiter 52 having dimensions that are larger than the resolution limits of diffraction of excitation variation. The light emanating from the field limiter 52 collimates to an essentially parallel beam incident on the rear side of the obturator assembly 54. At any given time only one of the light valves in the shutter assembly light is opened and its corresponding light valve in the detector shutter assembly is opened. The sequential illumination of the set of the volume elements within the sample in a manner similar to that described above, coupled with the synchronous opening of the appropriate light valve in the detector assembly ensures that at any time determined only the responses of the polled volume element are detected. Similarly, scanning in the x direction is provided by controller 18 which sequentially opens and closes the light valves in two sets of shutters in synchronism. It should be - it is understood that in this embodiment, the two field limiters 52 and 61 are conjugated one with respect to the other through each of the volume elements 63 of the sample 57. In Figure 4A, an arrangement essentially identical to that one is shown. described in Figure 4, with the exception that the microlens 58 assembly is replaced with a single large lens 58 '. Equal elements in Figures 4 and 4A have the same reference numbers. Still another embodiment of the invention is illustrated in Figure 5 which shows a microprobe 70 of array volume. The system includes a light source 71 and a detector 72 having its optical axes orthogonal to one another and separated by a first beam splitter 73. The light emanating from the source condenses to a set of field limiters 74 with a condenser lens 75 and a second beam splitter 76. The set of field limiters 74 consists of any set of micromirrors 77 that can be tilted inwa and out of the plane generally parallel to the plane of the set. The light reflected from any of these mirrors even when in an inclined position, is reflected again through the second beam splitter 76 and is formed in an image towards a sample 79 with an objective lens - - 77. As shown in Figure 5, only one micromirror 78 in any given period of time is oriented to reflect light towards the sample. All the other micromirrors in the array are tilted so that the light that falls on them is reflected away from the sample. In Figure 5, rays 1 and 4 are limiting rays for the total field and rays 2 and 3 are limiting rays for a single micromirror. In the operation, the micromirrors 77 are brought in sequence to the non-inclined position by the controller 18, and as a result of this non-tilt in sequence of the micromirrors, a sequence of responses from the volume elements in the detector is recorded in the detector 72. sample 79. An artificial image of the response can then be recorded and presented. As in the above embodiments, probing the sample with the volume microprobe assembly in the z direction (depth) can be accomplished either by moving the objective lens 77 or the assembly 74 in the z direction. The control of the tilted mirror is carried out by the controller 18 and the tilting mechanism can be implemented in a number of ways well known in the prior art. For example, the mirrors can be microlaborized in silicon leaving a cantilevered section in the middle of the back of the mirrors. Two opposite electrodes cause the mirror to tilt around the cantilevered section due to the loading of one or the other of the electrodes with a load opposite to the load on the mirror itself. Another method for obtaining inclined mirrors is one known in the deformable mirror art, whereby each micromirror is mounted on a bipolar piezoelectric element. Yet another embodiment of the invention, a variation of the embodiments illustrated in Figure 5, is illustrated in Figure 6. A microprobe 80 of set volume includes a light source 81 from which the light is conditioned to pass through a first field limiter (not illustrated) and through a lens 82. The light is collimated towards the array of micromirrors 83. The myco-mirrors are incunable, as described above. However, each of the micromirrors is configured to be a segment outside the axis of a paraboloid of revolution that has its focus point following an arc of radius that is somewhat larger than the distance of the assembly from the sample. The geometry is such that when the mirrors are not inclined (parallel to the plane of the set), the axis of the paraboloid of revolution (of which the specific mirror is a segment outside the axis) remains perpendicular to the plane of the set.

In this way, a line between the focus point (of the revolution paraboloid) and the micromirror is at a predetermined angle with respect to the perpendicular of the array. The micromirrors can be tilted through that angle to place the focus point of the paraboloid towards the sample. In one embodiment of the invention, the micromirrors are placed in right rows 89 and alternate left rows 88 of the segments outside the axis of a paraboloid. The right mirrors can be called the excitation mirrors, and the left mirrors can be determined detection mirrors. The focus points of each segment of the right rows 89 when inclining at the aforementioned angle, remain within the sample in the volume element 85 and their axis of revolution of the respective paraboloid is parallel to the optical axis of the excitation beam while the inclination in an opposite direction (at the same angle) of each micromirror in an adjacent left row causes the focusing point of each microspore to move towards the same volume element (85) in sample 84, and its axis of rotation of the - respective paraboloid is parallel to the optical axis of the detector. In this manner, all the mirrors in the right rows 89 are used to excite the volume element 85 in the sample 84 and all the left rows 88 are used to collect the responses from the volume element 85. In the operation, only one pair of mirrors is tilted in any given period of time and the axes of all the mirrors are oriented down to the sample. As a result, an excitation from the light source 81 is formed in an image towards the volume element 85 or more accurately the field limiter is first formed in an image while the light striking all the other mirrors is dispersed away of the sample in all directions. Similarly, only the responses emanating from the volume element 85 are formed in an image again towards the second field limiter in front of the receiver. As a result, a very high degree of discrimination is obtained, since the intensity of the excitation beam decreases very rapidly outside the volume element 85, and the responses from the external volume element 85 are essentially blocked by the second field limiter. in front of the detector 87. The controller 18 controls the tilt sequence of each mirror pair to obtain a set of responses of different volume elements in the sample. The depth of the volume element in the sample is also controlled by the controller 18 by moving the total set 83 along the z axis toward or away from the sample 84.

A slightly modified embodiment of the volume probe assembly shown in Figure 6 is presented in Figure 6A. This mode allows the parabolic micro-mirror to be used off-axis both as an excitation mirror and as a detection mirror. The system is equivalent to that shown in Figure 6 and is described above with the exception that the micromirrors of the set 83 'of the volume probe set 80' are rotated 90 ° to the right or to the left . Therefore, in the non-rotated position, the axis of revolution (and therefore, the optical axis) of each mirror is 90 ° with respect to the optical axis of the excitation and detection optics. However, when a mirror 89 'is rotated 90 ° to the right, its axis of revolution is parallel to the axis of the excitation and the focus point of the parabolic micromirror off the axis is the volume element 85'. If an adjacent mirror 88 'is simultaneously rotated 90 ° to the left, then its axis of revolution is parallel to the detection optics and its focus point is on the volume element 85'. The 85"volume element is determined by overlapping the images of two field limitersThis is explained in detail in Copending Application Serial Number 08 / 510,041 and Serial Number 08 / 510,043. In this embodiment, as well as in that shown in Figure 6, the conjugation of excitation and detection optical field limiters is used to provide spatial discrimination of the excitation beam to the target volume element as well as the spatial discrimination of the detected responses that are essentially of each volume element. In operation, the controller 18 causes two adjacent micromirrors (89 'and 88') to be rotated simultaneously, as described above and thus provides excitation of essentially only the element 85 'of desired volume and responses which emanate essentially from the 85 'element of volume. An advantage of the embodiment shown in Figure 6A is that a higher resolution of the volume elements for the same micromirror density is feasible, since each mirror can be used to excite a volume element or to collect the responses from an element of adjacent volume. This differs from the embodiment shown in Figure 6, where all the left mirrors can be used only to collect responses from all the right mirrors that can be used only to excite the volume elements. In the embodiment of Figure 6, the inclination of the paraboloids off the axis of each segment remains in a plane perpendicular to the plane of the assembly, while in the embodiment of Figure 6A, the plane of rotation is parallel to the plane of the assembly. In Figure 7, another embodiment of the invention is still shown. A co-microprobe 90 includes an optical illumination assembly with a light source 91 and a first collimation lens 92, and an optical response collection assembly having a detector 93 and a second collimation lens 94. The respective optical axes of the The set of the light source and the detector assembly are at 90 ° with respect to each other. A beam splitter 95 is placed at the intersection of the excitation beam and detected in order to separate the detected signal from the excitation signal. A lens 96 is used to focus the excitation beam towards the optical fiber 102 which is interconnected with the fiber switching element 97. The fiber switching element 97 is terminated on the opposite side with a plurality of fibers 98 and the switching element is capable of optically and sequentially connecting (under the control of the controller 18) the fiber 102 proximate with any of the fibers 98 in the remote bundle. The ends of the individual fibers in the bunch are then placed in a set 99 (this set can be a linear set or a two-dimensional set). An objective lens 100 then forms the image of the respective ends of the fibers in the bundle of fibers towards the specimen. Each individual fiber end (within the fiber retainer) defines a field limiter that is formed in an image towards the sample. The field limiter serves as a field limiter for both the excitation beam and the responses detected from the sample. As described in more detail in copending application serial number 08 / 510,041 and serial number 08 / 510,043, this arrangement involves the conjugation of both the excitation optics and the optics detected through the volume elements where it is formed the image of the field limiter and thus provides the spatial discrimination of both the excitation beam and the responses to be essentially from each volume element associated with each fiber in the array. During the operation, the fiber switching element 97 directs the excitation beam in sequence through all the fibers in the bundle 98. As a result, a plurality of volume elements in the sample 101 (having a distribution corresponding to the bundle of fibers in bundle 98) are excited in sequence. The responses are collected through the same field limiter (the natural opening at each end of the fiber) and separated from the excitation beam by the beam splitter 95 to be detected at the detector 93. In this way the responses from a set of volume elements that can then be presented as an artificial image of the sample. This embodiment has the advantage that a higher excitation intensity is feasible since the light source is used in sequence by the different fibers in the bundle. In Figure 8, another embodiment of the volume microprobe set 110 is still shown. The device includes two optical assemblies, an excitation or source assembly 111 and a detector assembly 112. Each of the sets is interconnected with its own bunch 113 and 114 of individual fibers, respectively. The individual fibers are organized in a two row pattern 116 and 117, respectively in a fiber retainer 115. When a linear assembly is desired, the fibers are organized in two opposite rows, one row consists of the excitation fibers in the bunch 113 and the other row of detection fibers in the bundle 114. When a two-dimensional assembly is desired, the fibers are organized in alternative rows of excitation fibers and detection fibers in a small tilt of these rows, one relative to the other . The excitation optics 111 includes a light source 118 and focusing optics 119 that can focus the light source output of each fiber in the bunch 113, in sequence. A rotating mirror 120 is used to direct the light source towards the openings of the fibers in the bundle 113. It should be appreciated that the entrance opening of the excitation fibers can be terminated in an appropriate manner to improve collection of the fiber. light from the rotating mirror. This termination may include, but is not limited to increasing the fiber input end or the termination of each fiber, with a small composite parabolic concentrator as is well known in the prior art. During the operation, the controller 18 causes the incremental rotation of the mirror 120 to direct the excitation beam towards the fibers in the bundle 113, in sequence. This light then emanates through an excitation field limiter at a far end of the fiber, being essentially the field limiter the opening of each fiber. These field limiters are formed in an image to a sample 124 with objective microlenses at the end of each fiber. The distal ends of both excitation and detection fibers are terminated in microlenses to serve as targets. The excitation and detection fibers may be at a slight angle with respect to each other and the conjugation of their respective field limiters (fiber openings) defines the volume elements probed. The volume elements in the sample will be a mirror image of the arrangement of the fibers, namely a row or a set of dots depending on the organization of the fibers in the fiber retainer 115. The distance between the volume elements may be the same as that between the fibers in the fiber retainer or may differ from the intersection of the fibers in the fiber retainer and will depend on the amplification of the relay lens 125. In some embodiments, it may allow movement of the relay lens relative to the fiber retainer to provide amplification (or de-amplification). However, the size of each volume element will also be modified to some degree. This configuration allows sequential illumination of a set of volume elements in sample 124. An excited volume element will emit a response to the excitation beam. To ensure that the responses that essentially emanate only from the desired volume element are detected, the response is picked up with a dedicated fiber from the bundle 114. The optics are configured in such a way that the field limiters of the response figures (their aperture natural) each is conjugated to the respective field limiters of the associated excitation fiber. As a result of this conjugation (or more precisely, of the conjugation, since the excitation and detection field limiters are slightly separated), the excitation beam has its highest intensity within the sample within the conjugation zone (the element of shaded volume), and the intensity decreases very rapidly outside the volume element. Furthermore, the responses collected by each detection fiber essentially emanate only from the volume element, and any response collected from the adjacent tissues is very small in relation to the response obtained from the conjugation zone of the excitation and detection field limiters. . Since the excitation of the set of volume elements is carried out in sequence, the response will be transmitted through the bunch 114 of fibers in sequence towards the detection optic 112. In a preferred embodiment of the invention, the response optics include a receiver rotary mirror 123 which directs (in sequence and in synchronism with the excitation mirror 120) the responses through a focusing lens 122 to a detector 121. This ensures that the scattered responses (namely, the responses that emanate outside the conjugation zone and therefore, outside the target volume element) and are picked up by the adjacent fibers do not reach the detector. In this way, as above, a spatial discrimination is obtained and the sequence detection of the responses of the specific volume elements is achieved. • In this mode, the use of a beam splitter is avoided and only very simple optics are used at the far end of the device. This device is particularly aparopiado when a distance between the sample and the optics (source and detector) such as laparoscopic and endoscopic devices is required. This modality has the additional advantage that they are possible higher energies of excitation since the resources of the light source are not distributed simultaneously through the complete set as in some embodiments described above and in this respect is similar to the mode shown in Figure 7, which is described in the foregoing. In Figures 9 and 10, two are shown • additional embodiments of the invention that differ from each other only at the position in the system of steerable light shutters. In Figure 9, a set 130 of light microscope that includes a light source 131, a 'detector 132 and a bundle 133 of optical fiber are shown. The proximal end of the fiber optic bundle is interconnected with a steerable array of optical shutters 134. The optical shutters are low control of the controller 18. Each fiber in the bundle 113 is placed in a set arrangement corresponding to the set of the steerable light shutters. The light source 131 is coupled to the set of light shutters through a condenser lens 135 and a lens 136 coupling the shutter assembly. As a result, light from the light source is distributed through the set of light shutters and, when one of the shutters is in the open position, the light is transmitted to the specific fiber coupled with that specific obtruder. At the far end of the bundle of fibers, the device has objective optics 137 that essentially image each of the openings 138 of the fibers in a sample 139. The distal openings of the fibers are essentially acting as the field limiters. of excitation and detection for each one of the volume microsondens in the volume microsonde set 130 of this modality. The responses of the excitation signals emitted from the volume elements in the sample are collected by the fibers through the same objective optics and the same fibers through which the excitation was carried out. Since the field limiters of both the excitation and detection optics are conjugated within the volume element probed, the excitations and responses are limited to the individual volume elements probed by each fiber. In the operation, the set of light shutters is controlled by the controller 18 to sequentially open the light shutters in front of the fiber bundle in sequence such that only one fiber is energized for a given period of time. In this way, by means of the synchronous detection of response from the fibers that are coupled with an open obturator, a complete artificial image of the pathologies in the target sample can be constructed. As in some of the embodiments described above, the response is separated from the excitation by a beam splitter 140 positioned at 45 ° with respect to the optical axis of the excitation optics and the detection optics. In Figure 10, a microprobe set 150 of similar volume is presented. The essential difference is that a set 154 of shutters is placed at the distal end of the fiber bundle. This allows selecting a set of field limiters that is determined by each of the openings within the shutter assembly rather than through the individual openings of the optical fibers. In some embodiments of the volume microprobe assemblies described above, a plurality of detectors is used which corresponds to the adjacent complete regions of the set of shutters. Each detector accepts the responses from a subset of the light shutter assembly, and therefore, from the view. In these modalities, the collection of data is accelerated by the simultaneous opening of the light valve in each of the sub-assemblies in the light shutter assembly and detecting the response in their respective detectors. When this approach is used, care must be taken to ensure that the interferences (or noise) of the responses to the outside of each specific region are smaller than a pre-graduated value of the expected response, from the sample in each region. In the various embodiments described above, a set of light shutters is used to sequence the excitation of the set of volume elements in the sample as well as to collect responses from the volume elements. In some embodiments, each obturator serves as an excitation and detection field limiter, while in other embodiments other optical elements in the system perform the function of field limiter. These light shutters are well known in the prior art and have been used in a number of display devices whereby the opening and closing sequence of the - Optical shutter sets that are backlit, provide either a fixed or variable image in time. The actual embodiments of these obturators in the prior art can take many forms. The most widely used light shutter assembly is a set of liquid crystal elements that have two polarizer sheets in each of the front and back of the assembly. In each element in the set, a voltage can be applied. When the voltage is sufficiently high, the liquid crystal causes rotation of the plane of polarization of the light that passes through it. The two polarizers are oriented in such a way that light does not pass through an element when a voltage is not applied. Therefore, the polarizers are cross-polarized (their relative orientation is 90 °, therefore, the first polarizer removes all the polarized light in one direction, while the second polarizer blocks the light that passes through the then inactive liquid crystal element). When a sufficiently high voltage is applied, the polarization plane of the light passing through the liquid crystal cell is rotated so that the second polarizer is essentially transparent to the light passing through the crystal cell active liquid. The approach can be carried out as in the prior art, either as a row and columns so that only the sum of the voltages applied to both a row and a column is sufficient to cause the desired rotation of the polarized light. Since the dimensions of our light shutters are relatively large and the number of shutters small relative to the current practice in liquid crystal display, this approach is quite sufficient and crosstalk is minimal and insignificant in view of the intense spatial discrimination due to the conjugation of the excitation and detection field limiters. When very large assemblies are desired, approaches such as in the presentation of active matrix liquid crystals (namely, the activation of a pixel through the direct switching of a single transistor in each pixel) can be implemented. Likewise . In still another embodiment, the set of shutters consists of ferroelectric elements activated in a manner similar to the sets of liquid crystal light shutters. These plug assemblies are useful when a switching regime is desired namely the rate of opening and closing a particular light shutter in the assembly is, of course, faster.

In yet another embodiment, the light switching means is a polymer dispersed liquid crystal (PDLC). In these films, a droplet dispersion of liquid crystal is embedded in a polymer having a refractive index equal to the refractive index oriented in the liquid crystal dispersion field. When not applied to an electric field, the droplets can be randomly oriented and light scattered in all directions. Therefore the shutter can be considered as closed. When a sufficiently large electric field is applied to the PDLC element, the droplets of liquid crystal are oriented by themselves with the field and therefore in the direction of the field, the refractive index is essentially constant and the light passes through of it in an uninterrupted manner. In this way the shutter is open. In yet another embodiment, essentially electromechanical seals are used. These can be easily implemented with piezoelectric bimorphs, which, when activated, bend the light path outwards and, when they are inactive, adopt a straight geometry that blocks the transmission of light through a specific shutter. In Figure 13a, a top view of a set 310 of light shutters is shown. This set of - - shutters consists of two main elements, a passive base element wherein a set of perforations 311 and a set 320 of active flags 321 are provided. The passive base can be made of an appropriate metal plastic or a silicon. In the present embodiment, the perforations 311 are approximately 0.1 millimeter in diameter and are separated in a grid in which the interspace between the perforations is approximately 1.0 millimeter. It should be understood that other dimensions may be selected without departing from the teachings of the invention. The perforations, which are preferably slightly conical with their bases at the proximal end and their apices truncated at the distal end, serve as receptacles for optical fibers, each having an external diameter of 0.1 millimeter. In production, these fibers can first be inserted and fixed with cement in place and then the surface of the passive base with the fibers in place, optically polished to ensure that the fibers are flush with the surface distant from the base and have an acceptable optical finish. The surface can then be treated with an anti-reflective coating in order to minimize optical reflections from the far ends of the fibers and thereby improve both the lighting efficiency and the signal collection.

In the set 320 of the active flags 321 consists of two sheets of piezoelectric material, such as polyvinyl difluoride (PVDF) with metallization on both sides. The two sheets are first cemented together (for example with an acrylonitrile compound). Then the metallization is recorded leaving a pattern of rows of electrodes 323 interconnected with common conductors 322 (in rows) on the upper side of the pair of PVDF sheets as shown in Figure 13a. The electrodes 323 have the same geometry as the flags 321 or they may just be a little smaller than the flags. In Figure 13b, the bottom side of the sets 320 of display active flags 321. The metallization of the bottom side is recorded to provide the second electrodes 324 for each flag, which are interconnected with the conductors 325 in the columns. After both sides of the PVDF sheets in pairs have been treated to leave rows of electrodes on one side and columns of electrodes on the opposite side, the flags are formed, the electrodes being congruent on both sides (overlapping but being separated by two sheets of PVDF). The set of flags 321 is created by piercing or engraving horseshoe-like perforations 326 around each of the metallized pairs of opposing electrodes in the assembly. It should be apparent to a person skilled in the art that the first form of flags can be selected and then the excess metallization between the rows and columns of electrodes recorded. In operation, applying a voltage to a row of the upper elements 323 through the common conductor 322 causes the upper half (formed by the upper PVDF sheet) in the flags 321 in that row to be shorter than its state not energized respectively, while the application of a similar voltage (but of opposite polarity) in a column of lower electrodes 324 through the common conductor 325, causes the lower half (formed by the lower PVDF sheet) of the flags 321 in that column it enlarges in relation to its non-energized state. Assume that the appropriate voltages are applied to a specific row through conductor 328 and no other, and to a specific column through conductor 327 and in no other. Flag 329, which is the only flag during that moment that has both its upper and lower electrodes energized, has a voltage in its upper portion that causes its upper half to shorten and has a voltage in its lower portion that causes its lower half lengthen. As a result, the 329 banner bends upward and exposes the perforation below it, allowing the illumination to reach the sample and allowing the responses from the sample to reach the fiber optic opening and therefore be transmitted to the sensor. All other flags in the row energized by row driver 328 are voltage-free at their respective lower electrodes, and, likewise, all other flags energized by column conductor 327 that are voltage-free at their upper electrodes respective. In this way only the flag 329 energized simultaneously by the row driver 328 and the column conductor 327 is forced to bend upwards. Therefore, the flags 321 can be reacted in a set of PVDF optical shutters by applying an appropriate voltage or a determined column and by sequentially applying voltage pulses in the rows, a flag can be randomly activated by applying the appropriate voltages to its Coordinated row and column. In Figure 14, a variation of a set 330 of optical shutters based on PVDF is shown. The PVDF flags 332 are structured in a manner similar to the system shown in Figures 13a and 13b and described above. By way of Two sheets of PVDF are cemented side by side and the flags 332 are formed with electrodes on both sides connected to the upper side in the columns with the conductors 333 and connected to the lower side in the rows with the conductors 334. This assembly is superimposed on a plate having a set of perforations 331. The flags are oriented at 45 ° with respect to the main network to allow a greater movement of the flag. This is important when the fibers have very large numerical openings and the emulating beams of the fibers are dispersed at a high angle, and the collection angles of the responses from the sample are similarly large. The operation of this set follows the principles described above. In particular, the application of a driving voltage to a given column and to a given row causes the actuation of the flag in that column and row. These are just two examples of embodiments of a set of optical shutters where the actuation and the optical shutters are based on the movement induced by the piezoelectric bimorphs. In another arrangement, the bimorphs are placed in rows perpendicular to the base surface of the assembly, and each bimorph has a flag (parallel to the plane of the assembly, and therefore, perpendicular to the bimorph) that covers its respective perforation in the assembly. The operation of each bimorph causes a movement parallel to the surface of the assembly instead of above the surface. This embodiment is somewhat difficult to implement, but has the advantage that the smaller bending of the bimorph is required, particularly when the optical fibers used in the assembly have a large numerical aperture. In Figure 15, still another embodiment of a set of optical shutters is shown. In this embodiment, the set 340 is best produced by microlabeling techniques of silicon wafers. Even though a certain order of description of the different elements in the set is followed below, this order is not necessarily the order used in the microlabeling process. The perforations 341 through which the optical fibers are inserted are provided in one assembly. In this mode, these perforations are approximately 0.1 millimeter in diameter and are separated in a grid with a separation of 1.0 millimeter. Each perforation is associated with its own shutter 342. The obturator 342 consists of a thin flexible arm 343 anchored on one side in the base plate 344 through an axis 345. On the opposite side of the arm, a flag 346 is provided. The flag is large enough to cover its respective perforation 341 when the shutter is in the closed position.

Two series of posts 347 and 348 placed on opposite sides of the arm 343 are connected with the appropriate electrical conductors (not shown). Similarly, the sealing element is connected in its own electrical conductor (not shown). There are a large number of possible variations of this modality and a few of these variations are described here. In one embodiment, the total set of optical shutters is manufactured monolithically from a single wafer. In that case, the arm and the flag are machined to be in position 349"open". Otherwise, it is impractical to record the perforations. In other modalities, the set is produced from two pieces fixed with cement. One piece may contain the set of arms and the other piece may contain the set of perforations. Then it is preferred that the resting position of the arms be in the closed position. The groups of posts 347 and 348 can be left in any of the two wafers, but due to practical reasons it is preferred to produce them in the set of arms. It is also possible to provide a single well-positioned post for the group of posts 347 and a single well-positioned post for the group of posts 348. The selection of the specific design depends on the required dynamic response of the light shutters in the assembly.

- - The operation of the arm as a light shutter is based on the electrostatic attraction and repulsion generated by the loading and unloading of several members of the assembly. In operation, the arm may be charged, for example, in a negative manner and the distant posts 347 may be positively charged to cause the arm to be attracted to this set of posts. To accelerate this action, the neighboring posts 348 can be negatively charged to cause simultaneous repulsion in the arm. It should be understood that the actual contact of the movable arm with the group of posts 348 or 347 is not required. It is preferred to actually avoid this contact and in order to achieve this aim, the whole assembly can be treated to have a thin layer of silicon oxide as an insulation, thus avoiding this contact. To facilitate the drive of the set of shutters, it is preferred to apply the activation voltages in the rows and columns and only the simultaneous operation of a given column and a given row causes the opening of the shutter at the intersection of the row and selected columns. This can be achieved in a number of ways. Consider the case where the device is manufactured from two independent wafers so that the resting position of the arm can be in the closed state. Therefore, when - there are no charges on the arm, the optical shutter is closed. Referring again to Figure 15, an impulse is applied by loading all the arms in the first row negatively and through the pair of conductors in the first column, a positive charge is applied to the posts 347 and a negative charge is applied a. the posts 348. The negatively loaded arm in the first row and the first column is repelled from the negatively charged posts 348 and is attracted to the positively loaded posts 347, thus opening the optical shutter previously covered by the flag 346. The others arms in the first row are not affected since their respective posts 347 and 348 are not loaded. Similarly, all the arms in the first column are unloaded and therefore, despite the fact that the posts 347 and 348 are loaded, the arms do not move, thus leaving the optical shutters closed. When the entire assembly is scanned, all the arms 343 in a given row can be kept loaded and the posts in the adjacent columns can be loaded in sequence. The back of the arm in the closed position can be achieved either through the spring forces in the arm or by actively reversing the loads on the posts 347 and 348. The selection of the passive return or an active return to the closed position, is determined by the dynamics of the exploration process. When an extremely fast scan is desired, the reversal of charges on the poles is preferred, but when the dynamic response can be somewhat slower, mechanical relaxation to the resting position can be carried out. In Figure 16 another modality of the set of microlaboured optical shutters is shown. Here, as in Figure 15, the assembly can be produced monolithically or can be assembled from two substructures. In the base plate, a set of perforations 361 having a diameter of approximately 0.1 millimeter separated in a grid whose points have a separation of 1.0 millimeter is provided. The active elements comprise flat arms 362 fixed to the base plate with a post capable of twisting around which the arm can rotate. The distal end of the arm is wide enough to cover the perforations and thus block the optical path to the fibers that are mounted within the perforations. Although in Figure 16 the arms have their width gradually expanded to cover the perforation 361 as shown, it should be understood that a narrow arm 362 terminated by a wide flag may be provided at its distal end, sufficient to cover the perforation. The proximal end of the arm is terminated with a structure 364 generally perpendicular to the axis of the arm. Two posts 365 protrude from the base plate positioned somewhat apart from the structure 364. When the arm, for example, is negatively charged and the posts 365 are positively charged, the electrostatic attraction causes the arm to rotate and expose the piercing thereby opening the optical shutter, as shown at position 366. Here as before, the assembly can be operated by maintaining a given row (loading arms 362 in that row) negatively and scanning the column that positively charges all pairs of 365 posts to obtain the opening and closing in sequence of the set of optical shutters. As before, the elastic properties of the silicon can be relied upon to return the arm to its rest position (through the spring action torsion base 363) or the load on the pairs of posts can be reversed before switching the next column. A variety of light sources can be used in conjunction with the bulk volume microprobes of the present invention. For example, when the desired responses are fluorescence responses, a laser source such as a nitrogen laser having a wavelength in the ultraviolet part of the spectrum, such as 337 nanometers, is often used. When the desired response is counterdispersion as well as absorption over a wider part of the spectrum, the light source is usually a broad spectrum source such as, but not limited to a xenon discharge lamp, a halogen incandescent lamp or any another appropriate broad-spectrum light source. In addition, this light source can be conditioned with an appropriate filter to homogenize or otherwise modify the spectral distribution of the light. The use of more than one light source in a given system is also proposed. Therefore, a volume microprobe assembly can include a UV laser source to carry out the fluorescence measurements, as well as a broadband light source to carry out the scattering and absorption measurements. A third light source particularly rich in near-infrared radiation can also be included. In operation, these light sources can be directed towards the optical excitation assembly in a predetermined sequence. For example, a typical UV laser source would operate in a pulse mode having a pulse of relatively short duration (e.g., less than one microsecond) and a slow repeat rate. In this way, a lapse of time is available between the excitation of milliseconds or fractions thereof (often carried out to avoid overheating of the laser source) between the measurements of the fluorescence responses. During this elapsed time, a broad-band light source can be directed to the excitation optics and measurements can be detected in the response of the target sample to that second light source. In addition to obtain additional diagnostic and analytical information from the surveyed volume elements, the Raman scattering data that provides molecular structural information in the probed material can be obtained. The light source or the excitation beam can then be a laser within the visible range of the spectrum. When it is desired to reduce the fluorescence signal generated with the intense beam in the visible part of the spectrum (which masks the much weaker Raman scattering responses) a laser can be used in the far end part or the near infrared part of the spectrum . These light sources can be a HeNe laser at 633 nanometers or a GaAlAs diode or laser diode at 783 nanometers or even a Nd: YAG laser at 1064 nanometers as well as other near infrared diodes or laser diodes. In some embodiments of the invention, when multiple light sources are used, multiple detectors may also be used. Each one is designed to be carried to the optimum for the spectral response and the anticipated response intensity. In these cases, the synchronization of the excitation from the plurality of sources and the responses of its associated detectors is controlled by the controller 18. In Figure 11, a typical volume microprobe set 170 is shown with its associated electronic modules and their computer modules. The optical system similar to that shown in Figures 9 and 10 and described above, except that the beam splitter is placed at the far end of the optical fiber assembly, and instead of using a set of light shutters both for the excitation optics as for detection, a set of detectors is used for the spatial discrimination of the responses, instead of a set of light shutters. Specifically, the volume microprobe 170 includes a data processing unit 171 and system control of an optical system 172. The optical system includes at least one light source 173. Lenses 174 and 175 are interposed between the light source and a set 176 of light shutters in order to form the image of the light source towards the assembly. Interposed between the lens 174 and 175, a device 176 can be included to condition the spectral distribution of the light source. This device can be a filter that is designed to modify the normal spectral distribution of the light source which can include portions of the intensity spectrum that are greater than other parts, and thus normalize the spectral distribution of the excitation beam, the element 176 it may be a plurality of filters mounted on a rotary filter wheel in order to interpose different types of filters (or non-filters) in the trajectory of the excitation beam. A second device 177 is also interposed between the two lenses 174 and 175 and may be included to modulate the excitation beam in time and intensity. This project can be used to improve the signal-to-noise ratio of the detection system by synchronizing the modulation and detection through an appropriate blocked phase amplifier (not shown) that is part of the electronic system 171 (indicated as control arrows 191 and 193). Similarly, the synchronization of the light source 173, including the sequence of a plurality of light source or pulse rate and the pulse width of a UV laser source, is also under the control of the controller 201 as it is indicated by the control arrow 192. The array 176 of light shutters engages a bundle 178 of optical fibers such that each fiber within the bundle engages a particular light shutter in the assembly. The distal ends of the fibers within the bundle 178 are placed in the same configuration as the assembly as the proximal ends of maintaining the same geometry of the assembly. The opening of the individual optical fiber determines the field limiter of the excitation optics in this mode. The light shutters within the assembly 176 are under the control of the contractor 201 through the control line 200, and in operation, the controller sequentially opens the light shutters in order to provide a sequence excitation for all fibers in the assembly. The light emanating from the distant ends of the fibers in the bundle is formed in an image towards a sample 185 with objective optics 179. In the embodiment shown in Figure 11, a beam driver mirror 184 is provided, the function of which is to select within the sample, the desired area from which a set of volume elements will be analyzed. The inclination of the steering mirror 184 is controlled by a driving lever 187, which can be opened manually, or be placed under the control of the controller 201 through the control line 196.

The responses from the target set of the volume elements within the sample 185 are directed again by the mirror 184 towards the objective optic 179, and a beam splitter 180 is used to separate the excitation beam from the responses. Since the illumination of the volume elements within the target set is in sequence at any time, only the responses of a given volume element are received by the detector set. The detector assembly contains a set of detectors 183 and the respective openings of each detector element within the assembly also serve as field limiters of the detection optics. Since both the excitation optics and the field limiters of the detection optics are conjugated within the target volume element in the sample, we can ensure that the detection of responses emanating essentially only from each volume element are recorded. for each volume element in the sample. The detector assembly also contains additional traditional optical elements such as the spectral filter 181, whose function is to eliminate the responses of the unwanted parts of the spectrum. For example, when the excitation beam is a nitrogen laser and the desired responses with fluorescence emissions, the filter blocks - any of the reflections of the excitation beam and prevents its registration in response. A spectral analyzer 182 is also included to determine the spectral distribution of the responses. The detector assembly is under the control of the controller 201 through a control line 194 to ensure the synchronization of the excitation and the response detection from each volume element in the target sample. The detector assembly, or in some embodiments a specific element of the assembly such as a target lens, may be caused to move in a direction parallel to the optical axis of the assembly with a drive mechanism 186 under the control of the controller 201 (across the line of control 197), in order to adjust the position z, or depth, of the volume elements probed by the set microprobe system, in a similar manner to that previously described. The signals from the detector, representing the optical responses, are routed to a signal processing unit 202 which then transfers the data to an analog-to-digital converter 203 for additional data conditioning in a data preparation module 204. The answers that represent the data (and marked to ensure that the processor recognizes the data of several volume elements that is achieved with a - - control line 199 from controller 201) are then processed in a calibrator / scaler 205 to normalize the data. This is achieved by monitoring the output of the light source and re-normalizing the data for variations in the output of the source through the line 220. The control and data unit 171 contains a memory unit 210 in which the stored data are stored. calibration and scaling constants 208 as well as the correlation transform matrices 209, as will be described further below. The system data is converted into diagnostic information by a computer 211 and presented as either diagnostic values or artificial maps at a presentation station 212. The computer has memory (resident or removable) where the data can be stored and retrieved for future analysis offline. In general, the invention is intended to function, at least partially, to record and generally also collect and analyze the responses it collects. In some low cost embodiments of the present invention, only diagnostic prediction of the pathologies is provided. In this case, the system is equipped with a library of correlation transform vectors or matrices for specific diagnosis, and the system registers only the signal Ij_j (response intensities at a specific wavelength, i, for element j) of specific volume, and calculates the functions F (I_j_j) required to provide a diagnostic score Cj, for a set of the volume element j, as described further below. The output of the detector 183 is fed to a data processor 206 after preprocessing in the signal processor 202, the analog-to-digital converter 203 and the data preparation mod204. The data processor 206 may process the output of the detector 183 or may store the data in the memory unit 210 for processing for a later time. The computer 211 may also provide the capability to compare a first set of data obtained from the detector 183 with a second set of data obtained from the memory unit 210, or carry out comparative studies of several volume elements within a set of volume elements measured at any given time, thus providing spatial correlation of volume elements within a given sample. For example, the data processor 206 can calculate the correlations between a first set of data representative of the material being probed and a second set of data in the memory unit 210. In accordance with a preferred embodiment of this aspect of the invention , the second data set can be an optical response data library or a mathematical model abstracted from this library, as will be described below in the section called "Methodology and Operation". The memory unit 210 can be used to store the large body of data about specific materials. For example, the memory unit 210 may store data related to the characteristics of the light that has been made to interact with a specific type of biological tissue, or the memory unit 210 may store the data related to the characteristics of the emitted light, particularly of fluorescence, by specific types of biological tissues in response to excitation by each set of wavelengths of light, or can store these spectra classified by the depth of the tissue, or other complex multidimensional spectra derived from a previous set of observations. The memory unit 210 can also store specific characteristics that associate the light information obtained from a biological tissue sample with a specific diagnosis. For example, the ratio of light reflected at a wavelength to light reflected at the second reference wavelength may be associated with a growth of cancerous tissue as in certain known observations or may be associated with a clinically related condition such as thickening of a tissue layer, a precancerous metabolic change or a malignancy, based on the correlation with the spectral library and the previous clinical characterizations. Therefore the correlation with stored or annotated digitized spectra can provide a diagnostic judgment even without the identification of any of the specific individual spectral particularities such as maximum values or absorbance bands that have been required for diagnosis in the past. Although in the embodiments shown here for example in Figure 11, the detector 183 is shown to accept specimen responses after being processed through the spectral analyzer 182, it should be apparent that the spectral analyzer can be replaced by another temporal interferometer (such as an interferometer). Michelson) or a spatial interferometer (such as the Sagnac interferometer). The resulting interferogram can then provide the Fourier transform of the optical responses obtained from each volume element probed for subsequent data analysis as described elsewhere in this application.

Similarly, when Raman spectroscopy is carried out, particularly when an infrared source is selected for an excitation beam, where the intensity of the Raman scattering is greatly reduced, it can be imposed on the response path instead of an interferometer, a Hadamard coding mask consisting of a set of multiple slots in order to obtain through the Hadamard transform of the Raman spectral response data of the polled volume elements.

Methodology and Operation of the Volume Microscope Assembly In the prior art, the spectral and chemical analysis of complex and heterogeneous matrices with good localization of this analysis was prevented by the inability to feed the response obtained from these matrices of the regions with high degree of homogeneity. A large group of microprobes was therefore developed to handle this problem and of course electron microprobes and ion microprobes and several other devices capable of providing analytical information are of course both morphological and to some degree chemical, mostly elementary (about point by point or even through sections) such as in the - - ion microprobe (from a specimen). Unfortunately, these methods all require the placement of the sample in vacuum and the eventual description of the specimen and furthermore these methods do not lead to the analysis of organic materials. In vivo microprobe analysis of biological tissue has requirements that are somewhat different than those of classical microprobes. Particularly, it is not desirable to have a higher resolution than the typical dimensions of the differentiated tissues, but it is necessary to have analytical tools that can be operated by personnel without specific training in the analytical branch such as doct process control personnel and other professionals. The use of the present invention allows the micro-sampling of biological samples and tissues in vivo, and allows spatial delineation of the compositional, morphological and pathological particulars of these specimens. There are numerous approaches by which the data of this bulk volume microprobe can be used and without limiting the scope of the present invention we will describe here, some of these approaches. In one embodiment of the present invention, the responses of the set of volume elements that represent the interactions of the material within each of the volume elements with the radiation of ¡o - excitation, or at least contain specific signatures of these interactions, are presented in terms of received light intensities for various wavelengths, or as is known in the art, as a spectrum of the response. A researcher trained in the specific analytical branch can then use these spectra to derive important information about each of the elements of volume in the set of his knowledge of the excitation radiation and the modes of interactions of the radiation in his target material . A variety of analytical tools such as software programs designed to carry out the adjustment of the maximum spectral value or the spectral deconvolution can be used to further increase the researcher's basic understanding of these interactions and provide the researcher with information about the nature chemical, morphological and physiological of the white volume elements in the set, since the answers correspond to each one to a specific volume element in the set probed. This is in accordance with the basic principles known in the art with the exception that the data provided to the researcher is derived from a well-defined volume element and thus interference and weakening of responses due to parasitic responses and interferences that originate outside of il - the white volume elements no longer impede the researcher's ability to differentiate specific specificities within a largely heterogeneous sample. Therefore, the volume microprobe of the set of the present invention can be used to carry out classical spectroscopic analysis, fluorescence analysis, Raman scattering and other parametric or characterization analysis involving the measurement of the responses of each volume element in the set up to a localized radiation while limiting the observed responses towards essentially each of the volume elements the whole only during any given time. In another embodiment of the present invention, aimed at users who do not possess the technical skills to derive meaningful conclusions from the observed responses, the system is equipped with a library of correlation transforms dedicated to the special needs of the user, so that the The system is essentially pre-calibrated for specific analytical tasks. The method of calibrating the volume microprobe of the set is further detailed herein. To simplify the following description, suppose that the aim of the method is to calibrate a volume microprobe of the set for the diagnosis of the presence or lack thereof of tissues that are affected by a certain cancer and that are accessible for optical visualization, either in the outer skin, or in the neck, or in other cavities that are accessible through endoscopes or laparoscopes, such as various segments of the gastrointestinal tract (starting from the mouth through the esophagus and the stomach by rectal examination of the colon), or several organs in the peripheral cavities that are accessible through exploratory laparoscopy. In many of these situations, a doctor who is not a trained spectroscopist sees suspicious tissues and when discoloration or other morphological abnormalities are present, samples from these areas are cut and sent to a pathological laboratory for microscopic examination of the tissues in order to to determine the presence or lack of it as well as the possible stage of cancer. It would be extremely useful if, during the visual examination, a diagnostic score was available to determine the nature of the suspected pathology of the suspect target tissue, so that immediate action could be taken if necessary to avoid unnecessary tissue cutting for biopsies. When calibrated as described below, the microprobes of the set volume will provide an artificial image of the pathology and its extent without the need to examine all tissues under the microscope by another professional pathologist. Figure 12 is a diagram 300 showing the different steps carried out in the calibration and then the use of the volume microprobe 'of the set. In order to calibrate a microprobe 301 of bulk volume for a specific pathology, a specimen training set 302 is first selected for the specific pathology. The term training set will be used herein to represent a group of tissue specimens where an accurate cytological and pathological determination of the state of each specimen was performed in a pathological laboratory, represented by step 303. In addition, prior to performing the cut for these biopsies, each specimen in the training set was subjected in vivo to an exact study with the microprobe assembly 301 of the present invention. For the purpose of this description suppose that the target volume elements in the training set (those tissues that are subsequently subjected to a pathological laboratory determination of their respective pathological states) are cut with either a laser UV source or a source luminous white wide band. To ensure a good spatial correlation 1 - between the cut tissues and the volume elements examined, during calibration, the assembly is used with only one open shutter or a single-channel, non-single-channel imaging volume microprobe can be used. Let the intensities of the response to the ultraviolet and white light excitations of the volume element within the specimen j be Juj and Ij_ respectively, where uei are central wavelengths within the spectral bands of the spectral responses to the excitations of ultraviolet radiation and white light, respectively. This data is stored in the memory (for example the memory unit 210 in Figure 11) for future analysis and determination of the master calibration in step 304. The volume elements in the training game are cut after resgis.trar the response obtained with the non-image-forming volume microprobe, and pathological determinations of the status of each specimen are recorded in the form of Cj scores, where j is the identity of the specimen and Cj is a number that is selected in accordance with the specimen status on a monotonic score scale, for example, from 0 to 10, where zero represents normal tissues and 10 fully entrenched deep cancerous tissues. Since this training game will calibrate the volume microprobes not! - Imaging for future determinations of the presence or lack thereof of these pathologies, it is important that excessive care be taken to reach an objective determination of the pathological state of the training game. In these cases, the same samples are examined microscopically by a number of independent pathologists in a blind experiment, and only those specimens for which there is a minimum agreement between the different pathological results are included in the training game. Once the Cj scores of the specimen have been determined completely, and that the medical records, and the patients associated with the specimens (volume element) in the training game are recorded (more than one item of volume per patient can be included in the training game, however, it is better to include a variety of patients in a training game for a certain pathology) , the values of Ij_j and Juj stored previously in the memory unit 210 are used to establish a set of n correlation equations (n would be the number of volume elements in the training game): S a, - F (Ii +? Bu F (Ju-jí) + S cs G (Msj (1) The bandwidths around the wavelengths i and u of the responses to white light and ultraviolet light, respectively, usually they are between 5 and 50 nm, depending on the spectral resolution capable of being achieved or desirable in the spectrograph or monochromator detection system (element 182 in Figure 11) .The selection of F functions depends to some degree on the nature of the received responses When spectral responses are received almost without particularities (namely a spectral response that is relatively smooth and slowly changes with the wavelength) then the intensities or normalized intensities are often selected from the responses namely F ( I_j_j) = I_j_j or F) I -j_j) = Ij_j / K, respectively, where K is either the maximum response in the received spectrum or the response at a predetermined wavelength (in biological tissues frequently a response). a associated with the presence of water or hemoglobin). When the expected spectrum contains a number of special features, you can often use F (Ij_j) = (dlj_j / d?) Ij_j, where? It is the wavelength. Of course, it is better to use the same function F for the responses to both the excitation of ultraviolet radiation Juj and the excitation of white light I_j_j. 7 - Functions G (Msj) are included to allow for the impact on the observed responses of the patient-specific "medical history", and usually includes a parameter such as sex, age, race and the presence or absence of systematic palliative diseases such as hypertension, diabetes, etc. In many situations, part or all of the coefficient cs is zero, and these factors have no impact on the calibration, but in special cases these factors play an important role and are included here for purposes of completion. A computer is now used in step 304 to perform a regression analysis to minimize the number of iyu wavelengths (and s that are "artificial wavelengths" representing the medical history) used to obtain a valid correlation and to solve the set of equations reduced to the minimum (1) for the correlation constants a_j_, bu (and cs). This regression analysis is carried out using the experimentally obtained n equations, essentially using the correlation constants as unknown, for which a solution having the best relation is sought. Minimization is carried out to extract those wavelengths where the responses contain independent related information that correlates the I-¡j and Juj responses with the Cj scores. It should be noted that during the calibration process, a greater amount of data is collected than absolutely necessary, and many of these data are interrelated. To obtain a sufficiently good relationship, only the responses that are independent of one another are necessary and therefore the process of minimizing the spectral responses in equations (I) is carried out. This minimization also allows during the actual diagnostic use that the non-image forming volume microprobe that takes a minimum set of responses and will therefore speed up the procedure. The methods used to obtain the minimum set of wavelengths and the correlation coefficients associated with a and bu are well known in the prior art and include multivariate linear regression analysis and univariate linear regression analysis. Other statistical tools such as analysis of neural networks are also available and can be used for this purpose. In general, we can mention the values Ij_j and Juj as the responses of the volume element to the white light of UV excitation, respectively. As we have mentioned, other responses can be used to characterize a volume element in a sample. Therefore we denominate all the answers that are responses of the volume elements that correlate with the pathologies like the answers R_j. As mentioned above, we have found that it is sometimes advantageous to include as part of the responses R-i_j other information about a volume element (or the volume element host) that was not determined with the help of a non-image forming microprobe that still contributes to the improvement in correlation between the observed responses and the pathologies diagnosed. This information may include general classification of the subject where the volume element is, such as, but not limited to sex, age or race, other systematic pathologies and weight. This information when included in the regression improves the confidence level of the regression, which can include additional artificial Rj_j responses (instead of the G (Msj) functions). The index i therefore represents the type of response obtained, whether obtained with a non-image-forming microprobe (one more types of responses as well as the spectral band from which the response is recorded) or by other means. The set of equations (1) from which the correlation coefficients are derived in this way can be simplified to be:? Ai F { R j) = Cj (2) To simplify, the values ordered a_j_ can be called the correlation vector (a) for pathology C, and the ordered Rj_j responses can be referred to as the response vector (Rj) for the volume element j in the training game. The functional response vector (F (Rj)) is defined similarly to the ordered functions of the elements of the responses in the response vectors (Rj). Similarly, the ordered Cj scores can be termed the pathology score vector (C) for the training game. The process of calibrating the microprobe of the set for a given pathology C therefore consists of obtaining all the response vectors (Rj) and their corresponding pathology scoring vector (C) and from these data, after generating the response vector functional (F (Rj)), obtaining a minimum correlation vector (a), which is a non-image forming volume microprobe calibration vector. As can be seen, the calibration is identical to the calibration designed for the non-image-forming volume microprobe of the co-pending applications Serial Numbers 08 / 510,041 and 08/510043. Calibration for a number of different pathologies can be stored in a calibration library 305 for future use of unknown specimens. Each microprobe set includes a correlation engine 307 that takes calibration vectors from the calibration library 305 and response vectors obtained in the microprobe array and other sources such as medical records 308 and reconstructs a C value for the response vector of the observed pathology. Since in the various embodiments of the invention the different optical channels representing the excitation and the determined volume element responses are equivalent, a single calibration is sufficient (for a given pathology). When we now want to determine the nature and distribution of a pathology in a target specimen, which is outside the training set, or an unknown specimen 306, and to simplify we will name each volume element in the set k (x, y, z ), delineating its coordinates x, y and z. The response vectors (R ^ ix ^ y, z)) are recorded by the instrument in the volume element k (x, y, z) and to the extent that some of the responses Rj ^ are artificial responses (such as sex or race as mentioned above) these are admitted into the correlation engine part of the microprobe set and the scoring for the pathology is predicted for the volume element (X and Z). C r. { x, y, z), is predicted by obtaining the product of the correlation vector (a) found above with the functional response vector (F (R ^ (x, y, z))), namely: ck (x, y , z) =? ai FÍR-L ^ (x, y, z)). Therefore the use of the calibrated microprobe set in a set of elements of volume k (x, y, z), whose pathological state C] (x, y, z) is unknown, allows the immediate and automatic diagnosis of the pathology in the volume element k (x, y, z). This procedure is repeated for all the volume elements in the set and the set of values C]? _. { x, y, z) for all the volume elements in the set can now be presented in a presentation device 309, either as numerical values or as artificial images of the examined set. The normal methods of handling and manipulation of three-dimensional images can now provide the doctor with a discernment as to the nature, degree, seriousness and depth of penetration of the suspected pathologies. This reduces the number of unnecessary biopsies required and provides the physician with immediate information on which to act during the examination. It will be appreciated that the functions F (R- ^ (x, y, z) can be derived from the Fourier Transforms obtained from the response with either a temporary interferometer such as a Michelson interferometer or a spatial interferometer such as a Seagnac interferometer. It is impossible to use the same interferograms instead of the Fourier transform generated by them.Also when polling for molecular structural information in the probed elements, it is used for the function F (Rj] c (x, y, z), values at various wavelengths obtained from the Hadamard transform of the Raman spectral response It should be appreciated by those skilled in the art that, as in our copending applications, the microprobe arrays of the invention can be calibrated to diagnose a plurality of pathologies Pm, where m represents a specific pathology.When used in this way, the task of calibrating the instrument for this plurality of patolo The first step is to obtain for a training game j, the answers Rj_j and the pathological Pmj scores where _i is the bandwidth of the response or the type of artificial response, j is the volume element or the specimen in the training game and P is the score for pathology n in specimen j. During calibration, we obtain a number of correlation vectors (am), each for the specific m pathology. In operation of the non-calibrated image-forming volume microprobe, the aforementioned correlation vector (a) is now replaced by a correlation matrix. { to} whose elements are a___m, the vector of - - functional response (F (R)?)) for a specimen, k, uncharacterized which it replaces with the matrix. { F (R.}. R)} whose elements are (Rj_m)?) and the results of the diagnosis are provided as a vector (P)] whose elements are P ^ obtaining the product of the correlation matrix. { to} with the functional response matrix. { FÍRj} . It should also be noted that in the practical mode of this method of analysis, the correlation created will use the same answers (if not all of them at least some of them) for different pathologies. Therefore, only one response vector (R_) is required (which has the elements i k) i (3 includes the minimum response set of the volume element k to obtain diagnostic scores P ^. The matrix { A.} can also be called the correlation transform matrix, since it transforms a set of measurable (or observable) values, into another set of numbers or values, which are the desired pathological scores.This is achieved by multiplying the correlation transform matrix, { a.}., with the vector (F (RX)), the functional response vector to obtain a transformation of the response vector (R)) to the diagnostic scoring vector (P)] - The correlation transform method exploited here of predicting the analytical diagnostic information of an unknown specimen by correlating the responses of a training set for independent determination of the data Diagnostic or analytical in-game training has been shown by Rosenthal to work well on artificially homogenized samples that are large enough to provide a set of responses that possess a large signal-to-noise ratio. It is surprising that the expanded method of the present invention yields good correlation in minute volume elements in vivo. In classical spectroscopy, for example, as practiced by Alfano, the spectra or optical responses of diseased tissues are compared with spectra or similar responses of healthy tissues to attempt a diagnostic reading on the target tissue. This method stops working due to the large variations found between patients and the nature of the tissue examined. When our correlation transform approach is used, we purposely avoid the use of comparison of spectral responses in a target tissue to the response of any existing tissue (healthy or pathological), since no specific tissue can represent all the variations found between the patients. These variations from patient to patient cause spectral distortions that invariably avoid the ability of the prior art to obtain a robust diagnostic determination of the pathologies. In addition, our inclusion of non-optical responses along with the optical responses as part of the correlation transform algorithm essentially builds a completely artificial model (based on the training game) of the pathology that in itself never reproduces any patient or tissue. Finally, this novel approach, coupled with the spatial filtering of the optical responses to a small volume element, thus avoiding the integration of the response through heterogeneous tissues, makes it possible to obtain valuable artificial pathological images that have not yet been feasible. Although the invention has been shown and described with reference to the preferred specific embodiments, those skilled in the art will understand that variations in shape and detail can be made without departing from the spirit and scope of the invention.

Claims (76)

CLAIMS:

1. The apparatus for determining a characteristic of a material sample by the interaction of electromagnetic radiation with the sample, comprising: a source of electromagnetic radiation; illumination optics for sequentially illuminating a plurality of volume elements in the sample with an intensity distribution in the sample that decreases considerably monotonically from a first region in a first optical path; collect the optics to collect the electromagnetic radiation that emanates from each of the volume elements, and pick up the optics that collects the electromagnetic radiation that emanates from each of the volume elements with a collection distribution that decreases considerably monotonically from a second region in a second optical path, the first and second regions overlap at least partially in each of the volume elements, the lighting and collection optics each having respective field limitations whose dimensions are large compared to a ratio of the wavelength of the electromagnetic radiation divided by a numerical working aperture of the lighting and collection optics respectively which is measured from the respective field limiters; and a detector for detecting the collected electromagnetic radiation emanating from each of the volume elements illuminated in sequence to produce a representative response of the characteristic in each of the volume elements.

2. The apparatus according to claim 1, wherein the volume elements comprise a three-dimensional assembly.

The apparatus according to claim 1, wherein the field limiters of the lighting optics comprise a set of individually controllable optical light shutters for sequential illumination of the volume elements.

The apparatus according to claim 3, wherein the field limiters of the collection optics comprise a set of individually controllable optical collection seals for sequentially collecting the electromagnetic radiation emanating from each of the volume elements.

The apparatus according to claim 1, wherein the lighting optics comprises a set of individually controllable lighting elements for sequential illumination of the volume elements and the collection optics comprises a set of individually controllable collection elements for controlling in sequence the electromagnetic radiation emanating from each of the volume elements.

6. The apparatus for determining a characteristic of a sample of the material by the interaction of the electromagnetic radiation with the sample comprising: a source of electromagnetic radiation; an optical assembly for sequential illumination of the plurality of volume elements in the sample with a distribution of intensity in the sample that decreases considerably monotonically from a first region in a first optical path and to collect the electromagnetic radiation emanating from each one of the volume elements, the optical assembly that collects the electromagnetic radiation emanates from each of the volume elements with a collection distribution that decreases considerably monotonically from a second region in a second optical path, the first and second regions by at least partially overlap in each of the volume elements, the optical assembly comprises at least one set of field limiters whose dimensions are large compared to a wavelength ratio of the electromagnetic radiation divided by a numerical aperture of optical assembly work measured from the field limiters; and a detector for detecting the collected electromagnetic radiation emanating from each of the volume elements illuminated in sequence to produce representative responses of the characteristic in each of the volume elements.

7. The apparatus according to claim 6, wherein the set of field limiters comprises a single set of individually controllable optical shutters to sequentially illuminate the volume elements and to collect in sequence the electromagnetic relationship emanating from each of the volume elements, wherein the first and Second optical trajectories are the same.

The apparatus according to claim 7, wherein the set of optical shutters comprises a set of individually controllable liquid crystal shutter elements.

9. The apparatus according to claim 7, wherein the set of optical shutters comprises a set of liquid crystal shutter elements dispersed in individually controllable polymer.

10. The apparatus according to claim 7, wherein the set of optical shutters comprises a set of individually controllable ferroelectric shutter elements.

The apparatus according to claim 7, wherein the set of optical shutters comprises a set of individually controllable piezoelectric bimorph sealing elements.

The apparatus according to claim 7, wherein the set of optical shutters comprises a microlaboured machine assembly of individually controllable electrostatically moveable sealing elements.

The apparatus according to claim 6, further including means for moving at least a portion of the optical assembly with respect to the sample in order to vary the locations of the volume elements within the sample along the length of the sample. optical axis of the first and second optical trajectories.

The apparatus according to claim 7, wherein the optical assembly further includes an optical target between the set of optical shutters and the sample.

The apparatus according to claim 14, wherein the optical target comprises a single objective lens aligned with the set of optical shutters.

16. The apparatus according to claim 14, wherein the optical target comprises a set of microlens elements respectively aligned with the optical shutters.

The apparatus according to claim 7, wherein the set of optical shutters is subdivided into non-interference zone assemblies of electromagnetic radiation that are simultaneously collected from the non-interference zone assemblies.

18. The apparatus according to claim 7, wherein the set of optical shutters comprises a plurality of rows and columns of sealing elements.

19. The apparatus according to claim 7, wherein the set of optical shutters comprises a set of radially distributed sealing elements.

The apparatus according to claim 7, wherein the set of optical shutters comprises a linear array of sealing elements.

21. The apparatus according to claim 7, wherein the set of optical shutters comprises a circumferential set of sealing elements.

22. The apparatus according to claim 6, wherein the set of field limiters comprises a set of individually movable micromirrors each of the micromirrors being movable between an active position to direct the illumination from the source to the sample and to direct the electromagnetic radiation collected from the sample to the detector, and an inactive position.

23. The apparatus according to claim 6, wherein the set of field limiters comprises a set of individually movable micromirrors, each of the micromirrors comprises a segment outside the axis of a paraboloid of revolution, the micromirrors being movable in pairs between active positions and inactive positions, a micromirror of an active pair directing the illumination from the source to the sample and the other micromircle of the active pair directing the electromagnetic radiation emanating from the detector sample.

24. The apparatus according to claim 23, wherein the micromirrors of the first group of micromirrors direct in sequence the illumination from the source to the sample and the micromirrors of the second group of the micromirrors direct in sequence the electromagnetic radiation collected from the sample. detector

25. The apparatus according to claim 23, wherein each of the micromirrors is movable between a lighting position to direct the illumination from the source to the sample and a collection position to direct the electromagnetic radiation collected from the sample of the detector where each of the mirrors is used for lighting and collection for different periods of time.

26. The apparatus according to claim 6, wherein the optical assembly comprises a bundle of optical fibers and a fiber optic switching device for sequentially activating each of the optical fibers to direct illumination from the source to the sample and to digest the electromagnetic radiation collected from the sample to the detector.

27. The apparatus according to claim 6, wherein the optical assembly comprises a bundle of optical fibers and a set of optical shutters placed at one end of the bundle of the optical fibers in such a way that the optical shutters are respectively aligned with the optical fibers. optical fibers, the set of optical shutters illuminates in sequence the volume elements and collects in sequence the electromagnetic radiation emanating from each of the volume elements.

28. The apparatus according to claim 6, wherein the detector comprises a single optical detector for detecting the electromagnetic radiation collected from each of the volume elements.

29. The apparatus according to claim 7, wherein the detector comprises a plurality of detector elements corresponding to the optical shutters or to the groups of optical shutters.

30. The apparatus according to claim 6, wherein the source comprises a laser source.

31. The apparatus according to claim 6, wherein the source comprises a nitrogen laser.

32. The apparatus according to claim 6, wherein the source comprises a broad spectral band light source.

33. The apparatus according to claim 32, wherein the source comprises a xenon discharge lamp.

34. The apparatus according to claim 32, wherein the source comprises a halogen incandescent lamp.

35. The apparatus according to claim 6, wherein the source comprises a source of ultraviolet wavelength.

36. The apparatus according to claim 6, wherein the optical assembly includes an optical filter to moderate the spectrum of illumination.

37. The apparatus according to claim 6, wherein the source comprises a plurality of lighting sources and means for activating the light source for different periods of time.

38. The apparatus according to claim 6, wherein the optical assembly further includes means for modulating the illumination of the sample.

39. The apparatus according to claim 6, wherein the response comprises natural fluorescence of the tissue after illumination by a limited wavelength excitation.

40. The apparatus according to claim 6, wherein the response is produced by a dye selectively absorbed in the pathological tissue.

41. The apparatus according to claim 6, wherein the response comprises Raman diffusion.

42. The apparatus according to claim 6, wherein the response is a combination of backscattering and reflection of the volume elements.

43. The apparatus according to claim 6, wherein at least one set of field limiters comprises a set of individually controllable optical light shutters for sequential illumination of the volume elements if a set of optical shutters is collected individually controllable. to collect in sequence the electromagnetic radiation emanating from each of the volume elements, and wherein the optical assembly further comprises illuminating the light conditioning optics to direct the illumination from the source to the set of optical illumination shutters, a target of illumination to focus the illumination on the volume elements, a collection objective to focus the optical collection shutters on the volume elements and the collection of the light conditioning optics to direct the electromagnetic radiation collected from the set of optical shutters of collection towards the detector.

44. The apparatus according to claim 6, wherein at least one set of field limiters comprises a set of individually controllable optical light shutters for sequentially illuminating the plurality of volume elements and a set of individually controllable optical collection shutters. to collect in sequence the electromagnetic radiation emanating from each of the volume elements.

45. The apparatus according to claim 44, wherein the set of optical lighting shutters and the collection of optical shutter assembly each comprise a set of individually controllable liquid crystal shutter elements.

46. The apparatus according to claim 44, wherein the set of optical illumination shutters and the collection of optical collection shutters each comprise a set of liquid crystal shutter elements individually dispersible in polymer.

47. The apparatus according to claim 44, wherein the set of optical illumination shutters and the set of optical shutters - of collection each comprises a set of individually controllable ferroelectric shutter elements.

48. The apparatus according to claim 44, wherein the set of optical illumination shutters and the set of optical collection shutters each comprise a set of individually controllable piezoelectric bimorph sealing elements.

49. The apparatus according to claim 44 wherein the set of optical illumination shutters and the collection of optical shutter assemblies each comprise a microlaboured machine assembly of electrostatically movable sealing elements individually controllable.

50. The apparatus according to claim 44, wherein the optical assembly further includes a single objective lens of illumination between the set of optical illumination shutters and the sample, and in single objective lens collection between the sample and the set of optical collection shutters.

51. The apparatus according to claim 44, wherein the optical assembly further includes a set of microlens elements illumination objectives respectively aligned with the shutters - - optical elements of the set of optical illumination shutters and placed between the set of optical illumination shutters and the sample, and a set of objective microlenses of collection aligned respectively with the optical obturators of the set of optical collection shutters and placed between the sample and the set of optical shutter collection.

52. The apparatus according to claim 44, wherein the set of optical illumination shutters and the set of optical collection shutters are subdivided into non-interference zone assemblies and the electromagnetic radiation is simultaneously collected from the zone set assemblies. no interference

53. The apparatus according to claim 44 wherein the optical illumination obturators and the collection optical collection assembly each comprise a plurality of rows and columns of sealing elements.

54. The apparatus according to claim 44, wherein the set of optical illumination shutters and the set of optical collection shutters each comprise a set of radially distributed sealing elements.

55. The apparatus according to claim 44, wherein the set of optical illumination shutters and the set of optical collection shutters each comprise a linear array of sealing elements.

56. The apparatus according to claim v 44, wherein the set of optical illumination shutters and the set of optical collection shutters each comprise a circumferential set of sealing elements.

57. The apparatus according to claim 6, wherein the optical assembly comprises illumination optics to sequentially illuminate the plurality of volume elements and collect optics to collect the electromagnetic radiation emanating from each of the volume elements, the Lighting optics comprises a bunch of illumination of optical fibers and a lighting control means for sequentially activating each of the optical fibers to direct illumination from the source to the sample, the collection optics comprises a bunch of fiber collection optics and a collection control means for sequentially activating each of the optical fibers in the collection bundle to direct the electromagnetic radiation collected from the sample to the detector.

58. The apparatus according to claim 57 wherein the lighting control means comprises a first rotary mirror for sequentially directing illumination to the optical fibers of the lighting bundle and wherein the harvest control means comprises a second rotary mirror for direct in sequence the electromagnetic radiation collected from the optical fibers of the collection bunch to the detector.

59. The apparatus according to claim 57, wherein the lighting control means comprises a set of individually controllable light optical shutters aligned respectively with the optical fibers of the lighting bundle wherein the collection control means comprises a set of individually controllable optical collection shutters aligned respectively with the optical fibers of the collection bunch.

60. The apparatus according to claim 6, further comprising a spectral analyzer positioned between the optical assembly and the detector.

61. The apparatus according to claim 6 further comprising a temporary interferometer positioned between the optical assembly and the detector.

62. The apparatus according to claim 6, further comprising a spatial interferometer placed between the optical assembly and the detector.

63. The apparatus according to claim 6, further comprising a Hadamard coding mask placed between the optical assembly and the detector.

64. A method for determining a characteristic of a sample of material by the interaction of electromagnetic radiation with the sample, comprising the steps of: illuminating in sequence as an optical assembly, a plurality of volume elements in the sample directing the electromagnetic radiation towards the sample with a distribution of intensity in the sample that decreases considerably monotonically from a first region in a first optical path; collecting in sequence with the optical assembly, the electromagnetic radiation emanating from each of the volume elements illuminated in sequence with a collection distribution that decreases considerably monotonically from a second region in a second optical path, the first and second regions they overlap at least partially in each of the volume elements, the optical assembly comprises at least one set of field limiters whose dimensions are large compared to a ratio of the wavelength of the electromagnetic radiation divided by an aperture. number of the optical set that is measured from the field limiters; and detecting the collected electromagnetic radiation emanating from the first volume elements illuminated in sequence to produce a representative response of the characteristic in each of the volume elements.

65. A method according to claim 64, wherein at least one set of field limiters comprises a single set of individually controllable optical shutters.

66. A method according to claim 64 wherein the method further includes the step of moving at least a portion of the optical assembly with respect to the sample in order to vary the locations of the volume elements within the sample, to along the optical axis of the first and second optical paths.

67. A method according to claim 64, wherein the step of illuminating a plurality of volume elements includes simultaneously illuminating two or more volume elements of non-interference and wherein the step of collecting the radiation - Electromagnetic includes simultaneously collecting the electromagnetic radiation emanating from the non-interference volume elements.

68. A method according to claim 64, wherein the set of field limiters comprises a set of individually movable micromirrors, the method further comprising sequentially moving the micromirrors of the set between an active position to direct the illumination towards the sample and to direct the electromagnetic radiation collected from the sample to a detector and an inactive position.

69. A method according to claim 64 wherein the set of field limiters comprises a set of individually movable micromirrors, each of the micromirrors comprises a segment outside the axis of a paraboloid of revolution, the method further comprising movable pairs of the micromirrors between active positions and inactive positions, a micromirror of an active pair directs the illumination to the sample and the other micromircle of the active pair directs the electromagnetic radiation that emanates from the sample to a detector.

70. A method according to claim 64, wherein the step of illuminating a plurality of volume elements includes directing the illumination through a bundle of illumination optical fibers.

71. A method according to claim 64, wherein the step of collecting the electromagnetic radiation includes directing the electromagnetic radiation collected through a bundle of collection optical fibers.

72. A method according to claim 64, wherein the step of illuminating a plurality of volume elements includes modulating the illumination of the sample.

73. A method according to claim 64, wherein at least one set of field limiters comprises a set of individually controllable optical light shutters and a set of individually controllable optical collection shutters.

74. A method according to claim 64, wherein at least one set of field limiters comprises a set of individually controllable lighting elements and a set of individually controllable collection elements.

75. A method according to claim 64, wherein the step of illuminating a plurality of volume elements includes illuminating the volume elements for different periods of time with sources having different spectra.

76. A method according to claim 64, wherein the step of detecting the collected electromagnetic radiation is carried out by a set of detector elements.