Systems and methods for measuring tissue parameters using capacitive tactile sensors

Abstract

An apparatus and method for detecting, recording, measuring, and mapping the size, shape, and location of an injury to the sub-surface layers of a subject's skin or other soft tissue by using a capacitive tactile sensor to measure changes in tactile pressure of the skin or other tissue surface under investigation are described. The capacitive tactile sensor includes at least one exposure window; a substrate including a plurality of electrodes disposed within a housing; an insulating layer; a non-conductive compressible membrane covering positioned on the insulating layer, wherein at least a portion of the membrane is accessible via the exposure window; and a controller configured to calculate at least one parameter of the subject's tissue. A method of measuring a parameter of a subject's tissue and a method of performing a self-guided examination of a subject's tissue are also described.

Description

[0001] Cross-citation of related applications

[0002] This application claims priority to U.S. Provisional Patent Application No. 62 / 875,485, filed July 17, 2019, the entire contents of which are incorporated herein by reference. Background Technology

[0003] Early detection is crucial for the successful treatment of many forms of cancer. Consequently, the early detection and identification of cancerous growths largely depends on the availability, relative cost, effectiveness, and associated risks of existing sensors and screening technologies. Currently, a variety of sensors and tools exist for studying the mechanical properties of soft tissues and for imaging them.

[0004] One type of conventional soft tissue sensor uses an external force applicator to guide the displacement and an external displacement gauge to measure resistance. The external force applicator can be hydraulic or piezoelectric, and the external displacement gauge can be optical or piezoelectric.

[0005] Exemplary soft tissue imaging tools include computed tomography (CT), magnetic resonance imaging (MRI), ultrasound (US), T-scan (TS), and ultrasound elastography (UE). CT scans capture 360-degree X-ray images and use computer software to reconstruct 3D tissue structures. MRI scans use strong magnetic fields and radio waves to form diagnostic images of the tissue. US scans send high-frequency waves through the tissue and capture the echoes to image the tissue structure. TS measures low-level bioelectric currents to generate real-time images of the tissue's electrical impedance properties. UE scans evaluate the echo time through the tissue under constant mechanical stress and compare it to the echo time of the same tissue under no stress. A tissue strain map is then obtained, from which a 2D image of the elastic modulus distribution is formed using conventional inversion techniques.

[0006] Tactile imaging tools such as mammography use arrayed pressure sensors to detect changes in the stiffness of spatial tissue. Currently, mammography is used in breast cancer screening to detect abnormal tissue through contrast in tissue density. Mammography is the only FDA-approved breast cancer screening technology with a typical sensitivity of 85%, decreasing to 65% in radio-dense breasts. However, a high false-positive rate exists in these screening procedures. In fact, only about 15%–30% of breast biopsies yield a malignant diagnosis. While effective for screening over 40% of women, mammography is less effective for screening women with dense breast tissue.

[0007] Because many tissues with abnormal growths are stiffer under compression than the surrounding normal tissue, detecting changes in tissue stiffness has become an increasingly important factor in detecting potential abnormal tissue. For example, breast cancer is a calcified tissue that is known to be seven times stiffer than normal breast tissue. Likewise, plaque-arranged blood vessels are stiffer than normal healthy blood vessels.

[0008] U.S. Patent No. 7,497,133, incorporated herein by reference, discloses a piezoelectric finger sensor that can detect tumors by measuring tissue stiffness. Tumor motility is assessed from the ratio of the ratio of the shear modulus to the elastic modulus (G / E) in the tumor or by sensitive direct tumor motility measurements using two piezoelectric finger sensors, one to push and one to measure the tumor movement caused by the push. The patent concludes that the G / E ratio in the tumor region is higher than the G / E ratio of the surrounding normal tissue and that a much higher G / E ratio in the cancer region than in the surrounding normal tissue indicates that the tumor moves much less under shear than under compression. The patent concludes that these measurements can provide potential for non-invasive breast cancer malignancy screening, however, it does not disclose a method for determining malignancy, invasiveness, or tumor type.

[0009] U.S. Patent No. 8,562,546, incorporated herein by reference, discloses a piezoelectric sensor system for assessing tissue, including determining whether the tissue contains an abnormal growth. The described system uses an array of piezoelectric elements that are actuated toward the tissue in a first direction, after which their relative positions are recorded to approximate tissue stiffness. The sensor is very difficult to calibrate and cannot be calibrated after continuous use or even accidental touching. Thus, it is not suitable for use in the hands of non-professionals.

[0010] Thus, there remains a significant need for an accurate, non-invasive, cheek, portable, and easy-to-use system for detecting, recording, measuring, and mapping the size, shape, and location of lesions beneath the surface of skin or other soft tissue. The present invention satisfies this need. SUMMARY

[0011] In one embodiment, a device for measuring a tissue parameter of a subject includes a housing having at least one exposure window, a substrate including a plurality of electrodes disposed within the window, an insulating layer positioned on the electrodes, a pliable membrane positioned on the insulating layer, wherein at least a portion of the pliable membrane is accessible via the exposure window, and a controller disposed within the housing configured to calculate at least one parameter of the subject's tissue based on a capacitance measured between the electrodes. In one embodiment, the pliable membrane includes a foam. In one embodiment, the foam has a hardness within the range 00-0 to 00-20. In one embodiment, the plurality of electrodes includes at least two electrodes. In one embodiment, each electrode of the plurality of electrodes has a surface area between 1 mm 2 and 16 mm 2 In one embodiment, the device includes a visualization device communicatively connected to the controller, the visualization device including a display. In one embodiment, the controller is connected to the visualization device via a Bluetooth connection. In one embodiment, the device includes a conductive element configured to deliver a reference voltage to a surface in contact with the pliable membrane. In one embodiment, the conductive element is positioned to substantially surround the exposure window. In one embodiment, the at least one parameter includes tissue hardness. In one embodiment, the subject's tissue includes breast tissue.

[0012] In one embodiment, a method of measuring a tissue parameter of a subject includes the steps of positioning a handheld device including a plurality of electrodes and a quantity of pliable material in substantial contact with a region of the subject's body, measuring a capacitance between two electrodes of the plurality of electrodes, determining a thickness of the pliable material based on the capacitance, and calculating the tissue parameter based on the thickness of the pliable material. In one embodiment, the method includes transmitting data selected from the group consisting of the capacitance, the thickness, and the tissue parameter to a visualization system. In one embodiment, the method includes measuring a plurality of capacitance values between a set of electrode pairs and displaying a graph of parameter values on the surface of the tissue on the visualization system. In one embodiment, the tissue parameter refers to hardness. In one embodiment, the method includes the step of making a provisional diagnosis based on the tissue parameter.

[0013] In one embodiment, a method of performing a guided self-examination of a subject's tissue includes the steps of positioning a handheld device including a plurality of electrodes and a quantity of pliable material in substantial contact with a region of the subject's body; measuring a capacitance between two of the plurality of electrodes; calculating a tissue parameter based on the capacitance; determining an instruction to the subject in a controller based on the tissue parameter; and issuing the instruction to the subject to guide the subject in manipulating the handheld device. In one embodiment, the instruction is an audible instruction issued via a speaker. In one embodiment, the instruction is configured to guide the subject to move the device to a new location on the tissue. In one embodiment, the instruction includes a visual cue presented on a display.

[0014] In one embodiment, a capacitive tactile sensor device for detecting, recording, measuring, and mapping the size, shape, and location of an injury beneath the surface of a subject's skin or other soft tissue by measuring changes in the tactile pressure of the subject's skin or other tissue surface, the capacitive tactile sensor device comprising: a housing having at least one exposed window and an exposed conductive surface positioned such that the operator or device is in constant contact with the conductive surface when operating the device; a substrate positioned within the housing measurement comprising a plurality of pairs of individual coplanar co-located electrodes arranged in a Cartesian grid on a non-conductive material and configured such that any two adjacent electrodes are electrically independent and capable of being independently stimulated by an externally generated stimulus voltage or current signal, thereby forming a capacitor between each such electrode pair, and the space above the outer surface of the electrode grid serves as a dielectric; a layer of insulating material positioned on the outward facing surface of the electrode grid; a homogeneous, compressible, non-ferrous, and non-conductive membrane covering the insulating layer positioned on the outward facing surface of the electrode grid, the membrane: (a) having a uniform thickness across the entire surface area of each pair of adjacent electrodes making up the capacitor and across the entire surface area of the Cartesian grid of electrodes; (b) having a fixed, uniform, and known compression ratio and hardness across the entire surface area of the Cartesian grid of electrodes; and (c) having a steady state equilibrium shape such that the volume of the membrane remains constant when not subjected to external forces; and a non-conductive covering material positioned on the outward facing surface of the homogeneous, compressible, non-ferrous, and compressible membrane, at least a portion of the non-conductive covering material being accessible through the exposed window of the housing, the exposed window serving as the outward facing surface of the sensor and, together with the membrane, effectively replacing air as the dielectric for the capacitor formed by each pair of adjacent electrodes, one electrode serving as a transmitting electrode and one electrode serving as a receiving electrode; wherein the sensor surface is configured to be placed in complete and secure contact with the surface of the subject's tissue such that the electro-mechanical properties, including normal surface pressure of the conductive tissue, disrupt the electric field in the dielectric made up of the compressible membrane and interfere with the capacitive coupling between the relevant pair of coplanar electrodes; wherein the sensor input device, in response to the pressure exerted on the sensor surface by contact with the skin or other soft tissue surface and the compression created by the compressible membrane and the interference with the capacitive coupling between the relevant pair of coplanar electrodes, directs and generates at least one signal as an indicator of the location, dynamics, and special features of the local area of hard tissue beneath the region of the skin or other tissue surface being studied according to the variable composition and properties of the underlying tissue structure; and a controller disposed within the housing comprising: (a) one or more commercially available IC capacitive sensor chips configured to: (i) generate signals for stimulating the electrode pairs positioned in the substrate;(ii) receiving and processing signals subsequently directed, generated, and transmitted by the capacitive tactile sensor input device in response to pressure exerted on the sensor surface by contact with a surface of skin or other soft tissue; and (iii) directing, generating, and transmitting signals derived from processing of signals directed, generated, and transmitted by the capacitive tactile sensor input device to the IC capacitive sensor chip; and (b) one or more integrated circuits and processors configured to: (i) receive and process signals directed, generated, and transmitted by the IC capacitive sensor chip to calculate one or more parameters of the underlying tissue structure based on changes in perceived capacitance between adjacent pairs of electrodes resulting from pressure exerted on the sensor surface by contact with a surface of skin or other soft tissue; and (ii) communicatively connect with a visualization device comprising a display and an integrated storage device. In one embodiment, the homogeneous, compressible, non-ferrous, and non-conductive film comprises polyurethane, silicon, or thermoplastic elastomer foam. In one embodiment, the foam has a hardness within the range 00-0 to 00-20. In one embodiment, the plurality of electrodes comprises at least two electrodes. In one embodiment, each electrode of the plurality of electrodes has a surface area between 1 mm; 2 and 16 mm 2 In one embodiment, the device comprises a visualization device communicatively connected to the controller, the visualization device comprising a display. In one embodiment, the controller is connected to the visualization device via a Bluetooth connection. In one embodiment, comprising: a conductive element located on the exterior of the housing configured to pass a reference voltage to be used for all subsequent capacitive calculations. In one embodiment, the device comprises: a grounding pad or strip providing conductive contact between a non-insulated portion of the electronic plane and the outer surface of the capacitive sensor configured to pass a reference voltage to be used for all subsequent capacitive calculations. In one embodiment, the at least one parameter comprises tissue hardness. In one embodiment, the tissue of the subject comprises breast tissue.

[0015] In one embodiment, a method of recording, measuring, and mapping the size, shape, and location of palpable lesions beneath the surface of a subject's skin or other soft tissue by measuring changes in normal tactile pressure on the surface of the skin or other soft tissue region using capacitive tactile sensing, comprising the steps of: positioning a handheld device comprising a plurality of electrodes and a quantity of non-conductive compressible material and covered in substantially contact with a surface region of the subject's skin or tissue; determining a baseline reference capacitance for the subject by measurement data obtained by an operator from an unimpaired region of the tissue; determining a baseline reference voltage potential by the operator through conductive contact between the operator and the handheld device; positioning the handheld device in substantially contact with the surface region of the skin or tissue under investigation; measuring the capacitance created between two of the plurality of electrodes as a result of contact with the surface region of the skin or tissue under investigation; measuring the change in perceived capacitance between adjacent pairs of electrodes as a result of the pressure exerted on the sensor surface (compressible membrane and cover) due to the destruction of the capacitive coupling between adjacent pairs of electrodes as a result of contact with the surface of the skin or tissue under investigation with reference to the baseline reference voltage potential; and calculating one or more tissue parameters from the baseline reference voltage potential based on the change in perceived capacitance. In one embodiment, the method comprises the step of: transmitting data selected from the group consisting of perceived capacitance, thickness, and tissue parameters to a visualization system. In one embodiment, the method comprises the steps of: measuring a plurality of capacitance values between a set of electrode pairs, and displaying a graph of parameter values on the surface of the tissue on a visualization system. In one embodiment, the tissue parameter refers to stiffness.

[0016] In one embodiment, a method of performing a guided self-examination of a subject's tissue, comprising the steps of: positioning a handheld device comprising a plurality of electrodes and a quantity of pliable material in substantially contact with a region of the subject's body; measuring the capacitance between two of the plurality of electrodes; calculating a tissue parameter based on the capacitance; determining an instruction to the subject in a controller based on the tissue parameter; and issuing the instruction to the subject to guide the subject in manipulating the handheld device. In one embodiment, the instruction refers to an audible instruction issued via a speaker. In one embodiment, the instruction is configured to direct the subject to move the device to a new location on the tissue. In one embodiment, the instruction comprises a visual cue presented on a display.

[0017] In one aspect, a method of dynamically calibrating data received from at least one sensor includes: obtaining a plurality of data values from the at least one sensor; calculating a first mean and a first standard deviation of the plurality of data values; obtaining a subset of the plurality of data values that are within one standard deviation of the first mean; calculating a second mean from the subset of the plurality of data values as a baseline value; and subtracting the baseline value from the plurality of data values to generate a calibrated data set.

[0018] In one embodiment, the method further includes: obtaining a second plurality of data values; calculating a third mean and a third standard deviation of the first and second plurality of data values; obtaining a second subset of the first and second plurality of data values that are within one standard deviation of the third mean; calculating a fourth mean from the second subset of the plurality of data values as a second baseline value; and subtracting the second baseline value from the first plurality of data values and the second plurality of data values to generate the calibrated data set.

[0019] In one embodiment, the method further includes: displaying a three-dimensional surface plot of the calibrated data set; displaying the baseline value; and providing visual feedback when the baseline value is within an optimal range. In one embodiment, the visual feedback includes: changing a color of a region of the three-dimensional surface plot. In one embodiment, the method further includes: calculating a moving average of the plurality of data values and calculating the first mean and the first standard deviation from the moving average.

[0020] In one embodiment, the method further includes: comparing the moving average to a maximum threshold value and a minimum threshold value; capturing the plurality of data values or the moving average when the moving average is between the maximum threshold value and the minimum threshold value; and storing the captured data values on a non-volatile computer readable medium when the moving average remains between the maximum threshold value and the minimum threshold value for a specified time period. In one embodiment, the specified time period refers to at least three seconds. BRIEF DESCRIPTION OF DRAWINGS

[0021] The above objects and features, and other objects and features, will become apparent from the following description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the application and constitute a part thereof, wherein like reference numerals indicate like elements throughout, and wherein:

[0022] Figure 1 is a diagram of a capacitive sheet according to one embodiment;

[0023] Figure 2 is a diagram of a capacitive sheet according to one embodiment;

[0024] Figure 3A is a cross-section of a pair of electrodes on a substrate according to one embodiment;

[0025] Figure 3Bis a cross-section of a portion of a capacitive tactile sensor device according to one embodiment;

[0026] Figure 3C is an exemplary plot of normal pressure applied to the surface of tissue of a portion of a capacitive tactile sensor device according to one embodiment;

[0027] Figure 3D is an exemplary cross-section of a portion of a capacitive tactile sensor input device in contact with a non-uniform surface according to one embodiment;

[0028] Figure 4A and Figure 4B are first and second embodiments of a housing with operator ground contacts;

[0029] Figure 5 is a visualization display graphic according to one embodiment;

[0030] Figure 6A , Figure 6B , and Figure 6C is a visualization display graphic according to one embodiment;

[0031] Figure 7 is a method of the invention according to one embodiment; and

[0032] Figure 8 is an illustration of sample comparison data for piezoelectric versus capacitive sensors according to experimental examples. DETAILED DESCRIPTION

[0033] It should be understood that the drawings and description of the application have been simplified to illustrate elements that are relevant for a clear understanding of the application, while eliminating, for the purpose of clarity, many other elements found in related systems and methods. Those of ordinary skill in the art will recognize that other elements and / or steps are desirable and / or required in implementing the application. However, because such elements and steps are well known in the art, and because they do not facilitate a better understanding of the application, a discussion of such elements and steps is not provided herein. The disclosure herein is directed to all such variations and modifications to the elements and methods known to augment and / or supplement the underlying engineering and technology.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present application, exemplary methods and materials are described.

[0035] As used herein, each of the following terms has the associated meaning.

[0036] As used herein, the article "a" is intended to refer to one or more (i.e., at least one) of the grammatical object of the article. By way of example, "an element" means one element or one or more elements.

[0037] "About" as used herein when used in connection with a measurable value or other quantitative description, refers to a value that is not exact but close to the stated value at the 20%, 10%, 5%, 1%, and 0.1% level, as appropriate.

[0038] Throughout this disclosure, various aspects of the application can be presented in a range format. It should be understood that the description in range format is merely for convenience and brevity and is to be interpreted -in the context of the specification as a whole. Therefore, the description of a range should be considered to have specifically recited each and every number within the range, sub-range that the range encompasses, as well as every combination of these ranges or sub-ranges. For example, a description of a range such as from 1 to 6 should be considered to have specifically recited each and every number within the range, such as, for example 1, 2, 2.7, 3, 4, 5, 5.3, 6, and any whole and fraction increments of these numbers, even if only a subset of the total set of numbers are explicitly listed. This applies regardless of the breadth of the range.

[0039] In some aspects of the application, software that performs the instructions provided herein can be stored on a non-transitory computer readable medium, where the software, when executed on a processor, performs some or all of the steps of the application.

[0040] Aspects of the application relate to algorithms performed in computer software. While specific implementations can be described as being written in a particular programming language or executed on a particular operating system or computing platform, it should be understood that the systems and methods of the application are not limited to any particular computing language, platform, or combination thereof. Software that performs the algorithms described herein can be written, compiled, or interpreted in any programming language known in the art, including but not limited to C, C++, C#, Objective-C, Java, JavaScript, Python, PHP, Perl, Ruby, or Visual Basic. It should further be understood that elements of the application can be run on any acceptable computing platform, including but not limited to servers, cloud instances, workstations, thin clients, mobile devices, embedded microcontrollers, televisions, or any other suitable computing device known in the art.

[0041] Portions of the application are described as running on computing devices. While the software described herein can be disclosed as operating on one particular computing device (e.g., a dedicated server or workstation), those skilled in the art will appreciate that the software is inherently portable and can also be run on any wide range of devices for the purposes of the present application, most of which run on dedicated servers. Included are desktop or mobile devices, laptop computers, tablet computers, smart phones, watches, wearable electronic devices, or other wireless digital / cellular phones, televisions, cloud instances, embedded microcontrollers, thin client devices, or any other suitable computing device known in the art.

[0042] Likewise, portions of the application are described as communicating over various wireless or wired computer networks. For the purposes of the present application, the words "network," "networked," and "networking" should be understood to include wired Ethernet, fiber optic connections, wireless connections including any of the various 802.11 standards, cellular WAN infrastructure such as 3G or 4G / LTE networks, Bluetooth® Low Energy (BLE), or communication links, or any other method by which one electronic device can communicate with another. In some embodiments, elements in the networked portions of the application can be implemented over a virtual private network (VPN).

[0043] The term "abnormal" when used in the context of a biological, tissue, cell, or constituent thereof refers to a biological, tissue, cell, or constituent thereof that differs in at least one observable or detectable characteristic (e.g., age, treatment, date and time, etc.) from a biological, tissue, cell, or constituent thereof that exhibits a "normal" (expected) corresponding characteristic. For different cell or tissue types, a characteristic that is normal or expected for one cell or tissue type can be abnormal.

[0044] The term "diagnosis" as used herein refers to a determination of the presence of a disease or disorder. In some embodiments of the application, a method is provided that permits a determination of the presence of a particular disease or disorder for making a diagnosis.

[0045] The term "screening" as used herein refers to the detection, recording, measurement, and / or mapping of the size, shape, and location of an abnormal characteristic of a subject's tissue that is indicative of the potential presence of a disease or disorder for further study.

[0046] Herein, the terms "patient," "subject," "individual," and the like are used interchangeably and refer to any animal, a cell thereof in vitro or in situ. In particular non-limiting embodiments, the patient, subject, or individual refers to a human.

[0047] One aspect of the present invention relates to a device for detecting features of a tissue surface, including normal surface pressure and changes in the surface pressure over the area under investigation, which can indicate the presence of an underlying tissue abnormality, such as a mass, lesion, cyst, or tumor. Exemplary devices of the present invention can be hand-held or compact in form factor. In some embodiments, the devices of the present invention include multiple components, while in other embodiments, the devices are self-contained and powered diagnostic devices.

[0048] Devices of the present invention can include Figure 1 A capacitive patch as shown in FIG. 1. Capacitive patch 101 can be rigid, flexible, or conformable, can be made of any suitable material, such as Kapton, fiberglass-reinforced (fiberglass) epoxy, or reinforced phenolic. The depicted exemplary capacitive patch includes a plurality of capacitive elements 102, 103. The depicted patch includes nine capacitive elements or electrodes arranged in a 3x3 Cartesian grid, although it should be understood that a capacitive patch of the present invention can include any number of individual capacitive elements ranging, for example, from 2 to 20 by 20 or more.

[0049] The depicted capacitive elements are square, although it should be understood that the capacitive elements can be any shape, including but not limited to circular, triangular, hexagonal, or square. Individual capacitive elements can be made of any conductive material, including but not limited to copper, gold, silver, steel, aluminum, carbon nanotubes, stainless steel, or platinum.

[0050] For example, the capacitive elements in a capacitive patch can be any size ranging from 1 mm 2 to 16 mm 2 and can typically have a thickness ranging from 0.5 mil to 3 mil. In some embodiments, all of the capacitive elements in a capacitive patch are approximately the same size, although in other embodiments, a capacitive patch of the present invention can include a plurality of capacitive elements having different sizes. Likewise, different capacitive elements on the same patch can be made of the same or different materials, or can have the same or different shapes.

[0051] Referring now to Figure 2 , an alternative capacitive patch 201 is shown. Exemplary patch 201 includes approximately square capacitive elements 202 and 203 and approximately circular capacitive elements, such as 204.

[0052] In some embodiments, the individual capacitive elements can be interconnected and can be arranged such that any two adjacent electrodes are electrically independent and can be independently excited. In this configuration, each pair of electrodes can be used as an independent capacitor, and the space above the surface of the capacitive sheet (including any material placed or disposed thereon) is used as the dielectric.

[0053] Referring now to the drawings Figures 3A to 3D An exemplary device of the present application is shown in cross-section. In Figure 3A The base device includes a substrate 301 having a plurality of capacitive elements (including 303 and 304) and an insulating surface 302 disposed over the elements. Elements 303 and 304 are electrically isolated from one another, and an electric field 305 is formed between the two elements when element 303 is held at a first potential and element 304 is held at a second potential. In Figure 3A In embodiments of the present application, the dielectric of the capacitor formed between elements 303 and 304 is air. Insulating surface 302 can be made of any insulating material, including but not limited to epoxy laminate materials such as FR-4 or standard solder mask materials. Insulating surface 302 can have a thickness of up to 80 microns.

[0054] Referring now to the drawings Figure 3B An alternative design includes a film 306 placed over insulating surface 302. Film 306 can be a homogenous, mechanical and compressible, non-ferrous, and non-conductive film that effectively replaces air as the dielectric for the capacitor formed by two adjacent electrodes. In some embodiments, the film can have a generally uniform thickness, although the thickness can vary, for example, to make the device more conformable against a curved or irregular body region. The film provides mechanical separation between the electrode surface and any external surface that abuts the parallel surface of the electrode-facing surface of the film. The film can be covered by a loosely fitting non-conductive material, such as nitrile.

[0055] Film 306 can be configured to have a generally fixed and uniform density, compression ratio, and hardness across the entire substrate or exposed subset of the substrate. Suitable materials for use in the film of the device of the present application include silicone, compressible foam, or saline encapsulants. The Shore hardness of the material can be in the range of Shore 00 0-20. The dielectric constant of the material can be in the range of 1.0 to about 5.0. The film material can be configured to return to a stable equilibrium shape when not exposed to any external forces.

[0056] As Figure 3CAs shown in FIG. 3, for example, when an external force is applied with a finger 307, the membrane 306 deforms, changing the characteristics of the electric field 305 and thereby changing the capacitance of the capacitor created between the capacitive elements 303 and 304. In an exemplary device, the external force is supplied by normal pressure of the subject's skin or other tissue surface in the area under study. This change in capacitance can be measured using any suitable means in the art (e.g., with series or parallel resistive / inductive elements), or by measuring the impedance response of the capacitor itself or of the capacitor in combination with other fixed or variable resistive, inductive, or capacitive elements. As such, the location and extent of the force applied by the external force can be measured and tracked over time.

[0057] In Figure 3D Another embodiment is shown in FIG. 4 and shows an exemplary device used in conjunction with an external surface 308 having dielectric properties such that when placed on the membrane, the dielectric constant between a pair of adjacent electrodes is disrupted and thus the electric field pattern is disrupted. This causes a change in capacitance measured, for example, using the methods outlined above. Suitable external surfaces used in conjunction with devices of the present application include, but are not limited to, human or other animal skin, human or other animal organs, or any ferrous or conductive or semi-conductive material. As shown, when normal pressure from the surface of the tissue under study is applied between the external surface 308 and the capacitive elements 303 and 304, the membrane 306 deforms. When the pressure is not uniform, for example, if the external surface 308 is tissue having a variable stiffness on the surface applied to the membrane 306, the membrane 306 will deform unevenly. For example, the membrane can deform in such a way as to reflect the underlying tissue structure, for example, a hard or soft lesion. Non-uniform deformation of the membrane on a surface having multiple capacitive elements will cause a measurable change in the distance between the external surface and the electrode surface on the electrode array. The changed distance will affect the overall dielectric perceived by any adjacent capacitor pair (e.g., adjacent pair 303 and 304). This will affect the dielectric constant of each capacitor, which can be used to calculate the distance between the external surface and the electrode surface on the array, which in turn can be used to calculate the normal force per square millimeter (mm) on the electrode surface. The change in capacitance is related to the change in perceived permittivity, i.e., is linearly proportional to the measured capacitance.

[0058] In Figure 3DA conductive element 309 is also shown. Element 309 is configured to provide a stable reference potential to outer surface 308. For example, element 309 can reference a ground potential within the device that is designed to provide a ground reference to the skin of a subject in the estimated body region. Alternatively, the ground reference can be obtained through conductive contact with the skin of the operator. In some embodiments, a fixed reference potential on the outer surface can greatly improve the quality of measurements on the electrode pairs. As contemplated herein, element 309 can be constructed of any conductive material, including but not limited to copper, gold, silver, or platinum. In some embodiments, element 309 is made substantially of a first material, e.g., a metal, and coated on an end proximate to outer surface 308 with a second conductive or semi-conductive material to provide better comfort to the user. In one embodiment, membrane 306 defines a treatment region, e.g., a circular, oval, square, rectangular, or elliptical treatment region. Conductive element 309 can extend substantially around the perimeter or edge of the treatment region, such that the probability of good electrical contact between conductive element 309 and outer surface 308, e.g., the skin of a subject, is maximized.

[0059] The device of the present application can further include a controller including specialized circuitry for reading capacitance values from the electrode pairs. The controller can include any computing device, e.g., an integrated microcontroller or processor, and can further include an amount of volatile and / or non-volatile memory storing instructions to perform the method steps of the present application. In some embodiments, the controller includes instructions configured to iterate through some or all of the possible electrode pairs continuously disposed in the array grid to provide continuous measurements of capacitance and thus characteristics of outer surface 308 in contact with membrane 306. In some embodiments, the controller can utilize any of several commercially available chips or modules suitable for capacitive sensing and related calculations.

[0060] As described herein, embodiments of the system are configured to detect and estimate subcutaneous soft tissue injury by measuring and quantifying changes in tactile pressure at the surface of the tissue through capacitive sensing and using measurements taken with multiple pairs (including at least one pair) of individual coplanar electrodes co-located on a substrate disposed within a housing, arranged in a Cartesian grid, and configured such that any two adjacent electrodes are electrically independent and can be independently excited, thereby forming a capacitor between the electrode pairs. Thus, the system can function as a capacitive sensor. In certain embodiments including a loose, non-conductive cover material, the sensor surface is placed on the outward facing surface of a compressible, non-ferrous, and non-conductive film positioned on the outward facing surface of the electrode grid, which functions as a dielectric for the capacitor formed by any two adjacent electrodes (one as a transmitting electrode and one as a receiving electrode). The sensor surface is configured to be placed in contact with the tissue with sufficient pressure to slightly compress the compressible dielectric. In certain instances, the term "slight compression" can be the minimum amount of pressure applied to ensure that the entire sensor surface is in full and fixed contact with the tissue. At this point, the electromagnetic properties of the tissue will disrupt the electric field in the dielectric and interfere with the capacitive coupling between the coplanar electrodes of the relevant pair. The interference with the capacitance is measured using a set of calibration baseline measurements taken by the operator from an undamaged area of the tissue and then by determining the difference between this baseline measurement and the capacitive measurements taken from each pair of electrodes facing the surface area of the tissue under study from the set. According to one embodiment, it is assumed that the electrical potential of the tissue (i.e., the patient) in contact with the sensor is constant throughout the set of measurements (including the baseline) and does not necessarily have to be 0 volts. It is also assumed that the electrical potential of the tissue (i.e., the operator holding the device) in contact with the device housing is also constant throughout the set of measurements (including the baseline) and again, does not necessarily have to be 0 volts. Classification of tissue hardness is achieved by measuring the difference in tactile pressure of the tissue surface on the sensor surface. These pressures are then quantified by the measured capacitance between the coplanar electrodes. The measured capacitance is compared to the set of baseline measurements defined above and then, the relative measurements for each set of electrodes are quantified. For consistent relative measurements, it must be determined that the reference voltage potential used in the baseline and measured capacitances is the same. As described above, this constant voltage potential can be obtained from either (1) the patient tissue or (2) the operator tissue. The ground option already described can utilize option (1). Option (2) requires a conductive surface to be placed on the housing of the device that is configured such that it is always in contact with the operator, including when taking the baseline capacitance measurements and the measured capacitance measurements for relative tissue hardness. Referring now to Figure 4A and Figure 4B , the conductive surface is built into the surface of portions of the housing (e.g., the handheld portion) and is configured to provide the reference voltage from the operator. Referring now to Figure 4AAn exemplary housing includes a grip surface 401 connected to two housing portions 402 and 403. In the depicted embodiment, the housing portion 402 includes a top grip surface 413. In some embodiments, the grip surface 413 includes one or more buttons or other control elements that allow an operator to control the sensor assembly, for example, to start or stop a measurement or to place the sensor at zero for calibration purposes. In the depicted embodiment, the grip surface 401 is held in place by two pegs 411 that mate with two corresponding holes 412 on the housing portions 402 and 403 (the second peg is on the opposite interior surface of 401). In some embodiments, one or both grip surfaces 401 and 413 include a conductive element or terminal that allows the sensor assembly to measure a reference voltage from the skin of the operator during use.

[0061] Referring to Figure 4B An exemplary housing includes a top handle surface 404 and a bottom ring 405. In various embodiments, one or both of the handle 404 and the ring 405 can include a conductive element or terminal configured to measure a reference voltage from the skin of the operator (in the case of the handle 404) or from the skin of the subject (in the case of the ring 405). In some embodiments, the user is the same as the subject, for example, during a self-examination.

[0062] Embodiments of the device can be integrated into a housing designed for self-examination. The integrated device can include a power source, for example, a battery, power management hardware; and one or more communication devices, for example, wired or wireless communication devices for transmitting or receiving data, configuration information, or operating instructions to and from a remote computing device. In one embodiment, the integrated device includes a Bluetooth transceiver, and a remote computing device can be paired with the integrated device to transmit and receive data.

[0063] The system of the present invention includes the above-described sensor device for detecting, recording, measuring, and mapping the size, shape, and location of an injury beneath the surface of the skin or other soft tissue of a subject by measuring changes in the tactile pressure of the surface of the tissue in a region of the subject's body via a wired or wireless connection to a visualization computing device that includes software for visualizing the results, and in some embodiments, for interpreting the results to provide a provisional analysis. The visualization computing device can include a wired or wireless transceiver for receiving, processing, displaying, and storing data from the diagnostic device configured to use any wired or wireless communication protocol known in the art. In some embodiments, the data connection between the visualization device and the sensor device is encrypted.

[0064] In some embodiments, the system of the present application is configured to perform a self-guided examination or assessment by the subject. For example, the system includes a guidance element integrated into either or both of the sensor device and the visualization device described above. The guidance element can be configured to receive information from one or both of the sensor device and the visualization device and deliver instructions or cues to the subject based on the information. The instructions or cues can include visual, audible, or tactile feedback. In one embodiment, the sensor device can be positioned on the subject's tissue such that the structure of interest is detected along the top edge of the device. The guidance element can then issue instructions to the subject to reposition the device, for example, to move the device further up so that the structure of interest is better centered in the detection area of the device. The guidance element can also instruct the user to reposition the device to span the entire breast, for example. In some cases, the guidance can instruct switching from one breast to the other.

[0065] Another aspect of the present application includes a method of visualizing a structure of interest in a subject's tissue. Using the system described above, the subject can position a sensor device having a detection surface on a body region with the detection surface in direct, approximate contact with the skin of the body region. Although not mandatory, the subject can then press a button or actuate some other control to begin the detection process. The device then collects data from the tissue region in contact with the detection surface and performs calculations based on the data. The processing can include a denoising algorithm and a basic smoothing algorithm. The processed data and / or the raw data are then sent via a wired or wireless connection to a visualization device, which can perform further calculations based on the received data. A visualization of the body region is then generated using the final processed data for viewing by the subject or another (e.g., a clinician).

[0066] Calibration

[0067] In one embodiment, the systems and methods disclosed herein can include components and methods for performing dynamic, real-time baseline, or calibration on array data obtained by a sensor array, such as a Cartesian array of capacitive and / or pressure sensors disclosed herein. In one embodiment, the system includes a set of capacitive and / or pressure sensors positioned on a surface and arranged, for example, in a Cartesian arrangement. The method can include periodically obtaining capacitive and / or pressure data from the set of sensors, for example, at a rate between 1 Hz and 1 kHz, or between 1 Hz and 500 Hz, or between 1 Hz and 100 Hz, or between 1 Hz and 30 Hz, or any suitable range. In one embodiment, the data obtained from the sensors is stored as a DC-shifted sparse matrix, where a portion of the data lies within 1.5 standard deviations of the mean. In one embodiment, a majority or a substantial portion of the measured data lies within 1.5 standard deviations of the mean.

[0068] The calibration method can include, first, collecting a quantity of data, and then, calculating a baseline calibration point or "zero" point from the data, where all data falling outside of one standard deviation of the mean of the data is considered for removal, and a second mean is calculated from a subset of the data that falls within one standard deviation (SD) of the first mean. While the previous embodiment uses one standard deviation of the mean as an exemplary threshold, it should be understood that any suitable threshold can be used in other embodiments, including but not limited to 0.3 SD, 0.5 SD, 0.75 SD, 0.8 SD, 0.9 SD, 1.1 SD, 1.25 SD, 1.5 SD, 2 SD, etc. The second mean can then be used as a baseline or zero point for the rest of the data. The second mean is then considered a deviation from all of the rest of the data, and for each data point measured, the second mean is subtracted, resulting in a majority of the data lying at or near the new zero point (i.e., the second mean), allowing for proper highlighting of outlier data from the full set of measured data.

[0069] In some embodiments, multiple measurements are performed by the full sensor before the initial calibration step is performed, while in other embodiments, calibration is performed continuously, i.e., by performing calibration on the first set of measured data and repeating the calibration after each new set of measured data. This novel approach eliminates the need for the use of a conventional, single, static calibration, which can not be accurate due to the difference in tissue hardness between the tissue area used for calibration and the tissue in the measurement area. The method also prevents errors between operators and within an operator when a single calibration is performed incorrectly. For example, in some embodiments, an operator can apply variable pressure to the tissue between measurements or during a single measurement, which can produce skewed data if a static calibration is used. By dynamically calibrating the measured data, the overall bias applied to the data can be adapted to properly distinguish true outliers from the skew produced by varying operator pressure.

[0070] In one embodiment, the calculated baseline level is used to validate and store a quantity of measured data. In one example, a quantity of data points are measured from at least one pressure or capacitive sensor arranged in an array, e.g., a Cartesian array. In one embodiment, a moving average of the measured data points is calculated to smooth the data over time. The moving average can be calculated in a window of at least three samples, at least five samples, at least ten samples, at least twenty samples, or any suitable quantity. The smoothed moving average data can then be monitored and when the moving average moves into a particular range, a capture trigger can be activated to indicate that the captured data is now valid for measurement. In some embodiments, the particular range can be between 40% and 60%, or between 45% and 55%, between 47% and 53%, between 49% and 51%, or about 50% of the dynamic measurement range of the sensor. In some embodiments, once the capture trigger is activated, the data is monitored to see if it remains valid for a certain period of time, e.g., two seconds, three seconds, or five seconds. When the data remains valid for the specified period of time, then the smoothed and / or raw data measured during that interval is stored as a valid data measurement.

[0071] Sample data visualization

[0072] In some embodiments and now referring to Figure 5 In addition to the visualization of the body region, the visualization device can display some indication of the perimeter or actual screening determination. In some embodiments, the diagnostic device performs the collection and processing of all the data and transmits the results via a wired or wireless connection to a remote computing system or cloud system for processing and later visualization.

[0073] In some embodiments, the method of the present application can include one or more guiding steps, for example, instructions or prompts delivered to the subject or clinician by the visualization device or sensor device, including steps to guide the subject through the self-screening. The method can include processing some or all of the data measured by the sensor device by a processor integrated into the device, by a processor integrated into the visualization device, or by another device located near or remotely from the diagnostic system including the diagnostic device and the visualization device. The guiding steps can also include instructing the subject or clinician to perform or utilize the device to perform one or more manipulation steps by the subject or clinician to the device, for example, move up, move down, move left, move right, press harder, press softer. With this self-screening system, a subject with little or no medical or device training can be enabled to perform a guided self-screening to collect data for review by a clinician.

[0074] In some embodiments, the graphical visualization can include or be updated based on the dynamic calibration method disclosed above. In some embodiments, a 3D surface plot can be displayed through the interface of the present application, where the surface of the tissue being measured is displayed in the X-Y plane and the data is represented on the Z axis. Due to the baseline update, the X-Y surface of the data plot is vertically shifted along the Z axis due to the subtraction of the calculated baseline amount. The color coding of the surface is used to indicate the deviation from the optimal baseline. When the baseline is within the optimal range, the surface appears green but is gradually colored yellow and red for deviations. As the baseline deviates from the optimal value, the surface turns yellow and eventually red, indicating a substantial deviation from the optimal baseline. Furthermore, in some embodiments, the calibration display can graphically display the calculated baseline itself on the screen, providing further feedback to the operator to allow the operator to adjust, for example, the pressure they exert to move the baseline within the optimal range. This novel visualization scheme optimizes user training by facilitating the capture of consistent baselines and maximizing measurement integrity.

[0075] Reference is made to Figure 6A , Figure 6B , and Figure 6C An embodiment is shown. As shown in Figure 6A , the uncalibrated surface plot can display most of the points in red, i.e., a deviation from the fixed "zero" value. In the depicted embodiment, most of the points in the measured surface plot are about 22%, i.e., significantly less than the fixed zero value of 50%. Thus, all points that are a deviation from the zero value are highlighted in red.

[0076] Figure 6B Visualization of the dynamic calibration data is shown. Figure 6BThe data plot shown in the middle shows the entire surface in green, i.e., normal. The data has been calibrated to remove bias, and thus, most falls within the green window, i.e., between 55% and 65% in the depicted embodiment.

[0077] Figure 6C A visualization of data that solves for optimal real-time calibration is shown. Most of the plot is shown in green, but some of the surface is yellow-green, indicating that some data still falls outside the zero window. The mean of the depicted data is about 44%, i.e., just outside the optimal window of 45% to 55%.

[0078] In Figure 7 An exemplary method of measuring a tissue parameter of a subject is shown in FIG. 7. The method includes the following steps: positioning a handheld device including a plurality of electrodes, and an amount of non-conductive compressible material and covered to be in general contact with a body region of a subject at step 701; measuring a capacitance between two electrodes of the plurality of electrodes at step 702; determining a thickness of the pliable material based on the capacitance at step 703; and calculating the tissue parameter based on the thickness of the pliable material at step 704.

[0079] According to one embodiment, a capacitive tactile sensor device for detecting, recording, measuring, and mapping the size, shape, and location of an injury beneath the surface of a subject's skin or other soft tissue by measuring changes in tactile pressure of the skin or other tissue surface, the capacitive tactile sensor device comprising: a housing having at least one exposed window and an exposed conductive surface placed so that the operator or device is in constant contact with the conductive surface when operating the device. A substrate is positioned within the housing measurement, comprising a plurality of pairs of individual co-planar co-located electrodes arranged in a Cartesian grid on a non-conductive material and configured so that any two adjacent electrodes are electrically independent and capable of being independently stimulated by an externally generated stimulus voltage or current signal, thereby forming a capacitor between each such pair of electrodes, and the space above the outer surface of the electrode grid serves as a dielectric. A layer of insulating material is positioned over the outward facing surface of the electrode grid. A homogeneous, compressible, non-ferrous, and non-conductive membrane covers the insulating layer positioned over the outward facing surface of the electrode grid, the membrane: (a) having a uniform thickness over the entire surface area of each pair of adjacent electrodes making up the capacitor and over the entire surface area of the Cartesian grid of electrodes; (b) having a fixed, uniform, and known compression ratio and stiffness over the entire surface area of the Cartesian grid of electrodes; and (c) having a steady state equilibrium shape such that the membrane volume remains constant when not subjected to external forces. A non-conductive cover material is positioned over the outward facing surface of the homogeneous, compressible, non-ferrous, and compressible membrane, at least a portion of the non-conductive cover material being accessible through the exposed window of the housing, which serves as the outward facing surface of the sensor and, together with the membrane, effectively displaces air as a dielectric for the capacitor formed by each pair of adjacent electrodes, one serving as a transmitting electrode and one as a receiving electrode. The sensor surface is configured to be placed in full and firm contact with the surface of the subject's tissue so that the electro-mechanical properties including normal surface pressure of the conductive tissue disrupts the electric field in the dielectric made up of the compressible membrane and interferes with the capacitive coupling between the co-planar electrodes of the relevant pair; wherein the sensor input device, in response to the pressure exerted on the sensor surface by contact with the skin or other soft tissue surface and the compression created by the compressible membrane and the interference with the capacitive coupling between the co-planar electrodes of the relevant pair, directs and generates at least one signal as an indication of the location, dynamics, and special features of the local area of hard tissue underlying the area of the skin or other tissue surface under investigation according to the variable composition and properties of the underlying tissue structure.The controller is disposed within the housing, the controller comprising: (a) one or more commercially available IC capacitive sensor chips configured to: (i) generate signals for stimulating pairs of electrodes located in the substrate; (ii) receive and process signals subsequently directed, generated, and transmitted by the capacitive tactile sensor input device in response to pressure exerted on the sensor surface by contact with a skin or other soft tissue surface; and (iii) direct, generate, and transmit signals derived from processing of signals directed, generated, and transmitted to the IC capacitive sensor chips by the capacitive tactile sensor input device; and (b) one or more integrated circuits and processors configured to: (i) receive and process signals directed, generated, and transmitted by the IC capacitive sensor chips to calculate one or more parameters of the underlying tissue structure based on changes in perceived capacitance between adjacent pairs of related electrodes resulting from pressure exerted on the sensor surface by contact with a skin or other soft tissue surface; and (ii) communicatively connect with a visualization device comprising a display and an integrated storage device.

[0080] In one embodiment, the homogeneous, compressible, non-ferrous, and non-conductive film comprises a polyurethane, silicon, or thermoplastic elastomer foam. In one embodiment, the foam has a hardness in the range 00-0 to 00-20. In one embodiment, the plurality of electrodes comprises at least two electrodes. In one embodiment, each electrode of the plurality of electrodes has a surface area between 1 mm 2 and 16 mm 2 In one embodiment, the device comprises a visualization device communicatively connected to the controller, the visualization device comprising a display. In one embodiment, the controller is connected to the visualization device via a Bluetooth connection. In one embodiment, the device comprises a conductive element located on the exterior of the housing configured to deliver a reference voltage used in all subsequent capacitance calculations. In one embodiment, the device comprises a ground pad or ground strap providing conductive contact between a non-insulated portion of the electronic plane and the outer surface of the capacitive sensor configured to deliver a reference voltage used in all subsequent capacitance calculations. In one embodiment, the at least one parameter comprises tissue hardness. In one embodiment, the tissue of the subject comprises breast tissue.

[0081] In one embodiment, a method of recording, measuring, and mapping the size, shape, and location of palpable lesions beneath the surface of a subject's skin or other soft tissue by measuring changes in normal tactile pressure on the surface of a skin or other soft tissue region of a tissue surface using capacitive tactile sensing, the method comprising the steps of: positioning a handheld device comprising a plurality of electrodes and a quantity of non-conductive compressible material and covered in substantially contact with a surface region of a subject's skin or tissue; determining a baseline reference capacitance for the subject by measurements taken by an operator from an unimpaired region of the tissue; determining a baseline reference voltage potential by the operator through conductive contact between the operator and the handheld device; positioning the handheld device in substantially contact with a surface region of the skin or tissue under investigation; measuring the capacitance created between two of the plurality of electrodes as a result of contact with the surface region of the skin or tissue under investigation; measuring the change in perceived capacitance between adjacent pairs of electrodes as a result of the pressure exerted on the sensor surface (compressible membrane and cover) due to the destruction of the capacitive coupling between adjacent pairs of electrodes as a result of contact with the surface of the skin or tissue under investigation with reference to the baseline reference voltage potential; and calculating one or more tissue parameters from the baseline reference voltage potential based on the change in perceived capacitance. In one embodiment, the method comprises the step of: transmitting data selected from the group consisting of perceived capacitance, thickness, and tissue parameters to a visualization system. In one embodiment, the method comprises the steps of: measuring a plurality of capacitance values between a set of electrode pairs and displaying a graph of parameter values on the surface of the tissue on a visualization system. In one embodiment, the tissue parameter refers to stiffness.

[0082] In one embodiment, a method of performing a guided self-examination of a subject's tissue, comprising the steps of: positioning a handheld device comprising a plurality of electrodes and a quantity of pliable material in substantially contact with a region of the subject's body; measuring the capacitance between two of the plurality of electrodes; calculating a tissue parameter based on the capacitance; determining an instruction for the subject in a controller based on the tissue parameter; and issuing the instruction to the subject to guide the subject in manipulating the handheld device. In one embodiment, the instruction refers to an audible instruction issued via a speaker. In one embodiment, the instruction is configured to direct the subject to move the device to a new location on the tissue. In one embodiment, the instruction comprises a visual cue presented on a display.

[0083] Experimental Examples

[0084] The present application will be further described in detail by reference to the following experimental examples. These examples are provided for purposes of illustration only, and are not intended to be limiting unless otherwise specified. Thus, the present application should in no way be limited to the following examples, but rather should be given the full scope of its content as described in the specification and as otherwise interpreted by the technical field of experts in the art.

[0085] Without further description, it is recognized that the systems and methods of the present application can be used in any number of embodiments by one of ordinary skill in the art having the benefit of the present disclosure. Accordingly, the following working examples illustrate exemplary implementations of the present application and should in no way be construed as limiting the remainder of the disclosure in any way.

[0086] According to one embodiment, reference is made to Figure 8 Simple comparison data for piezoelectric and capacitive sensors is provided.

[0087] The disclosures of each and every patent, patent application, and publication cited herein are hereby incorporated herein by reference in their entirety. While this application has been disclosed with reference to specific embodiments, it is apparent that other embodiments and variations of this application can be devised by others skilled in the art without departing from the true spirit and scope of the application. The appended claims are intended to be construed to include all such embodiments and equivalent variations.

Claims

1. A device for measuring tissue parameters of a subject, comprising: The housing has at least one exposed window; The substrate includes a plurality of electrodes disposed within the housing; An insulating layer is positioned on the electrode; A flexible membrane, positioned on the insulating layer, wherein at least a portion of the flexible membrane is accessible via the exposure window, wherein the flexible membrane is arranged to deform non-uniformly in response to non-uniform pressure applied between the outer surface and the plurality of electrodes to reflect changes in the stiffness of the subject's tissue; and A controller, disposed within the housing, is configured to calculate at least one parameter of the subject's tissue based on capacitance measured between the plurality of electrodes. Specifically, a first mean is calculated from a plurality of data values ​​based on the parameters; a subset of the plurality of data values ​​is obtained, wherein the values ​​in the subset are within one standard deviation of the first mean; a second mean is calculated from the subset of the plurality of data values ​​as a baseline value; and the baseline value is subtracted from the plurality of data values ​​to generate a calibration dataset.

2. The device according to claim 1, wherein, The flexible membrane includes foam.

3. The device according to claim 2, wherein, The Shore hardness of the foam is in the range of 00-0 to 00-20.

4. The device according to claim 1, wherein, The plurality of electrodes includes at least two electrodes.

5. The device according to claim 1, wherein, Each of the plurality of electrodes has a diameter of 1 mm. 2 With 16mm 2 The surface area between them.

6. The device of claim 1, further comprising a visualization device communicatively connected to the controller, the visualization device including a display.

7. The device according to claim 6, wherein, The controller is connected to the visualization device via Bluetooth.

8. The device of claim 1, further comprising a conductive element configured to transmit a reference voltage to a surface in contact with the flexible membrane.

9. The device according to claim 8, wherein, The conductive element is positioned to substantially surround the exposure window.

10. The device according to claim 1, wherein, At least one of the parameters includes tissue stiffness.

11. The device according to claim 1, wherein, The tissues mentioned in the subject's records include breast tissue.

12. A method for measuring tissue parameters of a subject, comprising: A positioning handheld device includes multiple electrodes and a certain amount of flexible material in general contact with a body area of ​​the subject, wherein the flexible material is arranged to deform unevenly in response to non-uniform pressure applied between the outer surface and the multiple electrodes to reflect changes in the stiffness of the subject's tissues. Measure the capacitance between two electrodes of the plurality of electrodes; The thickness of the flexible material is determined based on the capacitance; and The tissue parameters are calculated based on the thickness of the flexible material. Specifically, a first mean is calculated from a plurality of data values ​​based on the parameters; a subset of the plurality of data values ​​is obtained, wherein the values ​​in the subset are within one standard deviation of the first mean; a second mean is calculated from the subset of the plurality of data values ​​as a baseline value; and the baseline value is subtracted from the plurality of data values ​​to generate a calibration dataset.

13. The method of claim 12, further comprising: Data selected from the group consisting of the capacitance, the thickness, and the tissue parameters is sent to the visualization system.

14. The method of claim 13, further comprising: Multiple capacitance values ​​between a set of electrode pairs are measured, and a graph of the parameter values ​​across the tissue surface is displayed on the visualization system.

15. The method according to claim 12, wherein, The tissue parameter is hardness.

16. A capacitive tactile sensor device for detecting, recording, measuring, and mapping the size, shape, and location of damage to the subsurface layer of the skin or other soft tissue by measuring changes in tactile pressure on the surface of a subject's skin or other tissue, the capacitive tactile sensor device comprising: The housing has at least one exposed window and an exposed conductive surface, the exposed conductive surface being positioned such that the operator or the device is always in contact with the conductive surface when operating the device. A substrate, located within the housing measurement, comprises multiple pairs of separate coplanar and co-located electrodes arranged in a Cartesian grid on a non-conductive material, and is configured such that any two adjacent electrodes are electrically independent and can be independently stimulated by externally generated stimulation voltage or current signals, thereby forming a capacitor between each pair of electrodes, and the space above the outer surface of the electrode grid serves as a dielectric. An insulating material layer is positioned on the outward-facing surface of the electrode grid; A homogeneous, compressible, non-ferrite, and non-conductive membrane covers an insulating layer positioned above the outward-facing surfaces of the electrode grid, the membrane: (a) having a uniform thickness across the entire surface region of each pair of adjacent electrodes forming the capacitor, and across the entire surface region of the Cartesian grid of the electrodes; (b) having a fixed, uniform, and known compression ratio and stiffness across the entire surface region of the Cartesian grid of the electrodes; and (c) having a steady-state equilibrium shape such that the volume of the membrane remains constant when not subjected to external forces; and A non-conductive covering material is positioned on the outward-facing surface of the homogeneous, compressible, non-ferrite, and compressible membrane. At least a portion of the non-conductive covering material is accessible through the exposure window of the housing, which serves as the outward-facing surface of the sensor and, together with the membrane, effectively replaces air with a dielectric for the capacitor formed by each pair of adjacent electrodes, one electrode in each pair serving as a transmitting electrode and the other as a receiving electrode. The sensor surface is configured to be in full and firm contact with the surface of the subject's tissue, such that the electromechanical properties, including the conduction of normal surface pressure of the tissue, will disrupt the electric field in the dielectric composed of the compressible membrane and interfere with the capacitive coupling between the relevant coplanar electrode pairs. The sensor input device, in response to pressure applied to the sensor surface through contact with the skin or other soft tissue surface, compression generated by the compressible membrane, and interference with the capacitive coupling between the associated coplanar electrode pairs, guides and generates at least one signal based on the variable composition and characteristics of the underlying tissue structure, as an indication of the location, dynamic characteristics, and specific features of a local region of the hard tissue beneath the area of ​​the skin or other tissue surface under study; and A controller, disposed within the housing, includes: (a) one or more commercially available IC capacitive sensor chips configured to: (i) generate signals for stimulating electrode pairs located in the substrate; (ii) receive and process signals subsequently sensed, generated, and transmitted by a capacitive tactile sensor input device in response to pressure applied to the sensor surface through contact with the skin or other soft tissue surface; and (iii) sense, generate, and transmit to the device signals derived from the processing of the signals sensed, generated, and transmitted to the IC capacitive sensor chip by the capacitive tactile sensor input device; and (b) one or more integrated circuits and a processor configured to: (i) receive and process the signals sensed, generated, and transmitted by the IC capacitive sensor chip to calculate one or more parameters of the underlying tissue structure based on changes in the sensed capacitance between adjacent related electrode pairs caused by pressure applied to the sensor surface through contact with the skin or other soft tissue surface; and (ii) communicatively connect to a visualization device including a display and integrated storage devices. The membrane is arranged to deform non-uniformly in response to non-uniform pressure applied between its outer surface and the plurality of electrodes, in order to reflect changes in the stiffness of the subject's tissues. Specifically, a first mean is calculated from a plurality of data values ​​based on the parameters; a subset of the plurality of data values ​​is obtained, wherein the values ​​in the subset are within one standard deviation of the first mean; a second mean is calculated from the subset of the plurality of data values ​​as a baseline value; and the baseline value is subtracted from the plurality of data values ​​to generate a calibration dataset.

17. The device according to claim 16, wherein, The homogeneous, compressible, non-ferrite, and non-conductive membrane includes polyurethane, silicone, or thermoplastic elastomer foam.

18. The device according to claim 17, wherein, The Shore hardness of the foam is in the range of 00-0 to 00-20.

19. The device according to claim 16, wherein, The plurality of electrodes includes at least two electrodes.

20. The device according to claim 16, wherein, Each of the plurality of electrodes has a diameter of 1 mm. 2 With 16mm 2 The surface area between them.

21. The device of claim 16, further comprising a visualization device communicatively connected to the controller, the visualization device including a display.

22. The device according to claim 21, wherein, The controller is connected to the visualization device via Bluetooth.

23. The device of claim 16, further comprising a conductive element located outside the housing, the conductive element being configured to transmit the reference voltage to be used for all subsequent capacitance calculations.

24. The device of claim 16, further comprising a grounding pad or grounding strip providing conductive contact between a non-insulated portion of the electronic plane and the outer surface of the capacitive sensor, the grounding pad or grounding strip being configured to transmit all subsequent reference voltages to be used in capacitance calculations.

25. The device according to claim 16, wherein, At least one of the parameters includes tissue stiffness.

26. The device according to claim 16, wherein, The tissues mentioned in the subject's records include breast tissue.

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