Somanetics Corporation

Gary D Lewis

Hugh F Stoddart

Wayne P Messing

Oleg Gonopolskiy

Richard S Scheuing

Peter H Klose

Melville C Stewart, Ii

Richard A Farkas

A spectrophotometric instrument for conducting in vivo patient examinations has a sensor which is applied to the patient target area, e.g. the forehead, which includes a source for emitting electromagnetic energy e.g. selected wavelengths in the near infrared range, such that the energy passes through the underlying tissue and is emitted at other locations spaced from the point of entry. The sensor also includes detectors for receiving the resulting light energy at two or more such other locations and sending corresponding signals to a processor for analysis, by which characteristics of the tissue transmissed by the examination wavelengths may be determined. Processing of such signals includes the contrasting of detected intensity levels corresponding to a reference wavelength received at one detection location with intensity signals representative of an investigative wavelength also received at such location to determine a first resultant signal, repeating the process for the same wavelengths at another detection location, to thus determine another resultant signal, and the contrasting of such two resultant signals. In a particular application, the instrument is used to determine regional cerebral blood oxygenation by processing the detection signals to obtain a first resultant having a value proportional to the ratio of deoxygenated hemoglobin with respect to oxygenated hemoglobin and then using the value of such resultant to compute a further resultant having a value proportional to the ratio of oxygenated hemoglobin with respect to the sum of oxygenated hemoglobin and deoxygenated hemoglobin.

Optical cerebral oximeter

A method of conducting clinical examination procedures by use of electrically actuated spectrometric apparatus, of the type which uses a sensor that is placed in contact with the patient to transmit and receive electromagnetic energy of selected wavelengths for non-invasive in vivo examination of a selected area on the body, in which a conductive member is placed in contact with the patient near or at the location of the sensor and connected to the signal-processing circuitry of the processor for the spectrometric signals in a manner such that the examination signals have significantly less noise content than would otherwise be true. In so doing, the signal-processing circuitry is isolated from the power supply circuitry, and the sensor and conductive member are preferably coupled to the processor by use of an isolation preamplifier, such that the signal-processing ground potential reference is maintained separate and distinct from the power supply ground. The specially-grounded conductive member that is placed in contact with the patient is preferably made part of the sensor itself, as by using a conductive material on at least part of the sensor surface that is placed in contact with the patient, and such a conductive surface element may comprise a flexible outer coating or layer of a compliant sensor which is conformable to the shape of the patient extremity to which it is applied. In this manner, the surface potential of the patient at the location of the sensor may be equalized with that of the signal-processing circuitry ground potential to substantially reduce signal noise content, and ambient sources of electrical noise may be effectively shielded as well.

Method for improving signal-to-noise in clinical spectrometric procedures

A specially grounded sensor for improving signal-to-noise ratios in clinical spectrometric procedures includes a sensor body carrying electrically actuated spectrometric signal-producing and receiving components, e.g., electro-optical components, for transmittal and reception of particular examination energy wavelengths, in which the sensor body has an electrically conductive portion or element associated therewith for contacting the patient. This electrically conductive, member is coupled to the signal ground potential of associated signal-processing apparatus to thereby equalize the electrical potential of the patient surface area to which the sensor is applied with the aforementioned signal ground potential. Preferably, an isolation preamplifier is utilized between the sensor and a microprocessor wherein the examination signals are analyzed, to provide the aforementioned signal ground, but in any event this signal ground is maintained separate from and preferably isolated from the primary ground conductor and potential of the processor and/or of the driver circuitry which provides excitation for the electro-optical components. In a particular preferred embodiment, conductive shielding is used in the sensor for reducing electrical noise from ambient sources, and the aforementioned conductive sensor member is electrically connected to such shielding, for improved results. Also, in a preferred embodiment, this shielding substantially encloses an inner portion of the sensor carrying the electro-optical components, in particular, the light-detector, except for openings in the shielding of a size and shape to fit relatively closely around the detector and thereby provide maximal shielding effects for the detector and their associated electrical conductors.

Specially grounded sensor for clinical spectrophotometric procedures

Spectrophotometric apparatus and related methodology, including a sensor having a source and at least two receivers of electromagnetic radiation such as red and/or near-infrared light, which is applied non-invasively to the outer periphery of a patient or other animate test subject to examine a particular internal region to which is disposed beyond a peripheral extremity of specifically indeterminant thickness lying immediately inwardly of the outer periphery of the test subject. The location of the source and detectors test are selected to be at points spaced from one another by unequal first and second distances defining first and second mean optical paths of specifically differing length, with the second such path defining a primary internal area containing the particular region to be examined, the first optical path generally defining a second internal area located in the primary internal area but substantially separate from the particular internal region to be examined, and the first such optical path including the full thickness of a predetermined typical such peripheral extremity plus at least a small portion of the physiological substance immediately therebeyond. Signals are produced which are representative of the radiation detected by the first and second receivers, and such signals are processed to obtain data which particularly characterizes selected attributes of the substance within the particular internal region, substantially without effects attributable to the secondary internal volume, The second receiver is preferably disposed about thirty to forty millimeters from the source, and the first receiver positioned not closer than about twenty millimeters therefrom.

Method and apparatus for spectrophotometric cerebral oximetry and the

An apparatus and method which detects temperature variations of an LED used with spectroscopic devices. The apparatus and method uses a source to supply a signal to the LED. A detector coupled to the LED detects a signal at the LED. A controller is coupled to the detector to determine variations in operating characteristics of the LED resulting from changes in temperature.

Temperature compensation method and apparatus for spectroscopic devices

Methodology and apparatus for the clinical evaluation of biological matter, in particular human anatomy, examined in situ and in vivo, by selective spectral light transmissivity. An optical probe introduces selected light spectra into the examination subject at a first position and resulting light intensity at a second position located some distance from the infusion point is measured; also, light reception preferably occurs at at least one other location, and the effective distances between these locations and the infusion point are determined. The light energy received at the distant points is quantified and conditioned by use of the effective distances from the infusion point and/or from one another, and also by contrasting the data from the two differently-located reception points, such that the resulting data quantitatively characterizes intrinsic internal tissue characteristics in an absolute sense, devoid of particular individual characteristics and variations such as skin pigmentation, boundary composition or state, etc. The methodology is especially characterized by the selection and use of particularly-located first and second light-reception positions whose locations with respect to the point at which the light spectra are introduced define particular zones of interrogation and analysis, and whose location with respect to one another may be comparatively examined (e.g., differenced) to selectively define a particular internal volume whose structure or conditional state is to be examined, quantified, and/or analyzed, all of which is accomplished on a non-intrusive in vivo basis.

Method and apparatus for in vivo optical spectroscopic examination

A sensor for use in medical patient examination and monitoring by spectrophotometric apparatus, including a main body having a soft, resilient outer cover on at least one side for conformably contacting a selected area on the patient, in particular the forehead, also having and an electro-optical light source and a plurality of electro-optical light detectors spaced from the source and from one another, and exposed to the selected site on the patient by light-transmissive passages extending through the resilient cover, in which the resilient cover is formed of a thin, softly compressible member of light-absorbing and moisture-transmissible material, preferably of resilient cellular polymeric foam.

Patient sensor for optical cerebral oximeter and the like

An examination instrument for optical apparatus, including a pair of optical heads mounted for relative movement toward and away from one another upon an elongated support, and having means (e.g., an electrical transducer) for producing an electrical signal which is specifically representative of the distance between the optical heads at various positions of relative movement therebetween, for use in analyzing test data obtained by the optical heads. The instrument also includes a test sequence actuation switch disposed in a position where the operator may readily initiate a test sequence without changing his grip upon the instrument as it is held in place on the test subject. The optical heads are mounted on stand-off members which position the heads in spaced relation alongside the elongated support and at an angle relative to one another, to facilitate use on the human breast. The optical heads include internal light-guides for emitting and/or receiving light, and such light-guides are preferably matched optically to electro-optical detectors carried by the optical heads, for optimum performance.

Examination instrument for optical-response diagnostic apparatus

The internal physiological compositional state of an individual examination subject for example a human breast is assessed by transmission of selected light energy spectra into the interior of such subject, detecting the selected spectra after transversal of a distance within the object, quantifying the detected light energy at selected wavelengths, conditioning the obtained value sequence on the basis of distance, determining at least one composite averaged value from the conditioned value, and using such as a characterizing value in comparison with analogously obtained values representative for example of a norm in order to asses the internal state of the subject.

Method and apparatus for interpreting optical response data

The specification discloses a method for determining the nature (e.g., physiological and compositional state) of internal tissue or other such biological material within a human organ or extremity, or other such individual examination subject, by use of selected light energy spectra. The selected light energy is applied to infuse the light throughout the interior of the area to be examined and the relative intensities of the infused light spectra are detected after having traversed the interior of the examination area. The detected intensities are computer-analyzed in a manner which conditions the raw magnitudes initially detected on the basis of the internal distance traversed by the infused light energy and also on the basis of broad averages of such conditioned wavelength-specific detection data representative of a number of comparable examination subjects. The resulting conditioned data is then plotted or otherwise comparatively analyzed, and the data profile so provided is shown to characterize the internal tissue structure and compositional state, showing relative amounts of particular different organic substance (e.g., fibro-glandular tissue, fat, hemoglobin, protein-bound water, etc.). Normative data profiles are prepared for specified age groupings, for comparison with corresponding data from individual subjects within such age groupings, whereby departures from the norm are graphically illustrated and revealed. The conditioned data also provides numeric quantification characterizing the relative different amounts of different tissue found to be present in a given test subject.

Method and apparatus for in vivo evaluation of tissue composition

Methodology and apparatus for the clinical evaluation of biological matter, in particular the human breast, in situ and in vivo, by spectral light transmissivity. An optical probe introduces selected light spectra into the examination subject at a first position and resulting light is detected at a second position located some distance from the infusion point; also, reception preferably occurs at another location, and the distances of these locations from the infusion point are determined. The light energy received at the distant points is quantified and conditioned by use of the determined distances from the infusion point and also by contrasting the data from the two differently-located reception points, such that the resulting data is compensated or normalized to characterize intrinsic internal tissue characteristics in an absolute sense, devoid of individual characteristics such as skin pigmentation, breast thickness, etc. The methodology further includes analytical or diagnostic treatment of the conditioned data by specific comparison of conditioned data taken from different regions of the same subject, of conditioned data taken from the same region on physiologically paired and/or different subjects, and also provides for meaningful accumulation of large-scale 'background' or 'average' values based upon identified and selected patient populations.

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St. Clair Shores, MI, United States of America

Gary D Lewis