Method and apparatus for determining cerebral oxygen saturation
First Claim
1. Apparatus for spectrophotometrically monitoring hemoglobin oxygenation in a test subject, comprising in combination:
- a source of photons having a desired wavelength;
a probe coupled to said source to optically access a single location on the test subject by injecting photons into said subject from said source at said location and for receiving photons exiting said subject at said location after injection;
a photon-conducting device operatively associated with said probe to receive a stream of said exiting photons and to produce at least two differently timed streams of photons therefrom;
a shuttered device coupled to said photon-conducting device to receive said at least two differently-timed photon streams and simultaneously switch each of said two streams on and off to create a pair of different photon bursts therefrom; and
a detector coupled to said shutter device to receive said pair of separate photon bursts and provide corresponding output signals for processing.
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Accused Products
Abstract
A new and improved method and apparatus for determining cerebral oxygenation. In one basic aspect, a new processing methodology for oxygenation determination, in particular cerebral oxygenation, is provided based on the apprehension and discovery that time-based photon quantity determinations of the wavelength-specific light leaving the head of the patient may be significantly improved, and simplified, by determining the quantity of returning photons in at least one set of two different but closely spaced points in time following the instant of injection, and then taking the ratio of the determinations in each set, to thereby cancel and remove several important sources of error.
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Citations
24 Claims
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1. Apparatus for spectrophotometrically monitoring hemoglobin oxygenation in a test subject, comprising in combination:
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a source of photons having a desired wavelength; a probe coupled to said source to optically access a single location on the test subject by injecting photons into said subject from said source at said location and for receiving photons exiting said subject at said location after injection; a photon-conducting device operatively associated with said probe to receive a stream of said exiting photons and to produce at least two differently timed streams of photons therefrom; a shuttered device coupled to said photon-conducting device to receive said at least two differently-timed photon streams and simultaneously switch each of said two streams on and off to create a pair of different photon bursts therefrom; and a detector coupled to said shutter device to receive said pair of separate photon bursts and provide corresponding output signals for processing. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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- 12. A method of processing optically produced hemoglobin oxygenation data which includes at least two signals that are respectively representative of at least two quantities of examination light which are emitted from a test subject at different points in time with respect to each other following the input of related and corresponding examination light pulsed into said test subject, said method comprising the step of computing a value for each of said at least two signals, taking the ratio of said at least two signal values to thereby cancel out and thus remove error sources common to each of said at least two values, and at least one of displaying the ratio, and providing the ratio to a computer for further processing.
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19. A method of monitoring hemoglobin oxygenation in a test subject, comprising the steps of:
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injecting a quantity of photons having a predetermined wavelength into said test subject at a predetermined time and location; optically accessing said predetermined location on said test subject to receive photons exiting said test subject at at least two different timed intervals following said time of injecting; converting said received photons exiting said test subject at at least two different timed intervals into at least two corresponding concurrent signals for subsequent evaluative processing; and least one of displaying the at least two corresponding concurrent signals, and providing the at least two corresponding concurrent signals to a computer for further processing. - View Dependent Claims (20, 21, 22, 23, 24)
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Specification