Optical system for measuring metabolism in a body and imaging method
First Claim
1. A living body optical measurement system comprising:
- a plurality of light irradiation means for irradiating light rays having the wavelength range of from visible rays to near infrared rays on a subject;
a plurality of light receiving means for detecting light rays irradiated from said light irradiation means and transmitting through the interior of said subject;
memory means for storing, in time sequence, signals detected by said light receiving means and delivered out of the respective ones of said plurality of light receiving means;
arithmetic means for performing conversion into signals of objects to be measured at a plurality of presumptive measuring points by using the signals stored in said memory means; and
image preparation means for displaying the output of said arithmetic means as an image representative of an intensity signal on a two-dimensional display screen by calculating and determining signals at positions of the presumptive measuring points through an arithmetic operation.
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Abstract
Light rays of a plurality of wavelengths which are modulated in intensity with a plurality of different frequencies are irradiated on a plurality of irradiation positions on the surface of a living body, and time-variable changes in living body transmitting light intensity levels corresponding to the respective wavelengths and the respective irradiation positions are measured at different positions on the surface of the living body. After completion of the measurement or during the measurement, changes in concentration values of absorbers in the living body are determined from the living body transmitting light intensity levels of the plurality of wavelengths detected at the respective detection points and a measuring point is set on a perpendicular extending through an intermediate point between the incident point and each detection point so as to image a function of the living body. In living body optical measurement system and method, the measuring time is shortened by estimating fluctuation attributable to the living body, the presence or absence of a change in measured signal can be decided easily by displaying an estimation signal and a measured signal at a time, and a local change in hemodynamic movement can be measured by detecting light rays transmitting through the interior of the living body by means of two means for light detection disposed at different two sites (equidistant from the light incident point) on a subject and by separating only the local change in hemodynamic movement from an overall change in hemodynamic movement in the living body in accordance with a logarithmic difference between the two detection signals.
22 Citations
38 Claims
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1. A living body optical measurement system comprising:
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a plurality of light irradiation means for irradiating light rays having the wavelength range of from visible rays to near infrared rays on a subject;
a plurality of light receiving means for detecting light rays irradiated from said light irradiation means and transmitting through the interior of said subject;
memory means for storing, in time sequence, signals detected by said light receiving means and delivered out of the respective ones of said plurality of light receiving means;
arithmetic means for performing conversion into signals of objects to be measured at a plurality of presumptive measuring points by using the signals stored in said memory means; and
image preparation means for displaying the output of said arithmetic means as an image representative of an intensity signal on a two-dimensional display screen by calculating and determining signals at positions of the presumptive measuring points through an arithmetic operation. - View Dependent Claims (2, 3, 4)
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5. An imaging method comprising the steps of:
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irradiating light rays having the wavelength range of from visible rays to near infrared rays on a plurality of light irradiation positions of a subject;
detecting light rays transmitting through the interior of said subject at at least one light detection point associated with each of said plurality of light irradiation positions;
calculating signals at presumptive measuring points from said plurality of light irradiation positions;
determining concentration values of light absorbers included in the interior of said subject; and
displaying concentration values of light absorbers at the plurality of presumptive measuring points obtained in the above step as a two-dimensional plane image representative of said subject. - View Dependent Claims (6, 7, 8, 9, 10, 15)
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- 11. A living body optical measurement method for measuring the living body transmitting light intensity by irradiating light on a living body while alternately setting loading time during which load is applied to the living body and unloading time during which load is not applied to the living body, wherein relaxation time following the loading time is set, and a signal corresponding to fluctuation attributable to the living body and contained in the measured signal is estimated from a measured signal obtained during the unloading time exclusive of the relaxation time.
- 16. A signal display method in a living body optical measurement system in which the living body transmitting light intensity is measured by irradiating light on a living body and a measured signal or a signal resulting from calculation of the measured signal is displayed on a display unit, wherein a signal corresponding to fluctuation attributable to the living body and contained in the measured signal is estimated and the estimated signal is displayed together with the measured signal.
- 17. A signal display method in a living body optical measurement system in which the living body transmitting light intensity is measured by irradiating light on a living body while alternately setting loading time during which load is applied on the living body and unloading time during which load is not applied to the living body, and a measured signal or a signal calculated from the measured signal is displayed on a display unit, wherein a signal corresponding to fluctuation attributable to the living body and contained in the measured signal is estimated from a measured signal obtained during the unloading time, and the estimated signal, together with the measured signal, is displayed as an estimation non-load signal.
- 18. A signal display method in a living body optical measurement system in which the living body transmitting light intensity is measured by irradiating light on a living body while alternately setting loading time during which load is applied to the living body and unloading time during which load is not applied to the living body, and a measured signal or a signal calculated from the measured signal is displayed on a display unit, wherein relaxation time following the loading time is set, a signal corresponding to fluctuation attributable to the living body and contained in the measured signal is estimated from a measured signal obtained during the unloading time exclusive of the relaxation time, and the estimated signal, together with the measured signal, is displayed as an estimation non-load signal.
- 28. A living body optical measurement system comprising light irradiation means for irradiating light on the surface of a living body and light detecting means for detecting the intensity of light transmitting through the interior of the living body and going out of the surface of the living body, wherein at least two sets of combination of light irradiation and light detection positions are provided, and a logarithmic difference signal between detection signals for the respective sets is used as a measured signal.
Specification