Nihon Kohden Corporation

Cheng-tai Xie

Masayoshi Fuse

Takuo Aoyagi

Michio Kanemoto

Naoki Kobayashi

Sunao Takeda

Hideaki Hirahara

A probe includes a light irradiating device and a light receiving device , which are oppositely disposed sandwiching living tissue . The light irradiating device includes a light source and a scattering plate located in front of the light source . The light receiving device includes a photo diode and a light scattering portion. With such an arrangement, of the attenuation of the living tissue , non-absorbing attenuation is free from the wavelength. A ratio of absorbing attenuation and a thickness of a blood layer is not affected by a thickness of living tissue. Further, the absorbing attenuation is not dependent on a depth of the blood layer.

Probe and apparatus for determining concentration of light-absorbing materials in living tissue

Light beams of different wavelengths, emitted from a light generating device, are transmitted through a living tissue. The transmitted light beams are converted into electrical signals by a photoelectric transducing device. A pulsation calculating device calculates a pulsation of an absorbance of tissue of a living tissue for each wavelength on the basis of the output signal of the photoelectric transducing device. By using this, a pulsation ratio calculating device calculates the ratio of the pulsations of the absorbance values. A concentration calculating device puts the output signal of the pulsation ratio calculating device into a formula having a single unknown on the tissue term, which is constructed on the basis of the fact that a predetermined relation is present between the tissue terms of the respective wavelengths, thereby calculating a value of the tissue term and the concentration of light absorbing material in blood.

Apparatus for determining the concentration of light-absorbing materials

An external auditory canal arm having a photo sensing element at the distal end thereof is inserted into an external auditory meatus. A contact piece 1b having a light emitting element is set to a location near an ear lobe on the surface of a skin of the temporal region of a subject. Light that is emitted from the light emitting element and transmitted through the superficial temporal artery region, is received by the photo sensing element. A variation of the quantity of light when passing through blood flowing through the superficial temporal artery, which is caused by light absorptive materials in the blood, is detected, to thereby obtain oxygen saturation, cardiac output and blood volumes, and the like in the blood.

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Tokyo, Japan

Cheng-tai Xie