Hamamatsu-photonics K.k.

Hamamatsu Photonics Kabushiki Kaisha

Mark Cope

David T Delpy

Stephen John Matcher

A spectrometric technique is described for quantitatively determining the change in concentration of a substance which is contained in a medium which both absorbs and scatters spectroscopically interrogated radiation, and in particular to the specific case in which the change in concentration of the substance occurs in one spatially distinct region of the medium. The medium includes a plurality of such regions displaying potentially different absorption and scattering properties to the radiation. Specific applications are disclosed involving the noninvasive determination of changes in concentration of the substances oxyhemoglobin and deoxyhemoglobin and/or changes in the redox state of the substance cytochrome oxidase within the brain or skeletal muscle, and in cases where the brain or skeletal muscle is interrogated by radiation in the near-infrared part of the electromagnetic spectrum through intervening surface tissues, i.e., cortical bone or adipose tissue, where it may be assumed that no changes of concentration of said substances occur within said surface tissues.

Spectroscopic method for quantitatively determining the change of

A diagnostic apparatus includes light sources which emit near infrared light rays of different wavelengths. The light rays are introduced into human brain to be subjected to diagnosis and the light rays transmitted through the brain are picked up. There are provided a first detector which detects occurrences of respirations of the subject and outputs a respiration signal, and a second detector which detects occurrences of heartbeats of the subject and outputs a heartbeat signal. The light transmitted through the brain is derived in synchronism with both the respiration signal and the heartbeat signal and first and second modulated light transmission signals are produced which are respectively modulated by the respiration signal and the heartbeat signal. The first and second modulated light transmission signals are separately analyzed to provide variations in concentration of oxygenated media .DELTA.X.sub.02 and disoxygenated media .DELTA.X contained in venous and arterial blood of the brain, respectively. Based thereon, oxygen saturations of both venous and arterial blood flowing in the brain are separately computed and displayed in a monitor screen.

Diagnostic apparatus for measuring changes of arterial and venous blood

An optical examination apparatus for optically examining density, distribution, etc. of oxygen in an object to be examined such as organic tissue like brain tissue, of man or animal compressing a light source, an optical fibre bundle having one end on which light emitted from the light source is incident and which is divided at the other end into a first and second branch with a predetermined ratio of division, transmitted and scattered light detection means for detecting light is emitted from the first branch of the fibre bundle and transmitted through and scattered by the object to be examined, monitoring light detection means for detecting monitoring light emitted from the second branch fibre bundle, normalization means for normalizing an output of the transmitted and scattered light detected means on the basis of an output from the monitoring light detection means, representative sampling means for ensuring that the light output from the second branch fibre bundle is representative of that output by the light source. The representative sampling means may be provided by distributing the optical fibres forming the second branch fibre bundle uniformly over the one end of the optical fibre bundle or may comprise a mode scrambler interposed between the one end of the optical fibre bundle and the light source to distribute light from the light source over the whole fibre bundle.

Growing community of inventors

London, United Kingdom

Mark Cope