CT computed tomograph

• US 4,910,404 A
• Filed: 02/16/1989
• Issued: 03/20/1990
• Est. Priority Date: 02/17/1988
• Status: Expired due to Fees

• Current Assignee: Sumitomo Electric Industries Limited (Sumitomo Corporation)
• Original Assignee: Sumitomo Electric Industries Limited (Sumitomo Corporation)
• Inventors: Cho, Yoshio, Kanda, Masahiko
• Primary Examiner(s): FIELDS, CAROLYN
• Application Number:
  US07/311,658
• Time in Patent Office: 397 Days
• Field of Search: 250/358.1, 250/341, 250/350, 250/349, 128/633, 128/664
• US Class Current: 250/358.1
• CPC Class Codes: A61B 5/14553 specially adapted for cerebral tissue
• CPC Class Codes: G01N 21/59 Transmissivity G01N21/25 takes precedence

Abstract

A CT computed tomograph comprises a scanner (51) which surrounds a living body of a person to be examined. Ultrashort light pulses of the ith wavelength are applied to the living body from a sample light transmitting path (80k) corresponding to the kth cell of this scanner and the sample light pulses received by a sample light receiving path (81l) corresponding to the lth cell and reference light pulses transmitted from a reference light path (79) and a delay light path (78) are converged by a converging lens (75). A CPU(64) counts photons outputted from a photomultiplier (22) based on the converged light pulses and calculates an average value by averaging a predetermined number of count values. A delay amount of the reference light pulses through the delay light path (78) is changed based on the average value and, based on delay time and an average value in the delay time, a photon count value S_0i (k, l) obtained by counting the photons of the second harmonic when the delay amount of the reference light pulses is a predetermined value is stored. Based on the photon average value S_0i (k, l), a tomographic image of the metabolism of the living body is evaluated.

Claims

1. A CT computed tomograph for measuring metabolism of a living body of a human or an animal to be examined, comprising:

light sources (621, 622,

     623) for generating high-repetitive ultrashort light pulses of a plurality of wavelengths,

light branching means (85) for branching said ultrashort light pulses generated from said light sources to reference light pulses and sample light pulses,

a reference light path (79) for introducing the reference light pulses branched by said light branching means,

a scanner (51) formed in the shape of a ring surrounding the living body of said human or animal to be examined, and including a plurality of cells sectioned at predetermined intervals along its inner circumferential surface,

a plurality of sample light transmitting paths (801, 80n) having respective ends in the cells of said scanner, opposite to said living body, and having respective other ends to which the sample light pulses branched by said light branching means are applied,

sample light receiving paths (811 to 81n) having respective ends in the cells of said scanner opposite to said living body and respective other end from which the sample light pulses transmitted through said living body are introduced,

delay means for delaying the light pulses in any one of said reference light path, said sample light transmitting paths and said sample light receiving paths by a predetermined time,

converging means (75) for converging the reference light pulses introduced through said reference light path and the sample light pulses transmitted through said sample light receiving paths,

a crystal (74) for generating a second harmonic based on the light pulses converged by said converging means,

second harmonic detecting means (72) for detecting the second harmonic generated from said crystal, and

evaluation control means (64) for applying, to said living body in said scanner, the ultrashort light pulses of the ith wavelength from the sample light transmitting path corresponding to the kth cell, converging the sample light pulses received by the sample light receiving path corresponding to the lth cell and said reference light pulses by said converging means, counting photons outputted from said second harmonic detecting means based on the converged light pulses, obtaining an average value by averaging a predetermined number of count values, changing a delay amount of either the sample light pulses or the reference light pulses by said delay means based on said average value, storing a photon average value S_0i (k, l) (where k, l=1, 2, . . . n and i=1, 2, . . . m) of the count value of photons of said second harmonic when the delay amount of the reference light pulses and the sample light pulses is a predetermined value, based on delay time and an average value in said delay time, and evaluating a tomographic image of the metabolism in said living body based on said photon average value S_0i (k, l).

2. A CT computed tomograph in accordance with claim 1, further comprising

first shutter means (611 to 61n) provided corresponding to the respective sample light transmitting paths, for shutting off the sample light pulses supplied from said light branching means,

said evaluating control means including first shutter drive means (69) for opening any one of said first shutter means.

3. A CT computed tomograph in accordance with claim 1, further comprising

second shutter means (821 to 82n) provided corresponding to the respective sample light receiving paths, for shutting off the sample light pulses transmitted through said living body,

said evaluation control means including second shutter drive means (70) for opening any one of said second shutter means.

4. A CT computed tomograph in accordance with claim 1, further comprising

a filter (73) provided between said crystal and said second harmonic detecting means, for permitting only the second harmonic generated from said crystal to pass therethrough.

5. A CT computed tomograph in accordance with claim 1, wherein

said evaluation control means evaluates, as the metabolism of said living body, an oxygen saturation of hemoglobin, a quantity of hemoglobin and an oxidation-reduction degree of Cytaa3 from said photon average value S0i(k, l).

6. A CT computed tomograph in accordance with claim 5, further comprising

display means (67) for displaying the metabolism of said living body evaluated by said evaluation control means.

7. A CT computed tomograph in accordance with claim 5, further comprising

recording means (68) for recording the metabolism of said living body evaluated by said evaluation control means.