JPS63277037A - Diagnostic apparatus - Google Patents

Abstract

PURPOSE:To perform the detection of transmission quantity with good accuracy, by extending the detection period of transmission quantity until predetermined transmission quantity is detected when the predetermined transmission quantity is not detected within a predetermined period and extending the detection period of the output quantity of light in synchronous relation thereto. CONSTITUTION:A computer system 6 is constituted so that a processor 7, a memory 8, an output apparatus 9 and an input apparatus 10 are connected to a system bus 11. However, the computer system 6 sets the unit of the detection period of the transmission quantity of near infrared rays in a transmitted light detection apparatus 54 to one measuring period MK but extends the measuring period MK bringing transmission quantity to a predetermined value when the transmission quantity of wavelengths lambda1-lambda4 does not reach the predetermined value within one measuring period MK in a multichannel photon counter 61. That is, the computer system 6 performs the extension of the measuring period MK by extending the reading cycle of the transmission quantity data due to the processor 7.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a diagnostic device for measuring the amount of oxygen in internal organs such as the brain tissue of humans or animals, and in particular, the present invention relates to a diagnostic device for measuring the amount of oxygen in internal organs such as the brain tissue of humans or animals. The present invention relates to a diagnostic device that measures the amount of oxygen in internal organs by detecting the amount of oxygen in cytochromes using near-infrared light.

[Conventional technology]

Generally, when diagnosing the function of internal organs such as brain tissue,
Whether the amount of oxygen in the body's organs is sufficient and properly utilized is a fundamental and important parameter.The supply of sufficient oxygen to the body's organs is critical to the viability of the fetus and newborn. This is essential, and if the supply of oxygen is insufficient, the mortality rate of fetuses and newborns is high, and even if they survive, the aftereffects will have a large impact on internal organs. All organs in the body are affected, but brain tissue is particularly damaged.

In order to quickly and easily diagnose the oxygen levels in internal organs, a diagnostic device such as that disclosed in U.S. Pat. No. 4,281,645, issued on August 4, 1981, has been developed. being developed. This type of diagnostic device detects oxygen in internal organs, especially the brain, based on near-infrared absorption spectra of hemoglobin, an oxygen transport medium in the blood, and cytochrome a and a3 in cells that perform redox reactions. It is designed to measure changes in quantity. In other words, near-infrared light with a wavelength range of 700 to 1300 nm is shown in Figure 3(a).
Hemoglobin combined with oxygen (HbO2) as shown in
Hemoglobin (Hb) from which oxygen has been removed and hemoglobin (Hb) show different absorption spectra αHb02'αHb, and as shown in Figure 3(b), oxidized cytochrome a, a (
Cy02) and reduced cytochrome a, a3
(Cy) has a different absorption spectrum α. 9゜2. α
exhibits. Utilizing these properties of near-infrared light, four different wavelengths λ1. λ2. λ3゜λ4 (e.g. 775nm, 800nm, 825nm, 850nm)
By time-divisionally injecting near-infrared light of , that is, the respective concentrations of oxygen-bound hemoglobin (HbO2), deoxygenated hemoglobin (Hb), Mated cytochrome a, a (Cy02) *reduced cytochrome a, a3 (Cy) The amount of change is calculated, and based on this, for example, changes in the amount of oxygen in the brain are measured.

FIG. 4 is a schematic configuration diagram of such a diagnostic device. Fourth
In the figure, the conventional diagnostic device uses four different wavelengths λ1.
．． λ2. λ3. Light sources LD1 to LD4 such as laser diodes that each output near-infrared light of λ4, and light source LD
A light source control device that controls the output timing of I to LD4! F 55, optical fibers 50-1 to 50-4 for irradiating the head 60 with near-infrared light output from the light sources LDl to LD4, and optical fibers 50-1 to 50-5.
Irradiation side fixture 5 that holds the ends of 0-4 together in a bundle
1, a detection-side fixture 52 attached to a predetermined position of the head 60 on the opposite side to the side to which the irradiation fixture 51 is attached, and near-infrared light transmitted through the head 60 held by the detection-side fixture 52. Controls the optical fiber 53 that guides the light, the transmitted light detection device 54 that counts the number of photons of the near-infrared light guided by the optical fiber 53 and measures the amount of near-infrared light transmitted, and the entire diagnostic device, It further includes a computer system 56 that measures the amount of change in oxygen in brain tissue based on the amount of near-infrared light transmitted.

The computer system 56 includes a processor 62, a memory 63, and an output device 64 such as a display or a printer.
and an input device 65 such as a keyboard, which are connected to each other by a system bus 66. Further, a light source control device 55 and a transmitted light detection device 54 are connected to the system bus 66 of the computer system 56 as external I10.

The light source control device 55 drives the light sources LD1 to LD4 using drive signals ACT1 to ACT4 as shown in FIGS. 5(a) to 5(d) according to instructions from the computer system 56. In FIGS. 5(a) to 5(d), one measurement period Mk (k=1.2...) consists of N cycles CYI to CYN. Cycle CY1
Phase φ of any cycle CYn from CYH to
In phase n1, none of the light sources LDI to LD4 is driven, and the head 60 is not irradiated with near-infrared light from the light sources LDI to LD4. In phase φn2, the light source LDI is driven, and for example, 775 nm light is emitted from the light source LDI. Near-infrared light is output. Similarly, in phase φn3, the light source LD2 is driven and near-infrared light of, for example, 800 nm is output from the light source LD2, and in phase φn4, the light source LD3 is driven and near-infrared light of, for example, 825 nm is output from the light source LD3, and in phase φn5. Then, the light source LD4 is driven and the light source L
For example, near-infrared light of 850 nm is output from D4.

In this way, the light source control device 55 controls the light sources LDI to LD4.
are driven sequentially in a time-division manner.

The transmitted light detection device 54 also includes a filter 57 that adjusts the amount of near-infrared light from the optical fiber 53, and a lens 70.7.
1, a photomultiplier tube 58 that converts the light from the filter 57 into a pulse current and outputs it, an amplifier 59 that amplifies the pulse current from the photomultiplier tube 58, and a predetermined pulse current from the amplifier 59. a pulse height discriminator 60 that removes pulse currents below a pulse height threshold; a multichannel photon counter 61 that detects the photon number frequency for each channel; and a detection controller 67, for example, that controls the detection period of the multichannel photon counter 61. A temperature controller 68 is provided to adjust the temperature of a cooler 69 housing the photomultiplier tube 58.

In the diagnostic device having such a configuration, when in use, the irradiation-side fixture 51 and the detection-side fixture 52 are firmly attached to predetermined positions on the head 60 with tape or the like. Next, the light source control device 55 controls the light sources LD1 to LD4 as shown in FIG. 5(a).
When driven as shown in (d), four types of near-infrared light with different wavelengths are sequentially output from the light sources LDI to LD4 in a time-division manner, and are transmitted to the head via optical fibers 50-1 to 50-4. Since the bones and soft tissue fibers of the head 60 that are incident on the head 60 are transparent to near-infrared light, the near-infrared light mainly affects hemoglobin in the blood, cytochrome a, and a in the cells.
A part of the light is absorbed by the optical fiber 3 and output to the optical fiber 53, and is applied from the optical fiber 53 to the transmitted light detection device 54. 'xOh, in the phase φn1 in which none of the light sources LDl to LD4 is driven, the transmitted light from the light sources LDI to LD4 does not enter the transmitted light detection device 54, and at this time, the transmitted light detection device 54 detects dark light. It is done.

The photomultiplier tube 58 of the transmitted light detection device 54 is for photon counting, which operates with high sensitivity and high response speed. The output pulse current of the photomultiplier tube 58 is transmitted to the amplifier 5.
9 to the pulse height discriminator 60. Wave height discriminator 60
In this case, noise components below a predetermined pulse height threshold are removed and only signal pulses are input to the multi-channel photon counter 61. The multi-channel photon counter 61 operates according to the control signal CTL as shown in FIG. 5(e) from the detection controller 67 in FIGS.
Drive signal AC of light sources LDI to LD4 as shown in d)
Period T synchronized with TI to ACT4.

The number of photons detected for each wavelength of light incident from the optical fiber 53 is counted.

As a result, transmission amount data for each wavelength of near-infrared light is obtained.

That is, as shown in FIGS. 5(a) to 5(e), during one cycle CYn of the light source control bag W, 55, the phase φ
At n1, since none of the light sources LDI to LD4 are driven, the transmitted light detection device 54 counts the dark light data d. In addition, in phases φn2 to φn5, the light source L
Since DI to LD4 are sequentially driven in a time-division manner, the transmitted light detection device 54 detects four different wavelengths λ1. λ2.
Transmission data of near-infrared light of λ3゜λ4 1. 1
.

λ1 λ2 1. 1 is counted sequentially.

λ3 λ4 In this way, the dark light data d and the transmission amount data 1 . 1.
1. 1 is N times sai λ1 λ2 λ3
Counting continues over λ4 cycles CYI to CYN. That is, with N cycles, one measurement period Mk (k
=1.2. ...). Specifically, for example, one cycle CYn is 200 μs and N is 1oo
Assuming that there are oo times, one measurement period M is 2 seconds.

At the point when one measurement period Mk has not ended, the counting results of dark light data T , T , T , Tλ1 λ
2 λ3 λ4 (=Σ tλj/CYn) is transferred to the computer system n=1 and stored in the memory 63.

The processor 62 stores the memory 63 in one measurement period Mk.
Transmission amount data and dark light data (T
, TX2. T. , T 4. D) λ1 Ya, M at the start of measurement. Transmission amount data, dark light data (T, T□2.T.

Dark subtraction is performed from λ1 T , D>, and λ
4 MO Thereafter, the rate of change in transmission amount ΔT, ΔT, 2°λ1 ΔT, and ΔTA4 are calculated. That is, the rate of change in the amount of transmission λ3 is ΔT, ΔT. , 8T.

λ1 ΔT, ΔT ,=Nog[(T −D) /
λj λj Mk(T --
D)](j=1 to 4)λ no MO...(1) Calculated as follows. Note that the reason why ΔT□j is calculated using a logarithm is to represent a change in optical density.

The rate of change in the amount of transmission A'r”λ1 calculated in this way
．． ATλ2. ΔTλ3. From ΔTλ4, oxygen-bound hemoglobin (HbO2), deoxygenated hemoglobin (Hb), oxidized cytochrome a, a (Cy
02), reduced cytochrome a, a3 (Cy
), it is possible to detect the concentration changes ΔXHb02°ΔX, respectively, ΔX1lb·ΔXcy02·Cy. That is, the concentration change ΔXHb of each component. 2°ΔX ΔX, ΔX are detected as Hbl cy02 Cy (2). Here α2. is each component 1 (HbO
, Hb, CyO2, C, y), and is determined in advance from FIGS. 3(a) and (b).

Further, 1 is the length of the head 60 in the direction in which near-infrared light travels.

The concentration change of each component detected in the computer system 56 in this way ΔXHb02 'ΔX x
, ΔX is, in other words, 11b' cy0 in the brain
2 cy Since these are changes in the amount of oxygen, by outputting these to the output device 64, changes in the amount of oxygen in the brain can be known and diagnosed.

[Problem that the invention seeks to solve]

By the way, in the above-mentioned conventional diagnostic apparatus, the computer system performs one data collection, that is, transmittance amount data t, in units of one measurement period M, as shown in FIGS. 5(a) to 5(e).

1. 1. 1, 4, and the counting result λ2
λ3 T , T , T , T , T , T , However, there was a problem in that the multi-channel photon counter 61 could not count a sufficient number of photons in - times of data collection, and the transmitted light could not be detected with high accuracy.

SUMMARY OF THE INVENTION An object of the present invention is to provide a diagnostic device that can accurately detect the amount of permeation using simple means.

[Means for solving problems]

The present invention provides a plurality of light sources that respectively output near-infrared light of different wavelengths and make them enter internal organs, a transmission amount detection means for detecting the amount of near-infrared light transmitted through the internal organs, and Output light amount detection means for detecting the output light amount of near-infrared light output from the light source; and normalization means for normalizing the amount of transmission detected by the transmission amount detection means with the output light amount detected by the output light star detection means. When the predetermined amount of transmission is not detected within a predetermined detection period, the transmission amount detection means extends the detection period until the predetermined amount of transmission is detected, and in synchronization with this, the output light amount detection means solves the problems of the prior art described above with a diagnostic device characterized by extending the detection period of the output light amount and displaying this information when the ratio of the output light amount to the background noise becomes less than a predetermined value. This is an attempt to improve this point.

[Effect]

In the present invention, near-infrared light of different wavelengths is sequentially outputted from a plurality of light sources and made to enter internal organs. The transmission amount detection means detects the amount of near-infrared light transmitted through the internal organs, but if a predetermined amount of transmission is not detected within a predetermined detection period, the detection period is stopped until the predetermined amount of transmission is detected. On the other hand, the output light amount detection means detects the output light amount of near-infrared light from a plurality of light sources, but when the transmission amount detection period is extended, the output light amount detection period is extended in synchronization with this. Also postpone. The transmission amount detected by the transmission amount detection means is normalized by the output light amount detected by the output light amount detection means, and the oxygen amount is measured based on the standardized transmission amount. Further, in the present invention, when the ratio of the output light amount to the background noise becomes less than a predetermined value, this information is displayed to inform the operator.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a configuration diagram of an embodiment of a diagnostic device according to the present invention. In FIG. 1, the same parts as in FIG. 4 are given the same reference numerals, and their explanation will be omitted.

The diagnostic device 1 shown in FIG. 1 further includes light sources LDI to LD.
The output light detection device 2 is provided to detect the amount of near-infrared light outputted from the output light detector 4 . The output light detection device 2 is connected to the light sources LDI to LD4 via optical fibers 3-1 to 3-4. In addition, the output light detection device 2 is 1, a light source LD
Detects the output light amount of I to LD4 and outputs it as an output signal OT
an output optical monitor 4 that outputs analog electrical signals as
It is equipped with a multi-channel data accumulator 5 that converts the output signal OT from the output light monitor 4 into a digital signal and, like the multi-channel photon counter 61, integrates the input signal for each channel to create output light amount data. . The output light monitor 4 is composed of, for example, a photodiode.

Further, the computer system 6 includes a processor 7, a memory 8. The output device 9 and the input device 10 are connected to the system bus 11
It is configured to be connected to. However, although the computer system 6 basically uses one measurement period Mk as the unit of detection period for the amount of transmitted near-infrared light in the transmitted light detection device 54, the multi-channel photon counter 61 detects each wavelength within one measurement period Mh. When the amount of transmission of λ1 to λ4 does not reach the predetermined value, the measurement period M is continued until the amount of transmission reaches the predetermined value.

It is designed to prolong the period.

That is, the computer system 6 extends the measurement period Mk by extending the cycle of reading the transmission amount data by the processor 7.

In the diagnostic device 1 having such a configuration, the light sources LDI to LD
4 as a drive signal ACTI as shown in FIGS. 5(a) to (d).
When driven with ACT4 to ACT4, the light sources LDI to L
4 from D4? Near-infrared light of different wavelengths of class I is outputted sequentially in a time-sharing manner, enters the head 60 via the optical fibers 50-1 to 50-4, and further passes through the head 60 and exits from the optical fiber 53. It is added to the transmitted light detection device 54.

On the other hand, near-infrared light from the light sources LDI to LD4 is applied to the output light detection device 2 via optical fibers 3-1 to 3-4.

In the transmitted light detector W54, as described above, one cycle CYn width and different wavelengths λ1. λ2゜λ3. Transmission amount data t of near-infrared light of λ4.

te. , t□3. te, is sequentially detected, and this is detected by a multi-channel photon counter 6 over one measurement period Mk.
1, and count result T for each channel.
, T , T , T λ1 λ2
λ3 λ4

Similarly, in the output light detection device 2, one cycle C
In Yn, different wavelengths λ1. ^2. Near-infrared light output light intensity data of λ3゜λ4 ie1, 1e2゜1, Ra4 are sequentially detected, and this is accumulated by the multi-channel data accumulator 5 over one measurement period λ3 Mk, and is calculated for each channel. Integration result 1 ・
Iλ2・Engine λ3 λ4 yo1, find I.

At this time, the counting results T , T , T , T of the transmission amount data over one measurement period Mk are
λ2 λ3 λ4 When the fixed values have not been reached, one measurement period Mh is extended.

FIG. 2 is a diagram showing an example of extending one measurement period.

In FIG. 2, the measurement period M1. M2. For M4, the counting result T□1 of the permeation amount data.

T , T , Tλ4 all reach predetermined values λ
2 λ3, so the measurement period is not extended, but in the measurement period M3, a sufficient number of photons were not detected and the counting result of the transmission amount data T
, T□2. T. , T□4 have not reached the predetermined value λ1, the measurement period M3 is further extended by ΔM until they reach the predetermined value.

When one measurement period Mk is extended in this way, the output light amount data integration results I, I, 2. I. .

λ1 'A4 is also added up only for the extended bone.

Counting results of transmission amount data TAL to T□4 and output light amount data when one measurement period Mk is extended 9 (f)
f? In, the results A1 to 'A4 are stored in the memory 8 in the same manner as described above.

In this way, the dark light data stored in the memory 8, each transmission amount data T to T, each λ1
Based on the λ4 output light amount data A1 to 'A4, the processor 7 measures changes in the amount of oxygen and performs diagnosis.

That is, the processor 7 converts the weekly excess data T, 1 to T□4 in the memory 8 to the corresponding output light amount data A1 to I, respectively. The transmittances μE1 to μE4 are obtained by normalizing with . The transmittance μm1 to μ4 is μλi=Tλi/I^1 (i=1 to 24)...
・(3) This transmittance μ is determined as M at the start of diagnosis. Divide by the corresponding transmittance to find the amount of change Δ in the transmittance μ
μ, and in equation (2), by using the amount of change Δμm of this transmittance μe1 in place of the rate of change ΔTλ1 of the amount of transmission T□1, the hemoglobin bound to oxygen (Hbo2), Hemoglobin that is not bound to oxygen (H
b), oxidized cytochrome a, a3 (Cy0
2), reduced cytochrome a, a3
(Cy) concentration change ΔxHb02' AXllb=
AXCy02=CMΔX can be measured respectively.

Thus, according to this embodiment, one measurement period M.

When the counting results TAl to T of the transmission amount data do not reach the predetermined value within the unit of , one measurement period M is not extended until the predetermined value is reached. Counting result T of permeation amount data to be counted
At to T are large enough to ensure a predetermined measurement accuracy. That is, since the S/N ratio is proportional to the square root FX of the number N of photons detected, the S/N ratio can be improved by setting the predetermined values for the counting results TAl to TA4 of the transmission amount data sufficiently large. can. This makes it possible to obtain highly reliable diagnostic results.

Note that if the ratio of the integrated results IAI to A4 of the output light amount data during one measurement period M and the dark light data, that is, the background noise, is less than a predetermined value, it is determined that the diagnostic device 1 is not in an appropriate state. Therefore, the computer system 6 displays this state through the output device 9 to give some kind of warning to the operator.

〔Effect of the invention〕

As explained above, according to the present invention, when a predetermined amount of permeation is not detected within a predetermined period, the detection period of the amount of permeation is extended until the predetermined amount of permeation is detected, and output is performed in synchronization with this. Since the period for detecting the amount of light is extended, the amount of transmitted light can be detected with high accuracy, and the reliability of the diagnostic results can be improved.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of an embodiment of a diagnostic device according to the present invention, and FIG.
The figure is a diagram for explaining the extension of one measurement period M, Figures 3 (a) and (b) are diagrams showing the absorption spectra of hemoglobin and cytochrome, respectively, Figure 4 is a configuration diagram of a conventional diagnostic device, 5(a) to 5(d) are time charts of drive signals ACTI to ACT4, respectively, and FIG. 5(e)
is a time chart of control signal CTL. 1... Diagnosis device, 2... Output light detection device, 6...
Computer system, LD1 to LD4... Light source patent applicant Hamamatsu Photonics Co., Ltd. Agent Patent attorney Masaharu Uemoto Diagram 2 Procedural Amendment (0th printing 7 September 3, 1985 1 Indication of the case 1986 patent Application No. 110469 2 Invention name diagnosis device 3 Relationship with the person making the amendment Patent applicant address 1126 Ichino-cho, Hamamatsu City, Shizuoka Prefecture First name Hamamatsu Photonics Co., Ltd. Representative Teruo Toyoma 4 Agent residence Address (zip code 140) Tokyo Parts Ward 3-20-7 Higashioi Contents of the amendment (1) The scope of the patent claims will be amended as shown in the attached sheet. The text has been corrected to read "object to be measured such as internal organs" (3) Page 2, line 7 of the specification, page 13, line 16, page 13, line 18, page 13, lines 19 to 20, page 14, line 13 Lines 1 to 14, page 14, number 15
In line 14, page 14, line 19, replace “near infrared light” with “
"Electromagnetic waves," he corrected. (4) Specification page 2, line 8, page 13, line 17, page 13, lines 17 to 18, line 11, line 14,
On page 14, line 15, the words "internal organs" are corrected to "object to be measured." (5) Delete "plurality" from page 13, line 17, page 13, line 19, page 14, line 13, and page 14, line 19 of the specification. (6) On page 14, line 9 of the specification, and on page 15, line 7, “
Correct "display" to "output". (7) Next on page 21, line 19 of the specification: ``In the above embodiment, multiple light sources are used as light sources, but only one white light source is used to create electromagnetic waves of different wavelengths by filter grinding. The diagnostic target is not limited to internal organs, but can also be general objects to be measured such as pieces of meat, and the electromagnetic waves from the light source are not limited to near-infrared light.
Far-infrared light, visible light, microwaves, etc. may be used.'' The claim is characterized in that it outputs 1 ray of different wavelengths and 5-prongs A and 15 ヱ1 respectively. A transmission amount detection means for detecting the transmission amount of one wind difference transmitted, an output light amount detection means for detecting the WUIXJI eue 1, and an output light amount detection means for detecting the transmission amount detected by the transmission amount detection means. and normalizing means for standardizing the output light amount by the output light amount, and the transmission amount detecting means includes:
When the predetermined amount of permeation is not detected within the predetermined detection period, the detection period is extended until the predetermined amount of permeation is detected;
In synchronization with this, the output light amount detection means extends the detection period of the output light 1, and also includes means for disposing this information when the ratio of the output scene to the background noise becomes less than a predetermined value. Features a cutting device.

Claims (1)

[Claims] a plurality of light sources each outputting near-infrared light of different wavelengths and making it enter the internal organs; a transmission amount detection means for detecting the amount of near-infrared light transmitted through the internal organs; an output light amount detection means for detecting the output light amount of near-infrared light; and a normalization means for normalizing the amount of transmission detected by the transmission amount detection means by the output light amount detected by the output light amount detection means; When a predetermined amount of transmission is not detected within a predetermined detection period, the transmission amount detection means extends the detection period until a predetermined amount of transmission is detected, and in synchronization with this, the output light amount detection means detects the output light amount. A diagnostic device characterized by having means for extending the period and displaying this information when the ratio of the output light amount to the background noise becomes less than a predetermined value.