Abstrict A laser blood-flow meter includes a laser-beam irradiator for irradiating
laser beams to biological structure, a detector for detecting scattered
beams resulted from scattering of the laser beams in the biological
structure, the laser blood-flow meter measuring blood flow of the
biological structure in accordance with the scattered beams detected
by the detector, and a beam-collector for collecting the scattered
beams to direct the collected beams to the detector.
Claims What is claimed is:
1. A laser blood-flow meter comprising: a laser-beam irradiator
for irradiating laser beams to biological structure; a detector
for detecting scattered beams resulted from scattering of said laser
beams in said biological structure, said laser blood-flow meter
measuring blood flow of said biological structure in accordance
with said scattered beams detected by said detector; and a beam-collector
for collecting said scattered beams to direct the collected beams
to said detector.
2. The laser blood-flow meter as set forth in claim 1 wherein
said detector and said laser-beam irradiator are disposed on a common
side relative to said biological structure such that said detector
detects backward-scattered beams.
3. The laser blood-flow meter as set forth in claim 2 further
comprising a case in which said laser-beam irradiator, said beam-collector
and said detector are arranged, wherein said case has a flat contact-surface,
as at least a part of an external surface thereof, at which said
case makes contact with a surface of said biological structure when
blood flow of said biological structure is measured, and said laser-beam
irradiator, said beam-collector and said detector are arranged in
this order on a path substantially parallel with said flat contact-surface.
4. The laser blood-flow meter as set forth in claim 3 further
comprising a light-guide arranged between said detector and said
beam-collector for guiding beams collected by said beam-collector
to said detector.
5. The laser blood-flow meter as set forth in claim 3 further
comprising a first beam-turner for turning said laser beams irradiated
from said laser-beam irradiator towards said biological structure,
and a second beam-turner for turning said scattered beams towards
said beam-collector.
6. The laser blood-flow meter as set forth in claim 5 wherein
said contact-surface has a beam-transmissive portion through which
said laser beams can transmit, and said laser blood-flow meter further
comprising a beam-block which prevents laser beams having passed
through said beam-transmissive portion from being directed towards
said second beam-turner and said beam-collector without reaching
said biological structure.
7. The laser blood-flow meter as set forth in claim 1 wherein
said detector and said laser-beam irradiator are disposed on opposite
sides to each other relative to said biological structure such that
said detector detects forward-scattered beams.
8. The laser blood-flow meter as set forth in claim 1 wherein
said beam-collector is comprised of a semispherical lens.
9. The laser blood-flow meter as set forth in claim 4 wherein
said light-guide is comprised of one of a pin-hole, an optic fiber
and a bar lens.
10. The laser blood-flow meter as set forth in claim 6 wherein
said beam-block projects outwardly over said beam-transmissive portion.
11. A laser blood-flow meter comprising: a laser-beam irradiator
for irradiating laser beams to biological structure; a detector
for detecting scattered beams resulted from backward-scattering
of said laser beams in said biological structure, said laser blood-flow
meter measuring blood flow of said biological structure in accordance
with said scattered beams detected by said detector; a light-guide
for guiding said scattered beams to said detector; and a case in
which said laser-beam irradiator, said light-guide and said detector
are arranged, wherein said case has a flat contact-surface, as at
least a part of an external surface thereof, at which said case
makes contact with a surface of said biological structure when blood
flow of said biological structure is measured, and said laser-beam
irradiator, said light-guide and said detector are arranged in this
order on a path substantially parallel with said flat contact-surface.
12. The laser blood-flow meter as set forth in claim 11 further
comprising a first beam-turner for turning said laser beams irradiated
from said laser-beam irradiator towards said biological structure,
and a second beam-turner for turning said scattered beams towards
said light-guide.
13. The laser blood-flow meter as set forth in claim 12 wherein
said contact-surface has a beam-transmissive portion through which
said laser beams can transmit, and said laser blood-flow meter further
comprising a beam-block which prevents laser beams having passed
through said beam-transmissive portion from being directed towards
said second beam-turner and said light-guide without reaching said
biological structure.
14. The laser blood-flow meter as set forth in claim 11 wherein
said light-guide is comprised of one of a pin-hole, an optic fiber
and a bar lens.
15. The laser blood-flow meter as set forth in claim 13 wherein
said beam-block projects outwardly over said beam-transmissive portion.
16. A laser blood-flow meter comprising: a laser-beam irradiator
for irradiating laser beams to biological structure; and a detector
for detecting scattered beams resulted from scattering of said laser
beams in said biological structure, said laser blood-flow meter
measuring blood flow of said biological structure in accordance
with said scattered beams detected by said detector, wherein said
detector and said laser-beam irradiator are disposed on opposite
sides to each other relative to said biological structure such that
said detector detects forward-scattered beams.
17. The laser blood-flow meter as set forth in claim 16 further
comprising a clip for clipping said laser blood-flow meter to said
biological structure, said clip comprising a first portion in which
said laser-beam irradiator is arranged, and a second portion in
which said detector is arranged.
18. The laser blood-flow meter as set forth in claim 16 further
comprising a hinge through which said first and second portions
are swingable to each other.
19. The laser blood-flow meter as set forth in claim 18 further
comprising a phase-converter providing a first phase in which said
first and second portions sandwich said biological structure therebetween
such that said laser blood-flow meter is attached to said biological
structure, and a second phase in which said first and second portions
are open to each other such that said laser blood-flow meter is
released from said biological structure.
20. The laser blood-flow meter as set forth in claim 16 further
comprising a beam-collector for collecting said scattered beams
to direct the collected beams to said detector.
21. A system for monitoring bio-data of biological structure, including
a laser blood-flow meter measuring blood flow of said biological
structure in accordance with scattered beams resulted from scattering
of laser beams in said biological structure which laser beams have
been irradiated to said biological structure, said system monitoring
said bio-data, based on blood flow in a head of said bio-logical
structure and blood flow in any one of quarters of said biological
structure, said system including a controller which judges whether
a blood flow and a blood-flow waveform of a head of said biological
structure are in synchronization with a blood flow and a blood-flow
waveform of any one of quarters of said biological structure, and
does not use a blood flow and a blood-flow waveform obtained when
said blood flow and said blood-flow waveform of said head is not
in synchronization with said blood flow and said blood-flow waveform
of said any one of quarters, for monitoring said bio-data.
22. The system as set forth in claim 21 wherein said controller
compares the measured blood flow and blood-flow waveform to a reference
blood flow and a reference blood-flow waveform, respectively, to
judge whether said measured blood flow and blood-flow waveform are
properly measured, and wherein a blood flow and a blood-flow waveform
having been judged not to be properly measured are not used for
monitoring said bio-data.
23. The system as set forth in claim 21 wherein said controller
judges whether a person to be monitored is in a serious condition.
24. The system as set forth in claim 23 wherein said controller
compares the measured blood flow and blood-flow waveform to a reference
blood flow and a reference blood-flow waveform, respectively, to
judge whether a person to be monitored is in a serious condition.
25. The system as set forth in claim 21 further comprising an
annunciator which makes annunciation when said controller judges
that said person is in a serious condition.
26. The system as set forth in claim 21 wherein said system monitors
said bio-data while blood is circulated between a person and an
external device.
27. The system as set forth in claim 21 further comprising an
artificial dialysis device for carrying out artificial dialysis,
and wherein said system monitors said bio-data of a person while
dialysis is carried out to said person by said artificial dialysis
device.
28. The system as set forth in claim 21 wherein said laser blood-flow
meter is comprised of: a laser-beam irradiator for irradiating laser
beams to biological structure; a detector for detecting scattered
beams resulted from scattering of said laser beams in said biological
structure, said laser blood-flow meter measuring blood flow of said
biological structure in accordance with said scattered beams detected
by said detector; and a beam-collector for collecting said scattered
beams to direct the collected beams to said detector.
29. The system as set forth in claim 21 wherein said laser blood-flow
meter is comprised of: a laser-beam irradiator for irradiating laser
beams to biological structure; a detector for detecting scattered
beams resulted from backward-scattering of said laser beams in said
biological structure, said laser blood-flow meter measuring blood
flow of said biological structure in accordance with said scattered
beams detected by said detector; a light-guide for guiding said
scattered beams to said detector; and a case in which said laser-beam
irradiator, said light-guide and said detector are arranged, wherein
said case has a flat contact-surface, as at least a part of an external
surface thereof, at which said case makes contact with a surface
of said biological structure when blood flow of said biological
structure is measured, and said laser-beam irradiator, said light-guide
and said detector are arranged in this order on a path substantially
parallel with said flat contact-surface.
30. The system as set forth in claim 21 wherein said laser blood-flow
meter is comprised of: a laser-beam irradiator for irradiating laser
beams to biological structure; and a detector for detecting scattered
beams resulted from scattering of said laser beams in said biological
structure, said laser blood-flow meter measuring blood flow of said
biological structure in accordance with said scattered beams detected
by said detector, wherein said detector and said laser-beam irradiator
are disposed on opposite sides to each other relative to said biological
structure such that said detector detects forward-scattered beams.
Description BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The invention relates to a laser blood-flow meter and a
system for monitoring bio-data.
[0003] 2. Description of the Related Art
[0004] Japanese Patent Application Publication No. 2002-45342 has
suggested a laser blood-flow meter which irradiates laser beams
to biological structure to allow the laser beams to be scattered
in the biological structure, and detect power spectrum of scattered
laser beams to thereby measure blood flow in the biological structure.
[0005] The suggested laser blood-flow meter measures or calculates
blood flow by virtue of a speckle interference process making use
of diffraction of laser beams scattered in biological structure.
[0006] Herein, speckle interference indicates, with respect to
measurement of blood flow, a spotted noise or interference pattern
obtained when scattered beam resulted when laser beams irradiated
to biological structure are scattered with erythrocytes in blood
are observed at a facet. The noise or interference pattern varies
in accordance with movement of erythrocytes.
[0007] A laser blood-flow meter operates in accordance with such
a principle as mentioned above. A laser blood-flow meter detects
an interference pattern by irradiating laser beams to biological
structure such that the interference pattern appears on a detection
screen of a detector such as a photodiode, and measures blood flow,
based on correlation between variance in the interference pattern
and movement of erythrocytes.
[0008] Measurement of blood flow in a laser blood-flow meter is
made with a sensor of the laser blood-flow meter being attached
to a person to be monitored. Accordingly, when blood flow is measured
continuously for a long time, a laser blood-flow meter would receive
artifact noises caused by the person's slight movement and/or measurement
environment.
[0009] The artifact noises often become extremely high in proportion
with power spectrum of scattered beams, in which case, it is not
possible to properly measure blood flow.
[0010] Thus, it was difficult or almost impossible to properly
measure blood flow by applying a laser blood-flow meter to a monitor
system which was necessary to receive for a long time blood flow
data and biological data having correlation with the blood flow.
[0011] It is empirically known that blood flow in a head is different
from blood flow in quarters. Hence, it has been said that blood
flow in a head and quarters were necessary to be measured independently
of each other, but it was not possible to do so because of the above-mentioned
artifact noises.
[0012] Japanese Patent Application Publication No. 2001-120509
has suggested an apparatus for detecting power spectrum as a blood-flow
signal, including a laser-beam source emitting laser beams in a
longitudinal single mode, first means for stabilizing a wavelength
of the laser beams, and second means for converting laser beams
reflected from an object, into electric signals.
[0013] Japanese Patent Application Publication No. 1-256924 has
suggested a method of diagnosing eyes including the step of irradiating
laser beams to eyes wherein laser beams are received by a beam receiver
through an optical fiber, a lens being disposed between the beam
receiver and the optical fiber.
[0014] Japanese Utility Model Publication No. 37-31395 has suggested
a lumen mirror including a beam irradiator, a beam collector and
a detector.
[0015] Japanese Patent Application Publication No. 2-203838 has
disclosed a probe for measuring blood flow, as prior art, including
a prism for turning laser beams by 90 degrees.
[0016] Japanese Utility Model Publication No. 57-134658 has suggested
a device for detecting whether a droplet exists on an object, including
a beam block which prevents a beam irradiated from a beam emitter,
from being directly received at a beam receiver.
[0017] Japanese Utility Model Publication No. 58-185203 has suggested
an optical fiber sensor used for forward-scattered beams.
SUMMARY OF THE INVENTION
[0018] In view of the above-mentioned problem, it is an object
of the present invention to provide a laser blood-flow meter and
a system for monitoring bio-data both of which are capable of being
less influenced by artifact noises, and readily and stably measuring
blood flow in a head and quarters independently of each other.
[0019] Hereinbelow are described a laser blood-flow meter and a
system for monitoring bio-data both in accordance with the present
invention through the use of reference numerals used in later described
embodiments. The reference numerals are indicated only for the purpose
of clearly showing correspondence between claims and the embodiments.
It should be noted that the reference numerals are not allowed to
use in the interpretation of claims of the present application.
[0020] In one aspect of the present invention, there is provided
a laser blood-flow meter including a laser-beam irradiator (12)
for irradiating laser beams (L) to biological structure (11), a
detector (13) for detecting scattered beams (S) resulted from scattering
of the laser beams (L) in the biological structure (11), the laser
blood-flow meter measuring blood flow of the biological structure
(11) in accordance with the scattered beams (S) detected by the
detector (13), and a beam-collector (15) for collecting the scattered
beams (S) to direct the collected beams to the detector (13).
[0021] Since the laser blood-flow meter in accordance with the
present invention includes the beam-collector, it would be possible
to collect scattered beams, and amplify signals necessary for measurement
of blood flow. That is, it would be possible to reduce artifact
noises relatively to the signals, and hence, the laser blood-flow
meter could be less influenced by artifact noises. Thus, it is now
possible to solve the problem that blood flow cannot be properly
measured because of artifact noises. Hence, it is also possible
to apply the laser blood-flow meter in accordance with the present
invention to a monitor system which is necessary to receive for
a long time blood flow data and biological data having correlation
with the blood flow. Furthermore, the laser blood-flow meter in
accordance with the present invention can readily and stably measure
blood flow in a head and quarters independently of each other
[0022] The detector (13) and the laser-beam irradiator (12) may
be disposed on a common side relative to the biological structure
(11) such that the detector (13) detects backward-scattered beams
(S).
[0023] The laser blood-flow meter may further include a case (110a)
in which the laser-beam irradiator (12), the beam-collector (15)
and the detector (13) are arranged, in which case, it is preferable
that the case (110a) has a flat contact-surface (101), as at least
a part of an external surface thereof, at which the case (110a)
makes contact with a surface of the biological structure (11) when
blood flow of the biological structure (11) is measured, and the
laser-beam irradiator (12), the beam-collector (15) and the detector
(13) are arranged in this order on a path substantially parallel
with the flat contact-surface (101). Thus, it is possible to render
the contact-surface more stable, ensuring that the laser blood-flow
meter is less influenced by artifact noises during measurement of
blood flow.
[0024] The laser blood-flow meter may further include a light-guide
(17) arranged between the detector (13) and the beam-collector (15)
for guiding beams collected by the beam-collector (15) to the detector
(13).
[0025] The laser blood-flow meter may further include a first beam-turner
(14) for turning the laser beams (L) irradiated from the laser-beam
irradiator (12) towards the biological structure (11), and a second
beam-turner (16) for turning the scattered beams (S) towards the
beam-collector (15).
[0026] It is preferable that the contact-surface (101) has a beam-transmissive
portion (18) through which the laser beams (L) can transmit, and
the laser blood-flow meter further includes a beam-block (19) which
prevents laser beams (L) having passed through the beam-transmissive
portion (18) from being directed towards the second beam-turner
(16) and the beam-collector (15) without reaching the biological
structure (11).
[0027] It is preferable that the detector (13) and the laser-beam
irradiator (12) are disposed on opposite sides to each other relative
to the biological structure (11) such that the detector (13) detects
forward-scattered beams (S).
[0028] For instance, the beam-collector (15) may be comprised of
a semispherical lens.
[0029] For instance, the light-guide (17) may be comprised of one
of a pin-hole, an optic fiber and a bar lens.
[0030] It is preferable that the beam-block (19) projects outwardly
over the beam-transmissive portion (18).
[0031] There is further provided a laser blood-flow meter including
a laser-beam irradiator (12) for irradiating laser beams (L) to
biological structure (11), a detector (13) for detecting scattered
beams (S) resulted from backward-scattering of the laser beams (L)
in the biological structure (11), the laser blood-flow meter measuring
blood flow of the biological structure (11) in accordance with the
scattered beams (S) detected by the detector (13), a light-guide
(17) for guiding the scattered beams (S) to the detector (13), and
a case (110a) in which the laser-beam irradiator (12), the light-guide
(17) and the detector (13) are arranged, wherein the case (110a)
has a flat contact-surface (101), as at least a part of an external
surface thereof, at which the case (110a) makes contact with a surface
of the biological structure (11) when blood flow of the biological
structure (11) is measured, and the laser-beam irradiator (12),
the light-guide (17) and the detector (13) are arranged in this
order on a path substantially parallel with the flat contact-surface
(101).
[0032] The laser blood-flow meter may further include a first beam-turner
(14) for turning the laser beams (L) irradiated from the laser-beam
irradiator (12) towards the biological structure (11), and a second
beam-turner (16) for turning the scattered beams (S) towards the
light-guide (17).
[0033] There is still further provided a laser blood-flow meter
including a laser-beam irradiator (12) for irradiating laser beams
(L) to biological structure (11), and a detector (13) for detecting
scattered beams (S) resulted from scattering of the laser beams
(L) in the biological structure (11), the laser blood-flow meter
measuring blood flow of the biological structure (11) in accordance
with the scattered beams (S) detected by the detector (13), wherein
the detector (13) and the laser-beam irradiator (12) are disposed
on opposite sides to each other relative to the biological structure
(11) such that the detector (13) detects forward-scattered beams
(S).
[0034] The laser blood-flow meter may further include a clip (21)
for clipping the laser blood-flow meter to the biological structure
(11), the clip (21) including a first portion (21a) in which the
laser-beam irradiator (12) is arranged, and a second portion (21b)
in which the detector (13) is arranged.
[0035] The laser blood-flow meter may further include a hinge (22)
through which the first and second portions (21a, 21b) are swingable
to each other.
[0036] The laser blood-flow meter may further include a phase-converter
(23) providing a first phase in which the first and second portions
(21a, 21b) sandwich the biological structure (11) therebetween such
that the laser blood-flow meter is attached to the biological structure
(11), and a second phase in which the first and second portion (21a,
21b) are open to each other such that the laser blood-flow meter
is released from the biological structure (11).
[0037] The laser blood-flow meter may further include a beam-collector
(15) for collecting the scattered beams (S) to direct the collected
beams to the detector (13).
[0038] In another aspect of the present invention, there is provided
a system for monitoring bio-data of biological structure (11), including
a laser blood-flow meter measuring blood flow of the biological
structure (11) in accordance with scattered beams (S) resulted from
scattering of laser beams (L) in the biological structure (11) which
laser beams (L) have been irradiated to the biological structure
(11), the system monitoring the bio-data, based on blood flow in
a head (31a) of the biological structure (11) and blood flow in
any one of quarters (31b) of the biological structure (11), the
system including a controller (42) which judges whether a blood
flow and a blood-flow waveform of a head (31a) of the biological
structure (11) are in synchronization with a blood flow and a blood-flow
waveform of any one of quarters (31b) of the biological structure
(11), and does not use a blood flow and a blood-flow waveform obtained
when the blood flow and the blood-flow waveform of the head (31a)
is not in synchronization with the blood flow and the blood-flow
waveform of the any one of quarters (31b), for monitoring the bio-data.
[0039] In accordance with the above-mentioned system, blood flow
and a blood-flow waveform obtained when the blood flow and the blood-flow
waveform of the head is not in synchronization with the blood flow
and the blood-flow waveform of the any one of quarters are not used
for monitoring bio-data, ensuring that bio-data is monitored based
on blood flow and a blood-flow waveform both having been properly
measured. That is, blood flow and a blood-flow waveform both much
influenced by artifact noises are not used for monitoring bio-data,
and accordingly, it is ensured that the laser blood-flow meter is
less influenced by artifact noises. Furthermore, when blood flow
and a blood-flow waveform of a head and quarters are measured independently
of each other, it would be possible to readily and stably do so.
[0040] It is preferable that the controller (42) compares the measured
blood flow and blood-flow waveform to a reference blood flow and
a reference blood-flow waveform, respectively, to judge whether
the measured blood flow and blood-flow waveform are properly measured,
and wherein a blood flow and a blood-flow waveform having been judged
not to be properly measured are not used for monitoring the bio-data.
[0041] It is preferable that the controller (42) judges whether
a person (31) to be monitored is in a serious condition.
[0042] It is preferable that the controller (42) compares the measured
blood flow and blood-flow waveform to a reference blood flow and
a reference blood-flow waveform, respectively, to judge whether
a person (31) to be monitored is in a serious condition.
[0043] It is preferable that the system further includes an annunciator
which makes annunciation when the controller (42) judges that the
person (31) is in a serious condition.
[0044] It is preferable that the system monitors the bio-data while
blood is circulated between a person (31) and an external device
(50).
[0045] It is preferable that the system further includes an artificial
dialysis device (50) for carrying out artificial dialysis, and wherein
the system monitors the bio-data of a person (31) while dialysis
is carried out to the person (31) by the artificial dialysis device
(50).
[0046] As a laser blood-flow meter, there may be used the above-mentioned
one.
[0047] The advantages obtained by the aforementioned present invention
will be described hereinbelow.
[0048] In accordance with the present invention, it is possible
to reduce harmful influence caused by artifact noises, and readily
and stably measure blood flow of a head and quarters independently
of each other continuously for a long time.
[0049] The above and other objects and advantageous features of
the present invention will be made apparent from the following description
made with reference to the accompanying drawings, in which like
reference characters designate the same or similar parts throughout
the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0050] FIG. 1 is a cross-sectional view of the laser blood-flow
meter in accordance with the first embodiment of the present invention.
[0051] FIG. 2 is a perspective view of the laser blood-flow meter
in accordance with the first embodiment of the present invention.
[0052] FIG. 3 illustrates power spectrum of scattered beams detected
by the laser blood-flow meter in accordance with the first embodiment.
[0053] FIG. 4 illustrates power spectrum of scattered beams detected
by a conventional laser blood-flow meter.
[0054] FIG. 5 is a cross-sectional view of the laser blood-flow
meter in accordance with the second embodiment of the present invention.
[0055] FIG. 6 is a front view of the laser blood-flow meter in
accordance with the second embodiment of the present invention.
[0056] FIG. 7 illustrates a system for monitoring bio-data, in
accordance with the third embodiment of the present invention.
[0057] FIGS. 8A and 8B illustrate blood-flow waveforms in synchronization
with each other.
[0058] FIGS. 9A and 9B illustrate blood-flow waveforms not in synchronization
with each other.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0059] Preferred embodiments in accordance with the present invention
will be explained hereinbelow with reference to drawings.
[0060] [First Embodiment]
[0061] The laser blood-flow meter in accordance with the first
embodiment is of a backward-scattered type. Hereinbelow is explained
the laser blood-flow meter in accordance with the first embodiment
with reference to FIGS. 1 and 2 wherein FIG. 1 is a cross-sectional
view of the laser blood-flow meter, and FIG. 2 is a perspective
view of the laser blood-flow meter. A later-mentioned contact surface
101 faces downwardly in FIG. 1 whereas the same faces upwardly
in FIG. 2.
[0062] As illustrated in FIG. 1 the laser blood-flow meter 10
in accordance with the first embodiment is comprised of a laser-beam
irradiator 12 for irradiating laser beams L to biological structure
11 a detector 13 for detecting scattered beams S resulted from
scattering of the laser beams L in the biological structure 11
and an operation unit (not illustrated) which measures or calculates
blood flow of the biological structure 11 in accordance with power
spectrum of the scattered beams S detected by the detector 13.
[0063] The detector 13 is comprised of a photodiode.
[0064] In FIG. 1 reference signs L and S are given only to a part
of the laser beams and scattered beams.
[0065] In the laser blood-flow meter 10 the detector 13 and the
laser-beam irradiator 12 are disposed on a common side relative
to the biological structure 11 such that the detector 13 detects
backward-scattered beams S. That is, the laser blood-flow meter
10 is a backward-scattered type laser blood-flow meter.
[0066] The laser blood-flow meter 10 is comprised of a sensor unit
110 and a controller (not illustrated) including the operation unit
therein. The sensor unit 110 includes the laser-beam irradiator
12 the detector 13 and later-mentioned parts all arranged in a
unit.
[0067] The controller and the sensor unit 110 are electrically
connected to each other through a signal line 120. The detector
13 in the sensor unit 110 transmits a detection signal to the controller
through the signal line 120 and the controller transmits a command
signal to the laser-beam irradiator 12 through the signal line 120.
[0068] The laser-beam irradiator 12 is comprised of a laser diode,
for instance. The laser-beam irradiator 12 irradiates laser beams
L in a longitudinal single mode, having a wavelength in the range
of 500 to 900 micrometers both inclusive, for instance. The laser-beam
irradiator 12 is disposed such that it irradiates the laser beams
L along a surface of the biological structure 11 when blood flow
is measured.
[0069] Thus, the sensor unit 110 is designed to include a first
light-reflector 14 as a first beam-turner for reflecting the laser
beams L towards the biological structure 11. The first light-reflector
14 has a reflection surface inclining about 45 degrees, for instance,
relative to a direction in which the laser beams L are irradiated
from the laser-beam irradiator 12.
[0070] The sensor unit 110 is designed to further include a beam-collector
for collecting the scattered beams S and directing the collected
beams to the detector 13. The beam-collector is comprised of a semispherical
lens 15 in the first embodiment. The semispherical lens 15 has a
diameter in the range of 1 to 6 millimeters both inclusive, for
instance.
[0071] The semispherical lens 15 is comprised of a semispherical
portion 15a directing towards the detector 13 and a planar portion
15b directing towards the laser-beam irradiator 12.
[0072] Furthermore, the semispherical lens 15 has a central axis
substantially coincident with a direction in which the laser beams
L are irradiated from the laser-beam irradiator 12.
[0073] The semispherical portion 15a is formed at a summit thereof
with a laser-beam outlet 15c. The semispherical portion 15a is coated
at an inner surface thereof with a light-reflective film except
the laser-beam outlet 15c.
[0074] Accordingly, the scattered beams S introduced into the semispherical
portion 15a through the planar portion 15b are reflected at the
light-reflective film to converge to the laser-beam outlet 15c.
The thus converged scattered beams S are introduced into a later-mentioned
a pin-hole 17 as a light-guide through the laser-beam outlet 15c.
[0075] The laser-beam outlet 15c has a diameter in the range of
50 to 100 micrometers both inclusive, for instance, in accordance
with a diameter of the pin-hole 17.
[0076] The sensor unit 110 is designed to further include a second
light-reflector 16 as a second beam-turner for reflecting the scattered
beams S towards the semispherical lens 15 from the biological structure
11. The second light-reflector 16 has a reflection surface inclining
about 45 degrees, for instance, relative to a central axis of the
semispherical lens 15.
[0077] The first and second light-reflectors 14 and 16 are rectangular
in shape, for instance. They are arranged almost perpendicularly
to each other and make contact with each other at one side which
faces the biological structure 11 when blood flow is measured.
[0078] Because of the second light-reflector 16 the semispherical
lens 15 collects not only the scattered beams S directly arriving
from the biological structure 11 but also the scattered beams S
reflected at the second light-reflector 16.
[0079] The sensor unit 110 is designed to include a pin-hole 17
as a light-guide for guiding the scattered beams S collected by
the semispherical lens 15 to the detector 13. The pin-hole 17 as
a light-guide is arranged between the detector 13 and the semispherical
lens 15.
[0080] The pin-hole 17 has a diameter in the range of 50 to 100
micrometers both inclusive, for instance, in accordance with a size
of the laser-beam outlet 15c.
[0081] The sensor unit 110 includes a case 110a pin which the laser-beam
irradiator 12 the first and second light-reflectors 14 and 16
the semispherical lens 15 the pin-hole 17 and the detector 13
are arranged.
[0082] The case 110a has a flat contact-surface 101 as at least
a part of an external surface of the case 110a. The case 110a makes
contact with a surface of the biological structure 11 through the
flat contact-surface 101 when blood flow of the biological structure
11 is measured. Hence, the sensor unit 110 can make stable contact
with a surface of the biological structure 11 when blood flow of
the biological structure 11 is measured.
[0083] The laser-beam irradiator 12 the semispherical lens 15
the pin-hole 17 and the detector 13 are arranged in this order on
a linear path (for instance, a central axis of the semispherical
lens 15) substantially parallel with the flat contact-surface 101.
[0084] Since the laser-beam irradiator 12 the semispherical lens
15 the pin-hole 17 and the detector 13 are disposed along the contact-surface
101 the arrangement which enables the sensor unit 110 to make stable
contact with a surface of the biological structure 11 is efficiently
accomplished.
[0085] As illustrated in FIGS. 1 and 2 the contact-surface 101
is designed to have a glass plate 18 as a beam-transmissive portion
through which the laser beams can transmit. For instance, a transparent
resin plate may be used in place of the glass plate 18. Any plate
may be used as the beam-transmissive portion, if it is composed
of a material through which the laser beams L can transmit.
[0086] The glass plate 18 acts as a protector for protecting the
laser-beam irradiator 12 the first and second light-reflectors
14 and 16 and the semispherical lens 15 from external impact, and
accomplishes transmission of the laser beams L to the biological
structure 11 from the first light-reflector 14 and transmission
of the scattered beams S to the second light-reflector 16 and the
semispherical lens 15 from the biological structure 11.
[0087] The laser beams L may disadvantageously repeat reflection
between the glass plate 18 and a surface of the biological structure
11 without reaching interior of the biological structure 11 and
reach the second light-reflector 16 and the semispherical lens 15.
[0088] In order to avoid such a problem, the sensor unit 110 is
designed to include a beam-block 19. As illustrated in FIGS. 1 and
2 the beam-block 19 extends through the glass plate 18 and projects
outwardly beyond the case 110a. The beam block 19 is compressed
onto a surface of the biological structure 11 when blood flow is
measured.
[0089] The beam-block 19 removes the laser beams L repeating reflection
between the glass plate 18 and a surface of the biological structure
11. Accordingly, the semispherical lens 15 collects only the scattered
beams S returning back from the biological structure 11.
[0090] The laser blood-flow meter 10 has such a structure as mentioned
above.
[0091] The semispherical lens 15 as a beam-collector, the pin-hole
17 as a light-guide, and the detector 13 (photodiode) constitutes
a transducer unit.
[0092] Hereinbelow is explained an operation of the laser blood-flow
meter 10.
[0093] First, the sensor unit 110 of the laser blood-flow meter
10 is set on a surface of the biological structure 11 such as a
man such that the contact-surface 101 including the glass plate
18 makes contact with a surface of the biological structure 11.
The sensor unit 110 may be fixed onto a surface of the biological
structure 11 by means of a band, for instance.
[0094] Then, the laser-beam irradiator 12 irradiates the laser
beams L under control by the controller. The irradiated laser beams
L are reflected at the first light-reflector 14 and then, enters
the biological structure 11 through the glass plate 18.
[0095] There are generated scattered beams S as a result of scattering
of the laser beams L in the biological structure 11. A part of the
scattered beams S is backwardly scattered towards the sensor unit
110 from the biological structure 11. The backwardly scattered beams
S enter directly into the semispherical lens 15 through the glass
plate 18 or enter the semispherical lens 15 after reflected at
the second light-reflector 16.
[0096] Since the laser beams repeating reflection between the glass
plate 18 and the biological structure 11 are removed by the beam-block
19 only the scattered beams S (backwardly scattered beams) returning
back from the biological structure 11 are collected by the semispherical
lens 15.
[0097] The scattered beams S having been collected by the semispherical
lens 15 are detected by the detector 13 through the pin-hole 17.
[0098] Due to the Doppler shift phenomenon caused by speckle interference,
an interference pattern of the scattered beams S appears on a detection
screen of the detector 13. The interference pattern is detected
by the detector 13. Since the interference pattern varies in accordance
with movement of erythrocytes, it is possible to measure blood flow
in the biological structure 11 in accordance with variance in the
interference pattern.
[0099] That is, scattered beams resulted from movement of erythrocytes
among the backwardly scattered beams S are converted into an alternating
current (AC), and the detector 13 measures blood flow by detecting
the alternating current.
[0100] FIG. 3 illustrates power spectrum equivalent to the detected
alternating current, whereas FIG. 4 illustrates power spectrum detected
by a conventional laser blood-flow meter.
[0101] As is obvious in comparison between FIGS. 3 and 4 the laser
blood-flow meter 10 in accordance with the first embodiment provides
enhanced power spectrum in comparison with the conventional laser
blood-flow meter.
[0102] This is because the laser blood-flow meter 10 in accordance
with the first embodiment is designed to include the semispherical
lens 15 which collects the scattered beams S, that is, spatially
integrates the scattered beams S, and hence, provides a broader
range in which blood flow is measured.
[0103] Scattered beams resulted from stationary biological structure
and/or stationary erythrocytes among the backwardly scattered beams
S are converted into a direct current (DC).
[0104] Relation among the above-mentioned scattered beams is defined
in accordance with the following equation (I).
P=F(w)+N(w)+I(t) (I)
[0105] P: Power spectrum
[0106] F(w): Power at an average frequency of scattered beams resulted
from moving erythrocytes
[0107] N(w): Power resulted from noises in a laser-beam source
and quantum noises of a photoelectric converter
[0108] I(t): Volume of scattered beams resulted from stationary
biological structure and/or stationary erythrocytes
[0109] As illustrated in FIG. 1 artery and vein are disposed in
a blood vessel area 11a located deep from a surface of the biological
structure 11. Hence, only the scattered beams S resulted from that
the laser beams L reaching the blood vessel area 11a are backwardly
scattered by erythrocytes in the blood vessel area 11a contribute
to F(w).
[0110] Since the laser blood-flow meter 10 in accordance with the
first embodiment includes the semispherical lens 15 as a beam-collector,
it is possible to collect the scattered beams S, and increase F(w),
namely, signals necessary for measuring blood flow. In other words,
it is possible to reduce artifact noises relative to signals F(w),
and hence, the laser blood-flow meter 10 can be less influenced
by artifact noises.
[0111] Furthermore, collection of the scattered beams S by means
of the semispherical lens 15 would provide a broader range in which
blood flow is measured in the biological structure 11.
[0112] The laser blood-flow meter 10 is designed to include the
case 110a in which the laser-beam irradiator 12 the first and second
light-reflectors 14 and 16 the semispherical lens 15 the pin-hole
17 and the detector 13 are arranged. The case 110a is designed
to have a flat contact-surface 101 as at least a part of an external
surface of the case 110a. The case 110a makes contact with a surface
of the biological structure 11 through the flat contact-surface
101 when blood flow of the biological structure 11 is measured.
In addition, the laser-beam irradiator 12 the semispherical lens
15 the pin-hole 17 and the detector 13 are arranged in this order
on a linear path substantially parallel with the flat contact-surface
101. Hence, it is possible to make the contact-surface 101 broader
and more stable without increasing a size of the sensor unit 110.
Thus, the sensor unit 110 can be readily attached to a target, and
be less influenced by noises caused by oscillation.
[0113] As is obvious in view of the explanation having been made
above, it is possible to solve the problem that blood flow cannot
be properly measured due to artifact noises. Accordingly, blood
flow can be measured by applying the laser blood-flow meter 10 to
a monitor system which is necessary to receive for a long time blood
flow data and biological data having correlation with the blood
flow. In addition, it is possible to readily and stably measure
blood flow in a head and quarters independently of each other.
[0114] Since the laser blood-flow meter 10 is designed to have
the first light-reflector 14 for turning the laser beams L irradiated
from the laser-beam irradiator 12 to the biological structure 11
and the second light-reflector 16 for turning the scattered beams
S coming from the biological structure 11 to the semispherical lens
15 it is possible to efficiently collect the scattered beams S
through the semispherical lens 15.
[0115] In addition, since the laser blood-flow meter 10 is designed
to have the beam-block 19 which prevents the laser beams L having
passed through the glass plate 18 from reaching the second light-reflector
16 and the semispherical lens 15 without reaching the biological
structure 11 it is possible to remove the laser beams reflecting
at a surface of the biological structure 11 without entering the
biological structure 11 and collect only the scattered beams S
returning back from the biological structure 11 through the semispherical
lens 15 ensuring no necessity of measuring unnecessary signals.
[0116] The laser blood-flow meter 10 can monitor not only blood
flow, but also operation of a heart, a pulsating flow, and operation
of a blood vessel, and, based on monitoring of them, further monitor
physiological function such as autonomic nervous system and central
nervous system.
[0117] The laser blood-flow meter 10 in accordance with the first
embodiment can measure blood flow in semispherical biological structure
having a diameter of 2 to 4 millimeters both inclusive, for instance.
[0118] The sensor unit 110 may be mounted in a mobile communication
terminal such as a mobile phone or PHS, in which case, the detection
signals are transmitted to the controller through radio-signals.
[0119] Though the beam-block 19 is designed to be compressed onto
a surface of the biological structure 11 in the first embodiment,
the beam-block 19 may be designed to be inserted into the blood
vessel area 11a in the biological structure 11 ensuring it possible
to prevent detection of the scattered beams S resulted from the
laser beams L not reaching the blood vessel area 11a, and accordingly,
it would be possible to relatively increase the signal F(w) for
properly measuring blood flow.
[0120] [Variant 1]
[0121] The laser blood-flow meter 10 in accordance with the above-mentioned
first embodiment is of a backward-scattered type, and is designed
to include a beam-collector comprised of the semispherical lens
15. A laser blood-flow meter in accordance with the first variant
is designed not to include a beam-collector.
[0122] Though not illustrated, the laser blood-flow meter in accordance
with the first variant has the same structure as that of the laser
blood-flow meter 10 except that the laser blood-flow meter in accordance
with the first variant does not include the semispherical lens 15.
[0123] Specifically, the laser blood-flow meter in accordance with
the first variant includes a laser-beam irradiator 12 for irradiating
laser beams to biological structure, a detector 13 for detecting
scattered beams resulted from backward-scattering of the laser beams
in the biological structure, a light-guide or a pin-hole 17 for
guiding the scattered beams to the detector 13 and a case 110a
in which the laser-beam irradiator 12 the light-guide 17 and the
detector 13 are arranged. The case 110a has a flat contact-surface
101 as at least a part of an external surface of the case 110a,
at which the case 110a makes contact with a surface of the biological
structure 11 when blood flow of the biological structure 11 is measured.
The laser-beam irradiator 12 the light-guide 17 and the detector
13 are arranged in this order on a path substantially parallel with
the flat contact-surface 101. The laser blood-flow meter measures
blood flow of the biological structure 11 in accordance with the
scattered beams detected by the detector 13.
[0124] The laser blood-flow meter in accordance with the first
variant is designed to include the case 110a in which the laser-beam
irradiator 12 the first and second light-reflectors 14 and 16
the semispherical lens 15 the light-guide 17 and the detector
13 are arranged. The case 110a is designed to have a flat contact-surface
101 as at least a part of an external surface of the case 110a.
The case 110a makes contact with a surface of the biological structure
11 through the flat contact-surface 101 when blood flow of the biological
structure 11 is measured. In addition, the laser-beam irradiator
12 the semispherical lens 15 the light-guide 17 and the detector
13 are arranged in this order on a linear path substantially parallel
with the flat contact-surface 101. Hence, it is possible to make
the contact-surface 101 broader and more stable without increasing
a size of the sensor unit 110. Thus, the sensor unit 110 can be
readily attached to a target, and be less influenced by noises caused
by oscillation.
[0125] Since the laser blood-flow meter in accordance with the
first variant does not include the semispherical lens 15 as a light-guide,
the laser blood-flow meter could have a smaller beam-collection
efficiency than the laser blood-flow meter 10. However, the laser
blood-flow meter in accordance with the first variant can introduce
the scattered beams S returning back from the biological structure
11 to the detector 13 through the second light-reflector 16 and
the light-guide 17 similarly to the laser blood-flow meter 10.
[0126] [Second Embodiment]
[0127] FIG. 5 and 6 illustrate a laser blood-flow meter 20 in accordance
with the second embodiment.
[0128] Since the laser blood-flow meter 20 is structurally identical
with the laser blood-flow meter 10 except a later-mentioned difference,
parts or elements that correspond to the laser blood-flow meter
10 have been provided with the same reference numerals, and are
not explained.
[0129] As illustrated in FIG. 5 the detector 13 and the laser-beam
irradiator 12 in the laser blood-flow meter 20 are disposed on opposite
sides to each other relative to the biological structure 11 such
that the detector 13 detects forward-scattered beams S. That is,
the laser blood-flow meter 20 in accordance with the second embodiment
is of a forward-scattered type meter.
[0130] Unlike the laser blood-flow meter 10 in accordance with
the first embodiment, the laser blood-flow meter 20 is not necessary
to include the first and second light-reflectors 14 and 16 and
the beam-block 19.
[0131] The laser blood-flow meter 20 is designed to include a clip
20 for sandwiching biological structure therein. The clip 21 is
comprised of a first portion 21a in which the laser-beam irradiator
12 is arranged, and a second portion 21b in which the semispherical
lens 15 the light-guide 17 and the detector 13 are arranged.
[0132] As illustrated in FIG. 6 the first and second portions
21a and 21b are connected to each other through a hinge 22 such
that they are rotatable to each other. By rotating the first and/or
second portions 21a and 21b around the hinge 22 the first and second
portions 21a and 21b come close to each other or go away from each
other.
[0133] The hinge 22 may be a separate part independently of the
first and second portions 21a and 21b, or may be a part of the first
and/or second portions 21a and 21b.
[0134] The laser blood-flow meter 20 further includes a phase-converter
23 providing a first phase in which the first and second portions
21a and 21b sandwich the biological structure 11 therebetween such
that the laser blood-flow meter 20 is attached to the biological
structure 11 and a second phase in which the first and second portions
21a and 21b are open to each other such that the laser blood-flow
meter 20 is released from the biological structure 11.
[0135] The phase-converter 23 is comprised of an elastic hook 23a,
and a fixed portion 23b to which the elastic hook 23a is engaged.
The elastic hook 23a extends beyond the first portion 21a, and the
fixed portion 23b is formed as a part of the second portion 21b.
[0136] When the first and second portions 21a and 21b move from
the first phase to the second phase or vice versa, positional relation
between the fixed portion 23b and a planar portion 231a of the elastic
hook 23a varies. Specifically, the planar portion 231a of the elastic
hook 23a engages to a first planar portion 231b of the fixed portion
23b in the first phase, a second planar portion 232b of the fixed
portion 23b in the second phase, and a corner 233b of the fixed
portion 23b between the first and second phases.
[0137] In the first phase, the planar portion 231a of the elastic
hook 23a engages to the first planar portion 231b of the fixed portion
23b, and in the second phase, the planar portion 231a of the elastic
hook 23a engages to the second planar portion 232b of the fixed
portion 23b. Hence, the elastic hook 23a and the fixed portion 23b
are in a stable condition in the first and second phases.
[0138] In particular, in the first phase, the first and second
portions 21a and 21b sandwich the biological structure such as an
ear lobe therebetween. Hence, the sensor unit 110 can be kept hung
from the biological structure 11.
[0139] The corner 233b to which the elastic hook 23a engages between
the first and second phases is located remoter from a rotation axis
of the hinge 22 than the first and second planar portions 231b and
232b. Accordingly, elastic deformation of the elastic hook 23a observed
between the first and second phases is greater than the same observed
in the first or second phase. This means that the first and second
portions 21a and 21b are in an instable condition between the first
and second phases, and hence, the first and second portions 21a
and 21b are likely to transfer to the first or second phase.
[0140] Since the laser blood-flow meter 20 in accordance with the
second embodiment is designed to have the clip 20 for enabling the
laser blood-flow meter 20 to be attached to the biological structure
11 the laser blood-flow meter 20 can be used in a condition in
which the laser blood-flow meter 20 is attached to the biological
structure 11.
[0141] In accordance with the laser blood-flow meter 20 it is
possible to measure blood flow in a cylindrical biological structure
having a radius in the range of about 1 to 3 millimeters both inclusive,
if the biological structure has a thickness in the range of 1 to
6 millimeters both inclusive.
[0142] By dividing the measured blood flow by a volume of biological
structure through which the laser beams L pass, it is possible to
absolutize blood flow, whereas absolutization of blood flow was
impossible in a conventional forward-scattered type laser blood-flow
meter. Absolutized blood flow has a unit of milliliter/min/mm.sup.3
for instance.
[0143] [Variant 2]
[0144] The laser blood-flow meter 20 in accordance with the above-mentioned
second embodiment is of a forward-scattered type, and is designed
to include a beam-collector comprised of the semispherical lens
15. A laser blood-flow meter in accordance with the second variant
is designed not to include a beam-collector.
[0145] Though not illustrated, the laser blood-flow meter in accordance
with the second variant has the same structure as that of the laser
blood-flow meter 20 except that the laser blood-flow meter in accordance
with the second variant does not include the semispherical lens
15.
[0146] Specifically, the laser blood-flow meter in accordance with
the second variant includes a laser-beam irradiator 12 for irradiating
laser beams to biological structure, and a detector 13 for detecting
scattered beams resulted from scattering of the laser beams in the
biological structure. The detector 13 and the laser-beam irradiator
12 are disposed on opposite sides to each other relative to the
biological structure 11 such that the detector 13 detects forward-scattered
beams. The laser blood-flow meter measures blood flow of the biological
structure in accordance with the scattered beams detected by the
detector 13.
[0147] In the above-mentioned first and second embodiments, the
laser blood-flow meters 10 and 20 include the semispherical lens
15 as a beam-collector. It should be noted that a beam-collector
is not to be limited to the semispherical lens 15 but may be comprised
of any optical element such as a dome-type or convex lens, if it
can collect laser beams.
[0148] Furthermore, in the above-mentioned first and second embodiments
and their variants, any optical element may be used in place of
the pin-hole 17 if it can guide laser beams to the detector 13.
For instance, an optical fiber or a bar lens may be used.
[0149] [Third Embodiment]
[0150] The third embodiment relates to a system for monitoring
bio-data.
[0151] As illustrated in FIG. 7 a bio-data monitoring system 30
in accordance with the third embodiment of the present invention
includes the laser blood-flow meter 20 for measuring blood flow
of a head 31a (for instance, an ear lobe) of a man 31 and the laser
blood-flow meter 10 for measuring blood flow in any one of quarters
of the man 31 for instance, a leg 31b. The system 30 monitors bio-data
of the man 31 based on the measured blood flow in the head 31a
and the leg 31b.
[0152] The laser blood-flow meters 10 and 20 are controlled commonly
by a controller 40.
[0153] The controller 40 is comprised of an input section 41 which
receives detection signals transmitted from the sensor units 110
of the laser blood-flow meters 10 and 20 and converts the received
analog detection signals into digital signals, a calculator 42 which
calculates blood flow of the man 31 based on the digital detection
signals, and an output section 43 which outputs data indicative
of the blood flow calculated by the calculator 42.
[0154] The calculator 42 is comprised of a central processing unit
(CPU), a digital signal processor (DSP), a personal digital assistant
(PDA) or a personal computer (PC), for instance, and carries out
various judgments mentioned later and annunciation control as well
as calculation of blood flow and control of an operation of the
laser-beam irradiator 12.
[0155] The bio-data monitoring system 30 monitors bio-data, simultaneously
circulating blood between the man 31 and an external device. For
instance, the system 30 includes an artificial dialysis device 50
for carrying out artificial dialysis to the man 31 as well as monitoring
bio-data of the man 31.
[0156] The system 30 is designed to further include a monitor display
60 for monitoring blood flow data calculated by the calculator 42.
[0157] The output section 43 of the controller 40 transmits data
to the artificial dialysis device 50 and the monitor display 60
through wires or through radio-signals.
[0158] If not influenced by artifact noises, blood flow of the
head 31a and blood flow of any one of quarters of the man 31 are
in synchronization with each other. Similarly, if not influenced
by artifact noises, a blood-flow waveform of the head 31a and a
blood-flow waveform of any one of quarters of the man 31 are in
synchronization with each other.
[0159] Thus, the calculator 42 judges whether blood flow and a
blood-flow waveform of the head 31a such as an ear lobe and those
of any one of the quarters such as the leg 31b are in synchronization
with each other, respectively. The calculator 42 does not use blood
flow and a blood-flow waveform measured while the above-mentioned
blood flows and blood-flow waveforms are judged not to be in synchronization
with each other, for monitoring bio-data of the man 31.
[0160] Each of FIGS. 8A and 9A illustrates blood flow of the leg
31b and a waveform of the blood flow, and each of FIGS. 8B and 9B
illustrates blood flow of the head 31a such an ear lobe and a waveform
of the blood flow. The blood flows and its waveforms illustrated
in FIGS. 8A and 8B are measured by the laser blood-flow meters 10
and 20 and the blood flows and its waveforms illustrated in FIGS.
9A and 9B are measured by a conventional laser blood-flow meter.
[0161] Comparing FIGS. 8A and 8B to each other, the blood-flow
waveforms are almost in synchronization with each other every certain
period, and magnitudes of the blood flow are almost in synchronization
with each other.
[0162] When the blood flow of the leg 31b and its waveform as illustrated
in FIG. 8A are in synchronization with the blood flow of the head
31a (specifically, an ear lobe) and its waveform as illustrated
in FIG. 8B, they are used for monitoring bio-data of the man 31.
[0163] In contrast, comparing FIGS. 9A and 9B to each other, the
blood-flow waveforms in FIGS. 9A and 9B are different from each
other for every certain period, and magnitudes of the blood flows
in FIGS. 9A and 9B are different from each other. Specifically,
the blood flows and their waveforms in FIGS. 9A and 9B are not in
synchronization with each other.
[0164] When the blood flow of the leg 31b and its waveform as illustrated
in FIG. 9A are not in synchronization with the blood flow of the
head 31a (specifically, an ear lobe) and its waveform as illustrated
in FIG. 9B, they are not used for monitoring bio-data of the man
31.
[0165] In the above-mentioned way, the calculator 42 removes blood
flow and its waveform unusable for monitoring bio-data of the man
31 and selects only blood flow and its waveform usable for doing
the same.
[0166] A waveform of blood flow is inherent to an individual. Hence,
the calculator 42 compares a blood-flow waveform to a standard waveform
having been stored for each of individuals to thereby judge whether
a blood-flow waveform was properly measured. If the calculator 42
judges that a blood-flow waveform is not properly measured, the
calculator 42 does not use the blood-flow waveform for monitoring
bio-data of the man 31. Thus, accuracy in judgment is enhanced.
[0167] The calculator 42 is designed to judge whether the man 31
is in a serious condition.
[0168] Up and down of blood flow is in synchronization with up
and down of a blood pressure. Based on this fact, the calculator
42 continuously or periodically compares an average of blood flow
to measured blood flow to thereby judge whether the man 31 is in
a serious condition. Specifically, if measured blood flow is higher
or lower than the average by a predetermined degree or more, the
calculator 42 judges that the man 31 is in a serious condition.
[0169] Reduction in a blood pressure is accompanied with reduction
in an amplitude of a blood-flow waveform. Hence, the calculator
42 can judge whether the man 31 is in a serious condition by continuously
or periodically comparing an amplitude of a predetermined blood-flow
waveform to an amplitude of a real-time measured blood-flow waveform.
[0170] The calculator 42 may judge whether the man 31 is in a serious
condition, based on both of blood-flow and an amplitude of a blood-flow
waveform, or based on one of them.
[0171] For instance, a pattern of blood flow and a pattern of an
amplitude of a blood-flow waveform both observed in a certain dialysis
patient when a certain period of time in the range of 30 minutes
to an hour has passed after starting dialysis are recorded as standards.
The calculator 42 may judge whether the man 31 is in a serious condition,
based on reduction in blood flow relative to the standards, reduction
in an amplitude of a blood-flow waveform relative to the standards,
and an increase in a heartbeat number which can be read out of the
blood-flow waveform.
[0172] For instance, the calculator 42 may alarm when a product
F.times.S reduces by a predetermined degree relative to a predetermined
standard of the product, wherein F indicates reduction in an amplitude
of a blood-flow waveform, and S indicates 1/T wherein T indicates
a heartbeat number.
[0173] For instance, if the product reduces by 10%, the calculator
42 judges that the man 31 is in a condition in which small attention
has to be paid to a patient, and transmits a first level alarm.
If the product reduces by 20%, the calculator 42 judges that the
man 31 is in a condition in which normal attention has to be paid
to a patient, and transmits a second level alarm. If the product
reduces by 30%, the calculator 42 judges that the man 31 is in a
dangerous condition, and transmits a third level alarm. If the product
reduces by 40%, the calculator 42 judges that the man 31 is in a
serious condition, and transmits a top level alarm.
[0174] In place of the calculator 42 the controller 40 the artificial
dialysis device 50 or the monitor display 60 may alarm.
[0175] Since the system in accordance with the third embodiment
has the laser blood-flow meters 10 and 20 in accordance with the
first and second embodiments, it is possible to continuously measure
blood flow of the head 31a and the leg 31b of the man 31 stably
and independently of each other by attaching the sensor units 110
of the laser blood-flow meters 10 and 20 to the man 31 with reduced
influences by artifact noises.
[0176] In addition, the calculator 42 judges whether blood flow
and a blood-flow waveform of the head 31a such as an ear lobe and
those of any one of the quarters such as the leg 31b are in synchronization
with each other, respectively. The calculator 42 does not use blood
flow and a blood-flow waveform measured while the above-mentioned
blood flows and blood-flow waveforms are judged not to be in synchronization
with each other, for monitoring bio-data of the man 31. Thus, bio-data
of the man 31 is monitored based on blood flow and a blood-flow
waveform both properly measured. In other words, since blood flows
and blood-flow waveforms which are not in synchronization with each
other, respectively, due to artifact noises are not used for monitoring
bio-data, obtained bio-data is less influenced by artifact noises.
[0177] Furthermore, the calculator 42 is designed to compare measured
blood flow and blood-flow waveform to standard blood flow and blood-flow
waveform having been stored in advance to thereby judge whether
the man 31 is in a serious condition, and if the man 31 is judged
to be in a serious condition, the calculator 42 makes annunciation.
Thus, a user of the system 30 can soon become aware that the man
31 is in a serious condition.
[0178] Bio-data of a man has been conventionally monitored through
the use of a non-direct type hemadynamometer. Though the use of
a non-direct type hemadynamometer is non-invasive similarly to the
system 30 a non-direct type hemadynamometer cannot continuously
monitor bio-data unlike the system 30 in accordance with the third
embodiment.
[0179] A pulse-wave meter or a pulse oxi-meter has been conventionally
used for continuously monitoring bio-data. However, a pulse-wave
meter and a pulse oxi-meter are too late to respond to sudden change
in blood circulation, and cannot clearly show variance in an amplitude
of waveforms. Hence, they are merely assistants to a hemadynamometer.
[0180] In contrast, since the system 30 can monitor bio-data of
the man 31 in non-invasive manner by using the laser blood-flow
meters 10 and 20 almost no burden is exerted on a patient. In addition,
it is possible to continuously monitor bio-data, and hence, it is
also possible to swiftly and surely judge that the man 31 is in
a serious condition. Thus, the system 30 in accordance with the
third embodiment can have a higher rate and higher accuracy at which
the system 30 judges whether the man 31 is in a serious condition,
than the conventional ways.
[0181] The system 30 in accordance with the third embodiment may
be designed to transmits command signals to the artificial dialysis
device 50 for controlling a volume of deicing and/or a dialysis
temperature, and further for giving an alarm to a user to urge to
do so. Furthermore, the system 30 may be designed to estimate dynamics
of circulator organs to which dialysis is being carried out.
[0182] Though the system 30 is designed to include the artificial
dialysis device 50 the system 30 may be designed to include other
external device(s) for making circulation between itself and the
man 31. For instance, the system 30 may be designed to include a
blood transfusion device.
[0183] As an alternative, the system 30 may be designed not to
include the artificial dialysis device 50 or other external device(s).
The system 30 may be designed to simply include the controller 40
and the sensor units 110 (that is, the laser blood-flow meters 10
and 20).
[0184] The system 30 in accordance with the third embodiment can
monitor not only blood flow, but also operation of a heart, a pulsating
flow, and operation of a blood vessel, and, based on monitoring
of them, further monitor physiological function such as autonomic
nervous system and central nervous system. For instance, the system
30 is applicable to administration of athletes, space medicine,
monitoring of development of neonates, diagnosis of children, judgment
as to when medicine becomes efficacious, animal experiments, and
other uses.
[0185] In the system 30 in accordance with the third embodiment,
the laser blood-flow meter 20 in accordance with the second embodiment
is used for measuring blood flow of the head 31a. The laser blood-flow
meter 10 in accordance with the first embodiment may be used in
place of the laser blood-flow meter 20 in which case, an aid for
readily attaching the laser blood-flow meter 10 to the head 31a,
such as a head band, a head phone or a cap, may be integral with
the laser blood-flow meter 10. With such an aid, the laser blood-flow
meter 10 can be readily attached to and released from the head 31a.
[0186] While the present invention has been described in connection
with certain preferred embodiments, it is to be understood that
the subject matter encompassed by way of the present invention is
not to be limited to those specific embodiments. On the contrary,
it is intended for the subject matter of the invention to include
all alternatives, modifications and equivalents as can be included
within the spirit and scope of the following claims.
[0187] The entire disclosure of Japanese Patent Application No.
2003-156943 filed on Jun. 2 2003 including specification, claims,
drawings and summary is incorporated herein by reference in its
entirety. |