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JP2013233238

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DESCRIPTION JP2013233238
Abstract: To miniaturize a probe for a photoacoustic measurement device provided with a light
guide placed obliquely. A probe for a photoacoustic measurement apparatus comprising a light
guide 71 formed in a parallel plate shape having two side surfaces 71a parallel to each other, a
light incident end surface 71b, and a light emitting end surface 71c. When the light guide 71 is
used, one of the two side surfaces 71a is closer to the probe axis C facing the subject when the
probe is used, and the other becomes farther and the light emitting end face 71c to the probe
axis C. Are disposed closer to each other so that the light incident end face 71b becomes closer.
When the refractive index to the light of the light guide 71 and the refractive index to the light of
the light guide surrounding medium at the time of photoacoustic measurement are n1 and n2
(n2 <n1), respectively, the light emitting end face 71c is the probe axis The side surface 71a
closer to C is formed obliquely so as to form an angle α [°] (however, 90 °-arcsin (n2 / n1) <α
<90 °). [Selected figure] Figure 1
Photoacoustic measurement device and probe for photoacoustic measurement device
[0001]
The present invention relates to a photoacoustic measurement apparatus, that is, an apparatus
that irradiates a subject such as a living tissue with light, detects an acoustic wave generated by
the light irradiation, and measures the subject.
[0002]
The present invention also relates to a probe used for the photoacoustic measurement apparatus
as described above.
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[0003]
Conventionally, as shown, for example, in patent documents 1 and 2 and nonpatent literature 1,
the photoacoustic imaging device which image-forms the inside of a living body using a
photoacoustic effect is known.
In this photoacoustic imaging apparatus, for example, pulsed light such as pulsed laser light is
applied to the inside of a living body.
In the inside of the living body irradiated with the pulsed light, the living tissue that has absorbed
the energy of the pulsed light expands in volume due to heat and generates an acoustic wave.
Therefore, it becomes possible to visualize the inside of the living body based on the electrical
signal (photoacoustic signal) obtained by detecting this acoustic wave with an ultrasonic probe or
the like.
[0004]
In most cases, a probe used in a photoacoustic measurement apparatus such as the abovedescribed photoacoustic imaging apparatus is configured to also have a function of emitting light
to be irradiated to a subject. In such a case, it is desired that the imaging target site of the subject
be irradiated with a light flux whose light intensity is uniformed, so that light is made to enter the
light guide as described in, for example, Patent Document 2. It is considered to light the light flux
emitted from the light guide to the subject.
[0005]
The light guide makes total internal reflection of light repeated internally, and makes the light
intensity distribution of the irradiated light uniform. Generally, two side surfaces parallel to each
other and a light incident end face on which the light is incident And the light emitting end face
facing the light incident end face and the light emitting end face for emitting the light with the
side face interposed therebetween.
[0006]
JP, 2005-21380, A JP, 2009-31268, A
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2
[0007]
A High-Speed Photoacoustic Tomography System based on a Commercial Ultrasound and a
Custom Transducer Array, Xueding Wang, Jonathan Cannata, Derek DeBusschere, Changhong
Hu, J. Brian Fowlkes, and Paul Carson, Proc.
SPIE Vol.
7564, 756424 (Feb. 23, 2010)
[0008]
By the way, in the above-mentioned probe, an acoustic wave detection unit such as an ultrasonic
transducer for detecting an acoustic wave emitted from the inside of a living body or the like is
usually disposed on the probe axis. Therefore, it is considered to dispose the above-mentioned
parallel flat light guide obliquely with respect to the probe axis so as not to interfere with the
acoustic wave detection unit. In addition, by disposing the light guide obliquely as described
above, the surface of the subject is compared with the case where the light guide is vertically
disposed (that is, disposed parallel to the probe axis and perpendicular to the surface of the
subject). It is also possible to reduce the light absorbed in the vicinity and allow the light to reach
a deeper position.
[0009]
However, when the light guide is obliquely disposed, there arises a problem that the width of the
probe becomes longer as compared with the case where the light guide is vertically disposed.
[0010]
The present invention has been made in view of the above circumstances, and an object of the
present invention is to provide a probe for a photoacoustic measurement device which can be
formed compactly while keeping the width short even if the light guide is obliquely disposed. It
is.
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[0011]
Another object of the present invention is to provide a photoacoustic measurement apparatus
which can be formed in a small size by providing the above-described probe.
[0012]
A probe for a photoacoustic measurement device according to the present invention comprises: a
light irradiation unit that emits light emitted to a subject; an acoustic wave detection unit that
detects an acoustic wave emitted from the subject by receiving the light irradiation; A probe for a
photoacoustic measurement device having the light emission unit, wherein the light irradiation
unit faces the light incidence end surface with the side surface between the two side surfaces
parallel to each other and the light incidence end surface on which the light is made incident; A
probe for a photoacoustic measurement device, comprising: a light guide having a light emitting
end face for emitting light and formed in a parallel plate shape, wherein the light guide faces the
subject when the probe is used. It is disposed so that one of the two side faces is closer to the
probe axis and the other is more distant, and the light emitting end face is closer to the probe
axis and the light incident end face is further distant. , Said light guide The light emitting end face
is closer to the probe axis, where n1 and n2 (n2 <n1) are respectively the refractive index for the
light and the refractive index for the light of the medium around the light guide at the time of
photoacoustic measurement. It is characterized in that it is formed so as to make an angle α [°]
(where 90 ° -arcsin (n2 / n1) <α <90 °) with the side face of the above.
[0013]
In the probe for photoacoustic measurement apparatus of the present invention having the above
configuration, light traveling from the light emitting end surface after traveling in the light
guiding body in parallel to the two side surfaces is incident on a plane orthogonal to the probe
axis Where the incident angle of the light guide is β1, and the inclination angle of the light guide
relative to the probe axis is
[0014]
It is desirable that
[0015]
Moreover, in the probe for photoacoustic measuring devices of this invention, it is desirable for
the arrangement angle of the said light guide to be changeable.
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[0016]
In that case, in particular, the arrangement angle of the light guide can be changed between a
predetermined angle inclined to the probe axis and an angle parallel to the probe axis. desirable.
[0017]
Further, in the probe for a photoacoustic measurement device according to the present invention,
particularly when a plurality of acoustic wave detection units are arranged in a direction
orthogonal to the probe axis, the light guide has a plurality of acoustic waves at its light emitting
end surface. It is desirable to be disposed in a state of extending along the alignment direction of
the detection units.
[0018]
Moreover, in the probe for photoacoustic measuring devices of this invention, it is desirable for
two light guides to be provided in the state in which the said probe axis exists between each
other.
[0019]
In that case, shutters are provided corresponding to each of the two light guides so as to control
the passage of light so that the light passing through those light guides is irradiated to the
subject in different periods. Is particularly preferred.
[0020]
In the probe for photoacoustic measurement apparatus of the present invention, an optical fiber
for propagating light emitted from the light source is provided, and the optical fiber is optically
coupled to the light incident end face of the light guide. desirable.
[0021]
In that case, particularly if three or more optical fibers are provided, it is desirable that the
optical fibers be disposed in a staggered manner and coupled to the light incident end face of the
light guide.
[0022]
When the optical fiber is provided, it is preferable that a light absorber be attached to a portion
where the optical fiber is not disposed at the light incident end face of the light guide.
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[0023]
Furthermore, in the probe for a photoacoustic measuring device of the present invention, it is
desirable that an optical sensor for detecting light emitted from the light incident end face of the
light guide to the outside of the light guide is provided.
[0024]
Further, in the probe for a photoacoustic measurement device of the present invention, it is
desirable that a contact sensor for detecting the contact of the probe with the subject be
provided.
[0025]
Further, in the probe for a photoacoustic measurement device according to the present invention,
it is desirable that the angle α be in the range of 90 ° -arcsin (1.33 / n1) <α <90 °.
[0026]
On the other hand, the photoacoustic measurement apparatus according to the present invention
is characterized by including the probe for the photoacoustic measurement apparatus according
to the present invention described above.
[0027]
According to the probe for photoacoustic measurement apparatus according to the present
invention, the refractive index of the light guide to the light irradiated to the object and the
refractive index of the medium around the light guide at the photoacoustic measurement are n1
and n2, respectively. When (n2 <n1), the light emitting end face forms an angle α [°] (where 90
° -arcsin (n2 / n1) <α <90 °) with the side surface closer to the probe axis. As described
above, since the light is emitted at a common angle to the subject, the light guide end face is
more inclined than the case where the light emitting end face is not formed obliquely. It can be
made smaller, that is, closer to a vertical arrangement.
As a result, the probe for a photoacoustic measurement device of the present invention has a
small horizontal width and can be formed compact.
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[0028]
Further, in the probe for a photoacoustic measurement device according to the present invention,
particularly when the above-mentioned equation (2) is satisfied, the direction of the light beam
emitted from the light guide is a plane whose light beam center is orthogonal to the probe axis
Can be controlled to be incident at a desired incident angle β1.
The detailed reason will be described later according to the embodiment.
[0029]
Further, in the probe for a photoacoustic measurement device according to the present invention,
in particular, when the arrangement angle of the light guide is changeable, the direction of the
light flux emitted from the light guide is the measurement of the object (for example, an imaging
device In the above, the orientation can be set more appropriately depending on the depth of the
portion to be imaged.
For example, in more detail, if it is possible to change the arrangement angle of the light guide
between a predetermined angle inclined to the probe axis and an angle parallel to the probe axis,
the angle of the former should be set. It is possible to set and measure a deeper part of the
subject, and to set the latter angle to measure a shallower part of the subject.
[0030]
Further, in the probe for a photoacoustic measurement device according to the present invention,
in particular, when two light guides are provided with the probe axis being provided between
each other, an object to be examined using both light guides. Thus, it is possible to emit a large
amount of light.
[0031]
In that case, in particular, shutters are provided corresponding to each of the two light guides so
as to control the passage of light so that the light passing through those light guides is irradiated
to the subject during different periods. If so, it is also possible to obtain higher S / N
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measurement signals.
The detailed reason will be described in detail later on the basis of the embodiment applied to the
photoacoustic imaging apparatus.
[0032]
Further, in the probe for photoacoustic measurement apparatus according to the present
invention, particularly, three or more optical fibers for propagating light emitted from the light
source are provided, and these optical fibers are staggered relative to the light incident end face
of the light guide. When the light guide is arranged and coupled, the light intensity equalization
effect by the light guide can be made more remarkable.
[0033]
In the case where the optical fiber is provided, in particular, if the light absorber is attached to a
portion where the optical fiber is not disposed at the light incident end surface of the light guide,
light leaks from the light incident end surface. Can be prevented.
[0034]
Furthermore, in the probe for a photoacoustic measurement device according to the present
invention, particularly when an optical sensor for detecting light emitted from the light incident
end face of the light guide to the outside of the light guide is provided, the leaked light is
detected by the sensor. At the same time, it is possible to prevent adverse effects due to the
leaked light by reducing the output of the light source or the like.
[0035]
Further, in the probe for a photoacoustic measurement device according to the present invention,
in particular, when a contact sensor for detecting contact of the probe with the object is
provided, light of a predetermined intensity is generated from the light source only when the
contact is detected. By doing this, it is possible to prevent the irradiation of high intensity light
from the probe carelessly.
[0036]
Further, in the probe for a photoacoustic measurement device of the present invention, in
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particular, when the angle α is in the range of 90 ° -arcsin (1.33 / n1) <α <90 °, the abovementioned various items are observed when the subject is a living body. The effect of
That is, when the subject is a living body, the refractive index n2 of the living body serving as the
medium around the light guide is basically equal to the refractive index of water.
And in that case, light with a wavelength of about 750 nm to 800 nm is often irradiated to the
living body, but the refractive index of water for those wavelengths is about 1.33 (for example,
20 for a wavelength of 780 nm) 1.28 ° C).
Therefore, when the angle α is within the above range where n 2 = 1.33, the various effects can
be obtained when the subject is a living body.
[0037]
On the other hand, since the photoacoustic measurement device according to the present
invention includes the above-described probe for the photoacoustic measurement device
according to the present invention, the portion around the probe can be formed in a smaller size.
[0038]
The schematic side view which shows the principal part of the probe for photoacoustic
measuring devices by one Embodiment of this invention The block diagram which shows
schematic structure of the photoacoustic imaging apparatus provided with the probe of FIG. 1 In
order to demonstrate the effect of the probe of FIG. FIG. 5 is a schematic side view showing a
part of a conventional probe, and a partially broken perspective view showing a light guide of a
probe according to another embodiment of the present invention. Side view top view showing a
portion of a conventional probe Top view showing a portion of a probe according to yet another
embodiment of the invention Side view showing another portion of the probe of FIG. 8 along line
A-A of FIG. 12 is a cross-sectional view showing a cross-sectional shape of a portion of the side
view of a portion of a probe according to still another embodiment of the present invention. FIG.
12 is a plan view showing a portion of a probe according to still another embodiment of the
present invention. Block diagram 12 shown The block diagram showing the modification of the
device. The block diagram showing another modification of the device of FIG. 12. The schematic
diagram explaining the light irradiation state by the probe of the present invention. The side view
showing a part of the probe according to another embodiment of the present invention. 17 is a
plan view showing a plan view of the probe shown in FIG. 17 A side view showing another state
of the probe shown in FIG. 17 A plan view showing another state of the probe shown in FIG. Top
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view A plan view showing another state of the mechanism of FIG. 21 A perspective view showing
an example of a light guide and a mechanism for holding an optical fiber
[0039]
Hereinafter, embodiments of the present invention will be described in detail with reference to
the drawings.
FIG. 1 shows a schematic side view of a main part of an ultrasonic probe (hereinafter referred to
as a probe) 70 according to an embodiment of the present invention, and FIG. 2 shows the probe
70 applied thereto. 1 shows a photoacoustic imaging apparatus 10 as an example of a
photoacoustic measurement apparatus.
[0040]
First, the photoacoustic imaging apparatus 10 will be described with reference to FIG.
The photoacoustic imaging apparatus 10 is capable of acquiring both a photoacoustic image and
an ultrasound image as an example, and in addition to the probe 70, the ultrasound unit 12, the
laser light source unit 13, and the image display means 14 Is equipped.
[0041]
The laser light source unit 13 emits pulsed laser light of a predetermined wavelength, and the
pulsed laser light emitted therefrom is irradiated to the subject.
The pulsed laser light is schematically illustrated in FIG. 1 for the emission path, but as described
in detail later, it is guided to the probe 70 using a light guiding means such as a plurality of
optical fibers, for example. After the light guide (light guide plate) provided in the probe 70 is
propagated, the light is irradiated from the light guide toward the subject.
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[0042]
The probe 70 performs output (transmission) of ultrasonic waves to the subject and detection
(reception) of reflected ultrasonic waves reflected back from the subject.
For that purpose, the probe 70 has, for example, a plurality of ultrasonic transducers (ultrasound
transducers) arranged in one dimension.
Further, the probe 70 detects ultrasonic waves (acoustic waves) generated by the observation
object in the subject absorbing the laser light from the laser light source unit 13 with a plurality
of ultrasonic transducers.
The probe 70 detects the acoustic wave to output an acoustic wave detection signal, and detects
the reflected ultrasonic wave to output an ultrasonic wave detection signal.
[0043]
The light guide provided on the probe 70 will be described later, but the light guide is formed in
a parallel flat plate shape, and the light emitting end face thereof is a direction in which a
plurality of ultrasonic transducers are arranged (left and right in FIG. The laser beam is emitted
toward the subject from there.
Hereinafter, the case where this configuration is applied will be described as an example.
[0044]
When acquiring a photoacoustic image or an ultrasonic image of the subject, the probe 70 is
moved in a direction substantially perpendicular to the one-dimensional direction in which the
plurality of ultrasonic transducers are arranged, whereby the subject is a laser beam and an
ultrasonic wave. Two-dimensional scanning is performed by
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This scan may be performed manually by the examiner by moving the probe 70, or a more
accurate two-dimensional scan may be realized using a scan mechanism.
[0045]
The ultrasound unit 12 includes a receiving circuit 21, an AD conversion unit 22, a reception
memory 23, a data separation unit 24, a photoacoustic image reconstruction unit 25, a detection
/ logarithmic conversion unit 26, and a photoacoustic image construction unit 27. There is.
[0046]
The receiving circuit 21 receives the acoustic wave detection signal and the ultrasonic wave
detection signal output from the probe 70.
The AD conversion means 22 is a sampling means, which samples the acoustic wave detection
signal and the ultrasonic wave detection signal received by the receiving circuit 21 and converts
them into photoacoustic data and ultrasonic wave data which are digital signals.
This sampling is performed at a predetermined sampling period, for example, in synchronization
with an externally input AD clock signal.
[0047]
In addition to the ultrasonic image reconstruction unit 40 receiving the output of the data
separation unit 24, the ultrasonic unit 12 includes a detection / logarithmic conversion unit 41,
an ultrasonic image construction unit 42, the ultrasonic image construction unit 42, and An
image synthesizing unit 43 receiving the output of the photoacoustic image constructing unit 27
is provided.
The output of the image combining means 43 is input to an image display means 14 composed
of, for example, a CRT or a liquid crystal display.
The ultrasound unit 12 further includes a transmission control circuit 30 and a control unit 31
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that controls the operation of each unit in the ultrasound unit 12 and the like.
[0048]
The photoacoustic data or ultrasonic data output from the AD conversion means 22 is once
stored in the reception memory and then input to the data separation means 24.
The data separation means 24 separates the input photoacoustic data and the ultrasound data
from each other, and the photoacoustic data is input to the photoacoustic image reconstruction
means 25 and the ultrasound data is input to the ultrasound image reconstruction means 40 .
[0049]
The laser light source unit 13 is a solid state laser unit provided with a Q switch pulse laser 32
made of, for example, an Nd: YAG laser, a Ti: Sapphire laser, or an alexandrite laser, and a flash
lamp 33 serving as an excitation light source.
For example, when acquiring the photoacoustic image which shows a blood vessel, what emits
the pulse laser beam of the wavelength which is favorably absorbed in a blood vessel as laser
light source unit 13 is selected and utilized.
[0050]
When the laser light source unit 13 receives a light trigger signal instructing light emission from
the control means 31, it turns on the flash lamp 33 to excite the Q switch pulse laser 32.
The control means 31 outputs a Q switch trigger signal, for example, when the flash lamp 33
sufficiently excites the Q switch pulse laser 32.
When receiving the Q switch trigger signal, the Q switch pulse laser 32 turns on the Q switch to
emit pulse laser light.
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[0051]
Here, the time required for the Q switch pulse laser 33 to be in a sufficient excitation state after
lighting of the flash lamp 33 can be estimated from the characteristics of the Q switch pulse laser
33 or the like.
Instead of controlling the Q switch from the control means 31 as described above, the Q switch
may be turned on after the Q switch pulse laser 32 is sufficiently excited in the laser light source
unit 13.
In that case, a signal indicating that the Q switch has been turned on may be notified to the
ultrasonic unit 12 side.
[0052]
Further, the control means 31 inputs an ultrasonic wave trigger signal for instructing ultrasonic
wave transmission to the transmission control circuit 30.
When the transmission control circuit 30 receives this ultrasonic wave trigger signal, it causes
the probe 70 to transmit an ultrasonic wave. The control means 31 first outputs the light trigger
signal and then outputs an ultrasonic trigger signal. The light trigger signal is output to irradiate
the laser light to the subject and the acoustic wave is detected, and then the ultrasonic trigger
signal is output to transmit the ultrasonic wave to the subject, and the reflected ultrasonic wave.
Detection is performed.
[0053]
The control means 31 further outputs a sampling trigger signal instructing the start of sampling
to the AD conversion means 22. The sampling trigger signal is output after the light trigger
signal is output and before the ultrasonic trigger signal is output, more preferably, at a timing
when the object is actually irradiated with the laser light. Therefore, the sampling trigger signal is
05-05-2019
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output in synchronization with, for example, the timing when the control means 31 outputs the Q
switch trigger signal. When the AD conversion means 22 receives the sampling trigger signal, the
probe 70 outputs and starts sampling of the acoustic wave detection signal received by the
receiving circuit 21.
[0054]
After outputting the light trigger signal, the control means 31 outputs an ultrasonic wave trigger
signal at the timing when the detection of the acoustic wave ends. At this time, the AD conversion
means 22 continuously carries out the sampling without interrupting the sampling of the
acoustic wave detection signal. In other words, the control means 31 outputs an ultrasonic wave
trigger signal while the AD conversion means 22 continues sampling of the acoustic wave
detection signal. The probe 70 transmits ultrasonic waves in response to the ultrasonic wave
trigger signal, whereby the detection target of the probe 70 changes from acoustic waves to
reflected ultrasonic waves. The AD conversion means 22 continuously samples the acoustic wave
detection signal and the ultrasonic wave detection signal by continuing sampling of the detected
ultrasonic wave detection signal.
[0055]
The AD conversion means 22 stores the photoacoustic data and the ultrasound data obtained by
sampling in the common reception memory 23. The sampling data stored in the reception
memory 23 is photoacoustic data up to a certain point in time, and becomes ultrasound data
from some point in time. The data separation means 24 separates the photoacoustic data and the
ultrasound data stored in the reception memory 23, inputs the photoacoustic data to the
photoacoustic image reconstructing means 25, and the ultrasound image reconstructing means
Enter 40
[0056]
Hereinafter, generation and display of an ultrasonic image and a photoacoustic image will be
described. The ultrasonic image reconstruction means 40 adds the above-mentioned ultrasonic
data which is data of each of a plurality of ultrasonic transducers which the probe 70 has, and
generates ultrasonic tomographic image data for one line. The detection / logarithmic conversion
means 41 generates an envelope of this ultrasonic tomographic image data, and then
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logarithmically converts the envelope to expand the dynamic range, and then inputs this data to
the ultrasonic image construction means. The ultrasonic image construction means 42 generates
an ultrasonic tomographic image (ultrasound echo image) based on the data of each line
outputted by the detection / logarithmic conversion means 41. That is, the ultrasonic image
constructing unit 42 generates an ultrasonic tomographic image, for example, such that the
position in the time axis direction of the peak portion of the ultrasonic detection signal described
above is converted to the position in the depth direction in the tomographic image. .
[0057]
The above processing is sequentially performed along with the scan movement of the probe 70,
whereby ultrasonic tomographic images regarding a plurality of locations in the scan direction of
the subject are generated. The image data carrying these ultrasonic tomographic images is input
to the image combining means 43. When it is desired to display only the ultrasonic tomographic
image alone, the image data carrying the ultrasonic tomographic image is sent to the image
display means 14 by passing the image synthesizing means 43 and the ultrasonic wave is sent to
the image display means 14. A tomographic image is displayed.
[0058]
Next, generation and display of the photoacoustic image will be described. The photoacoustic
image reconstructing means 25 receives the photoacoustic data separated from the ultrasonic
data by the data separating means 24, for example, photoacoustic data obtained by irradiating
the subject with pulsed laser light having a wavelength absorbed by the blood vessel. Is input.
The photoacoustic image reconstruction unit 25 adds the photoacoustic data, which is data of
each of a plurality of ultrasonic transducers included in the probe 70, to generate one line of
photoacoustic image data. The detection / logarithmic conversion means 26 generates an
envelope of this photoacoustic image data, then logarithmically converts the envelope to expand
the dynamic range, and then inputs this data to the photoacoustic image construction means 27.
The photoacoustic image construction means 27 generates a photoacoustic image based on
photoacoustic image data for each line. That is, the photoacoustic image construction means 27
generates a photoacoustic image, for example, such that the position in the time axis direction of
the peak portion of the photoacoustic image data is converted to the position in the depth
direction in the tomographic image.
[0059]
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The above processing is sequentially performed along with the scanning movement of the probe
70, whereby photoacoustic images regarding a plurality of locations in the scanning direction of
the subject are generated. The image data carrying these photoacoustic images is input to the
image synthesizing means 43, where it is synthesized with the image data carrying the ultrasonic
tomographic image described above, and the image carried by the synthesized data is sent to the
image display means 14. Is displayed. The image displayed based on the combined data is a
ultrasonic tomographic image in which a blood vessel image, which is a photoacoustic image, is
shown. The blood vessel image may be colored in a predetermined color so as to be clearly
distinguished from other parts.
[0060]
Next, the probe 70 will be described in detail with reference to FIG. As shown here, the probe 70
is emitted from the subject by receiving the two light guides 71 and 71 constituting a light
irradiation unit that emits the laser light to be irradiated to the subject, and the laser light. And a
plurality of ultrasonic transducers 72 functioning as an acoustic wave detection unit for
detecting an acoustic wave. These ultrasonic transducers 72 generate ultrasonic waves to acquire
an ultrasonic image echo, and also function to detect the ultrasonic waves reflected by the object
as described above. is there.
[0061]
The plurality of ultrasonic transducers 72 are arranged in a direction perpendicular to the paper
surface in FIG. 1 (in the left-right direction in FIG. 2, which is referred to as the detection portion
juxtaposed direction), and the lower end of the substantially rectangular parallelepiped base
portion 73 Is attached to The direction in which the detection units are juxtaposed is a direction
orthogonal to the axis extending the center of the probe axis C facing the object when using the
probe, that is, the base 73.
[0062]
On the other hand, the light guide 71 has two side surfaces 71a and 71a parallel to each other, a
light incident end surface 71b for making laser light incident, and the side surfaces 71a and 71a
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interposed therebetween to face the light incident end surface 71b. It has a light emitting end
surface 71c to be emitted, and is formed in a substantially parallel plate shape. Then, in each of
the two light guides 71, one of the two side surfaces 71a is closer to the probe axis C and the
other is farther, and the light emitting end surface 71c is closer to the probe axis C and light is
incident The end face 71b is further away, and the light emitting end face 71c is disposed to be
inclined so as to extend along the direction in which the detection portions are arranged.
[0063]
Here, the light emitting end surface 71 c of the light guide 71 is formed obliquely so as to form
an angle α [°] with the side surface 71 a closer to the probe axis C. In this case, assuming that
the refractive index of the light guide 71 is n1 and the refractive index of the medium around the
light guide is n2, the angle α satisfies the following relationship: 90 ° −arcsin (n2 / n1) <α
<90 ° It is set to be satisfactory. Since the light guide 71 is generally formed of an optical glass
or the like described later, and the medium around the light guide is a living tissue which is
generally considered to be equivalent to air or refractive index with water, usually n2 <n1. It is.
[0064]
Hereinafter, the operation obtained by satisfying the above relationship will be described with
reference to FIG. For example, a plurality of optical fibers are optically coupled to the light
incident end face 71 b of the light guide 71, and laser light after propagating through the optical
fibers is introduced to the light guide 71. The laser light propagates while repeating total
reflection in the light guide 71 and is emitted from the light incident end surface 71 toward the
subject.
[0065]
As described above, when light is introduced into the light guide 71 through the optical fiber,
basically all the light obliquely enters the light incident end face 71b of the light guide 71. There
is almost no light traveling in parallel with the side surface 71a. However, here, as shown in FIG.
1 and FIG. 3, it is assumed that there is a laser beam LB traveling in such a manner, and
conditions are set such that the laser beam LB is refracted from the light emitting end face 71c
toward the inside of the probe.
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[0066]
That is, in this case, the luminous flux emitted from the light emitting end surface 71c while
expanding (a hatched portion in FIG. 1, which is a set of light emitted from the light emitting end
surface 71c at a variable angle) Will be bent towards the inside of the probe. If so, when it is
desired to irradiate a predetermined region directly below the ultrasonic transducer 72 with a
light beam, as shown in FIG. 4, the case of irradiating with a normal light guide 71 'in which the
light emitting end face 71c is not formed obliquely As compared with the above, the inclination
angle β2 of the light guide 71 can be set smaller, and hence the lateral width of the probe 70
depending on the position of the outer end of the light guide 71 can be further reduced.
[0067]
Here, in order to refract the laser beam LB traveling as described above from the light emitting
end surface 71c toward the inside of the probe, the angle α may be an acute angle, that is, α
<90 °. On the other hand, in order to prevent the laser beam LB traveling as described above
from being totally reflected at the interface between the light emitting end surface 71c and the
surrounding medium, the incident angle θA of the laser beam LB on the light emitting end
surface 71c is It is necessary to satisfy the condition of being small. Since the incident angle θA
= 90 ° −α and the critical angle = arcsin (n2 / n1), this condition is 90 ° −α <arcsin (n2 /
n1), that is, 90 ° −arcsin (n2 / n1). n1) <α.
[0068]
From the above, if the condition of 90 ° -arcsin (n2 / n1) <α <90 ° is satisfied, the light
amount emitted from the light emitting end surface 71c is sufficiently secured, and then the
width of the probe 70 is It becomes possible to make it smaller compared with the case where
the light guide which is not obliquely formed in the end surface is used.
[0069]
Next, referring to FIG. 3, the condition in the case where the laser light LB traveling in the light
guide 71 parallel to the side surface 71 a is made incident at a desired incident angle with
respect to the plane P orthogonal to the probe axis C. Explain.
05-05-2019
19
Here, although the light guide 71 on the right side in FIGS. 1 and 3 will be described, the same
can be said for the light guide 71 on the left side.
[0070]
First, also in this case, regarding the refractive index n1 of the light guide 71 and the refractive
index n2 of the surrounding medium, it is assumed that n2 <n1. Further, the desired incident
angle is assumed to be β1, and the inclination angle of the light guide 71 with respect to the
probe axis C is assumed to be β2.
[0071]
The laser beam LB traveling in the light guide 71 in parallel with the side surface 71a is refracted
at the interface between the light emitting end surface 71c and the surrounding medium as
described above, and is emitted from the light emitting end surface 71c. Assuming that the
incident angle and the refraction angle of the laser beam LB with respect to the interface at this
time are θA and θB, respectively, from Snell's law,
[0072]
である。
[0073]
Here, θA = 90 ° −α.
Further, assuming that the difference between the incident angle θA and the refraction angle
θB is θOUT, since θOUT = β1−β2, θB = θA + θOUT = (90 ° −α) + β1−β2.
Substituting the above θA and θB into the above equation (3) results in the above equation (2).
That is, if equation (2) is satisfied, the laser beam LB emitted from the light emitting end surface
71c after traveling in the light guide 71 parallel to the side surface 71a is in the plane P
orthogonal to the probe axis C. The light is incident at a desired incident angle β1.
05-05-2019
20
[0074]
As described above, when light is introduced into the light guide 71 from the optical fiber, almost
no light travels in the light guide 71 parallel to the side surface 71a. However, assuming that the
above equation (2) is satisfied on the assumption of such light, a light flux (hatched portion)
which is expanded and emitted from the light emitting end surface 71c of the light guide 71 as
shown in FIG. However, approximately the center thereof is incident on the plane P at a desired
incident angle β1.
[0075]
In the case where the light emitting end face 71c is not formed obliquely and the light guide 71
is formed in a perfect rectangular parallelepiped shape, to obtain the above-mentioned state, as
shown in FIG. The inclination angle β2 with respect to the probe axis C of 71 is set equal to the
incident angle β1. As compared with such a case, when the equation (2) is satisfied, the
inclination angle β2 can be set smaller by an amount corresponding to the refraction at the light
emitting end face 71c.
[0076]
The difference in the total lateral width of the probe 70 between the case where the light
emitting end face 71c is formed obliquely and the case where the light emitting end face 71c is
not oblique is approximately twice the difference between the dimensions W1 and W2 in FIG.
Assuming that this difference is 2ΔW and the total length of the light guide 71 (length in the
central portion in the thickness direction) is L, 2ΔW = 2 (W1−W2) = 2L (sin β1−sin β2).
[0077]
In the present invention, it is not always necessary to satisfy the above equation (2). It is
desirable that the site of the subject for which a photoacoustic image is to be obtained is basically
located directly below the ultrasonic transducer 72 and that the site is most preferably irradiated
with light, but the desired incident angle β1 is Even if it is realized, the region to which light is
best irradiated may be located directly under the ultrasonic transducer 72 depending on the
05-05-2019
21
distance between the portion of the object and the ultrasonic transducer 72, or otherwise. It
exists in the position. If this is conversely considered, even if the equation (2) is not satisfied, by
adjusting the distance between the portion of the object and the ultrasonic transducer 72, the
region immediately below the ultrasonic transducer 72 can be obtained. It becomes possible to
irradiate light best to the desired site located.
[0078]
Next, preferable values of the angle α in the probe 70 of the present embodiment will be
described. For the light guide 71 using synthetic quartz (refractive index n1 = 1.45) and BK7
glass (refractive index n1 = 1.51), the surrounding medium is water (living body) and The angle
α and the inclination angle β2 were individually set for a total of four cases where air was used
and in the case of air, and the effect of probe miniaturization in each case was examined by
computer simulation.
[0079]
Here, the value of 2ΔW described above is defined as the amount of reduction in size as
compared to the case where the light emitting end face 71c is not formed obliquely, that is, the
amount of reduction in lateral width. At this time, the length L of the light guide is 25 mm, its
thickness is 3 mm, the desired incident angle β1 is 30 °, and the spread angle of light emitted
from the light source is defined by 1 / e <2> diameter. It is defined as 2 ° (defined as a peak
intensity, that is, a spread angle of a portion having an intensity of 1 / e <2> with respect to the
light intensity at the center of the beam). Also, in this example, the use light is considered as
sodium D line (wavelength = 589.3 nm), but if light other than that is used, it should be
considered as the refractive index n1 and n2 for the use light Of course there is one.
[0080]
The results are shown in Table 1. In these cases, the angle α is set to a value such that the
incident angle θA = (90 ° −α) becomes smaller than the critical angle θC by 0.1 °, and
under such conditions, a large amount of miniaturization 2ΔW Is obtained. However, as the
incident angle θA is closer to the critical angle θC, the amount of light totally reflected at the
interface between the light emitting end surface 71c of the light guide 71 and the surrounding
medium increases, so the irradiation efficiency decreases.
05-05-2019
22
[0081]
In order to further reduce the light quantity of the total reflection, the angle α may be increased
so as to reduce the incident angle θA. Therefore, for the four examples described above, the
angle α in the case where the total reflected light amount is 10% of the total incident light
amount is further determined by simulation. The results are shown in Table 2. As shown here,
the size reduction amount 2ΔW is clearly smaller than in the case of Table 1, that is, the effect of
size reduction diminishes, but in order to sufficiently secure the light intensity for irradiating the
object, Table 2 shows It is preferable to set the angle α to the extent shown.
[0082]
Although the light guide 71 in the present embodiment has a shape in which the light emitting
end face 71c extends long along the direction in which the plurality of ultrasonic transducers 72
are arranged, it does not have such a long light emitting end face Thus, it is also possible to use a
light guide formed in a thin rod shape as a whole. The present invention is similarly applicable to
a probe for a photoacoustic measurement apparatus including such a rod-like light guide, and in
this case as well, the light emitting end face is formed obliquely, as described above. The same
effect can be achieved.
[0083]
Moreover, as shown in FIG. 5, it is desirable to provide the light absorber 75 attached to the
light-incidence end surface 71b in the light guide 71 mentioned above. The light absorber 75 is
formed of a light absorbing material such as black rubber or carbon, and when the abovementioned optical fiber 76 is installed as a means for introducing light, a hole 75a for passing
the optical fiber 76 is provided. It is By providing such a light absorber 75, the light totally
reflected at the interface between the light emitting end surface 71c and the surrounding
medium returns to the inside of the light guide 71 and then leaks out from the light incident end
surface 71b. Thus, it is possible to prevent the leaked light from inadvertently irradiating the
subject or entering the eye of the probe operator. In FIG. 5, elements equivalent to the elements
in FIGS. 1 to 4 have the same reference numerals, and the description thereof will be omitted
unless particularly necessary (the same applies hereinafter).
05-05-2019
23
[0084]
The configuration for preventing the problem due to the leak light as described above will be
further described with reference to FIG. In this configuration, a probe housing 74 for housing the
light guide 71, the base portion 73, and the optical fiber 76 is provided. In the probe housing 74,
an optical sensor 77 is installed at a position facing close to the light incident end face 71b of
one light guide 71.
[0085]
According to this optical sensor 77, it is possible to detect light leaked out of the light guiding
body from the light incident end face 71b as described above. Then, when the sensor 77 detects
leaked light, if the output of the light source such as the laser light source unit 13 described
above is reduced, it is possible to prevent the above-mentioned problems from being caused by
strong leaked light. Become.
[0086]
The optical sensor 77 may be installed at a position shown by a broken line in FIG. 6, particularly
when the optical sensor 77 is relatively large. In this case, the space formed at the upper part of
the light guide 71 by tilting the light guide 71 is effectively used for the installation of the light
sensor.
[0087]
Furthermore, as shown in the figure, the probe housing 74 is provided with a contact sensor 78
for detecting contact with the subject, and the output of the light source such as the laser light
source unit 13 is adjusted according to the output of the contact sensor 78. It may be controlled.
That is, in this case, the weak light is output from the light source immediately after startup of
the photoacoustic imaging apparatus 10 or at the end of the operation before the use of the
probe, and the contact sensor 78 is Only when the probe contact with the sample is detected, the
output of the light source is raised to a predetermined value required for imaging. By doing this,
it is possible to prevent the strong light from being inadvertently irradiated to the subject or from
05-05-2019
24
being incident on the eye of the probe operator under a state where the use of the probe is not
ready.
[0088]
It is desirable that the subject be irradiated with more uniform light intensity. Hereinafter, a
configuration for meeting such a demand will be described. FIGS. 7 and 8 each show an
arrangement example of the plurality of optical fibers 76 with respect to the light incident end
face 71 b of the light guide 71. As shown in these figures, if the same number of optical fibers 76
are coupled to the light incident end face 71b, as shown in FIG. 8, it is better than simply
arranging the optical fibers 76 in one row as shown in FIG. The optical fibers 76 are generally
arranged in a grid form longitudinally and laterally in a staggered fashion (ie, between adjacent
fiber rows, fibers of one fiber row are located between fibers of the other fiber row). In the
arrangement, the light emitted from the optical fiber 76 is made to be more uniform in the light
guide 71 and then emitted.
[0089]
In the example of FIG. 8, the optical fiber rows are arranged in two rows in the thickness
direction of the light guide 71 (vertical direction in the figure), but the number is not limited to
two, and three rows The above fiber rows may be arranged.
[0090]
A preferred fiber fixing structure in the case of arranging a plurality of optical fibers 76 as shown
in FIG. 8 is shown in FIG. 9 and FIG.
FIG. 9 shows a side view of this structure, and FIG. 10 shows a plan cross-sectional view of a
portion taken along the line AA of FIG. This structure includes a fiber holding member 80 in
which a plurality of longitudinal grooves 80a for containing fibers are formed on the left and
right sides, and a pair of fiber pressing members 81 for holding the lower end portions of the
optical fibers 76 accommodated in the respective longitudinal grooves 80a. And four screws 82
for attaching the fiber holding member 81 to the fiber holding member 80, and a fiber guide
member connected to the fiber holding member 81 to align and hold a portion slightly above the
lower end of the optical fiber 76. And 83. The light guide 71 is held by the light guide holding
member 84 with the light incident end face 71b, which is the upper end face, slightly separated
05-05-2019
25
from the lower end face (light exit end face) of each optical fiber 76.
[0091]
Further, in order to irradiate the subject with uniform light intensity, it is effective to form the
light incident end face 71b of the light guide 71 so that the cross section has a concave shape as
shown in FIG. is there. That is, with such a shape, light Lf incident on the light guide 71 from the
optical fiber 76 is refracted to the outer side (side surface 71 a side) at the light incident end
surface 71 b as illustrated. Therefore, the number of times of total reflection of light at the
interface between the side surface 71a of the light guide 71 and the surrounding medium is
increased, whereby the intensity distribution of the light emitted from the light emitting end
surface 71c is more highly uniformed.
[0092]
Next, an embodiment in which the image quality of the acquired photoacoustic image is
improved will be described with reference to FIG. The probe shown in FIG. 12 includes a pair of
light guides 71, and these light guides 71 are basically formed in the same manner as the light
guides 71 described above. Laser light is introduced to these light guides 71 via a plurality of
optical fibers 76. The light incident ends of the plurality of optical fibers 76 coupled to one light
guide 71 and the plurality of optical fibers 76 coupled to the other light guide 71 are grouped
together and the upstream side, that is, the laser A shutter 86 is provided on the light source
side. The shutter 86 may be, for example, a liquid crystal cell or a mechanical shutter.
[0093]
The laser light emitted from the laser light source such as the laser light source unit 13 described
above is passed through the light branching portion 85 formed of, for example, a branching
optical waveguide or the like, branched into two systems, and each branched laser light One
group of optical fibers 76 is incident on the other group of optical fibers 76 via the other group.
The above configuration is shown as a block diagram as shown in FIG.
[0094]
05-05-2019
26
According to this configuration, when imaging a part of the subject, the laser light emitted from
the pair of light guides 71 is irradiated to the part, and at this time, the opening / closing timing
of the two shutters 86 is controlled. First, the shutter 86 on the upstream side of one of the light
guides 71 is closed, and the shutter 86 on the upstream side of the other light guide 71 is then
opened for a predetermined time. After this predetermined time has elapsed, the shutter 86
located upstream of one of the light guides 71 is then opened for a predetermined time, and the
shutter 86 located upstream of the other light guide 71 is then closed. Thereafter, by repeating
the same operation, the above-described portions are sequentially and selectively irradiated with
light from two directions different from one side and the other side of the two light guides 71.
[0095]
Thus, when light is irradiated to the site to be imaged from two different directions, the abovedescribed photoacoustic data is collectively captured for each light irradiation direction in
synchronization with the opening / closing timing of the two shutters 86. Then, when
constructing a photoacoustic image, two data for each light irradiation direction regarding the
same pixel are added and averaged to be data of the pixel. By performing this process, the S / N
ratio of the constructed image is theoretically doubled as compared with that in the normal case.
In addition, it is also possible to suppress an artifact signal that may be generated outside the
portion immediately below the ultrasonic transducer 72 (see FIG. 1), that is, other than the
portion irradiated with light from two different directions.
[0096]
Note that the arrangement position of the shutter 86 is on the upstream side of the optical fiber
76 as in this example, and as shown in the block diagram of FIG. 14, between the optical fiber 76
and the light guide 71 and further in FIG. It may be on the downstream side of the light guide 71
as shown.
[0097]
Next, an embodiment in which both relatively shallow and deep regions of the subject can be
imaged with high image quality will be described with reference to FIGS.
When the light guide 71 is obliquely disposed as shown in FIG. 16, a relatively shallow portion
05-05-2019
27
just below the ultrasonic transducer 72 (the hatched portion indicates the irradiation state of the
laser light Lf emitted from the light guide 71) Since an area which is not irradiated with light is
generated in a portion indicated by T in the drawing, a photoacoustic image signal may not be
obtained for a portion near the surface of the object. On the other hand, the photoacoustic image
signal can be favorably acquired for the deep part of the subject.
[0098]
On the other hand, when the light guide 71 is disposed vertically, that is, parallel to the probe
axis C and vertically opposed to the surface of the subject, the light absorption in a portion near
the surface is large. In many cases, only weak photoacoustic image signals can be obtained for
the deep part of the specimen. On the other hand, the photoacoustic image signal can be
favorably acquired for the vicinity of the surface of the subject.
[0099]
In the present embodiment, in order to cope with the above, it is possible to switch between the
state in which the light guides 71 are obliquely disposed and the state in which the light guides
71 are vertically disposed. That is, in the present embodiment, as shown in FIG. 17 and FIG. 18,
respectively, the probe housing 90 is elongated in the direction in which the pair of light guides
71 are arranged and the light guides 71 are diagonally disposed. Further, as shown in FIGS. 19
and 20, respectively, the side surface shape and the planar shape are shown, it is possible to
arbitrarily set a state in which the light guide 71 is vertically disposed by shortening the probe
housing 90 in the above direction.
[0100]
As shown in detail in FIGS. 18 and 20, the probe housing 90 includes a pair of side end portions
91 having a U-shaped cross section, and a flexible portion 92 connected to the end of the bent
portion of the side end portions 91. It comprises a central portion 93 communicating between
the flexible portion 92 and the flexible portion 92. The flexible portion 92 can be formed of, for
example, a rubber material.
[0101]
05-05-2019
28
In this configuration, as shown in FIG. 18, the light guide alignment direction size of the probe
housing 90 is increased in a state in which the bent portion of the side end portion 91, the
flexible portion 92 and the central portion 93 extend linearly. Can. Therefore, under this state, it
is possible to arrange the light guide 71 obliquely. When imaging the deep part of the subject,
imaging in this state is preferable.
[0102]
On the other hand, as shown in FIG. 20, the pair of side end portions 91 are brought close to
each other, and the flexible portion 92 is bent to position the central portion 93 outside the bent
portion of the side end portion 91. Can be made smaller. Under this condition, the light guide 71
is vertically disposed to realize miniaturization of the probe. When it is going to image the
surface vicinity part of a subject, it is preferable to image in this state.
[0103]
The photoacoustic image obtained under the condition of FIG. 17 and the photoacoustic image
obtained under the condition of FIG. 19 are synthesized with each other, and an image in which
the region from the surface vicinity of the subject to the deep region is displayed together is It is
desirable to be formed. Such a composite image has high diagnostic performance. Specifically, to
give numerical examples, imaging is performed in the state of FIGS. 19 and 20 for the region up
to about 5 mm deep from the surface of the subject, and in the state of FIGS. Preferably, imaging
is performed.
[0104]
Here, an example of a mechanism for changing the installation angle of the light guide 71 will be
described with reference to FIGS. 21 and 22. FIG. 21 and FIG. 22 show planar shapes of this
mechanism, respectively, in the case where the light guide 71 is vertically disposed and in the
case where the light guide 71 is obliquely disposed. As illustrated, this mechanism includes a pair
of guide rails 94, 94, and a light guide holder 95 whose end is assembled to each of the guide
rails 94, 94 and is movable in the lateral direction in the drawing. A pin fixing portion 96 fixed to
the light guide holder 95 with a pin 96a extending in a direction perpendicular to the plane of
05-05-2019
29
the drawing, and an arm 97 having an elongated hole 97a engaged with the pin 96a. It
comprises a first spur gear 98a to which the arm 97 is fixed, a second spur gear 98b meshing
with the first spur gear 98a, and a motor 99 for rotating the second spur gear 98b.
[0105]
The light guide 71 is swingable between the oblique arrangement position shown in FIG. 17 and
the vertical arrangement position shown in FIG. 19, and is held by a light guide holding member
(not shown). Further, a part near the upper end of the light guide 71 is connected to the light
guide holder 95 by connecting means (not shown).
[0106]
In the state shown in FIG. 21, the light guide holder 95 is set at the left end position in the figure,
and the light guide 71 connected thereto is in the vertical arrangement state. From this state,
when the motor 99 is driven and the second spur gear 98b rotates clockwise by a predetermined
rotation angle, the first spur gear 98a rotates counterclockwise, and the pin fixing portion 96 is
blocked by the arm 97, that is, The light guide holder 95 is pushed to the right in the figure.
Thus, when the light guide holder 95 moves to the right in the figure by a length corresponding
to the predetermined rotation angle of the second spur gear 98b, the state shown in FIG. 22 is
obtained. When the light guide holder 95 moves to this position, the upper end of the light guide
71 connected thereto moves, and the light guide 71 is placed obliquely as shown in FIG.
[0107]
When the motor 99 is driven in the opposite direction to that in the above case and the second
spur gear 98b rotates counterclockwise by a predetermined rotation angle, the first spur gear
98a is turned clockwise. By rotating in the direction, the pin fixing portion 96, that is, the light
guide holder 95 is pulled to the left in the drawing by the arm 97, and the state of FIG. 21
returns to the state where the light guide 71 is vertically disposed.
[0108]
In addition, although the diagonal arrangement angle of the light guide 71 is set as one direction
here, you may comprise so that the angle of diagonal arrangement can be set in two or more
ways.
05-05-2019
30
[0109]
Next, with reference to FIG. 23, an example of a structure for holding the plurality of optical
fibers 76 and the light guide 71 in an optically coupled state will be described.
The holding structure shown in FIG. 23 includes a pair of light guide fixing members 61 disposed
so as to put a base 73 (see FIG. 1) or the like (not shown) between them, and these light guide
fixing members A pair of fiber holding members 61 each having a substantially L-shaped cross
section fixed to 61 by screws or the like, and fiber pressing members 62 and 63 fixed to the
outer surface of the fiber holding members 61 by screws or the like It is.
[0110]
The light guide 71 is adhered and fixed to the light guide fixing member 61 by, for example, an
epoxy adhesive at the position shown in the figure.
The emission angle when the light guided through the light guide 71 is emitted therefrom
depends on the attachment angle of the light guide 71. If the accuracy of this attachment angle is
low, the intensity distribution of the irradiation light may change. Generally, there is a demand
for fixing the light guide 71 while maintaining a predetermined mounting angle with high
accuracy. When the light guide 71 is bonded and fixed thereto using the light guide fixing
member 61, the above-mentioned requirements can be easily satisfied.
[0111]
Further, it is desirable that the plurality of optical fibers 76 be replaceable because problems
such as disconnection may occur, and it is also necessary to appropriately perform maintenance
work. Therefore, in the optical fiber 76, the portion near the end is pressed against the fiber
holding member 61 by the fiber holding member 63, and the portion slightly above it is pressed
and fixed to the fiber holding member 61. Each of the optical fibers 76 is fixed, for example, in
such a state that the end face to be the light emitting end face faces the light incident end face 71
b of the light guide 71 at a minute interval.
05-05-2019
31
[0112]
Here, a groove (not shown) or the like may be formed in the inner surface of each of the fiber
holding members 62 and 63 to receive the optical fiber 76. Further, it is desirable that the outer
side surface 61a of the fiber holding member 61 be a smooth curved surface so that the optical
fiber 76 can be curved and held at, for example, the minimum bending radius along the surface.
[0113]
According to the above fiber holding structure, by removing the fiber holding members 62 and
63 screwed and fixed to the fiber holding member 61, it is possible to remove the respective
optical fibers 76 for the maintenance work and the like.
[0114]
As mentioned above, although the present invention was explained based on the suitable
embodiment, the probe for photoacoustic measuring devices of the present invention is not
limited only to the above-mentioned embodiment, and various corrections and changes from the
composition of the above-mentioned embodiment Also included in the scope of the present
invention.
Moreover, the probe for photoacoustic measuring devices of this invention is applicable similarly
to photoacoustic measuring devices other than the photoacoustic imaging apparatus
demonstrated above.
[0115]
DESCRIPTION OF SYMBOLS 10 Photoacoustic imaging apparatus 12 Ultrasonic unit 13 Laser
light source unit 14 Image display means 15 Light guide means 21 Receiving circuit 22 AD
conversion means 23 Reception memory 24 Data separation means 25 Photoacoustic image
reconstruction means 26, 41 Detection and logarithmic conversion Means 27 Photoacoustic
image constructing means 30 Transmission control circuit 31 Control means 32 Q switch laser
33 Flash lamp 40 Ultrasonic image reconstructing means 42 Ultrasonic image constructing
means 43 Image synthesizing means 44 Arithmetic means 61, 80 Fiber holding member 62, 63 ,
81 fiber holding member 70 probe 71 light guide 71 a light guide side surface 71 b light
incident end face of light guide 71 c light output end face of light guide 72 ultrasonic transducer
05-05-2019
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73 base portion 74, 90 probe housing 75 light absorption Body 76 Optical fiber 77 Optical
sensor 78 Contact sensor 85 Optical component Part 86 Shutter 86 91 Side end part of probe
housing 92 Flexible part of probe housing 93 Center part of probe housing 94 Guide rail 95
Light guide holder 96 Pin fixing part 97 Arm 98a, 98b Spur gear 99 Motor C Probe axis LB, Lf
laser light
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