JP7227049B2 - Photoacoustic wave measurement device - Google Patents

Description

The present invention relates to measurement of photoacoustic waves.

Photoacoustic wave measurement devices have been known for some time (see Patent Documents 1, 2 and 3, for example). By moving the photoacoustic wave measurement device, the position of the focal point of the acoustic lens of the photoacoustic wave measurement device with respect to the object to be measured can be changed (see, for example, Patent Document 1), or the measurement result by the photoacoustic wave can be changed. It is known to display as an image (see Patent Documents 2 and 3, for example).

JP 2016-101260 A JP 2013-220145 A Japanese Patent Application Publication No. 2011-519281

However, according to the photoacoustic wave measurement apparatus such as the above-described conventional technology, even if the position of the focal point of the acoustic lens with respect to the object to be measured can be changed, the position of the focal point of the acoustic lens with respect to the object to be measured can be changed to a desired position. Alignment is difficult. This is because the position of the focal point of the acoustic lens is difficult to understand in the first place.

Accordingly, an object of the present invention is to make it easier to understand the position of the focal point of an acoustic lens in a photoacoustic wave measuring apparatus.

A first photoacoustic wave measurement apparatus according to the present invention includes a pulsed light output unit that outputs pulsed light, a lens that receives a photoacoustic wave generated in a measurement target by the pulsed light and converts it into an electrical signal, the electrical A measurement unit for measuring a signal, a waveform display unit for displaying the waveform of the measurement result of the measurement unit, and a focus position display unit for displaying the focus position of the lens in the waveform.

According to the first photoacoustic wave measurement device configured as described above, the pulsed light output unit outputs pulsed light. A lens receives a photoacoustic wave generated in the measurement target by the pulsed light and converts it into an electrical signal. A measurement unit measures the electrical signal. A waveform display section displays the waveform of the measurement result of the measurement section. A focus position display displays the position of the lens focus in the waveform.

The first photoacoustic wave measurement apparatus according to the present invention includes an output end moving unit that moves the output end of the pulsed light output unit, and a display figure displayed by the focus position display unit that is displayed on the output end. A display figure moving unit for moving the waveform according to the amount of movement may be provided.

In addition, in the first photoacoustic wave measuring device according to the present invention, the display figure moving unit moves the output direction of the pulsed light in the waveform according to the amount of movement of the output end in the output direction of the pulsed light. You may make it move the said display figure to the direction corresponding to.

In the first photoacoustic wave measuring device according to the present invention, the focal position display unit displays coordinates obtained by adding the distance between the output end and the focal point to the coordinates corresponding to the output end in the waveform. , the position of the focus may be displayed as the position of the focus.

In addition, in the first photoacoustic wave measuring device according to the present invention, the waveform display section may display the waveform within a range of a predetermined distance from the initial position of the output end.

A second photoacoustic wave measurement apparatus according to the present invention includes a pulsed light output unit that outputs pulsed light, a lens that receives a photoacoustic wave generated in a measurement target by the pulsed light and converts it into an electric signal, and the electric A measurement unit that measures a signal, a tomographic image display unit that displays the tomographic image of the measurement target based on the measurement result of the measurement unit, and a focus position display unit that displays the focal position of the lens in the tomographic image. is configured to include

According to the second photoacoustic wave measurement device configured as described above, the pulsed light output unit outputs pulsed light. A lens receives a photoacoustic wave generated in the measurement target by the pulsed light and converts it into an electrical signal. A measurement unit measures the electrical signal. A tomographic image display unit displays a tomographic image of the measurement object based on the measurement result of the measurement unit. A focal position display unit displays the focal position of the lens in the tomographic image.

The second photoacoustic wave measurement apparatus according to the present invention includes an output end moving unit that moves the output end of the pulsed light output unit, and a display figure displayed by the focus position display unit that is displayed on the output end. A display figure moving unit for moving the tomographic image according to the amount of movement may be provided.

In the second photoacoustic wave measuring apparatus according to the present invention, the display figure moving unit outputs the pulsed light in the tomographic image according to the amount of movement of the output end in the output direction of the pulsed light. The display graphic may be moved in a direction corresponding to the direction.

In the second photoacoustic wave measuring device according to the present invention, the focal position display unit displays coordinates obtained by adding the distance between the output end and the focal point to the coordinates corresponding to the output end in the tomographic image. may be used as the focal position to display the focal position.

In addition, in the second photoacoustic wave measurement apparatus according to the present invention, the tomographic image display section may display the tomographic image within a range of a predetermined distance from the initial position of the output end.

In the second photoacoustic wave measuring device according to the present invention, the output terminal moves in a plane normal to the output direction of the pulsed light, and the measurement is performed at each position of the output terminal. The tomographic image may be obtained by synthesizing the measurement results of the parts.

In the first photoacoustic wave measuring device according to the present invention, the focal position display section may display coordinates of the focal point in the output direction of the pulsed light.

In the second photoacoustic wave measurement device according to the present invention, the focus position display section may display coordinates of the focus with respect to the output direction of the pulsed light.

In addition, in the first and second photoacoustic wave measurement apparatuses according to the present invention, the lens may be a piezoelectric element.

In addition, in the first and second photoacoustic wave measurement apparatuses according to the present invention, the lens may have a concave surface facing the measurement target.

In the first and second photoacoustic wave measuring apparatuses according to the present invention, the lens outputs an ultrasonic wave, and the ultrasonic wave receives a reflected ultrasonic wave reflected by the measurement object to produce a reflected electric signal , and the measurement result of the reflected electrical signal may be displayed.

1 is a cross-sectional view of a measuring head 10 according to a first embodiment of the invention; FIG. 1 is a functional block diagram showing the configuration of a photoacoustic wave measurement device 1 according to a first embodiment of the present invention; FIG. FIG. 4 is a cross-sectional view of the measurement head 10 according to the first embodiment in a state where the focal point fp is too shallower than the blood vessel 2a; Waveform display section 20, focus position display section 22, and display graphic movement in the state where the focus fp is too shallow than the blood vessel 2a (Fig. 4(a)) and the state where the focus fp is aligned with the blood vessel 2a (Fig. 4(b)) 3 is a diagram showing a display mode of a section 24; FIG. FIG. 10 is a diagram showing a state in which an output end 10d is moved in the Z direction (downward) by a Z-direction moving unit (output end moving unit) 14, and a focal point fp is aligned with a blood vessel 2a; FIG. 4 is a cross-sectional view of the measuring head 10 according to the first embodiment in a state where the focal point fp is too deep than the blood vessel 2a; Waveform display section 20, focus position display section 22, and display graphic movement in the state where the focus fp is too shallow than the blood vessel 2a (Fig. 7(a)) and the state where the focus fp is aligned with the blood vessel 2a (Fig. 7(b)) 3 is a diagram showing a display mode of a section 24; FIG. FIG. 10 is a diagram showing a state in which an output end 10d is moved in the Z direction (upward) by a Z-direction moving unit (output end moving unit) 14, and a focal point fp is aligned with a blood vessel 2a; FIG. 7 is a diagram showing display modes of a waveform display section 20 and a focus position display section 22 according to a modification of the first embodiment; FIG. 3 is a functional block diagram showing the configuration of a photoacoustic wave measurement device 1 according to a second embodiment of the present invention; The tomographic image display unit 30, the focal position display unit 22, and the displayed graphics in the state where the focus fp is too shallow than the blood vessel 2a (FIG. 11(a)) and the state where the focus fp is aligned with the blood vessel 2a (FIG. 11(b)). 4 is a diagram showing a display mode of a moving unit 24; FIG. The tomographic image display unit 30, the focus position display unit 22, and the display graphics in the state where the focus fp is too deep than the blood vessel 2a (Fig. 12(a)) and the state where the focus fp is aligned with the blood vessel 2a (Fig. 12(b)). 4 is a diagram showing a display mode of a moving unit 24; FIG. FIG. 5 is a cross-sectional view of a measuring head 10 according to a third embodiment of the invention; FIG. 3 is a functional block diagram showing the configuration of a photoacoustic wave measurement device 1 according to a third embodiment of the present invention; FIG. 11 is a functional block diagram showing the configuration of a photoacoustic wave measurement device 1 according to a fourth embodiment of the present invention;

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

First Embodiment FIG. 1 is a sectional view of a measuring head 10 according to a first embodiment of the invention. FIG. 2 is a functional block diagram showing the configuration of the photoacoustic wave measurement device 1 according to the first embodiment of the present invention.

A photoacoustic wave measurement apparatus 1 according to the first embodiment is for measuring a measurement target 2 (for example, but not limited to a human body). A measurement object 2 has a blood vessel 2a.

The photoacoustic wave measurement apparatus 1 according to the first embodiment includes a measurement head 10, an XY-direction moving unit 12, a Z-direction moving unit (output end moving unit) 14, a measuring unit 16, a focal position recording unit 18, and a waveform display. It has a section 20, a focus position display section 22, and a display figure moving section 24. FIG.

The measurement head 10 has an optical fiber (pulse light output section) 10a, an optical fiber holding section 10b, and a lens 10c.

An optical fiber (pulsed light output unit) 10a outputs pulsed light P from an output end 10d. Note that the output direction of the pulsed light P is the Z direction. Further, when the blood vessel 2a of the measurement target 2 receives the pulsed light P, it generates a photoacoustic wave AW.

The optical fiber holding part 10b is arranged around the optical fiber 10a and holds the optical fiber 10a.

The lens 10c is an acoustic lens that receives the photoacoustic wave AW generated in the measurement object 2 by the pulsed light P and converts it into an electric signal. Lens 10c is a piezoelectric element. The lens 10c has a concave surface facing the object 2 to be measured. Note that the measurement area MA is an area in which the photoacoustic wave AW measurable by the lens 10c exists. A member (not shown) that transmits ultrasonic waves (for example, water contained in a plastic container) is arranged between the measurement head 10 and the object 2 to be measured. The photoacoustic wave AW reaches the lens 10c via a member that transmits ultrasonic waves (the same applies to other embodiments).

The Z-direction moving unit (output end moving unit) 14 moves the output end 10d of the optical fiber 10a in the Z direction (output direction of the pulsed light P). As an example of mounting the Z-direction moving unit 14, it is conceivable to manually move the measuring head 10 up and down in the Z-direction (for example, by turning a knob). Of course, manual operation is just an example, and electric operation may be used, for example.

The XY-direction moving unit 12 moves the output end 10d of the optical fiber 10a in the X-direction and the Y-direction perpendicular to the Z-direction.

The measurement unit 16 measures the electrical signal received from the lens 10c.

The focal position recording unit 18 records the distance fd (see FIGS. 3 and 6) between the output end 10d and the focal point fp of the lens 10c. However, the time t1 for the sound wave to reciprocate between the output end 10d and the focal point fp of the lens 10c may be recorded. If the speed of sound is Vs, then (1/2)*Vs*t1=fd. The time t1 is the result of measuring the reciprocating time of the ultrasonic wave between the output end 10d and the focal point fp of the lens 10c by using a digital oscilloscope or the like.

The waveform display section 20 displays the waveform AW of the measurement result of the measurement section 16 (see FIGS. 4 and 7).

The focal position display section 22 displays the focal position of the lens 10c in the waveform AW (see marker M in FIGS. 4 and 7). The focus position display unit 22 displays the position of the focus fp as the position of the focus fp, which is obtained by adding the distance fd to the coordinate 0 corresponding to the output end 10d in the waveform AW.

The display figure moving unit 24 shifts the marker (display figure) M displayed by the focus position display unit 22 to the waveform AW according to the movement amounts d1 and d2 (see FIGS. 5 and 8) of the output terminal 10d. Move (see FIGS. 4 and 7).

More specifically, the display figure moving unit 24 shifts the pulsed light in the waveform AW according to the moving amounts d1 and d2 (see FIGS. 5 and 8) of the pulsed light P from the output end 10d in the output direction (Z direction). The marker (display figure) M is moved in the direction (see the horizontal axis in FIGS. 4 and 7) corresponding to the output direction of P (Z direction).

Next, operation of the first embodiment will be described.

When the pulsed light P is output from the output end 10d of the optical fiber 10a, the blood vessel 2a receives the pulsed light P and generates photoacoustic waves AW. The photoacoustic wave AW is converted into an electric signal by the lens 10c and measured by the measurement unit 16. FIG. The measurement result is displayed as a waveform AW by the waveform display section 20 (see FIGS. 4 and 7). The position of the focal point fp is displayed by the focal point display unit 22 in accordance with the display of the waveform AW (marker M). Further, the marker M is moved with respect to the waveform AW by the display graphic moving unit 24 according to the amount of movement of the output terminal 10d.

(1) Operation in a state where the focus fp is too shallow than the blood vessel 2a FIG. 3 is a cross-sectional view of the measurement head 10 according to the first embodiment when the focus fp is too shallow than the blood vessel 2a. FIG. 4 shows the waveform display section 20 and the focus position display section 22 in a state where the focus fp is too shallow than the blood vessel 2a (FIG. 4A) and a state where the focus fp is aligned with the blood vessel 2a (FIG. 4B). and a display mode of a display graphic moving unit 24. FIG. FIG. 5 is a diagram showing a state in which the output end 10d is moved in the Z direction (downward) by the Z-direction moving section (output end moving section) 14 and the focal point fp is aligned with the blood vessel 2a. However, in FIG. 5, only the lens 10c and the output end 10d of the measuring head 10 are shown.

Referring to FIG. 3, the focal point fp is too shallow by d1 from the blood vessel 2a. If the focus fp does not match the blood vessel 2a, the XY plane image of the blood vessel 2a will be blurred. Therefore, it is necessary to match the focal point fp to the blood vessel 2a.

With reference to FIG. 4(a), the display modes of the waveform display section 20, the focus position display section 22, and the display figure moving section 24 when the focal point fp is too shallow than the blood vessel 2a will be described. In addition, in FIG. 4A, the coordinates 0, t0, and (fd) are shown for convenience of explanation, so they do not necessarily need to be displayed (the same applies to FIG. 4B).

The horizontal axis in FIG. 4A is time, and the waveform AW of the photoacoustic wave is illustrated. Coordinate 0 is the output timing of the pulsed light P from the output end 10d. A coordinate t0 is the time from when the pulsed light P is output from the output end 10d to when the photoacoustic wave AW (generated at the focal point fp) is received by the lens 10c. Since the speed of the pulsed light P (speed of light) is very high, the time from when the pulsed light P is output until it reaches the focal point fp can be ignored. Therefore, t0=(1/2)×t1.

As described above, (1/2)*Vs*t1=fd, so Vs*t0=fd. Therefore, the horizontal coordinate in FIG. 4A can be converted to a Z-direction distance (referred to as "depth") from the initial position of the output end 10d by multiplying the sound velocity Vs (see FIG. 4A). 4(b) as well). In FIG. 4, the depth-converted coordinates are shown in brackets.

In FIG. 4A, in the waveform AW, the coordinate (fd) obtained by adding the distance fd between the output end 10d and the focus fp to the coordinate 0 corresponding to the initial position of the output end 10d is the position of the focus fp. A focus position display unit 22 displays the position of the focus fp. Specifically, a marker (display figure) M is displayed directly above the coordinate t0 (fd). Note that the marker M is positioned within a rectangular area B. FIG. Region B is a rectangular region extending in the horizontal direction.

Since the blood vessel 2a is located deeper than the focal point fp, the coordinates at which the waveform AW is located are larger than the coordinates t0 (fd).

Here, the user moves the output end 10d together with the measuring head 10 in the direction in which the coordinate in the Z direction increases (downward in FIG. 5) using the Z-direction moving unit 14, and tries to bring the focal point fp to the blood vessel 2a. .

Then, the marker M moves in the direction corresponding to the Z direction (horizontal axis direction) according to the amount of movement of the output end 10d in the Z direction. For example, when the output end 10d is moved in the direction in which the coordinate in the Z direction increases (downward in FIG. 5), the marker M moves to the right in the region B (in the direction in which the coordinate in the Z direction increases).

Referring to FIG. 4B, when the output end 10d is moved by d1 in the direction in which the coordinate in the Z direction increases (downward in FIG. 5), the coordinate t0 (fd) of the focal point fp changes to the coordinate of the waveform AW. Overlap. At this time, referring to FIG. 5, the focus fp is on the blood vessel 2a.

(2) Operation when the focus fp is too deep than the blood vessel 2a FIG. 6 is a cross-sectional view of the measurement head 10 according to the first embodiment when the focus fp is too deep than the blood vessel 2a. 7 shows the waveform display section 20 and the focus position display section 22 in a state where the focus fp is too shallow than the blood vessel 2a (FIG. 7A) and a state where the focus fp is aligned with the blood vessel 2a (FIG. 7B). and a display mode of a display figure moving unit 24. FIG. FIG. 8 is a diagram showing a state in which the output end 10d is moved in the Z direction (upward) by the Z-direction moving section (output end moving section) 14 and the focal point fp is aligned with the blood vessel 2a. However, in FIG. 8, only the lens 10c and the output end 10d of the measuring head 10 are shown.

Referring to FIG. 6, the focal point fp is too deep by d2 than the blood vessel 2a. If the focus fp does not match the blood vessel 2a, the XY plane image of the blood vessel 2a will be blurred. Therefore, it is necessary to match the focal point fp to the blood vessel 2a.

With reference to FIG. 7(a), the display modes of the waveform display section 20, the focus position display section 22 and the display figure moving section 24 when the focal point fp is deeper than the blood vessel 2a will be described. In addition, in FIG. 7A, the coordinates 0, t0, and (fd) are shown for convenience of explanation, so they do not necessarily need to be displayed (the same applies to FIG. 7B).

The horizontal axis in FIG. 7A is time, and the waveform AW of the photoacoustic wave is illustrated. Coordinate 0 is the output timing of the pulsed light P from the output end 10d. A coordinate t0 is the time from when the pulsed light P is output from the output end 10d to when the photoacoustic wave AW (generated at the focal point fp) is received by the lens 10c. Since the speed of the pulsed light P (speed of light) is very high, the time from when the pulsed light P is output until it reaches the focal point fp can be ignored. Therefore, t0=(1/2)×t1.

As described above, (1/2)*Vs*t1=fd, so Vs*t0=fd. Therefore, the horizontal coordinate in FIG. 7(a) can be converted to a distance in the Z direction (referred to as "depth") from the initial position of the output end 10d by multiplying it by the sound velocity Vs (see FIG. 7(a)). 7(b) is the same). In FIG. 7, coordinates converted to depth are shown in parentheses.

In FIG. 7A, in the waveform AW, the coordinate (fd) obtained by adding the distance fd between the output end 10d and the focus fp to the coordinate 0 corresponding to the initial position of the output end 10d is defined as the position of the focus fp. A focus position display unit 22 displays the position of the focus fp. Specifically, a marker (display figure) M is displayed directly above the coordinate t0 (fd). Note that the marker M is positioned within a rectangular area B. FIG. Region B is a rectangular region extending in the horizontal direction.

Since the blood vessel 2a is located shallower than the focal point fp, the coordinates at which the waveform AW is located are smaller than the coordinates t0 (fd).

Here, the user moves the output end 10d together with the measuring head 10 in the direction in which the coordinate in the Z direction decreases (upward in FIG. 8) using the Z-direction moving unit 14, and tries to bring the focal point fp to the blood vessel 2a. .

Then, the marker M moves in the direction corresponding to the Z direction (horizontal axis direction) according to the amount of movement of the output end 10d in the Z direction. For example, when the output end 10d is moved in the direction in which the coordinate in the Z direction decreases (upward in FIG. 8), the marker M moves leftward within the region B (in the direction in which the coordinate in the Z direction decreases).

Referring to FIG. 7B, when the output end 10d is moved by d2 in the direction in which the coordinate in the Z direction decreases (upward in FIG. 8), the coordinate t0 (fd) of the focal point fp changes to the coordinate of the waveform AW Overlap. At this time, referring to FIG. 8, the focus fp is on the blood vessel 2a.

According to the photoacoustic wave measurement device 1 according to the first embodiment, the position of the focal point fp of the lens 10c, which is an acoustic lens, is displayed by the marker M, making it easy to understand.

Moreover, since the marker M moves with respect to the waveform AW in accordance with the amount of movement of the output end 10d (see FIGS. 4 and 7), when the output end 10d together with the measuring head 10 is moved up and down in the Z direction, It is easy to understand whether or not the focal point fp is on the blood vessel 2a.

Note that although the display range of the waveform AW is not limited in the first embodiment, the display range of the waveform AW may be limited.

FIG. 9 is a diagram showing display modes of the waveform display section 20 and the focus position display section 22 according to the modification of the first embodiment.

Referring to FIG. 9, a waveform AW within a predetermined distance range from the initial position 0 of output terminal 10d (range Za to Zb obtained by multiplying ta to tb by Vs and converted into distance) is displayed. This is possible by converting the electric signal (analog signal) acquired from the lens 10c of the measurement head 10 into a digital signal within a predetermined range and displaying it on the waveform display section 20. FIG. Alternatively, the lens 10c of the measurement head 10 may acquire electrical signals (analog signals) only within a predetermined range.

The range Za to Zb (ta·Vs to tb·Vs) is determined according to the sum of the distance between the initial position of the output end 10d and the skin surface and the depth of the blood vessel 2a from the skin surface.

Second Embodiment A photoacoustic wave measurement apparatus 1 according to a second embodiment differs from the first embodiment in that a tomographic image display section 30 is provided instead of the waveform display section 20 .

FIG. 10 is a functional block diagram showing the configuration of the photoacoustic wave measurement device 1 according to the second embodiment of the invention. Note that the measurement head 10 according to the second embodiment is the same as that of the first embodiment, so description thereof is omitted (see FIG. 1).

A photoacoustic wave measurement apparatus 1 according to the second embodiment is for measuring a measurement target 2 (for example, but not limited to a human body), as in the first embodiment. A measurement object 2 has a blood vessel 2a.

A photoacoustic wave measurement apparatus 1 according to the second embodiment includes a measurement head 10, an XY direction moving unit 12, a Z direction moving unit (output end moving unit) 14, a measurement unit 16, a focal position recording unit 18, a tomographic image A display unit 30, a focus position display unit 22, and a display figure moving unit 24 are provided.

The XY-direction moving unit 12, the Z-direction moving unit (output end moving unit) 14, the measuring unit 16, and the focal position recording unit 18 are the same as those in the first embodiment, and descriptions thereof are omitted.

The tomographic image display unit 30 displays a tomographic image of the measurement object 2 based on the measurement result of the measurement unit 16 (see FIGS. 11 and 12). Note that the XY-direction moving unit 12 moves the output end 10d within a plane (XY plane) whose normal direction is the output direction of the pulsed light P (Z direction). A tomographic image is obtained by the tomographic image display unit 30 synthesizing (for example, aperture synthesis) the measurement results of the measuring unit 16 for each position of the output end 10d at that time.

11 and 12, a tomographic image within a predetermined distance range (range Za to Zb obtained by multiplying ta to tb by Vs) from the initial position 0 of the output end 10d is displayed on the tomographic image display unit. 30. This is possible by converting the electric signal (analog signal) acquired from the lens 10c of the measurement head 10 into a digital signal within a predetermined range and displaying it on the waveform display section 20. FIG. Alternatively, the lens 10c of the measurement head 10 may acquire electrical signals (analog signals) only within a predetermined range.

The focal position display unit 22 displays the focal position of the lens 10c in the tomographic image (see marker M in FIGS. 11 and 12). The focus position display unit 22 displays the position of the focus fp as the position of the focus fp in the tomographic image by adding the distance fd to the coordinate 0 corresponding to the output end 10d.

The display figure moving unit 24 moves the marker (display figure) M displayed by the focal position display unit 22 to the tomographic image according to the movement amounts d1 and d2 (see FIGS. 5 and 8) of the output terminal 10d. Move (see FIGS. 11 and 12).

More specifically, the display graphic moving unit 24 shifts the pulsed light in the tomographic image according to the movement amounts d1 and d2 (see FIGS. 5 and 8) of the pulsed light P from the output end 10d in the output direction (Z direction). The marker (display figure) M is moved in the direction (see the vertical axis in FIGS. 11 and 12) corresponding to the output direction of P (Z direction).

Next, the operation of the second embodiment will be explained.

When the pulsed light P is output from the output end 10d of the optical fiber 10a, the blood vessel 2a receives the pulsed light P and generates photoacoustic waves AW. The photoacoustic wave AW is converted into an electric signal by the lens 10c and measured by the measurement unit 16. FIG. The measurement result is displayed as a tomographic image by the tomographic image display unit 30 (see FIGS. 11 and 12). The focal position display unit 22 displays the position of the focal point fp (marker M) in accordance with the display of the tomographic image. Furthermore, the marker M is moved with respect to the tomographic image by the display graphic moving unit 24 according to the amount of movement of the output end 10d.

(1) Operation when the focus fp is too shallower than the blood vessel 2a The state where the focus fp is too shallower than the blood vessel 2a is the same as in the first embodiment (see FIG. 3). The state in which the output end 10d is moved in the Z direction by the Z-direction moving unit (output end moving unit) 14 and the focal point fp is aligned with the blood vessel 2a is also the same as in the first embodiment (see FIG. 5).

FIG. 11 shows the tomographic image display section 30 and the focus position display section in a state where the focus fp is too shallow than the blood vessel 2a (FIG. 11A) and a state where the focus fp is aligned with the blood vessel 2a (FIG. 11B). 22 and a display figure moving unit 24. FIG.

Referring to FIG. 3, the focal point fp is too shallow by d1 from the blood vessel 2a. If the focus fp does not match the blood vessel 2a, the XY plane image of the blood vessel 2a will be blurred. Therefore, it is necessary to match the focal point fp to the blood vessel 2a.

With reference to FIG. 11(a), display modes of the tomographic image display section 30, the focus position display section 22, and the display figure moving section 24 when the focal point fp is too shallow than the blood vessel 2a will be described. In FIG. 11(a), the vertical axis, the coordinates 0, t0, (fd), and the focal point fp are shown for convenience of explanation, so they do not necessarily need to be displayed (the same applies to FIG. 11(b)). However, in FIGS. 11 and 12, one or both of the focus fp and a line segment (dotted line) passing through the focus fp may be displayed as the display graphic.

The vertical axis in FIG. 11(a) is time, and a tomographic image is illustrated. Coordinate 0 is the output timing of the pulsed light P from the output end 10d. A coordinate t0 is the time from when the pulsed light P is output from the output end 10d to when the photoacoustic wave AW (generated at the focal point fp) is received by the lens 10c. Since the speed of the pulsed light P (speed of light) is very high, the time from when the pulsed light P is output until it reaches the focal point fp can be ignored. Therefore, t0=(1/2)×t1.

As described above, (1/2)*Vs*t1=fd, so Vs*t0=fd. From this, the coordinate of the vertical axis in FIG. 11(a) can be converted into a distance in the Z direction (referred to as "depth") from the initial position of the output end 10d by multiplying the speed of sound Vs (see FIG. 11(a)). 11(b)). In FIG. 11, coordinates converted to depth are shown in parentheses.

In FIG. 11A, in the tomographic image, the coordinate (fd) obtained by adding the distance fd between the output end 10d and the focal point fp to the coordinate 0 corresponding to the initial position of the output end 10d is the position of the focal point fp. A focus position display unit 22 displays the position of the focus fp. Specifically, a marker (display figure) M is displayed right beside the coordinate t0 (fd). Note that the marker M is positioned within a rectangular area B. FIG. Region B is a rectangular region extending in the longitudinal direction.

Since the blood vessel 2a is located deeper than the focal point fp, the coordinates of the tomographic image of the blood vessel 2a are larger than the coordinate t0 (fd).

Here, the user moves the output end 10d together with the measuring head 10 in the direction in which the coordinate in the Z direction increases (downward in FIG. 5) using the Z-direction moving unit 14, and tries to bring the focal point fp to the blood vessel 2a. .

Then, the marker M moves in the direction corresponding to the Z direction (vertical axis direction) according to the amount of movement of the output end 10d in the Z direction. For example, when the output end 10d is moved in the direction in which the coordinate in the Z direction increases (downward in FIG. 5), the marker M moves downward in the region B (in the direction in which the coordinate in the Z direction increases).

Referring to FIG. 11(b), when the output end 10d is moved by d1 in the direction in which the coordinate in the Z direction increases (downward in FIG. 5), the coordinate t0 (fd) of the focal point fp becomes the tomographic image of the blood vessel 2a. overlaps the coordinates of At this time, referring to FIG. 5, the focus fp is on the blood vessel 2a.

(2) Operation when the focus fp is too deep than the blood vessel 2a The state where the focus fp is too deep than the blood vessel 2a is the same as in the first embodiment (see FIG. 6). The state in which the output end 10d is moved in the Z direction by the Z-direction moving unit (output end moving unit) 14 and the focal point fp is aligned with the blood vessel 2a is also the same as in the first embodiment (see FIG. 8).

12 shows the tomographic image display section 30 and the focus position display section in a state where the focus fp is too deep than the blood vessel 2a (FIG. 12(a)) and a state where the focus fp is aligned with the blood vessel 2a (FIG. 12(b)). 22 and a display figure moving unit 24. FIG.

Referring to FIG. 6, the focal point fp is too shallow by d2 from the blood vessel 2a. If the focus fp does not match the blood vessel 2a, the XY plane image of the blood vessel 2a will be blurred. Therefore, it is necessary to match the focal point fp to the blood vessel 2a.

With reference to FIG. 12(a), display modes of the tomographic image display section 30, the focus position display section 22, and the display graphic moving section 24 when the focal point fp is deeper than the blood vessel 2a will be described. In FIG. 12(a), the vertical axis, the coordinates 0, t0, (fd), and the focal point fp are shown for convenience of explanation, so they do not necessarily need to be displayed (the same applies to FIG. 12(b)).

The vertical axis in FIG. 12(a) is time, and a tomographic image is illustrated. Coordinate 0 is the output timing of the pulsed light P from the output end 10d. A coordinate t0 is the time from when the pulsed light P is output from the output end 10d to when the photoacoustic wave AW (generated at the focal point fp) is received by the lens 10c. Since the speed of the pulsed light P (speed of light) is very high, the time from when the pulsed light P is output until it reaches the focal point fp can be ignored. Therefore, t0=(1/2)×t1.

As described above, (1/2)*Vs*t1=fd, so Vs*t0=fd. From this, the coordinate on the vertical axis in FIG. 12(a) can be converted into a distance in the Z direction (referred to as “depth”) from the initial position of the output end 10d by multiplying it by the speed of sound Vs (see FIG. 12(a)). 12(b) as well). In FIG. 12, coordinates converted to depth are shown in parentheses.

In FIG. 12A, in the tomographic image, the coordinate (fd) obtained by adding the distance fd between the output end 10d and the focal point fp to the coordinate 0 corresponding to the initial position of the output end 10d is the position of the focal point fp. A focus position display unit 22 displays the position of the focus fp. Specifically, a marker (display figure) M is displayed right beside the coordinate t0 (fd). Note that the marker M is positioned within a rectangular area B. FIG. Region B is a rectangular region extending in the longitudinal direction.

Since the blood vessel 2a is located shallower than the focal point fp, the coordinates of the tomographic image of the blood vessel 2a are smaller than the coordinate t0 (fd).

Here, the user moves the output end 10d together with the measuring head 10 in the direction in which the coordinate in the Z direction decreases (upward in FIG. 8) using the Z-direction moving unit 14, and tries to bring the focal point fp to the blood vessel 2a. .

Then, the marker M moves in the direction corresponding to the Z direction (vertical axis direction) according to the amount of movement of the output end 10d in the Z direction. For example, when the output end 10d is moved in the direction in which the coordinate in the Z direction decreases (upward in FIG. 8), the marker M moves upward within the region B (in the direction in which the coordinate in the Z direction decreases).

Referring to FIG. 12(b), when the output end 10d is moved by d2 in the direction in which the coordinate in the Z direction decreases (upward in FIG. 8), the coordinate t0 (fd) of the focal point fp becomes the tomographic image of the blood vessel 2a. overlaps the coordinates of At this time, referring to FIG. 8, the focus fp is on the blood vessel 2a.

According to the second embodiment, the same effects as those of the first embodiment are obtained.

Third Embodiment The photoacoustic wave measurement apparatus 1 according to the third embodiment is different from the first embodiment in that in addition to the pulsed light P, an ultrasonic wave P1 is applied to the measurement target 2 to perform measurement. different.

FIG. 13 is a cross-sectional view of a measuring head 10 according to a third embodiment of the invention. FIG. 14 is a functional block diagram showing the configuration of the photoacoustic wave measurement device 1 according to the third embodiment of the invention.

A photoacoustic wave measurement apparatus 1 according to the third embodiment is for measuring a measurement target 2 (for example, but not limited to a human body). A measurement object 2 has a blood vessel 2a.

A photoacoustic wave measurement apparatus 1 according to the third embodiment includes a measurement head 10, an XY direction moving unit 12, a Z direction moving unit (output end moving unit) 14, a measurement unit 16, a focal position recording unit 18, a waveform display It has a section 20, a focus position display section 22, and a display figure moving section 24. FIG.

The measurement head 10 has an optical fiber (pulse light output section) 10a, an optical fiber holding section 10b, and a lens 10c. The optical fiber 10a and the optical fiber holding portion 10b are the same as those in the first embodiment, and description thereof is omitted.

The lens 10c is also the same as in the first embodiment, but it also outputs an ultrasonic wave P1. By using the lens 10c as a piezoelectric element and applying a voltage to the lens 10c, the ultrasonic wave P1 can be output from the lens 10c. The lens 10c further receives a reflected ultrasonic wave P2 (see FIG. 14), which is the ultrasonic wave P1 reflected by the measurement object 2, and converts it into a reflected electric signal. The ultrasonic wave P1 reaches the measurement object 2 via the ultrasonic wave transmitting member described in the first embodiment (the same applies to the fourth embodiment). The reflected ultrasonic wave P2 reaches the lens 10c via the ultrasonic wave transmitting member described in the first embodiment (the same applies to the fourth embodiment).

The measurement unit 16 measures the electrical signal received from the lens 10c and the reflected electrical signal. The waveform display section 20 displays waveforms (AW and P2) of the measurement results of the measurement section 16 .

The XY-direction moving section 12, the Z-direction moving section 14, the focal position recording section 18, the focal position display section 22, and the display figure moving section 24 are the same as those in the first embodiment, and the description thereof is omitted. However, the coordinate of the focal point fp in the waveform P2 of the reflected electric signal is t1.

Next, the operation of the third embodiment will be explained.

When the pulsed light P is output from the output end 10d of the optical fiber 10a, the blood vessel 2a receives the pulsed light P and generates photoacoustic waves AW. Further, an ultrasonic wave P1 is output from the lens 10c, reflected by the measurement object 2, and a reflected ultrasonic wave P2 is given to the lens 10c. The photoacoustic wave AW and the reflected ultrasonic wave P2 are converted into an electric signal and a reflected electric signal by the lens 10c and measured by the measurement unit 16. FIG. The measurement results are displayed by the waveform display section 20 as waveforms AW and P2. Along with the display of the waveforms AW and P2, the focus position display unit 22 displays the position of the focus fp (marker M). Further, the marker M is moved with respect to the waveforms AW and P2 by the display graphic moving unit 24 according to the amount of movement of the output terminal 10d. The display mode of the waveform P2 is the same as that of the waveform AW (see FIGS. 4 and 7).

According to the third embodiment, the same effects as those of the first embodiment are obtained.

Fourth Embodiment The photoacoustic wave measurement apparatus 1 according to the fourth embodiment performs measurement by applying an ultrasonic wave P1 to the measurement object 2 in addition to the pulsed light P, which is different from the second embodiment. different.

FIG. 15 is a functional block diagram showing the configuration of the photoacoustic wave measurement device 1 according to the fourth embodiment of the invention. Note that the measurement head 10 according to the fourth embodiment is the same as that of the third embodiment, and the description thereof is omitted.

A photoacoustic wave measurement apparatus 1 according to the fourth embodiment is for measuring a measurement target 2 (for example, but not limited to a human body). A measurement object 2 has a blood vessel 2a.

A photoacoustic wave measurement apparatus 1 according to the fourth embodiment includes a measurement head 10, an XY direction moving unit 12, a Z direction moving unit (output end moving unit) 14, a measurement unit 16, a focal position recording unit 18, a tomographic image A display unit 30, a focus position display unit 22, and a display figure moving unit 24 are provided.

The measurement unit 16 measures the electrical signal received from the lens 10c and the reflected electrical signal. A tomographic image display unit 30 displays a tomographic image based on the measurement result of the measurement unit 16 . The tomographic image obtained from the photoacoustic wave AW clearly displays the blood vessel 2a, while the tomographic image obtained from the reflected ultrasound P2 clearly displays the internal structure of the measurement object 2 (for example, skin). be done. Note that the tomographic image obtained from the photoacoustic wave AW and the tomographic image obtained from the reflected ultrasound P2 may be superimposed and displayed.

The XY-direction moving section 12, the Z-direction moving section 14, the focal position recording section 18, the focal position display section 22, and the display figure moving section 24 are the same as those in the third embodiment, and the description thereof is omitted.

Next, operation of the fourth embodiment will be described.

When the pulsed light P is output from the output end 10d of the optical fiber 10a, the blood vessel 2a receives the pulsed light P and generates photoacoustic waves AW. Further, an ultrasonic wave P1 is output from the lens 10c, reflected by the measurement object 2, and a reflected ultrasonic wave P2 is given to the lens 10c. The photoacoustic wave AW and the reflected ultrasonic wave P2 are converted into an electric signal and a reflected electric signal by the lens 10c and measured by the measurement unit 16. FIG. A tomographic image display unit 30 acquires and displays a tomographic image from the measurement result. The focal position display unit 22 displays the position of the focal point fp (marker M) in accordance with the display of the tomographic image. Furthermore, the marker M is moved with respect to the tomographic image by the display graphic moving unit 24 according to the amount of movement of the output end 10d. Note that the display mode of the tomographic image is the same as in the second embodiment (see FIGS. 11 and 12).

According to the fourth embodiment, the same effects as those of the first embodiment are obtained.

In the first to fourth embodiments, the display figure is displayed, but instead of the display figure, the coordinates of the focal point fp in the output direction (Z direction) of the pulsed light P are displayed. You may make it For example, the coordinates of the focal point fp (corresponding to the depth from the skin surface) may be displayed when the origin is the Z coordinate of the skin surface. By subtracting the distance between the output end 10d and the skin surface from the distance fd (known) between the output end 10d and the focus fp, the depth of the focus fp from the skin can be obtained. In addition, the distance between the output end 10d and the skin surface is calculated from the output of the ultrasonic wave P1 (see the third and fourth embodiments), the reflected ultrasonic wave P2 reflected by the skin surface (see the third and fourth embodiments). morphology).

Also, the above embodiment can be implemented as follows. A computer equipped with a CPU, a hard disk, a media (USB memory, CD-ROM, etc.) reading device, each of the above parts, for example, the focus position recording unit 18, the waveform display unit 20, the tomographic image display unit 30, the focus position display unit 22 and the program for realizing the display figure moving unit 24 is read and installed on the hard disk. Such a method can also realize the above function.

P pulsed light MA measurement area AW photoacoustic wave Vs speed of sound fp focus M marker (display figure)
B area d1, d2 movement amount P1 ultrasonic wave P2 reflected ultrasonic wave 2 measurement object 2a blood vessel 1 photoacoustic wave measuring device 10 measurement head 10a optical fiber (pulse light output unit)
10b optical fiber holding part 10c lens 10d output end 12 XY direction moving part 14 Z direction moving part (output end moving part)
16 measurement section 18 focus position recording section 20 waveform display section 22 focus position display section 24 display figure movement section 30 tomographic image display section

Claims (12)

a pulsed light output unit that outputs pulsed light;
a lens that receives a photoacoustic wave generated in a measurement target by the pulsed light and converts it into an electrical signal;
a measuring unit that measures the electrical signal;
a waveform display unit that displays the waveform of the measurement result of the measurement unit;
a focal position display unit that displays the focal position of the lens in the waveform;
A photoacoustic wave measurement device with The photoacoustic wave measurement device according to claim 1,
an output end moving unit that moves the output end of the pulsed light output unit;
a display figure moving unit that moves the display figure displayed by the focus position display unit with respect to the waveform in accordance with the amount of movement of the output end;
A photoacoustic wave measurement device with The photoacoustic wave measurement device according to claim 2,
The display figure moving unit moves the display figure in the waveform in a direction corresponding to the output direction of the pulsed light according to the amount of movement of the output end in the output direction of the pulsed light.
Photoacoustic wave measurement device. The photoacoustic wave measurement device according to claim 1,
The focus position display unit is
In the waveform, the position of the focus is displayed with the coordinates obtained by adding the distance between the output end and the focus to the coordinates corresponding to the output end of the pulsed light output unit as the position of the focus.
Photoacoustic wave measurement device. The photoacoustic wave measurement device according to claim 1,
wherein the waveform display section displays the waveform within a range of a predetermined distance from an initial position of the output end of the pulsed light output section ;
Photoacoustic wave measurement device. a pulsed light output unit that outputs pulsed light;
a lens that receives a photoacoustic wave generated in a measurement target by the pulsed light and converts it into an electrical signal;
a measuring unit that measures the electrical signal;
a tomographic image display unit that displays a tomographic image of the measurement target based on the measurement result of the measurement unit;
a focal position display unit that displays the focal position of the lens in the tomographic image;
an output end moving unit that moves the output end of the pulsed light output unit;
a display figure moving unit that moves the display figure displayed by the focus position display unit with respect to the tomographic image according to the amount of movement of the output end;
A photoacoustic wave measurement device with The photoacoustic wave measurement device according to claim 6 ,
The display figure moving unit moves the display figure in the direction corresponding to the output direction of the pulsed light in the tomographic image according to the amount of movement of the output end in the output direction of the pulsed light.
Photoacoustic wave measurement device. a pulsed light output unit that outputs pulsed light;
a lens that receives a photoacoustic wave generated in a measurement target by the pulsed light and converts it into an electrical signal;
a measuring unit that measures the electrical signal;
a tomographic image display unit that displays a tomographic image of the measurement target based on the measurement result of the measurement unit;
a focal position display unit that displays the focal position of the lens in the tomographic image;
with
the output end of the pulsed light output unit moves in a plane whose normal direction is the output direction of the pulsed light;
Obtaining the tomographic image by synthesizing the measurement results of the measurement unit for each of the positions of the output end;
Photoacoustic wave measurement device. The photoacoustic wave measurement device according to claim 1,
the focus position display unit displays the coordinates of the focus in the output direction of the pulsed light;
Photoacoustic wave measurement device. The photoacoustic wave measurement device according to any one of claims 1 to 9 ,
A photoacoustic wave measurement device, wherein the lens is a piezoelectric element. The photoacoustic wave measurement device according to any one of claims 1 to 9 ,
the lens
Having a concave surface facing the measurement object,
Photoacoustic wave measurement device. The photoacoustic wave measurement device according to any one of claims 1 to 9 ,
The lens outputs ultrasonic waves, and the ultrasonic waves receive reflected ultrasonic waves reflected by the measurement object and convert them into reflected electric signals,
a measurement result of the reflected electrical signal is displayed;
Photoacoustic wave measurement device.

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