CN111743511A

CN111743511A - Photoacoustic wave measuring apparatus

Info

Publication number: CN111743511A
Application number: CN202010127047.XA
Authority: CN
Inventors: 岩崎秀明; 宫岛淳; 伊田泰一郎
Original assignee: Advantest Corp
Current assignee: Advantest Corp
Priority date: 2019-03-26
Filing date: 2020-02-28
Publication date: 2020-10-09
Anticipated expiration: 2040-02-28
Also published as: JP2020156737A; DE102020201914A1; JP7227049B2; CN111743511B

Abstract

In the photoacoustic wave measurement device of the present invention, the position of the focal point of the acoustic lens is easily known. A photoacoustic wave measurement device (1) is provided with: a pulsed light output unit (10a) that outputs pulsed light (P); a lens (10c) that receives a photoacoustic wave (AW) generated in the measurement object (2) by the pulsed light (P) and converts the photoacoustic wave (AW) into an electrical signal; a measurement unit (16) that measures an electrical signal; a waveform display unit (20) that displays the waveform (AW) of the measurement result of the measurement unit (16); a focal position display unit (22) that displays the position of the focal point (fp) of the lens (10c) in the waveform (AW); a Z-direction moving unit (14) that moves the output end (10d) of the pulsed light output unit (10 a); and a display pattern moving unit (24) that moves the marker (M) displayed by the focal position display unit (22) relative to the waveform (AW) in accordance with the movement amounts (d1, d2) of the output terminal (10 d).

Description

Photoacoustic wave measuring apparatus

Technical Field

The present invention relates to measurement of photoacoustic waves.

Background

Conventionally, a photoacoustic wave measurement device is known (see, for example, patent documents 1, 2, and 3). It is known that a photoacoustic wave measurement device is moved to change the position of the focal point of an acoustic lens provided in the photoacoustic wave measurement device with respect to a measurement object (see, for example, patent document 1), and the measurement result of the photoacoustic wave is displayed as an image (see, for example, patent documents 2 and 3).

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2016-10260

Patent document 2: japanese patent laid-open publication No. 2013-220145

Patent document 3: japanese Kohyo publication 2011-519281

Problems to be solved by the invention

However, according to the photoacoustic wave measurement device of the above-described conventional technique, even if the position of the focal point of the acoustic lens with respect to the object to be measured can be changed, it is difficult to align the position of the focal point of the acoustic lens with respect to the object to be measured at a desired position. This is because it is inherently difficult to know the position of the focal point of the acoustic lens.

Disclosure of Invention

To this end, the subject of the present invention is: in the photoacoustic wave measurement device, the position of the focal point of the acoustic lens is easily known.

Solution scheme

A first photoacoustic wave measurement device according to the present invention includes: a pulse light output unit that outputs pulse light; a lens that receives a photoacoustic wave generated in a measurement object by the pulsed light and converts the photoacoustic wave into an electric signal; a measuring unit that measures the electric signal; a waveform display unit for displaying a waveform of a measurement result of the measurement unit; and a focal position display unit that displays a position of a focal point 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. The lens receives a photoacoustic wave generated in the measurement object by the pulsed light and converts the photoacoustic wave into an electric signal. The measuring section measures the electric signal. The waveform display unit displays a waveform of the measurement result of the measurement unit. The focus position display unit displays a position of a focus of the lens in the waveform.

Further, the first photoacoustic wave measurement apparatus of the present invention may further include: an output end moving unit that moves an output end of the pulse light output unit; and a display pattern moving unit that moves the display pattern displayed by the focal position display unit with respect to the waveform according to a movement amount of the output terminal.

In the first photoacoustic wave measurement device according to the present invention, the display pattern moving unit may move the display pattern in a direction corresponding to an output direction of the pulsed light in the waveform, based on a moving amount of the output end in the output direction of the pulsed light.

In the first photoacoustic wave measurement device according to the present invention, the focal point position display unit may display the position of the focal point by setting, as the position of the focal point, a coordinate obtained by adding a distance between the output end and the focal point to a coordinate corresponding to the output end in the waveform.

In the first photoacoustic wave measurement device according to the present invention, the waveform display unit may display the waveform within a range of a predetermined distance from an initial position of the output terminal.

A second photoacoustic wave measurement device according to the present invention includes: a pulse light output unit that outputs pulse light; a lens that receives a photoacoustic wave generated in a measurement object by the pulsed light and converts the photoacoustic wave into an electric signal; a measuring unit that measures the electric signal; a tomographic image display unit that displays a tomographic image of the measurement target based on a measurement result of the measurement unit; and a focal position display unit that displays a position of a focal point of the lens in the tomographic image.

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

Further, the second photoacoustic wave measurement apparatus of the present invention may further include: an output end moving unit that moves an output end of the pulse light output unit; and a display pattern moving unit that moves the display pattern displayed by the focal position display unit with respect to the tomographic image in accordance with a movement amount of the output terminal.

In the second photoacoustic wave measurement device according to the present invention, the display pattern moving unit may move the display pattern in a direction corresponding to an output direction of the pulsed light in the tomographic image, based on a moving amount of the output end in the output direction of the pulsed light.

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

In the second photoacoustic wave measurement device according to the present invention, the tomographic image display unit may display the tomographic image within a range of a predetermined distance from the initial position of the output terminal.

In the second photoacoustic wave measurement apparatus according to the present invention, the output end may be moved in a plane in which the output direction of the pulsed light is the normal direction, and the measurement results of the measurement unit for each position of the output end may be combined to obtain the tomographic image.

In the first photoacoustic wave measurement device according to the present invention, the focal position display unit may display coordinates of the focal point with respect to an output direction of the pulsed light.

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

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

In the first and second photoacoustic wave measurement devices according to the present invention, the lens may have a concave surface facing the measurement object.

In the first and second photoacoustic wave measurement devices according to the present invention, the lens may output an ultrasonic wave, and may receive a reflected ultrasonic wave reflected by the measurement object and convert the reflected ultrasonic wave into a reflected electric signal, and the first and second photoacoustic wave measurement devices may display a measurement result of the reflected electric signal.

Drawings

Fig. 1 is a sectional view of a measurement head 10 according to a first embodiment of the present invention.

Fig. 2 is a functional block diagram showing the configuration of the photoacoustic wave measurement apparatus 1 according to the first embodiment of the present invention.

Fig. 3 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 shallow with respect to the blood vessel 2 a.

Fig. 4 is a diagram showing the display forms of the waveform display unit 20, the focal position display unit 22, and the display pattern moving unit 24 in a state where the focal point fp is too shallow with respect to the blood vessel 2a (fig. 4 a) and in a state where the focal point fp is aligned with the blood vessel 2a (fig. 4 b).

Fig. 5 is a diagram showing a state in which the Z-direction moving unit (output end moving unit) 14 moves the output end 10d in the Z direction (downward) to align the focal point fp with the blood vessel 2 a.

Fig. 6 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 deep in the blood vessel 2 a.

Fig. 7 is a diagram showing the display forms of the waveform display unit 20, the focal position display unit 22, and the display pattern moving unit 24 in a state where the focal point fp is too deep with respect to the blood vessel 2a (fig. 7 a) and in a state where the focal point fp is aligned with the blood vessel 2a (fig. 7 b).

Fig. 8 is a diagram showing a state in which the Z-direction moving unit (output end moving unit) 14 moves the output end 10d in the Z direction (upward) to align the focal point fp with the blood vessel 2 a.

Fig. 9 is a diagram showing a display format of the waveform display unit 20 and the focal position display unit 22 according to a modification of the first embodiment.

Fig. 10 is a functional block diagram showing the configuration of a photoacoustic wave measurement apparatus 1 according to a second embodiment of the present invention.

Fig. 11 is a diagram showing the display forms of the tomographic image display unit 30, the focal position display unit 22, and the display pattern moving unit 24 in a state where the focal point fp is too shallow with respect to the blood vessel 2a (fig. 11 a) and in a state where the focal point fp is aligned with the blood vessel 2a (fig. 11 b).

Fig. 12 is a diagram showing the display forms of the tomographic image display unit 30, the focal position display unit 22, and the display pattern moving unit 24 in a state where the focal point fp is too deep with respect to the blood vessel 2a (fig. 12 a) and in a state where the focal point fp is aligned with the blood vessel 2a (fig. 12 b).

Fig. 13 is a sectional view of the measurement head 10 according to the third embodiment of the present invention.

Fig. 14 is a functional block diagram showing the configuration of a photoacoustic wave measurement apparatus 1 according to a third embodiment of the present invention.

Fig. 15 is a functional block diagram showing the configuration of a photoacoustic wave measurement device 1 according to a fourth embodiment of the present invention.

Description of the reference numerals

P: pulsed light; MA: a measurement area; AW: a photoacoustic wave; vs: speed of sound; fp: a focal point; m: indicia (display graphics); b: an area; d1, d 2: a movement amount; p1: ultrasonic waves; p2: reflecting the ultrasonic wave; 2: a measurement object; 2 a: a blood vessel; 1: a photoacoustic wave measuring device; 10: a measuring head; 10 a: an optical fiber (pulse light output unit); 10 b: an optical fiber holding section; 10 c: a lens; 10 d: an output end; 12: an XY-direction moving unit; 14: a Z-direction moving unit (output end moving unit); 16: a measurement section; 18: a focal position recording section; 20: a waveform display unit; 22: a focal position display unit; 24: a display pattern moving unit; 30: a tomographic image display unit.

Detailed Description

Embodiments of the present invention will be described below with reference to the drawings.

First embodiment

Fig. 1 is a sectional view of a measurement head 10 according to a first embodiment of the present invention. Fig. 2 is a functional block diagram showing the configuration of the photoacoustic wave measurement apparatus 1 according to the first embodiment of the present invention.

The photoacoustic wave measurement apparatus 1 according to the first embodiment is used to measure a measurement object 2 (for example, a human body, but is not limited thereto). The measurement target 2 includes a blood vessel 2 a.

The photoacoustic wave measurement device 1 of the first embodiment includes a measurement head 10, an XY-direction movement unit 12, a Z-direction movement unit (output end movement unit) 14, a measurement unit 16, a focal position recording unit 18, a waveform display unit 20, a focal position display unit 22, and a display pattern movement unit 24.

The measuring head 10 includes an optical fiber (pulse light output unit) 10a, an optical fiber holding unit 10b, and a lens 10 c.

The optical fiber (pulse light output unit) 10a outputs pulse light P from the output end 10 d. Further, the output direction of the pulsed light P is taken as the Z direction. Further, if the blood vessel 2a of the measurement object 2 receives the pulsed light P, a photoacoustic wave AW is generated.

The optical fiber holding portion 10b is disposed around the optical fiber 10a and holds the optical fiber 10 a.

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 the photoacoustic wave AW into an electric signal. The lens 10c is a piezoelectric element. The lens 10c has a concave surface facing the measurement object 2. The measurement area MA is an area where the photoacoustic wave AW measurable by the lens 10c exists. An ultrasonic wave transmitting member (not shown) (for example, water contained in a plastic container) is disposed between the measuring head 10 and the object 2. The photoacoustic wave AW reaches the lens 10c via a member that transmits an ultrasonic wave (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 pulse light P). As an example of the realization of the Z-direction moving unit 14, it is conceivable to manually (for example, turn a knob) move the measurement head 10 up and down in the Z-direction. Of course, manual is an example, and may be, for example, electric.

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 10 c.

The focal position recording unit 18 records a distance fd between the output end 10d and the focal point fp of the lens 10c (see fig. 3 and 6). Therein, the time t1 of the round trip of the acoustic wave between the output end 10d and the focal point fp of the lens 10c can also be recorded. If the sound speed is Vs, it is (1/2) × Vs × t1 ═ fd. Further, the time t1 is a result of measuring the round trip time of the ultrasonic wave between the output end 10d and the focal point fp of the lens 10c by a digital oscilloscope or the like.

The waveform display unit 20 displays a waveform AW (see fig. 4 and 7) of the measurement result of the measurement unit 16.

The focal position display unit 22 displays the position of the focal point of the lens 10c in the waveform AW (see reference symbol M in fig. 4 and 7). The focal position display unit 22 displays the position of the focal point fp by using, as the position of the focal point fp, the coordinate obtained by adding the distance fd to the coordinate 0 corresponding to the output end 10d in the waveform AW.

The display pattern moving unit 24 moves the marker (display pattern) M displayed by the focal position display unit 22 with respect to the waveform AW in accordance with the movement amounts d1 and d2 (see fig. 5 and 8) of the output terminal 10d (see fig. 4 and 7).

More specifically, the display pattern moving unit 24 moves the marker (display pattern) M in the waveform AW in a direction (see the horizontal axis in fig. 4 and 7) corresponding to the output direction (Z direction) of the pulsed light P in accordance with the amounts of movement d1, d2 (see fig. 5 and 8) of the output end 10d in the output direction (Z direction) of the pulsed light P.

Next, the 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 a photoacoustic wave AW. The photoacoustic wave AW is converted into an electric signal by the lens 10c and measured by the measuring unit 16. The measurement result is displayed as the waveform AW by the waveform display unit 20 (see fig. 4 and 7). The position of the focus fp (mark M) is displayed by the focus position display unit 22 together with the display of the waveform AW. Further, the display pattern moving unit 24 moves the marker M with respect to the waveform AW in accordance with the amount of movement of the output terminal 10 d.

(1) Operation in a state where focal point fp is too shallow with respect to blood vessel 2a

Fig. 3 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 shallow with respect to the blood vessel 2 a. Fig. 4 is a diagram showing the display forms of the waveform display unit 20, the focal position display unit 22, and the display pattern moving unit 24 in a state where the focal point fp is too shallow with respect to the blood vessel 2a (fig. 4 a) and in a state where the focal point fp is aligned with the blood vessel 2a (fig. 4 b). Fig. 5 is a diagram showing a state in which the Z-direction moving unit (output end moving unit) 14 moves the output end 10d in the Z direction (downward) to align the focal point fp with the blood vessel 2 a. Fig. 5 shows only the lens 10c and the output end 10d of the measuring head 10.

Referring to fig. 3, the focal point fp is shallower than the vessel 2a by d 1. If the focal point fp is not aligned with the blood vessel 2a, the XY plane image of the blood vessel 2a is blurred. Therefore, the focal point fp must be aligned with the blood vessel 2 a.

With reference to fig. 4(a), the display forms of the waveform display unit 20, the focal position display unit 22, and the display pattern moving unit 24 in the state where the focal point fp is too shallow with respect to the blood vessel 2a will be described. Note that, in fig. 4(a), the coordinates 0, t0, and (fd) are illustrated for convenience of explanation, and therefore, they are not necessarily displayed (the same applies to fig. 4 (b)).

The horizontal axis of fig. 4(a) is time, and illustrates a waveform AW of the photoacoustic wave. The coordinate 0 is the output timing of the pulsed light P output from the output end 10 d. The coordinate t0 is the time until pulsed light P is output from the output end 10d until photoacoustic waves AW (which are generated at the focal point fp) are received by the lens 10 c. Further, since the speed (light speed) of the pulse light P is very high, the time from when the pulse light P is output to when the pulse light P reaches the focal point fp can be ignored. Thus, t0 is (1/2) × t 1.

As described above, (1/2) × Vs × t1 is fd, and therefore Vs × t0 is fd. Accordingly, the coordinates on the horizontal axis in fig. 4(a) can be converted into a distance (referred to as "depth") in the Z direction with respect to the initial position of the output end 10d by multiplying the sound velocity Vs (the same applies to fig. 4 (b)). In fig. 4, coordinates converted into depth are shown with parentheses.

In fig. 4(a), in the waveform AW, 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 set as the position of the focal point fp, and the focal point position display unit 22 displays the position of the focal point fp. Specifically, a mark (display pattern) M is displayed directly above the coordinate t0 (fd). Further, the mark M is located within the rectangular area B. The region B is a rectangular region extending in the horizontal axis direction.

Further, the blood vessel 2a is located deeper than the focal point fp, and therefore the waveform AW is located at a coordinate larger than the coordinate t0 (fd).

Here, it is assumed that the user moves the output end 10d in a direction (downward in fig. 5) in which the coordinate in the Z direction increases for each measurement head 10 by the Z-direction moving unit 14, and aligns the focal point fp with the blood vessel 2 a.

In this way, the mark M moves in the direction (horizontal axis direction) corresponding to the Z direction in accordance with the amount of movement of the output terminal 10d in the Z direction. For example, if the output end 10d is moved in a direction in which the coordinate in the Z direction increases (downward in fig. 5), the mark M moves to the right side (direction in which the coordinate in the Z direction increases) within the area B.

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

(2) Operation in a state where focal point fp is too deep with respect to blood vessel 2a

Fig. 6 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 deep in the blood vessel 2 a. Fig. 7 is a diagram showing the display forms of the waveform display unit 20, the focal position display unit 22, and the display pattern moving unit 24 in a state where the focal point fp is too deep with respect to the blood vessel 2a (fig. 7 a) and in a state where the focal point fp is aligned with the blood vessel 2a (fig. 7 b). Fig. 8 is a diagram showing a state in which the Z-direction moving unit (output end moving unit) 14 moves the output end 10d in the Z direction (upward) to align the focal point fp with the blood vessel 2 a. Fig. 8 shows only the lens 10c and the output end 10d of the measuring head 10.

Referring to fig. 6, the focal spot fp is too deep compared to the depth d2 of the blood vessel 2 a. If the focal point fp is not aligned with the blood vessel 2a, the XY plane image of the blood vessel 2a is blurred. Therefore, the focal point fp must be aligned with the blood vessel 2 a.

With reference to fig. 7(a), the display forms of the waveform display unit 20, the focal position display unit 22, and the display pattern moving unit 24 in the state where the focal point fp is too deep with respect to the blood vessel 2a will be described. Note that, in fig. 7(a), the coordinates 0, t0, and (fd) are illustrated for convenience of explanation, and therefore, they are not necessarily displayed (the same applies to fig. 7 (b)).

The horizontal axis of fig. 7(a) is time, and illustrates a waveform AW of the photoacoustic wave. The coordinate 0 is the output timing of the pulsed light P output from the output end 10 d. The coordinate t0 is the time until pulsed light P is output from the output end 10d until photoacoustic waves AW (which are generated at the focal point fp) are received by the lens 10 c. Further, since the speed (light speed) of the pulse light P is very high, the time from when the pulse light P is output to when the pulse light P reaches the focal point fp can be ignored. Thus, t0 is (1/2) × t 1.

As described above, (1/2) × Vs × t1 is fd, and therefore Vs × t0 is fd. Accordingly, the coordinates on the horizontal axis in fig. 7(a) can be converted into a distance (referred to as "depth") in the Z direction with respect to the initial position of the output end 10d by multiplying the sound velocity Vs (the same applies to fig. 7 (b)). In fig. 7, coordinates converted into depth are shown with parentheses.

In fig. 7(a), in the waveform AW, 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 set as the position of the focal point fp, and the focal point position display unit 22 displays the position of the focal point fp. Specifically, a mark (display pattern) M is displayed directly above the coordinate t0 (fd). Further, the mark M is located within the rectangular area B. The region B is a rectangular region extending in the horizontal axis direction.

Further, the blood vessel 2a is located at a position shallower than the focal point fp, and therefore the waveform AW is located at a coordinate smaller than the coordinate t0 (fd).

Here, it is assumed that the user moves the output end 10d in a direction (upward in fig. 8) in which the coordinate in the Z direction is decreased for each measurement head 10 by the Z-direction moving unit 14, and aligns the focal point fp with the blood vessel 2 a.

In this way, the mark M moves in the direction (horizontal axis direction) corresponding to the Z direction in accordance with the amount of movement of the output terminal 10d in the Z direction. For example, if the output end 10d is moved in a direction in which the coordinate in the Z direction decreases (upward in fig. 8), the mark M moves to the left side (direction in which the coordinate in the Z direction decreases) within the area B.

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

According to the photoacoustic wave measurement apparatus 1 of the first embodiment, the position of the focal point fp of the lens 10c, which is an acoustic lens, is indicated by the mark M, and therefore, it is easy to understand.

Since the mark M is moved relative to the waveform AW in accordance with the amount of movement of the output end 10d (see fig. 4 and 7), it is easy to know whether or not the focal point fp coincides with the blood vessel 2a when the output end 10d is moved up and down in the Z direction for each measurement head 10.

In the first embodiment, no limitation is placed on the display range of the waveform AW, but a limitation may be placed on the display range of the waveform AW.

Referring to fig. 9, a waveform AW is displayed within a range (ranges Za to Zb obtained by multiplying ta to tb by Vs and converting the result into a distance) of a predetermined distance from the initial position 0 of the output terminal 10 d. The measurement can be realized by converting an electric signal (analog signal) acquired from the lens 10c of the measurement head 10 into a digital signal only within a predetermined range and displaying the digital signal on the waveform display unit 20. Alternatively, the lens 10c of the measurement head 10 may acquire an electric signal (analog signal) only in a predetermined range.

The ranges Za to Zb (ta × Vs to tb × Vs) are determined by adding the distance between the initial position of the output terminal 10d and the skin surface to the depth of the blood vessel 2a with respect to the skin surface.

Second embodiment

The photoacoustic wave measurement apparatus 1 of the second embodiment is different from the first embodiment in that: a tomographic image display unit 30 is provided instead of the waveform display unit 20.

Fig. 10 is a functional block diagram showing the configuration of a photoacoustic wave measurement apparatus 1 according to a second embodiment of the present invention. The measurement head 10 of the second embodiment is the same as that of the first embodiment, and therefore, description thereof is omitted (see fig. 1).

The photoacoustic wave measurement apparatus 1 of the second embodiment is used for measuring a measurement object 2 (for example, a human body, but not limited thereto) in the same manner as the first embodiment. The measurement target 2 includes a blood vessel 2 a.

The photoacoustic wave measurement device 1 of the second embodiment includes a measurement head 10, an XY-direction movement unit 12, a Z-direction movement unit (output end movement unit) 14, a measurement unit 16, a focal position recording unit 18, a tomographic image display unit 30, a focal position display unit 22, and a display pattern movement unit 24.

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 of the first embodiment, and the description thereof is 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 fig. 11 and 12). Further, the output end 10d is moved by the XY-direction moving unit 12 in a plane (XY plane) having the output direction (Z direction) of the pulsed light P as a normal direction. The tomographic image display unit 30 obtains a tomographic image by combining (for example, aperture combining) the measurement results of the measurement unit 16 at each position of the output terminal 10d at this time.

Referring to fig. 11 and 12, the tomographic image display unit 30 displays tomographic images within a range (ranges Za to Zb in which ta to tb are multiplied by Vs and converted into distances) having a predetermined distance from the initial position 0 of the output terminal 10 d. The measurement can be realized by converting an electric signal (analog signal) acquired from the lens 10c of the measurement head 10 into a digital signal only within a predetermined range and displaying the digital signal on the waveform display unit 20. Alternatively, the lens 10c of the measurement head 10 may acquire an electric signal (analog signal) only in a predetermined range.

The focal position display unit 22 displays the position of the focal point of the lens 10c in the tomographic image (see reference symbol M in fig. 11 and 12). The focal position display unit 22 displays the position of the focal point fp by using, as the position of the focal point fp, the coordinate obtained by adding the distance fd to the coordinate 0 corresponding to the output end 10d in the tomographic image.

The display pattern moving unit 24 moves the marker (display pattern) M displayed by the focal position display unit 22 with respect to the tomographic image (see fig. 11 and 12) in accordance with the movement amounts d1 and d2 (see fig. 5 and 8) of the output terminal 10 d.

More specifically, the display pattern moving unit 24 moves the marker (display pattern) M in the direction (see the vertical axis in fig. 11 and 12) corresponding to the output direction (Z direction) of the pulsed light P in the tomographic image, based on the moving amounts d1 and d2 (see fig. 5 and 8) of the output end 10d in the output direction (Z direction) of the pulsed light P.

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

If 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 a photoacoustic wave AW. The photoacoustic wave AW is converted into an electric signal by the lens 10c and measured by the measuring unit 16. The measurement result is displayed as a tomographic image on the tomographic image display unit 30 (see fig. 11 and 12). Along with the display of the tomographic image, the position of the focal point fp (mark M) is displayed by the focal point position display unit 22. Further, the display pattern moving unit 24 moves the marker M with respect to the tomographic image in accordance with the amount of movement of the output terminal 10 d.

The state where the focal point fp is too shallow with respect to the blood vessel 2a is the same as the first embodiment (see fig. 3). The state in which the Z-direction moving unit (output end moving unit) 14 moves the output end 10d in the Z direction to align the focal point fp with the blood vessel 2a is also the same as in the first embodiment (see fig. 5).

With reference to fig. 11(a), the display forms of the tomographic image display unit 30, the focal position display unit 22, and the display pattern moving unit 24 in the state where the focal point fp is too shallow with respect to the blood vessel 2a will be described. Note that, in fig. 11(a), the vertical axis, coordinates 0, t0, (fd), and focal point fp are illustrated for convenience of explanation, and therefore, they are not necessarily displayed (the same applies to fig. 11 (b)). However, in fig. 11 and 12, one or both of the focal point fp and a line segment (broken line) passing through the focal point fp may be displayed as display graphics.

The horizontal axis of fig. 11(a) is time, and the graph shows a tomographic image. The coordinate 0 is the output timing of the pulsed light P output from the output end 10 d. The coordinate t0 is the time until pulsed light P is output from the output end 10d until photoacoustic waves AW (which are generated at the focal point fp) are received by the lens 10 c. Further, since the speed (light speed) of the pulse light P is very high, the time from when the pulse light P is output to when the pulse light P reaches the focal point fp can be ignored. Thus, t0 is (1/2) × t 1.

As described above, (1/2) × Vs × t1 is fd, and therefore Vs × t0 is fd. Accordingly, the coordinate on the vertical axis in fig. 11(a) can be converted into a distance (referred to as "depth") in the Z direction from the initial position of the output end 10d by multiplying the sound velocity Vs (the same applies to fig. 11 (b)). In fig. 11, coordinates converted into depth are shown with parentheses.

In fig. 11(a), 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 set as the position of the focal point fp, and the focal point position display unit 22 displays the position of the focal point fp. Specifically, the mark (display pattern) M is displayed on the obverse side of the coordinate t0 (fd). Further, the mark M is located within the rectangular area B. The region B is a rectangular region extending in the longitudinal axis direction.

Further, since the blood vessel 2a is located at a position deeper than the focal point fp, the coordinates at which the tomographic image of the blood vessel 2a is located are larger than the coordinates t0 (fd).

In this way, the mark M moves in the direction (vertical axis direction) corresponding to the Z direction in accordance with the amount of movement of the output end 10d in the Z direction. For example, if the output end 10d is moved in a direction in which the coordinate in the Z direction increases (downward in fig. 5), the mark M moves downward (in a direction in which the coordinate in the Z direction increases) within the area B.

Referring to fig. 11(b), when the output end 10d is moved d1 in the direction in which the Z-direction coordinate increases (downward in fig. 5), the coordinate t0(fd) of the focal point fp coincides with the coordinate of the tomographic image of the blood vessel 2 a. At this time, referring to fig. 5, the focal point fp coincides with the blood vessel 2 a.

The state where the focal point fp is too deep in the blood vessel 2a is the same as in the first embodiment (see fig. 6). The state in which the Z-direction moving unit (output end moving unit) 14 moves the output end 10d in the Z direction to align the focal point fp with the blood vessel 2a is also the same as in the first embodiment (see fig. 8).

With reference to fig. 12(a), the display forms of the tomographic image display unit 30, the focal position display unit 22, and the display pattern moving unit 24 in the state where the focal point fp is too deep with respect to the blood vessel 2a will be described. Note that, in fig. 12(a), the vertical axis, coordinates 0, t0, (fd), and focal point fp are illustrated for convenience of explanation, and therefore, they are not necessarily displayed (the same applies to fig. 12 (b)).

The vertical axis of fig. 12(a) is time, and the graph shows a tomographic image. The coordinate 0 is the output timing of the pulsed light P output from the output end 10 d. The coordinate t0 is the time until pulsed light P is output from the output end 10d until photoacoustic waves AW (which are generated at the focal point fp) are received by the lens 10 c. Further, since the speed (light speed) of the pulse light P is very high, the time from when the pulse light P is output to when the pulse light P reaches the focal point fp can be ignored. Thus, t0 is (1/2) × t 1.

As described above, (1/2) × Vs × t1 is fd, and therefore Vs × t0 is fd. Accordingly, the coordinates on the horizontal axis in fig. 12(a) can be converted into a distance (referred to as "depth") in the Z direction with respect to the initial position of the output end 10d by multiplying the sound velocity Vs (the same applies to fig. 12 (b)). In fig. 12, coordinates converted into depth are shown with parentheses.

In fig. 12(a), 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 set as the position of the focal point fp, and the focal point position display unit 22 displays the position of the focal point fp. Specifically, the mark (display pattern) M is displayed on the obverse side of the coordinate t0 (fd). Further, the mark M is located within the rectangular area B. The region B is a rectangular region extending in the longitudinal axis direction.

Further, since the blood vessel 2a is located at a position shallower than the focal point fp, the coordinates at which the tomographic image of the blood vessel 2a is located are smaller than the coordinates t0 (fd).

In this way, the mark M moves in the direction (vertical axis direction) corresponding to the Z direction in accordance with the amount of movement of the output end 10d in the Z direction. For example, when the output end 10d is moved in a direction in which the coordinate in the Z direction decreases (upward in fig. 8), the mark M moves upward (in a direction in which the coordinate in the Z direction decreases) within the area B.

Referring to fig. 12(b), when the output end 10d is moved d2 in a direction (upward in fig. 8) in which the Z-direction coordinate decreases, the coordinate t0(fd) of the focal point fp coincides with the coordinate of the tomographic image of the blood vessel 2 a. At this time, referring to fig. 8, the focal point fp coincides with the blood vessel 2 a.

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

Third embodiment

The photoacoustic wave measurement apparatus 1 of the third embodiment is different from the first embodiment in that: in addition to the pulsed light P, the ultrasonic wave P1 is applied to the measurement object 2 to perform measurement.

Fig. 13 is a sectional view of the measurement head 10 according to the third embodiment of the present invention. Fig. 14 is a functional block diagram showing the configuration of a photoacoustic wave measurement apparatus 1 according to a third embodiment of the present invention.

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

The photoacoustic wave measurement device 1 of the third embodiment includes a measurement head 10, an XY-direction movement unit 12, a Z-direction movement unit (output end movement unit) 14, a measurement unit 16, a focal position recording unit 18, a waveform display unit 20, a focal position display unit 22, and a display pattern movement unit 24.

The measuring head 10 includes an optical fiber (pulse light output unit) 10a, an optical fiber holding unit 10b, and a lens 10 c. The optical fiber 10a and the optical fiber holding portion 10b are the same as those of the first embodiment, and therefore, the description thereof is omitted.

The lens 10c is also the same as the first embodiment, but outputs ultrasonic waves P1. The lens 10c is a piezoelectric element, and by applying a voltage to the lens 10c, the ultrasonic wave P1 can be output from the lens 10 c. The lens 10c receives the reflected ultrasonic wave P2 (see fig. 14) reflected by the object 2 to be measured and the ultrasonic wave P1, and converts the reflected ultrasonic wave P2 into a reflected electric signal. The ultrasonic wave P1 reaches the measurement object 2 through the member that transmits ultrasonic waves described in the first embodiment (the same applies to the fourth embodiment). The reflected ultrasonic wave P2 reaches the lens 10c through the member that transmits ultrasonic waves described in the first embodiment (the same applies to the fourth embodiment).

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

The XY-direction moving unit 12, the Z-direction moving unit 14, the focal position recording unit 18, the focal position display unit 22, and the display pattern moving unit 24 are the same as those of the first embodiment, and the description thereof will be omitted. However, the coordinate of the focal point fp in the waveform P2 of the reflected electric signal is t 1.

Next, the operation of the third 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 a photoacoustic wave AW. Further, the ultrasonic wave P1 is output from the lens 10c, and the object 2 to be measured is reflected, and the reflected ultrasonic wave P2 is applied to the lens 10 c. 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 are measured by the measuring unit 16. The measurement results are displayed on the waveform display unit 20 as the waveforms AW and P2. The position of the focus fp (mark M) is displayed by the focus position display unit 22 together with the display of the waveforms AW, P2. Further, the display pattern moving unit 24 moves the marker M with respect to the waveform AW in accordance with the amount of movement of the output terminal 10 d. The waveform P2 is displayed in the same manner as the waveform AW (see fig. 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 of the fourth embodiment is different from the second embodiment in that: in addition to the pulsed light P, the ultrasonic wave P1 is applied to the measurement object 2 to perform measurement.

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

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

The photoacoustic wave measurement device 1 of the fourth embodiment includes a measurement head 10, an XY-direction movement unit 12, a Z-direction movement unit (output end movement unit) 14, a measurement unit 16, a focal position recording unit 18, a tomographic image display unit 30, a focal position display unit 22, and a display pattern movement unit 24.

The measurement unit 16 measures the electric signal received from the lens 10c and the reflected electric signal. The tomographic image display unit 30 displays a tomographic image based on the measurement result of the measurement unit 16. Further, the tomographic image obtained from the photoacoustic wave AW clearly shows the blood vessel 2a, while the tomographic image obtained from the reflected ultrasonic wave P2 clearly shows the structure inside the measurement object 2 (for example, the skin). Further, a tomographic image obtained from the photoacoustic wave AW and a tomographic image obtained from the reflected ultrasonic wave P2 may be displayed in a superimposed manner.

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

Next, the 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 a photoacoustic wave AW. Further, the ultrasonic wave P1 is output from the lens 10c, and the object 2 to be measured is reflected, and the reflected ultrasonic wave P2 is applied to the lens 10 c. 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 are measured by the measuring unit 16. The tomographic image display unit 30 acquires and displays a tomographic image from the measurement result. Along with the display of the tomographic image, the position of the focal point fp (mark M) is displayed by the focal point position display unit 22. Further, the display pattern moving unit 24 moves the marker M with respect to the tomographic image in accordance with the amount of movement of the output terminal 10 d. Note that the display format of the tomographic image is the same as that of the second embodiment (see fig. 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 pattern is displayed, but instead of the display pattern, the coordinates of the focal point fp corresponding to the output direction (Z direction) of the pulsed light P2 may be displayed. For example, the coordinates of the focal point fp (corresponding to the depth from the skin surface) may be displayed with the Z-coordinate of the skin surface as the origin. The depth of the focal point fp relative to the skin is found by subtracting the distance of the output end 10d from the skin surface from the distance fd (known) of the output end 10d from the focal point fp. Further, the distance between the output end 10d and the skin surface can be obtained from the time from the output of the ultrasonic wave P1 (see the third and fourth embodiments) to the reception of the reflected ultrasonic wave P2 (see the third and fourth embodiments) reflected by the skin surface.

The above-described embodiment can be realized as follows. A computer provided with a CPU, a hard disk, and a medium (such as a USB memory or a CD-ROM) reading device is caused to read a medium on which a program for realizing the above-described respective sections, for example, the focal point position recording section 18, the waveform display section 20, the tomographic image display section 30, the focal point position display section 22, and the display pattern shifting section 24 is recorded, and is installed in the hard disk. In such a method, the above-described functions can be realized.

Claims

1. A photoacoustic wave measurement device is characterized in that,

the photoacoustic wave measurement device includes:

a pulse light output unit that outputs pulse light;

a lens that receives a photoacoustic wave generated in a measurement object by the pulsed light and converts the photoacoustic wave into an electric signal;

a measuring unit that measures the electric signal;

a waveform display unit for displaying a waveform of a measurement result of the measurement unit; and

and a focal position display unit that displays a position of a focal point of the lens in the waveform.

2. The photoacoustic wave measurement apparatus according to claim 1,

the photoacoustic wave measurement device includes:

an output end moving unit that moves an output end of the pulse light output unit; and

and a display pattern moving unit that moves the display pattern displayed by the focal position display unit with respect to the waveform according to a movement amount of the output terminal.

3. The photoacoustic wave measurement apparatus according to claim 2,

the display pattern moving unit moves the display pattern in a direction corresponding to an output direction of the pulsed light in the waveform according to a movement amount of the output end in the output direction of the pulsed light.

4. The photoacoustic wave measurement apparatus according to claim 1,

in the waveform, the focal position display unit displays the position of the focal point by using, as the position of the focal point, a coordinate obtained by adding a distance between the output end and the focal point to a coordinate corresponding to the output end.

5. The photoacoustic wave measurement apparatus according to claim 1,

the waveform display unit displays the waveform within a range of a predetermined distance from an initial position of the output terminal.

6. A photoacoustic wave measurement device is characterized in that,

the photoacoustic wave measurement device includes:

a pulse light output unit that outputs pulse light;

a measuring unit that measures the electric signal;

a tomographic image display unit that displays a tomographic image of the measurement target based on a measurement result of the measurement unit; and

and a focal position display unit that displays a position of a focal point of the lens in the tomographic image.

7. The photoacoustic wave measurement apparatus according to claim 6,

the photoacoustic wave measurement device includes:

and a display pattern moving unit that moves the display pattern displayed by the focal position display unit with respect to the tomographic image in accordance with a movement amount of the output terminal.

8. The photoacoustic wave measurement apparatus according to claim 7,

the display pattern moving unit moves the display pattern in a direction corresponding to an output direction of the pulsed light in the tomographic image, based on a moving amount of the output end in the output direction of the pulsed light.

9. The photoacoustic wave measurement apparatus according to claim 6,

in the tomographic image, the focal position display unit displays the position of the focal point by using, as the position of the focal point, a coordinate obtained by adding a distance between the output end and the focal point to a coordinate corresponding to the output end.

10. The photoacoustic wave measurement apparatus according to claim 6,

the tomographic image display unit displays the tomographic image within a range of a predetermined distance from an initial position of the output terminal.

11. The photoacoustic wave measurement apparatus according to claim 6,

the output end moves in a plane with the output direction of the pulsed light as a normal direction,

the tomographic image is obtained by combining the measurement results of the measurement unit for each position of the output terminal.

12. The photoacoustic wave measurement apparatus according to claim 1,

the focal position display unit displays coordinates of the focal point with respect to an output direction of the pulsed light.

13. The photoacoustic wave measurement apparatus according to claim 6,

14. The photoacoustic wave measurement device according to any one of claims 1 to 13, wherein the measurement unit is a photoacoustic wave measurement device,

the lens is a piezoelectric element.

15. The photoacoustic wave measurement device according to any one of claims 1 to 13, wherein the measurement unit is a photoacoustic wave measurement device,

the lens has a concave surface facing the measurement object.

16. The photoacoustic wave measurement device according to any one of claims 1 to 13, wherein the measurement unit is a photoacoustic wave measurement device,

the lens outputs ultrasonic waves, receives reflected ultrasonic waves of the ultrasonic waves reflected by the measurement object, converts the reflected ultrasonic waves into reflected electric signals,

the photoacoustic wave measurement device displays the measurement result of the reflected electric signal.