CN111743511B

CN111743511B - Photoacoustic wave measuring device

Info

Publication number: CN111743511B
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: 2023-07-21
Anticipated expiration: 2040-02-28
Also published as: CN111743511A; DE102020201914A1; JP2020156737A; JP7227049B2

Abstract

In the photoacoustic wave measurement apparatus 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 pulse light output unit (10 a) that outputs pulse light (P); a lens (10 c) that receives a photoacoustic wave (AW) generated in the measurement object (2) by the pulse 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 A 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 (10 c) in the waveform (AW); a Z-direction moving unit (14) that moves the output end (10 d) of the pulsed light output unit (10 a); and a display pattern moving unit (24) that moves the mark (M) displayed by the focus position display unit (22) relative to the waveform (AW) according to the movement amounts (d 1, d 2) of the output terminal (10 d).

Description

Photoacoustic wave measuring device

Technical Field

The present invention relates to measurement of photoacoustic waves.

Background

Conventionally, a photoacoustic wave measurement apparatus has been known (for example, see patent documents 1, 2, and 3). It is known that the 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 the object to be measured (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).

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open publication 2016-10260

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

Patent document 3: japanese patent application laid-open No. 2011-519281

Problems to be solved by the invention

However, according to the photoacoustic wave measuring apparatus of the above-described conventional art, 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 focal point of the acoustic lens with a desired position with respect to the position of the object to be measured. This is because it is inherently difficult to know the position of the focal point of the acoustic lens.

Disclosure of Invention

In this regard, the subject of the present invention is: in the photoacoustic wave measuring apparatus, the position of the focal point of the acoustic lens is easily known.

Solution scheme

The first photoacoustic wave measurement device of the present invention is configured to include: a pulse light output unit that outputs pulse light; a lens that receives a photoacoustic wave generated in the measurement object by the pulsed light and converts the photoacoustic wave into an electrical signal; a measuring unit for measuring the electric signal; a waveform display unit that displays a waveform of a measurement result of the measurement unit; and a focal position display unit that displays a focal position of the lens in the waveform.

According to the first photoacoustic wave measuring apparatus configured as described above, the pulse light output unit outputs the pulse light. The lens receives the photoacoustic wave generated in the measurement object by the pulse light and converts the photoacoustic wave into an electrical signal. The measuring unit measures the electric signal. The waveform display unit displays a waveform of the measurement result of the measurement unit. The focal position display unit displays the position of the focal point of the lens in the waveform.

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

In the first photoacoustic wave measuring apparatus according to the present invention, the display pattern moving unit may move the display pattern in a direction corresponding to the output direction of the pulse light in the waveform according to a movement amount of the output end in the output direction of the pulse light.

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

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

The second photoacoustic wave measurement apparatus of the present invention includes: a pulse light output unit that outputs pulse light; a lens that receives a photoacoustic wave generated in the measurement object by the pulsed light and converts the photoacoustic wave into an electrical signal; a measuring unit for measuring the electric signal; a tomographic image display unit that displays a tomographic image of the measurement object based on a measurement result of the measurement unit; and a focal position display unit that displays a focal position of the lens in the tomographic image.

According to the second photoacoustic wave measuring apparatus configured as described above, the pulse light output unit outputs the pulse light. The lens receives the photoacoustic wave generated in the measurement object by the pulse light and converts the photoacoustic wave into an electrical signal. The measuring unit measures the electric signal. The 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 a focal position of the lens in the tomographic image.

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 pulsed light output unit; and a display pattern moving unit that moves the display pattern displayed by the focus position display unit with respect to the tomographic image in accordance with the movement amount of the output end.

In the second photoacoustic wave measuring apparatus according to the present invention, the display pattern moving unit may move the display pattern in a direction corresponding to the output direction of the pulse light in the tomographic image according to a movement amount of the output end in the output direction of the pulse light.

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

In the second photoacoustic wave measuring apparatus according to the present invention, the tomographic image display unit may display the tomographic image within a predetermined distance from the initial position of the output end.

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

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

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

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

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

In the first and second photoacoustic wave measuring apparatuses according to the present invention, the lens may output ultrasonic waves, receive reflected ultrasonic waves of the ultrasonic waves reflected by the measurement object, and convert the reflected ultrasonic waves into reflected electric signals, and the first and second photoacoustic wave measuring apparatuses may display measurement results of the reflected electric signals.

Drawings

Fig. 1 is a cross-sectional view of a measuring 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 measuring head 10 according to the first embodiment in a state where the focal point fp is too shallow relative to the blood vessel 2a.

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

Fig. 6 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 relative to the blood vessel 2a.

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

Fig. 9 is a diagram showing display forms of the waveform display unit 20 and the focus position display unit 22 according to a modification example 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 of 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 a state where the focal point fp is aligned with the blood vessel 2a (fig. 11 (b)).

Fig. 12 is a diagram of 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 relative to the blood vessel 2a (fig. 12 (a)) and a state where the focal point fp is aligned with the blood vessel 2a (fig. 12 (b)).

Fig. 13 is a cross-sectional view of a measuring head 10 according to a 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 apparatus 1 according to a fourth embodiment of the present invention.

Description of the reference numerals

P: pulsed light; MA: a measurement region; AW: photoacoustic waves; vs: sound velocity; fp: a focal point; m: marking (displaying graphics); b: a region; d1, d2: a moving amount; p1: ultrasonic waves; p2: reflecting the ultrasonic waves; 2: a measurement object; 2a: a blood vessel; 1: a photoacoustic wave measuring device; 10: a measuring head; 10a: an optical fiber (pulse light output section); 10b: an optical fiber holding section; 10c: a lens; 10d: an output end; 12: an XY direction moving unit; 14: a Z-direction moving unit (output end moving unit); 16: a measuring unit; 18: a focal position recording unit; 20: a waveform display unit; 22: a focal position display unit; 24: a display pattern moving part; 30: and a tomographic image display unit.

Detailed Description

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

First embodiment

Fig. 1 is a cross-sectional view of a measuring 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 of the first embodiment is used for measuring a measurement object 2 (for example, a human body, but not limited thereto). The 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 measurement unit 16, a focal position recording unit 18, a waveform display unit 20, a focal position display unit 22, and a display pattern moving unit 24.

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

The optical fiber (pulse light output unit) 10a outputs pulse light P from an output terminal 10d. The output direction of the pulse light P is referred to as the Z direction. In addition, if the blood vessel 2a of the measurement object 2 receives the pulse 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 10a.

The lens 10c is an acoustic lens that receives the photoacoustic wave AW generated in the measurement object 2 by the pulse light P and converts the photoacoustic wave AW into an electrical 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 that can be measured by the lens 10c exists. Further, an ultrasonic wave-transmitting member (not shown) (for example, water contained in a plastic container) is disposed between the measuring head 10 and the measuring object 2. The photoacoustic wave AW reaches the lens 10c via an ultrasonic wave-transmitting member (the same applies to other embodiments).

The Z-direction moving section (output end moving section) 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 implementation of the Z-direction moving unit 14, it is conceivable to move up and down in the Z-direction for each measuring head 10 manually (for example, by turning a knob). Of course, manual operation is an example, and may be electric, for example.

The XY-direction moving section 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 measuring unit 16 measures the electric signal received from the lens 10c.

The focal position recording unit 18 records the distance fd between the output end 10d and the focal point fp of the lens 10c (see fig. 3 and 6). Here, the time t1 of the sound wave going back and forth between the output end 10d and the focal point fp of the lens 10c may also be recorded. If the sound velocity is Vs, (1/2) ×vs×t1=fd. Further, the time t1 is a result of measuring the time for the ultrasonic wave to travel 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 the 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 fp with the position 0 corresponding to the output terminal 10d added with the distance fd as the position of the focal fp in the waveform AW.

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

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

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

When the pulse light P is output from the output end 10d of the optical fiber 10a, the blood vessel 2a receives the pulse light P, and generates a photoacoustic wave AW. The photoacoustic wave AW is converted into an electrical signal by the lens 10c, and is measured by the measuring unit 16. As the waveform AW, the measurement result is displayed by the waveform display unit 20 (see fig. 4 and 7). Along with the display of the waveform AW, the position of the focal point fp (mark M) is displayed by the focal point position display section 22. Further, by the display pattern moving section 24, the mark M is moved with respect to the waveform AW in accordance with the movement amount of the output terminal 10d.

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

Fig. 3 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 shallow relative to the blood vessel 2a. Fig. 4 is a diagram showing display forms of the waveform display unit 20, the focus position display unit 22, and the display pattern moving unit 24 in a state where the focus fp is too shallow with respect to the blood vessel 2a (fig. 4 (a)) and a state where the focus 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 2a. 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 blood 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 2a.

Referring to fig. 4 (a), a description will be given of a display form of the waveform display unit 20, the focus position display unit 22, and the display pattern moving unit 24 in a state where the focus fp is too shallow with respect to the blood vessel 2a. In fig. 4 (a), the coordinates 0, t0, and fd are shown for convenience of explanation, and therefore, the coordinates are not necessarily displayed (fig. 4 (b) is also the same).

The horizontal axis of fig. 4 (a) is time, and the waveform AW of the photoacoustic wave is illustrated. The coordinate 0 is the output timing at which the pulse light P is output from the output terminal 10d. The coordinate t0 is the time from the output end 10d to the reception of the photoacoustic wave AW (which is generated at the focal point fp) by the lens 10c. Further, since the speed (light velocity) of the pulse light P is extremely high, the time from the output of the pulse light P to the arrival of the focal point fp can be ignored. Thus, t0= (1/2) ×t1.

As described above, (1/2) ×vs×t1=fd, and thus vs×t0=fd. Thus, the coordinates of the horizontal axis in fig. 4 (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 sound velocity Vs (the same applies to fig. 4 (b)). In fig. 4, the coordinates converted to depth are illustrated with brackets.

In fig. 4 (a), in the waveform AW, a coordinate (fd) obtained by adding a distance fd between the output terminal 10d and the focal point fp to a coordinate 0 corresponding to the initial position of the output terminal 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 coordinates t0 (fd). Further, the mark M is located in the rectangular region B. The region B is a rectangular region extending in the horizontal axis direction.

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

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

In this way, the mark 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, if the output terminal 10d is moved in the direction in which the Z-direction coordinates increase (downward in fig. 5), the mark M moves to the right (direction in which the Z-direction coordinates increase) in the area B.

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

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

Fig. 6 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 relative to the blood vessel 2a. Fig. 7 is a diagram showing display forms of the waveform display unit 20, the focus position display unit 22, and the display pattern moving unit 24 in a state where the focus fp is too deep relative to the blood vessel 2a (fig. 7 (a)) and in a state where the focus 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 2a. Fig. 8 illustrates only the lens 10c and the output end 10d of the measuring head 10.

Referring to fig. 6, focal point fp is too deep relative to blood vessel 2a by depth d 2. 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 2a.

Referring to fig. 7 (a), the display forms of the waveform display unit 20, the focus position display unit 22, and the display pattern moving unit 24 in a state where the focus fp is too deep with respect to the blood vessel 2a will be described. In fig. 7 (a), the coordinates 0, t0, and fd are shown for convenience of explanation, and therefore, the coordinates are not necessarily displayed (fig. 7 (b) is also the same).

The horizontal axis of fig. 7 (a) is time, and the waveform AW of the photoacoustic wave is illustrated. The coordinate 0 is the output timing at which the pulse light P is output from the output terminal 10d. The coordinate t0 is the time from the output end 10d to the reception of the photoacoustic wave AW (which is generated at the focal point fp) by the lens 10c. Further, since the speed (light velocity) of the pulse light P is extremely high, the time from the output of the pulse light P to the arrival of the focal point fp can be ignored. Thus, t0= (1/2) ×t1.

As described above, (1/2) ×vs×t1=fd, and thus vs×t0=fd. Thus, the coordinates of the horizontal axis in fig. 7 (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 sound velocity Vs (the same applies to fig. 7 (b)). In fig. 7, the coordinates converted to depth are illustrated with brackets.

In fig. 7 (a), in the waveform AW, a coordinate (fd) obtained by adding a distance fd between the output terminal 10d and the focal point fp to a coordinate 0 corresponding to the initial position of the output terminal 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 coordinates t0 (fd). Further, the mark M is located in the rectangular region 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 coordinates at which the waveform AW is located are smaller than the coordinates t0 (fd).

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

In this way, the mark 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, if the output terminal 10d is moved in the direction in which the Z-direction coordinates decrease (upward in fig. 8), the mark M moves to the left (direction in which the Z-direction coordinates decrease) in the area B.

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

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

Since the mark M moves with respect to the waveform AW (see fig. 4 and 7) according to the movement amount of the output end 10d, 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 measuring head 10.

In the first embodiment, the display range of the waveform AW is not limited, but may be limited.

Referring to fig. 9, waveforms AW within a range (ta to tb multiplied by Vs and converted into ranges Za to Zb of distances) having a predetermined distance from the initial position 0 of the output terminal 10d are shown. This can be achieved by converting an electric signal (analog signal) obtained from the lens 10c of the measuring 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 measuring head 10 may acquire an electric signal (analog signal) only within a predetermined range.

Further, the ranges Za to Zb (ta×vs to tb×vs) are determined from a value obtained by adding the distance of the initial position of the output terminal 10d from 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: the 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 measuring 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 the measurement object 2 (for example, a human body, but not limited thereto) as in the first embodiment. The measurement object 2 has a blood vessel 2a.

The 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 display unit 30, a focal position display unit 22, and a display pattern moving 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). 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 pulse light P as a normal direction. The tomographic image display unit 30 synthesizes (for example, aperture synthesis) the measurement results of the measurement unit 16 at the respective positions of the output terminal 10d at this time, thereby obtaining a tomographic image.

Referring to fig. 11 and 12, tomographic images in a range (ta to tb multiplied by Vs and converted into ranges Za to Zb in which the distance is obtained) having a predetermined distance from the initial position 0 of the output terminal 10d are displayed by the tomographic image display unit 30. This can be achieved by converting an electric signal (analog signal) obtained from the lens 10c of the measuring 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 measuring head 10 may acquire an electric signal (analog signal) only within 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 numeral M in fig. 11 and 12). The focal position display unit 22 displays the position of the focal point fp on the tomographic image, with the coordinate obtained by adding the distance fd to the coordinate 0 corresponding to the output terminal 10d being the position of the focal point fp.

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

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

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

If the pulse light P is output from the output end 10d of the optical fiber 10a, the blood vessel 2a receives the pulse light P, and generates a photoacoustic wave AW. The photoacoustic wave AW is converted into an electrical signal by the lens 10c, and is measured by the measuring unit 16. As a tomographic image, the measurement result is displayed by 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 section 22. Further, by the display pattern moving section 24, the mark M is moved with respect to the tomographic image in accordance with the movement amount of the output terminal 10d.

The state where the focal point fp is too shallow with respect to the blood vessel 2a is the same as that of 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 that of the first embodiment (see fig. 5).

Fig. 11 is a diagram showing 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 a state where the focal point fp is aligned with the blood vessel 2a (fig. 11 (b)).

Referring 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 a state where the focal point fp is too shallow with respect to the blood vessel 2a will be described. In fig. 11 (a), the vertical axis, coordinates 0, t0, (fd), and focal point fp are shown for convenience of explanation, and therefore, they are not necessarily displayed (fig. 11 (b) is also the same). 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 a display pattern.

The horizontal axis of fig. 11 (a) is time, and a tomographic image is illustrated. The coordinate 0 is the output timing at which the pulse light P is output from the output terminal 10d. The coordinate t0 is the time from the output end 10d to the reception of the photoacoustic wave AW (which is generated at the focal point fp) by the lens 10c. Further, since the speed (light velocity) of the pulse light P is extremely high, the time from the output of the pulse light P to the arrival of the focal point fp can be ignored. Thus, t0= (1/2) ×t1.

As described above, (1/2) ×vs×t1=fd, and thus vs×t0=fd. As a result, the coordinates 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 sound velocity Vs (the same applies to fig. 11 (b)). In fig. 11, the coordinates converted to depth are illustrated with brackets.

In fig. 11 (a), in the tomographic image, a coordinate (fd) obtained by adding a coordinate 0 corresponding to the initial position of the output terminal 10d to a distance fd between the output terminal 10d and the focal point fp 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 on the positive lateral side of the coordinate t0 (fd). Further, the mark M is located in the rectangular region B. 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 according to the amount of movement of the output end 10d in the Z direction. For example, if the output terminal 10d is moved in the direction in which the Z-direction coordinates increase (downward in fig. 5), the mark M moves downward (direction in which the Z-direction coordinates increase) in the area B.

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

The state where the focal point fp is too deep with respect to 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 that of the first embodiment (see fig. 8).

Fig. 12 is a diagram showing 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 relative to the blood vessel 2a (fig. 12 (a)) and a state where the focal point fp is aligned with the blood vessel 2a (fig. 12 (b)).

Referring 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 a state where the focal point fp is too deep with respect to the blood vessel 2a will be described. In fig. 12 (a), the vertical axis, coordinates 0, t0, (fd), and focal point fp are shown for convenience of explanation, and therefore, they are not necessarily displayed (fig. 12 (b) also).

The vertical axis of fig. 12 (a) is time, and a tomographic image is illustrated. The coordinate 0 is the output timing at which the pulse light P is output from the output terminal 10d. The coordinate t0 is the time from the output end 10d to the reception of the photoacoustic wave AW (which is generated at the focal point fp) by the lens 10c. Further, since the speed (light velocity) of the pulse light P is extremely high, the time from the output of the pulse light P to the arrival of the focal point fp can be ignored. Thus, t0= (1/2) ×t1.

As described above, (1/2) ×vs×t1=fd, and thus vs×t0=fd. As a result, the coordinates of the horizontal 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 terminal 10d by multiplying the sound velocity Vs (the same applies to fig. 12 (b)). In fig. 12, coordinates converted to depth are illustrated with brackets.

In fig. 12 (a), in the tomographic image, a coordinate (fd) obtained by adding a coordinate 0 corresponding to the initial position of the output terminal 10d to a distance fd between the output terminal 10d and the focal point fp 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 on the positive lateral side of the coordinate t0 (fd). Further, the mark M is located in the rectangular region B. 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 according to the amount of movement of the output end 10d in the Z direction. For example, when the output terminal 10d is moved in the direction in which the Z-direction coordinates decrease (upward in fig. 8), the mark M moves upward (the direction in which the Z-direction coordinates decrease) in the area B.

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

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 pulse light P, an ultrasonic wave P1 is applied to the measurement object 2 to perform measurement.

Fig. 13 is a cross-sectional view of a measuring head 10 according to a 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 of the third embodiment is used for measuring the measurement object 2 (for example, a human body, but not limited thereto). The measurement object 2 has a blood vessel 2a.

The 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 unit 20, a focal position display unit 22, and a display pattern moving unit 24.

The measuring head 10 includes an optical fiber (pulse light output unit) 10a, an optical fiber holding unit 10b, and a lens 10c. 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 similar to the first embodiment, but also outputs the ultrasonic wave P1. By providing 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 receives the reflected ultrasonic wave P2 (see fig. 14) reflected by the object 2 to be measured of the ultrasonic wave P1, and converts the reflected ultrasonic wave P2 into a reflected electric signal. The ultrasonic wave P1 reaches the object 2 to be measured 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 measuring unit 16 measures the electric signal received from the lens 10c and the reflected electric signal. The waveform display unit 20 displays waveforms (AW and P2) of the measurement results 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 t1.

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

When the pulse light P is output from the output end 10d of the optical fiber 10a, the blood vessel 2a receives the pulse light P, and generates a photoacoustic wave AW. The ultrasonic wave P1 is output from the lens 10c, reflected by the object 2 to be measured, and the reflected ultrasonic wave P2 is applied 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 are measured by the measuring unit 16. The measurement results are displayed on the waveform display unit 20 as waveforms AW and P2. Along with the display of the waveforms AW, P2, the position of the focal point fp (mark M) is displayed by the focal point position display section 22. Further, by the display pattern moving unit 24, the mark M is moved with respect to the waveform AW in accordance with the movement amount of the output terminal 10d. 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 achieved.

Fourth embodiment

The photoacoustic wave measurement apparatus 1 of the fourth embodiment is different from the second embodiment in that: in addition to the pulse light P, an 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 apparatus 1 according to a fourth embodiment of the present invention. The measuring head 10 according to the fourth embodiment is the same as that according to the third embodiment, and the description thereof is omitted.

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

The 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 measuring unit 16, a focal position recording unit 18, a tomographic image display unit 30, a focal position display unit 22, and a display pattern moving unit 24.

The measuring 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 within the measurement object 2 (for example, 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 superposition.

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 will be omitted.

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

When the pulse light P is output from the output end 10d of the optical fiber 10a, the blood vessel 2a receives the pulse light P, and generates a photoacoustic wave AW. The ultrasonic wave P1 is output from the lens 10c, reflected by the object 2 to be measured, and the reflected ultrasonic wave P2 is applied 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 are measured by the measuring unit 16. The tomographic image display unit 30 acquires a tomographic image from the measurement result and displays the tomographic image. 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 section 22. Further, by the display pattern moving section 24, the mark M is moved with respect to the tomographic image in accordance with the movement amount of the output terminal 10d. The display form 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 achieved.

In the first to fourth embodiments, the display pattern is shown, but the coordinates of the focal point fp corresponding to the output direction (Z direction) of the pulse light P2 may be displayed instead of the display pattern. For example, the coordinate of the focal point fp (corresponding to the depth relative to the skin surface) with the Z coordinate of the skin surface as the origin may be displayed. The depth of the focal spot fp with respect 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 spot 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 embodiment can be realized as follows. A computer including a CPU, a hard disk, and a medium (such as a USB memory or a CD-ROM) reading device is read out and installed on the hard disk, together with a medium in which programs for realizing the above-described respective 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 display pattern moving unit 24 are recorded. In such a method, the above-described functions can also be realized.

Claims

1. A photoacoustic wave measuring apparatus, 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 the measurement object by the pulsed light and converts the photoacoustic wave into an electrical signal;

a measuring unit for measuring the electric signal;

a waveform display unit that displays a waveform of a measurement result of the measurement unit; and

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

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

the photoacoustic wave measurement device includes:

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

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

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

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

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

in the above-described waveform, the focal position display unit displays the focal position by adding coordinates obtained by adding a distance between the output end and the focal to coordinates corresponding to the output end of the pulse light output unit as the focal position.

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

the waveform display unit displays the waveform within a predetermined distance from an initial position of an output end of the pulse light output unit.

6. The photoacoustic wave measurement apparatus according to claim 1, wherein,

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

7. The photoacoustic wave measurement apparatus according to any one of claims 1 to 6, wherein,

the lens is a piezoelectric element.

8. The photoacoustic wave measurement apparatus according to any one of claims 1 to 6, wherein,

the lens has a concave surface facing the object to be measured.

9. The photoacoustic wave measurement apparatus according to any one of claims 1 to 6, wherein,

the lens outputs ultrasonic waves, receives reflected ultrasonic waves of the ultrasonic waves reflected by the object to be measured, converts the reflected ultrasonic waves into reflected electric signals,

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