JP2013248239A - Subject information acquisition device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a subject information acquisition device for detecting an acoustic wave, which suppresses a decrease in the signal intensity of the acoustic wave by increasing an area of contact between a holding plate and a subject.SOLUTION: A subject information acquisition device for use, which acquires subject information on the basis of an acoustic wave propagated from a subject, includes: a first holding member; a plurality of second holding members which hold the subject between itself and the first holding member; a probe which receives the acoustic wave from the subject via the first holding member; and a movement mechanism which makes the plurality of second holding members each move in an independently translational manner and abut on the subject.

Description

  The present invention relates to a subject information acquisition apparatus.

  Research on a photoacoustic imaging apparatus that irradiates light to a living body from a light source such as a laser and images in vivo information obtained based on incident light has been actively promoted in the medical field. As one of the photoacoustic techniques, photoacoustic tomography (PAT: photoacoustic tomography) has been proposed. Photoacoustic tomography irradiates a living body with pulsed light generated from a light source, and detects acoustic waves (typically ultrasonic waves) generated from living tissue that absorbs the energy of pulsed light that has propagated and diffused in the living body. The biological information is imaged based on the detection signal.

  Non-Patent Document 1 discloses a photoacoustic image apparatus developed for breast cancer testing. FIG. 11 shows an outline of Non-Patent Document 1. This apparatus presses a subject (breast) with a glass plate and an acoustic wave probe, and irradiates the breast with illumination light using an Nd: YAG laser as a light source through the glass plate. Then, an acoustic wave generated in the subject is detected as a signal by the acoustic probe, and the detection signal is processed to obtain image data of angiogenesis in the tissue inside the subject, particularly in breast cancer.

Srirang Manohar, et al., "The Twente photoacoustic mammoscope: system overview and performance", Physics in Medicine and Biology 50 (2005) 2543-2557.

  However, in the apparatus of Non-Patent Document 1, a region that cannot be brought into contact with the acoustic wave probe is generated in a part of the subject (indicated by symbol A in FIG. 11). This non-contactable area becomes a gap in which air is interposed, so that the acoustic impedance is significantly different from that of the subject. As a result, most of the acoustic waves generated in the subject are reflected at the interface between the subject and the gap. Therefore, the intensity of the signal detected by the acoustic wave probe is reduced in the region. As a result, an area in which image data cannot be acquired by signal processing is generated.

  This problem can occur with any apparatus that compresses a subject with parallel plates and acquires image data inside the subject. For example, this problem may occur not only in an apparatus using photoacoustic tomography but also in an apparatus that transmits ultrasonic waves and images biological information from the reflected waves.

  The cause of this problem is due to the fact that the pressing mechanism is a form in which the subject is sandwiched between two parallel flat plates, and the target to be pressed is rounded. In addition, since there are individual differences in the shape of the subject, the shapes of the gaps through which air intervenes are diverse, complicating the problem.

  The present invention has been made in view of the above problems, and an object of the present invention is to increase the contact area between the holding plate and the subject in the subject information acquisition device for detecting acoustic waves, thereby increasing the signal intensity of the acoustic waves. It is in suppressing the decrease.

  The present invention employs the following configuration. That is, a subject information acquisition device that acquires information in the subject based on an acoustic wave propagating from the subject, the subject being between the first holding member and the first holding member A plurality of second holding members for holding the probe, a probe for receiving an acoustic wave from the subject via the first holding member, and the plurality of second holding members are independently translated. And a moving mechanism that makes the moving object come into contact with the object.

  According to the present invention, in the subject information acquiring apparatus that detects acoustic waves, it is possible to increase the contact area between the holding plate and the subject and suppress a decrease in the signal strength of the acoustic waves.

The schematic diagram which shows the structure of embodiment of this invention. It is the figure which showed the mode of the holding | maintenance in the conventional compression system. The figure which showed the mode of the holding | maintenance in the compression system of this invention. The figure which showed the mode of the holding | maintenance in the compression system of this invention. The figure which showed the mode of the holding | maintenance in the compression system of this invention. The figure which showed the arrangement pattern of the holding member of this invention. The figure which showed the example which subdivided and arrange | positioned the holding member of this invention. BRIEF DESCRIPTION OF THE DRAWINGS The structure schematic of Example 1 of this invention. The structure schematic of Example 2 of this invention. The structure schematic of Example 3 of this invention. The structure schematic of Example 4 of this invention. The structure schematic of Example 5 of this invention. FIG. 2 is a schematic configuration diagram of Non-Patent Document 1.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. However, the dimensions, materials, shapes, and relative arrangements of the components described below should be changed as appropriate according to the configuration of the apparatus to which the invention is applied and various conditions. It is not intended to limit the following description.

  The subject information acquisition apparatus of the present invention transmits ultrasonic waves to a subject, receives reflected waves (echo waves) reflected inside the subject, and acquires subject information as image data. Includes devices that use. Further, the apparatus includes a device using a photoacoustic effect that receives acoustic waves generated in the subject by irradiating the subject with light (electromagnetic waves) and acquires subject information as image data.

  In the case of the former apparatus using the ultrasonic echo technique, the acquired object information is information reflecting the difference in acoustic impedance of the tissue inside the object. In the case of an apparatus using the latter photoacoustic effect, the acquired object information is derived from the source distribution of acoustic waves generated by light irradiation, the initial sound pressure distribution in the object, or the initial sound pressure distribution. Light energy absorption density distribution, absorption coefficient distribution, and concentration distribution of substances constituting the tissue are shown. The concentration distribution of the substance is, for example, an oxygen saturation distribution or an oxidized / reduced hemoglobin concentration distribution.

  The acoustic wave referred to in the present invention is typically an ultrasonic wave, and includes an elastic wave called a sound wave, an ultrasonic wave, or an acoustic wave. For example, an acoustic wave generated inside the subject when the subject is irradiated with light such as near infrared rays can be mentioned. An acoustic wave generated by the photoacoustic effect is called a photoacoustic wave or an optical ultrasonic wave. An acoustic detector (for example, a probe) receives an acoustic wave generated or reflected in a subject.

  First, with reference to FIGS. 1A and 1B, a system using a photoacoustic image apparatus will be described as an example of the subject information acquisition apparatus of the present invention.

(Device configuration)
Reference numeral 1 denotes a probe-side holding plate (corresponding to a first holding member), and reference numeral 2 (2a, 2b, 2c) denotes a non-probe-side holding member (corresponding to a plurality of second holding members). is there. Reference numeral 3 (3 a, 3 b, 3 c) is a moving mechanism that can independently translate and move the plurality of holding members 2 on the non-probe side to the holding plate 1 side. Each holding member 2 can be moved to a position where each of the holding members 2 comes into contact with the subject 8, and the contact state with the holding plate 1 can be enhanced by pressing the subject 8.

  Reference numeral 9 denotes a light source for irradiating the subject with light. Reference numeral 4 denotes a probe that detects acoustic waves from within the subject. Reference numeral 10 denotes a piezoelectric element included in the probe 4, which converts an acoustic wave and an analog signal. In addition, if it can convert an acoustic wave into a signal, it will not be restricted to a piezoelectric element. Reference numeral 5 denotes a signal processing unit that processes detected analog signals and reconstructs image data. Reference numeral 6 denotes an image display unit that displays image data processed by the signal processing unit 5.

(Configuration and operation of image creation unit)
An image creation unit that images acoustic waves from the subject 8 will be described. The image creation unit includes a light source 9, a probe 4, a signal processing unit 5, and an image display unit 6.

  First, pulse light is irradiated from the light source 9 to the subject 8. A laser is preferable as the light source, but a light emitting diode or the like can be used instead of the laser. Examples of the laser include a solid laser, a gas laser, a dye laser, and a semiconductor laser, and can be used as appropriate. The light from the light source is preferably near-infrared, and the wavelength of about 650 nm to 1100 nm can be used.

  The light emitted from the light source propagates through the subject 8 and is absorbed. For example, when the subject 8 is a living body and is irradiated with the above-described near infrared rays, it is specifically absorbed by blood and blood vessels in the living body, and an acoustic wave is generated due to thermal expansion. When cancer is present in a living body, light is specifically absorbed in a new blood vessel of the cancer like other blood vessels, and an acoustic wave is generated.

  The generated acoustic wave reaches the piezoelectric element 10 constituting the probe 4 and is converted into an analog signal. The analog signal from each piezoelectric element 10 is converted into a digital signal by the signal processing unit 5, and then image data is reconstructed. By performing this series of steps while scanning the probe 4, image data of the entire area of the subject 8 can be acquired.

  The image display unit 6 displays the image data reconstructed by the signal processing unit 5. As the image display unit 6, a liquid crystal display, a plasma display, an organic EL display, an FED, or the like can be used.

(Configuration of holding mechanism)
Next, a holding mechanism for the subject 8 will be described.
As the material of the holding plate 1, since it is necessary to pass the acoustic wave generated in the subject 8, a material that suppresses reflection of the acoustic wave at the interface between the subject 8 and the holding plate 1 is preferable. Specifically, a material having a small difference in acoustic impedance with the subject 8 is preferable. For example, resin materials such as polymethylpentene can be used.

The thickness of the holding plate 1 is preferably thinner because the attenuation increases as the thickness increases when the acoustic wave passes through the holding plate 1. On the other hand, the thickness is required to be strong enough to suppress deformation of the plate due to holding. Typically, about 5 mm to 10 mm is preferably used. The size may be any size as long as the subject 8 can be held, but is preferably the same size as the subject.

  The material of the plurality of holding members 2 needs to be rigid enough to withstand the subject 8. For example, glass, polymethylpentene, polycarbonate, acrylic and the like can be mentioned. Since the Young's modulus is 1 to 100 kPa when the subject 8 is a breast, a material having a Young's modulus higher than this is suitable.

  Further, as shown in FIG. 1B, when the holding member 2 exists between the subject 8 and the light source 9, a material with high transparency is suitable for the holding member 2. As a guide, a transmittance of 60% or more per 10 mm thickness in the target wavelength region is suitable. Here, the target wavelength region means a wavelength region corresponding to the spectral half-value width of light irradiated on the subject.

  The thickness of the holding member 2 may be any thickness as long as it can maintain the strength with which deformation of the plate due to holding can be suppressed, but typically 10 mm or more is preferably used. There is no problem with the size as long as the subject 8 can be held by the entire holding member 2. Although the size per one depends on the form of the moving mechanism 3, the width is preferably about 20 mm to 100 mm.

  The moving mechanism 3 is a mechanism that can translate and move each holding member 2 in the direction of the probe 4. First, as a means for defining the movable direction of the holding member 2, it is desirable that a mechanism for defining the linearly moving direction such as a linear guide is disposed on the side surface of each holding member 2. Further, if a straight traveling direction can be defined, an extrusion mechanism such as a piston can be disposed on the back surface of the holding member 2. Regarding the distance to be moved, it is assumed that at least the holding member 2 can reach a position where it contacts the subject 8.

  The direction (angle) of movement is preferably a direction perpendicular to the surface of the holding plate 1. However, as long as each holding member 2 translates and comes into contact with the subject 8 and presses each subject 8 toward the holding plate 1, it does not have to be completely vertical.

  As power for moving the holding member 2, it is desirable to use a linear motor added to the linear guide. Besides a linear motor, an air cylinder, a hydraulic cylinder, an extrusion mechanism using an air bag or a water back, an extrusion mechanism combining a ball screw and a pulse motor, and the like can be used. Further, a mechanism in which an operator manually pushes out without using power may be used.

  As a mechanism for holding the subject 8, it is possible to use a holding force of a motor, adjustment of air pressure / water pressure, or a physical fixing mechanism using screws or stoppers.

(Effects of holding mechanism)
2A and 2B, FIGS. 3A to 3C, and FIGS. 4A to 4C, the holding plate 1 and the subject according to the present invention are used. The effect of increasing the contact area of 8 will be described.

  FIG. 2 shows a conventional state, and FIGS. 3A to 3C are views showing a state of compression / holding of a subject 8 in the present invention. 4 shows a state in which the plurality of holding members 2 are seen through the subject 8 from the Z direction in FIG. 3, and FIG. 4 (A) shows FIG. 3A and FIG. FIG. 3B corresponds to FIG. 3C and FIG. 4C corresponds to FIG. 3C, respectively. In each figure, the surface of the holding plate 1 is the XY plane, and the direction from the holding plate 1 toward the plurality of holding members 2 is the Z direction.

Conventionally, since the second holding plate 11 uniformly presses the subject 8, a gap (shaded area in FIG. 2) is generated between the holding plate 1 and the tip of the subject 8 and both sides.
On the other hand, in the present invention, the gap can be eliminated by further moving only the holding member 2 located in the gap portion. This state is shown in the hatched area in FIGS. 3A to 3C.

  For example, consider an arrangement pattern in which the subject 8 is a breast and the holding member 2 is divided into three parts in the Y direction as shown in FIGS. 3A and 4A. At this time, as shown in FIG. 3A (X) and FIG. 3A (Y), the plurality of holding members 2 are moved so that the ratio of the movement amount is 2a ≧ 2b ≧ 2c. Can be reduced.

Further, an arrangement pattern in which the holding member 2 is divided into three in the X direction as shown in FIG. 3B and FIG. 4B will be considered. At this time, as shown in FIG. 3B (X) and FIG. 3B (Y), the plurality of holding members 2 are moved so that the ratio of the moving amounts is 2b≈2c ≧ a. Can be reduced.

  Although the basic configuration has been described using the two patterns, as shown in FIG. 4C, each holding member 2 is placed at the center (2c), the tip (2a), and both side surfaces (2b) of the subject 8. 2d) is more preferred. In this pattern, as shown in FIG. 3C (X) and FIG. 3C (Y), the holding members 2 (a, b, d) arranged at the tip and both side surfaces with respect to the holding member 2c at the center of the subject 8 are used. ) With a larger amount of movement. Thereby, the gap | interval of a breast front-end | tip part and both sides can be reduced simultaneously, without applying an excessive burden to the center part of the subject 8. FIG.

  Moreover, as shown in FIG. 5, the location controllability of the compression can be improved by further subdividing the holding member 2. This control will be described later.

  The holding member 2 preferably processes the contact surface on the side in contact with the subject 8. When the holding member 2 is highly rigid with respect to the subject 8, it is effective to chamfer or round the surface. In order to reduce the burden on the subject 8, it is also effective to attach a cushion material to the tip of the holding member 2 (the portion in contact with the subject). As a material for the cushion material, materials such as rubber, gel, and silicon, and members such as small air bags and water bags can be used.

(Operation of holding mechanism)
A method for controlling the plurality of holding members 2 will be described.
The actual subject 8 has individual differences. Therefore, a change occurs in the position of the gap and its thickness. In the present invention, since the plurality of holding members 2 can be moved independently, it is possible to cope with gaps having individual differences.

  This will be described with reference to FIG. FIG. 5 shows the holding member 2 subdivided from 2a to 2g. FIG. 5A shows a case where the subject 8 is large, and FIG. 5B shows a case where the subject 8 is small. In the case of FIG. 5A, the position where the gap is generated is the position of the holding members 2a, 2c, and 2g. Therefore, the amount of movement of these holding members may be made larger than the others. On the other hand, in the case of FIG. 5B, the position where the gap is generated is the position of the holding members 2b, 2d, and 2f. Therefore, the amount of movement of these holding members should be larger than that of the central portion 2e of the subject 8. . At that time, the holding members 2a, 2c, and 2g do not need to be moved. By performing control according to the size of the subject 8 in this way, the tip and both sides are brought into close contact with the holding plate 1.

Differences in the size of the gap caused by differences in the thickness of the subject can be dealt with by setting the movement amount of each holding member 2 to a value corresponding to the gap.
Thus, since each holding member 2 can be controlled independently, the movement amount can be changed according to the individual difference of the subject 8, and the gap between the holding plate and the subject can be reduced.

  In addition, the elastic modulus of the subject 8 varies depending on individual differences. When the subject 8 is a breast, the elastic modulus is generally high in young women. In order to reliably press the subject 8 having a high elastic modulus against the holding member 1, it is preferable to press the subject 8 against the holding plate 1 in the vertical direction. Further, by translating each holding member 2, it is possible to press the entire subject 8 against the holding plate 1 without escaping.

  It is also effective to control the order of compression on the shape of the subject 8. A case where the subject 8 is a breast will be described with reference to FIG. As an order of compression for reducing the gap as much as possible, first, compression is started from the holding member 2e at the center of the subject 8, and then the holding members 2b, 2d, and 2f are moved, and finally the outer holding is performed. It is preferable to move the members 2a, 2c and 2g. If the rounded subject 8 is compressed from the outside, the subject 8 may escape on the holding plate 1 and may not be held. The subject 8 can be fixed by pressing from a central portion that is almost parallel to the pressing surface. After that, the air layer as a gap can be driven out to the outside by sequentially pressing the outside.

  As described above, in the present invention, by having a mechanism that independently translates the plurality of holding members 2 in the direction of the holding plate 1, the gap between the subject 8 and the holding plate 1 having individual differences is reduced, and the image data acquisition area is expanded. it can.

<Example 1>
Hereinafter, the present invention will be described in detail with specific examples.
In this example, a photoacoustic image device was created as the subject information acquisition device, and the subject was measured. FIG. 6A shows a system schematic diagram of the subject information acquisition apparatus of the present embodiment.

(Device configuration)
The subject information acquisition apparatus includes an image creation unit and a subject holding unit. The image creation unit includes a light source 9, a probe 4, a signal processing unit 5, and an image display unit 6. The subject holding unit includes a holding plate 1, a plurality of holding members 2, a plurality of moving mechanisms 3, and a motor control unit 12.

(Device operation)
As the light source 9, a titanium sapphire laser, which is a kind of solid-state laser, was installed in an area where the subject 8 can be irradiated with light. The wavelength of the titanium sapphire laser is set to 750 nm. In the measurement, pulse light is emitted from the light source 9 and the acoustic wave generated in the subject 8 is detected by the probe 4. The acoustic wave is converted into an analog signal by each piezoelectric element 10 constituting the probe 4. The analog signal is reconstructed into image data in the signal processing unit 5. By moving the probe 4 onto the holding plate 1, the image data of the entire area of the subject 8 can be reconstructed. The reconstructed image data is confirmed on a liquid crystal display which is the image display unit 6.

Next, the subject holding unit will be described.
A resin plate made of polymethylpentene having a width of 250 mm, a length of 150 mm, and a thickness of 10 mm was prepared as the holding plate 1. In the holding plate 1 and the holding member 2, the thickness is a direction in which stress acts when the subject is pressed, and for example, in FIG. 6A, indicates a distance in the Z direction.

An acrylic member having a thickness of 20 mm was prepared as the holding member 2. The shape and arrangement of each holding member 2 are shown in FIG. The holding member 2a located at the distal end of the subject 8 is one, and the size is 250 mm wide and 50 mm long. There are two holding members 2b and 2d located on both side surfaces, and the size is 90 mm in width and 50 mm in length. There is one holding member located at the center of the subject and the like, which is a T-shaped 2c. When the four holding members are combined, the width is 250 mm and the length is 150 mm. These four holding members were arranged so as to face the first holding plate 1 along the XY plane shown in FIG.

  A linear motor was attached as a moving mechanism 3 to the side surface of each holding member 2. By this linear motor, the holding member 2 moves to the holding plate 1 side. Each holding member 2 can be freely moved and stopped by wiring the motor control unit 12 and the linear motor.

  The above system was actually used. The breast was placed between the holding plate 1 and the holding member 2 as the subject 8 and pressed and held. The operation of the motor control unit 12 was performed in a range in which the state of the gap between the holding plate 1 and the subject 8 and the state of the subject were visually confirmed and the subject did not suffer. As a result of comparison with the conventional method, it was confirmed that the gap was reduced and the image data acquisition area was expanded by about 20%.

<Example 2>
Example 2 of the subject information acquisition apparatus will be described with reference to FIG.

(Device configuration)
The subject information acquisition apparatus according to the present embodiment is obtained by adding a pressure sensor 13 and a pressure measurement unit 14 to the subject holding unit according to the first embodiment. The other components are denoted by the same reference numerals, and the description is simplified.

(Device operation)
The second embodiment differs from the first embodiment in that the pressure applied to the holding member 2 is measured and the movement amount of the holding member 2 is adjusted based on the information.

  The pressure sensor 13 is a cylinder type pressure sensor attached to each holding member 2. Each pressure sensor 13 is connected to the pressure measuring unit 14 and acquires a pressure value applied to each holding member 2. The motor control unit 12 reads this pressure value and controls the linear motor of each moving mechanism 3 based on the value. That is, the motor is moved until each pressure value reaches a specified value. The specified value can be set, for example, at the time of product shipment, or the user may set a value depending on the state of the subject 8.

As the pressure sensor 13, a pressure sensor may be installed on the contact surface with the subject 8. In addition, when an extruding mechanism such as an air cylinder or a water back is used to drive the moving mechanism 3, a dedicated air pressure gauge or water pressure gauge can be used.
The moving amount of the holding member 2 is preferably set to about 1 mm / s by the motor control unit 12, and it is preferable to add a function capable of emergency stop when the subject complains of pain.

  There are two advantages to measuring the pressure value in this way. First, the subject 8 can be compressed within a safe pressurizing range. When the subject 8 is a living body, generally, a safety reference value for the compression force is set, and compression is performed within a range not exceeding this value. Regardless of the movement method of the holding member 2, it is possible to confirm whether or not the compression action is safe by grasping the pressure applied to the subject 8. In particular, in the case of a system that automatically compresses to a set specified value, the subject 8 can be compressed to the maximum extent within a safe range for the subject.

Another advantage is that compression can be performed with pressure values having a distribution that is nearly uniform over the entire subject 8. In the conventional second holding plate as shown in FIG. 2, pressure is applied only to the central portion of the subject 8, and no pressure is applied to the peripheral portion. For this reason, an excessive burden is often applied to the central portion to reduce the gap. In this embodiment, since the pressure applied to the central portion and the peripheral portion of the subject 8 can be individually adjusted, an excessive pressure is not applied to only a part of the subject 8, and the burden on the subject is reduced.

  As a result of actually using the above system, it was confirmed that the image data acquisition area was expanded by about 20% as in the first embodiment. Moreover, it was confirmed that a series of steps could be automatically performed.

<Example 3>
A third embodiment of the subject information acquiring apparatus will be described with reference to FIG.

(Device configuration)
The subject information acquiring apparatus according to the present embodiment is obtained by adding a displacement meter 15 and a displacement measuring unit 16 to the subject holding unit according to the first embodiment. The other components are denoted by the same reference numerals, and the description is simplified.

(Device operation)
The third embodiment is different from the first embodiment in that the movement amount of the holding member 2 is measured and the scanning area of the probe 4 and the depth of the image data are determined based on the information.

  The displacement meter 15 is a laser displacement meter attached to each holding member 2. Each displacement meter 15 is connected to the displacement measurement unit 16 and acquires the amount of movement of each holding member 2. Then, the thickness of the subject 8 in contact with each holding member 2 is calculated. When the holding member 2 is in contact with the subject 8, the thickness corresponds to the distance between the holding plate 1 and the holding member 2. The signal processing unit 5 receives the thickness data, and determines the depth of the image data to be reconstructed and the scanning area of the probe 4.

  As for the displacement meter 15, a contact-type displacement meter can also be used. When the drive mechanism of the moving mechanism 3 uses an extrusion mechanism such as an air cylinder or a water back, it is possible to estimate the amount of displacement using a flow meter of air or water. Further, it is possible to estimate the amount of displacement by transmitting the number of steps of the motor and the like to the displacement measuring unit 16 without using the displacement meter 15.

  The above system was actually used. As a result, as in the case of Example 1, it was confirmed that the image data acquisition area was expanded by about 20%. It was also confirmed that the amount of calculation for reconstructing image data can be suppressed more than before.

<Example 4>
Embodiment 4 of the subject information acquisition apparatus will be described with reference to FIG.

(Device configuration)
The subject information acquisition apparatus of this embodiment is obtained by adding a camera 17, an image monitor 18, and an image processing unit 19 to the apparatus of the first embodiment. The other components are denoted by the same reference numerals, and the description is simplified.

(Device operation)
The fourth embodiment is different from the first embodiment in that the contact surface between the holding plate 1 and the subject 8 is photographed by the camera 17 and displayed on the image monitor 18, and the contact area is calculated by the image processing unit 19. This is a point for determining the scanning area of the probe 4.

A camera 17 capable of photographing the entire region of the holding plate 1 is installed on the probe 4 side of the holding plate 1. A CCD camera can be used as the camera 17. A liquid crystal display is used for the image monitor 18 on which the photographed image from the camera 17 is displayed, and the contact area between the holding plate 1 and the subject 8 can be confirmed in real time.

  As for the camera 17, a CMOS camera or the like can be used in addition to the CCD camera. As the image monitor 18, a plasma display, an organic EL display, an FED, or the like can be used. The operator performs the compression work while checking the image monitor 18.

  Next, the acquired image data is transmitted to the image processing unit 19, and binarization processing is performed. Thereby, the contact area between the holding plate 1 and the subject 8 can be calculated. By determining the scanning area of the probe 4 based on the contact area, the time required for scanning is limited, and the measurement time can be shortened.

  The above system was actually used. As a result, as in the case of Example 1, it was confirmed that the image data acquisition area was expanded by about 20%. It was also confirmed that the measurement time was reduced by about 30% compared to the conventional method.

<Example 5>
In this example, an ultrasonic imaging apparatus was created and the subject was measured. FIG. 10 shows a system schematic diagram of the subject information acquisition apparatus of the present embodiment.

(Device configuration)
The subject information acquisition apparatus according to the present embodiment is obtained by eliminating the light source 9 from the apparatus according to the first embodiment and adding a transmission signal processing unit 7. The other components are denoted by the same reference numerals, and the description is simplified.

(Device operation)
The fifth embodiment is different from the first embodiment in that an ultrasonic wave is irradiated from the probe 4 to the subject 8 instead of irradiating the pulsed light.

  The probe 4 is a linear probe having a center frequency of 7 MHz and the piezoelectric element 10 made of PZT. First, the transmission signal control unit 7 calculates a delay timing for adjusting the ultrasonic transmission focus to an arbitrary place in the subject. This delay timing was calculated from the sound velocity in the holding plate 1 and the subject 8, the focus position, the piezoelectric element 10 pitch of the probe 4, and the like. An analog signal is transmitted from the transmission signal control unit 7 to the 64 piezoelectric elements 10 at the calculated timing, and an ultrasonic wave is irradiated toward the inside of the subject 8. The irradiated ultrasonic waves are reflected in the subject 8, reach the piezoelectric elements 10 again as acoustic signals, and are converted into analog signals.

  The converted analog signal is reconstructed into image data in the signal processing unit 5. The processing contents in the signal processing unit 5 were performed in the order of filter processing, phasing delay processing, Hilbert transform, and LOG compression.

  The above system was actually used. As a result, as in the case of Example 1, it was confirmed that the image data acquisition area was expanded by about 20%.

  1: holding plate (first holding member), 2: holding member (a plurality of second holding members), 3: moving mechanism, 4: probe, 5: signal processing unit, 10: piezoelectric element

Claims (14)

A subject information acquisition apparatus for acquiring information in the subject based on an acoustic wave propagating from the subject,
A first holding member;
A plurality of second holding members for holding the subject with the first holding member;
A probe for receiving an acoustic wave from the subject via the first holding member;
A plurality of second holding members that are each independently translated and moved to contact the subject; and
A subject information acquisition apparatus characterized by comprising: 2. The subject according to claim 1, wherein the plurality of second holding members include a member that abuts on a central portion of the subject and a member that abuts on a peripheral portion of the subject. Information acquisition device. The movement mechanism controls the movement so that a movement amount of a member contacting the central part of the subject is smaller than a movement amount of a member contacting the peripheral part of the subject. 2. The subject information acquisition apparatus according to 2. In the moving mechanism, a distance between the first holding member and a member that contacts the central portion of the subject is larger than a distance between the first holding member and a member that contacts the peripheral portion of the subject. The subject information acquiring apparatus according to claim 2, wherein the movement is controlled to be The moving mechanism performs control so as to move the member that contacts the peripheral part of the subject after moving the member that contacts the central part of the subject when holding the subject. 3. The subject information acquisition apparatus according to claim 2, wherein The subject information according to any one of claims 2 to 5, wherein the subject is a breast of the subject, and peripheral portions of the subject are a front end portion and both side portions of the breast. Acquisition device. The subject information acquisition according to claim 1, wherein the moving mechanism moves the plurality of second holding members in a direction perpendicular to the first holding member. apparatus. The object information acquiring apparatus according to claim 1, wherein the plurality of second holding members are made of a material having higher rigidity than the object. A pressure sensor for measuring pressure applied to the plurality of second holding members;
The object information acquiring apparatus according to claim 1, wherein the moving mechanism controls movement of the second holding member according to the pressure. A displacement meter for measuring the thickness of the subject at a portion where each of the plurality of second holding members abuts;
9. The object information acquiring apparatus according to claim 1, wherein a depth at which the information in the object is acquired is determined based on the thickness. 10. A camera that captures a contact state between the subject and the first holding member;
The object information acquiring apparatus according to claim 1, wherein a scanning region of the probe is determined based on the contact state.   The object information acquiring apparatus according to claim 1, wherein the acoustic wave propagating from the subject is a reflection of an acoustic wave transmitted to the subject. The object information acquiring apparatus according to claim 1, wherein the acoustic wave propagating from the subject is a photoacoustic wave generated from the subject irradiated with light. The plurality of second holding members are made of a material having a transmittance of 60% or more per 10 mm thickness in a wavelength region corresponding to a spectral half-value width of light irradiated to a subject. The subject information acquisition apparatus described.

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