JP2016002373A - Object information acquisition apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an object support apparatus capable of reducing light leakage from between an opening of a support member into which an object is inserted and the object.SOLUTION: The object information acquisition apparatus comprises: a light source 210; a support member 110 for supporting a subject, an opening being formed in the support member, into which an object, a part of the subject, is inserted; a detection part 220 for detecting acoustic waves generated from the object onto which light from the light source 210 is projected and converting the detected acoustic waves into electric signals; and a processing part for acquiring characteristic information of the inside of the object on the basis of the electrical signals. The support member comprises an opening shape definition part 600 for defining the shape of the opening in the circumference of the opening.

Description

  The present invention relates to a subject information acquisition apparatus.

  Research on an optical imaging apparatus that irradiates a subject such as a living body with light from a light source such as a laser and images information in the subject obtained based on incident light has been actively promoted in the medical field. As one of the optical imaging techniques, there is Photoacoustic Imaging (PAI: photoacoustic imaging). In photoacoustic imaging, a subject is irradiated with pulsed light generated from a light source, and acoustic waves generated from the subject tissue that absorbs the energy of pulsed light that has propagated and diffused within the subject are received. The subject information is imaged.

  In photoacoustic imaging, the difference occurs in the absorption rate of light energy between a target site such as a tumor and other tissues, and this occurs when the test site absorbs irradiated light energy and expands instantaneously. Elastic waves (photoacoustic waves) are received by the probe. By mathematically analyzing the received signal, information in the subject, in particular, an initial sound pressure distribution, a light energy absorption density distribution, an absorption coefficient distribution, or the like can be acquired. Such information can also be used for quantitative measurement of a specific substance in the subject, for example, oxygen saturation in blood. In recent years, preclinical research for imaging a blood vessel image of a small animal using this photoacoustic imaging and clinical research for applying this principle to diagnosis of breast cancer or the like have been actively promoted (Non-patent Document 1).

  Similar to PAI, DOT (Diffused Optical Tomography) is an optical imaging technique for illuminating a subject such as a living body and imaging information in the subject. DOT images subject information by measuring an optical signal scattered inside a living body.

  Non-Patent Document 1 describes a photoacoustic apparatus in which an opening is provided in a support member that supports a part of a subject, and a breast is inserted into the opening to perform photoacoustic imaging of the breast. This device is provided with a cup for holding a breast inserted from the opening, and a probe located under the cup and having a transducer disposed on the hemisphere. The lower part of the hemispherical probe is provided with an irradiating unit for irradiating light from the light source, and the breast is irradiated with light through the cup.

“Photoacoustic angiography of the breast”, Medical Physics, Vol. 37, No. 11, November 2010

  However, in an apparatus for acquiring subject information by irradiating light to a subject inserted into an opening, a gap is formed between the subject and the opening, and light irradiated to the subject from this gap is emitted. There was a possibility of leakage to the subject.

  The present invention has been made in view of such problem recognition, and an object thereof is to reduce light leakage from between the opening of a support member for inserting a subject and the subject.

The present invention employs the following configuration. That is,
A light source;
A support member for supporting the subject, and a support member having an opening for inserting a subject that is a part of the subject; and
A detection unit that detects an acoustic wave generated from the subject irradiated with light from the light source and outputs an electrical signal;
A processing unit that acquires characteristic information in the subject based on the electrical signal;
Have
The support member is an object information acquiring apparatus including an opening shape defining portion that defines the shape of the opening around the opening.

  According to the present invention, light leakage from between the opening of the support member for inserting the subject and the subject can be reduced.

Perspective view of subject information acquisition apparatus Internal configuration diagram of subject information acquisition apparatus Schematic of detector Schematic diagram of light-shielding member that deforms opening by elastic member The figure which showed the state by which the detector was scanned to the Y direction Schematic diagram of a light-shielding member that deforms an opening by driving a blade Schematic diagram of a light shielding member that deforms the shape of the opening by linearly moving the light shielding plate Schematic of light shielding member provided with a wire for controlling the shape of the opening Monitor display screen Schematic of light shielding member 600 provided with a gear Schematic diagram of light shielding member with linear members arranged Schematic diagram of light shielding member with distance sensor Schematic diagram of light shielding member with strain gauge Internal configuration diagram of diffuse optical tomography device

  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 present invention relates to a technique for detecting acoustic waves propagating from a subject, generating characteristic information inside the subject, and acquiring the characteristic information. Therefore, the present invention can be understood as a subject information acquisition apparatus or a control method thereof, a subject information acquisition method, or a signal processing method. The present invention can also be understood as a program that causes an information processing apparatus including hardware resources such as a CPU to execute these methods, and a storage medium that stores the program.

  The subject information acquisition apparatus of the present invention irradiates a subject with light (electromagnetic waves) and receives (detects) an acoustic wave generated and propagated at a specific position in the subject or on the subject surface according to the photoacoustic effect. Includes equipment using photoacoustic tomography technology. Such an object information acquiring apparatus can also be called a photoacoustic imaging apparatus because it obtains characteristic information inside the object in the form of image data or the like based on photoacoustic measurement.

The characteristic information in the photoacoustic device is the distribution of the source of acoustic waves generated by light irradiation, the initial sound pressure distribution in the subject, or the optical energy absorption density distribution, absorption coefficient distribution, and tissue derived from the initial sound pressure distribution. The concentration distribution of the constituent substances is shown. Specifically, it is a blood component distribution such as an oxygenated / reduced hemoglobin concentration distribution, an oxygen saturation distribution obtained therefrom, or a distribution of fat, collagen, and water.
Further, the characteristic information may be obtained as distribution information of each position in the subject, not as numerical data. That is, distribution information such as an absorption coefficient distribution and an oxygen saturation distribution may be used as the subject information.

  The acoustic wave referred to in the present invention is typically an ultrasonic wave and includes an elastic wave called a sound wave or an acoustic wave. An acoustic wave generated by the photoacoustic effect is called a photoacoustic wave or an optical ultrasonic wave. An electric signal converted from an acoustic wave by the probe is also called an acoustic signal.

The present invention can be applied to an apparatus that acquires subject information by irradiating light to a subject inserted into an opening. Therefore, the present invention can be applied to DOT technology in addition to PAI technology.
In an apparatus for acquiring subject information by irradiating light to a subject inserted into an opening, a gap is formed between the subject and the opening, and light irradiated on the subject from the gap is examined. There was a possibility of leaking to the person side.

  In order to reduce light leakage, a method of closing the gap between the subject and the opening with a light shielding member is conceivable. In order to close the gap, a light shielding member must be provided in accordance with the shape and size of the subject (hereinafter referred to as the shape including the size), but the shape of the subject is not uniform. Therefore, in the case of a light shielding member having a fixed shape, the light shielding member must be changed according to the shape of the subject. Furthermore, various shapes of light shielding members are required.

  Therefore, in the present invention, the shape of the opening into which the subject is inserted is variable. As a result, the opening shape is deformed in accordance with the shape of the subject, and the gap between the subject and the opening can be narrowed, so that the amount of leaked light from the gap to the subject can be reduced. The opening shape does not necessarily have to be deformed so as to match the shape of the subject. If the members around the opening can move so as to block at least a part of the gap between the subject and the opening, an effect of reducing light leakage can be obtained. More specifically, an opening shape base portion having a variable shape may be provided in a portion around the opening of the support member.

<Embodiment 1>
In the present embodiment, an example of an apparatus that irradiates a subject that is a part of a subject and receives acoustic waves generated from the subject by a detector to acquire subject information (PAI device) will be described. ).

  First, the units constituting this embodiment will be described. FIG. 1 is a perspective view of a subject information acquisition apparatus. FIG. 2A is a side view showing the internal configuration of the subject information acquisition apparatus, and FIG. 2B is an enlarged view of the vicinity of a light shielding member 600 described later.

(Bed unit 100)
The bed unit 100 is a unit for placing the subject in a prone position (prone position). The bed unit 100 includes a bed 110 that is a support member that maintains the posture of the subject, a bed column 120 that supports the bed, and a base 130. The couch 110 is provided with a light shielding member 600 provided with an opening S for inserting a breast 1 as a subject. The light shielding member 600 can change the shape of the opening S and is configured to close the gap A formed between the breast 1 and the bed 110.

The bed unit 100 or the bed 110 corresponds to a support member that supports the subject. The opening S is a hole that is vacant for inserting a subject that is a part of the subject, and the shape of the periphery (edge) of the opening S is defined by various types of light shielding members to be described later. Accordingly, the portion of the support member that defines the shape of the opening can be called an opening shape defining portion.
The support member of the subject is not limited to the type that supports the subject in a prone position like a bed. It may be of a type in which the subject leans while standing or leans diagonally. The support member may have any structure as long as it has a hole-like hole for inserting the breast of the subject and is internally irradiated with light from the light source.

Under the light shielding member 600, a cup 310 is provided as a holding member for holding the breast 1 inserted from the opening S. The cup 310 has substantially the same acoustic impedance (1.5 to 1.6 × 10 ⁶ kg / m ² sec) with the breast, and has a high light transmittance (preferably 90% in a device using the photoacoustic effect). It is preferable to use a member. Specific materials corresponding to this include polymethylpentene, PET, polycarbonate, and elastomer. The thickness of the cup 310 is preferably thin so that attenuation of ultrasonic waves can be reduced. Further, it is preferable to add a matching agent such as gel or water to the cup 310 in order to achieve acoustic matching between the breast 1 and the cup 310 at the time of measurement. As the holding member for holding the breast 1, a sheet-like film, a rubber sheet, or the like can be applied in addition to the cup shape.

(Measurement unit 200)
The measurement unit 200 is a unit that irradiates light to the breast 1 and receives ultrasonic waves generated from the breast 1 by the detector 220. The measurement unit 200 includes a light irradiation unit 210 that irradiates light to the breast 1, a hemispherical detector 220 that receives ultrasonic waves from the breast 1, and a scanning stage for two-dimensionally scanning the light irradiation unit 210 and the detector 220. 230 and a measurement unit base 260.

FIG. 3 is a schematic diagram of the detector 220. The detector 220 is provided with a plurality of acoustic detection elements 223 on the inner surface. A light irradiation unit 210 and a camera 270 described later are provided at the bottom of the detector 220. The acoustic detection element 223 is an element that receives a photoacoustic wave and converts it into an electrical signal. As a member constituting the acoustic detection element 223, a piezoelectric ceramic material typified by PZT (lead zirconate titanate), a polymer piezoelectric film material typified by PVDF (polyvinylidene fluoride), or the like can be used. Further, an element other than the piezoelectric element may be used. For example, CMUT (Capacitive Micro-machined Ultrasonic
Capacitance-type elements such as Transducers can be used. Detector 22
0 corresponds to the detection unit of the present invention.

  The light irradiation unit 210 is provided so as to emit light from the bottom of the detector 220 toward the breast 1. Light is guided to the light irradiation unit 210 from a light source (not shown) through an optical system. The light source is a device that generates pulsed light. As a light source, a laser is desirable to obtain a large output, but a light emitting diode or the like may be used. In order to generate photoacoustic waves effectively, light must be irradiated in a sufficiently short time according to the thermal characteristics of the subject. When the subject is a living body, the pulse width of the pulsed light generated from the light source 100 is preferably set to several tens of nanoseconds or less. The wavelength of the pulsed light is in the near infrared region called a biological window, and is preferably about 700 nm to 1200 nm. The light in this region can reach relatively deep in the living body, and information on the deep portion can be obtained. If it is limited to the measurement of the surface of the living body, the visible light to near infrared region of about 500 to 700 nm may be used. Further, it is desirable that the wavelength of the pulsed light has a high absorption coefficient with respect to the observation target.

The optical system is a device that guides pulsed light generated by a light source to a subject. Specifically, it is an optical device such as a lens, a mirror, a prism, an optical fiber, and a diffusion plate. When guiding light,
These optical devices may be used to change the shape and light density so that a desired light distribution is obtained. The optical apparatus is not limited to those listed here, and may be any apparatus that satisfies such functions.

  Further, the maximum permissible exposure (MPE) is determined by the safety standard shown below for the intensity of light allowed to irradiate the living tissue. (For example, there is IEC 60825-1: Safety of laser products. Also, JIS C 6802: Safety standard of laser products, FDA: 21 CFR Part 1040.10, ANSI Z136.1: Laser Safety Standards, etc.). The maximum allowable exposure amount defines the intensity of light that can be irradiated per unit area. For this reason, a large amount of light can be guided to the breast 1 by collectively irradiating the surface of the breast 1 with a large area, so that a photoacoustic wave can be received with a high S / N ratio. For this reason, it is preferable to spread the light over a certain area as shown by the broken line in FIG.

  The detector 220 is integrated with a matching container 221 that holds a matching liquid for achieving acoustic matching between the detector 220 and the cup 310. The matching liquid is supplied to and discharged from the matching container 221 by a pump (not shown) and a matching liquid circulation system. The matching liquid is preferably oil or water having high transmission characteristics and low attenuation characteristics for photoacoustic waves.

  The scanning stage 230 includes an X scanning stage 240 that scans the light irradiation unit 210 and the detector 220 in the X direction, and a Y scanning stage 250 that scans in the Y direction. Here, the X direction is a direction in which the subject is supported in a prone posture and is moved in the left-right direction with respect to the subject. Similarly, the Y direction is a direction in which the subject is moved in the cranial and caudal directions with respect to the subject. The X scanning stage is provided on the Y scanning stage, and the detector 220 is fixed to the X scanning stage by a support 224. Each of the XY scanning stages is controlled by a command from an arithmetic unit 710 described later by a motor 241 (251), a linear guide 242 (252), and a ball screw 243 (253). With this configuration, the detector 220 can be two-dimensionally scanned in the XY directions.

  The scanning stage is not limited to the above-described mechanism, and any mechanism such as a link mechanism, a gear mechanism, and a hydraulic mechanism may be used as long as the detector 220 can be driven to scan. Further, instead of linear driving by a linear guide, scanning may be performed using a rotation mechanism. The X scanning stage 240 and the Y scanning stage 250 each have an origin sensor and a linear encoder (not shown), and can detect the position of the detector 220 relative to the measurement unit 200. In addition, the movement is preferably performed continuously, but may be repeated in a certain step.

(Shape information acquisition unit 400)
The shape information acquisition unit 400 is a device that acquires shape information representing the outer shape of the breast 1.
The shape information acquisition unit 400 acquires an image with the camera 270 provided at the bottom of the detector 220, performs image processing, and acquires shape information. The camera is not limited to the bottom of the detector 220 and may be any place where the shape of the breast 1 can be acquired. A plurality of cameras for photographing the subject are provided, and a stereo method is used based on captured images taken from a plurality of directions. The shape information of the breast 1 may be acquired using a three-dimensional measurement technique.

The shape information acquisition unit 400 may include a transducer and ultrasonic imaging means, and may acquire the outer shape of the breast 1 using an echo image obtained by normal ultrasonic transmission / reception. Moreover, you may employ | adopt at least 1 of the some acoustic detection element 223 provided in the detector 220 as a transducer.
As another example, the shape may be acquired by scanning the breast 1 by applying a laser beam. The shape information of the breast 1 can be acquired by any means such as a camera, a US, or a scanner. Alternatively, the user may input the shape information of the breast 1 by looking at the captured image displayed on the monitor 900.

(Computer 700)
The computer 700 includes a calculation unit 710 and a storage unit 720.
The arithmetic unit 710 is typically composed of elements such as a CPU, GPU, A / D converter, and circuits such as an FPGA and an ASIC. Note that the arithmetic unit is not limited to a single element or circuit, but may be composed of a plurality of elements or circuits. In addition, any element or circuit may execute each process performed by the computer 700.
The storage unit 720 typically includes a storage medium such as a ROM, a RAM, and a hard disk. Note that the storage unit is not limited to a single storage medium, and may be configured from a plurality of storage media.

The arithmetic unit 710 can perform signal processing on the electrical signals output from the plurality of acoustic detection elements 223. Moreover, the calculating part 710 as a control part can control the action | operation of each structure which comprises a photoacoustic apparatus.
In addition, the computer 700 is preferably configured to be able to pipeline process a plurality of signals simultaneously. As a result, it is possible to shorten the time until the object information is acquired.
Each process performed by the computer 700 can be stored in the storage unit 720 as a program to be executed by the calculation unit 710. However, the storage unit 720 in which the program is stored is a non-temporary recording medium. The computer 700 corresponds to a processing unit of the present invention.

(Monitor 900)
The monitor 900 is a device that displays object information output from the computer 700 as a distribution image or numerical data of a specific region of interest. The monitor 900 includes a touch panel, and also serves as an input unit for the user to input desired information to the computer 700. Furthermore, the external shape of the breast 1 can be displayed by the shape information acquisition unit 400, and the user can check the shape of the breast 1 on the monitor 900. The input unit may use a keyboard, a mouse, a dial, a button, and the like.

<Example 1>
Next, a description will be given of an embodiment of the light shielding member 600 configured to be able to deform the shape of the opening of the present invention.
The light shielding member 600 of the present embodiment has a configuration in which the opening follows the shape of the breast 1 when the breast 1 is inserted into the opening of the light shielding member 600. An example of the configuration will be shown below, but any configuration may be used as long as the mechanism acts to close the opening and move in the closing direction when the breast 1 is inserted into the opening and the opening is opened. .

  FIG. 4 is a schematic view showing the light shielding member 600. FIG. 4A is a plan view of the light shielding member 600. The light shielding member 600 is composed of an expandable member 610 provided with an opening S for inserting the breast 1 and a fixing member 611 for attaching it to the bed 110. The elastic member 610 can be deformed so that the opening area is enlarged or reduced. As the elastic member 610, rubber or sponge having elasticity that can reduce light transmission and elastic cloth can be applied. In FIG. 4, the expansion / contraction member 610 is disposed in a shape that covers a portion other than the central portion of the opening, and a hole for inserting a breast is formed at the center. The hole is not limited to a substantially circular shape, and may be, for example, a slit shape.

FIG. 4B is a side view of the light shielding member 600 before the breast is inserted. FIG. 4C is a side view of the light shielding member 600 after the breast is inserted. The opening S1 of the elastic member 610 before breast insertion is narrower than the width S2 at the position where the elastic member 610 of the breast 1 contacts. With this configuration, when the breast 1 is inserted, the breast 1 spreads the expansion / contraction member 610. A force acts on the expanded elastic member 610 in the direction of closing the opening S, and the gap between the opening S and the breast 1 can be reduced. By using a stretchable member as in this embodiment, the area of the opening S can be easily deformed to follow the shape of the breast 1 and the gap between the opening S and the breast 1 can be reduced. It becomes.

  Furthermore, in order to facilitate insertion when the breast 1 is inserted and to make it easier for the light-shielding member to follow the shape of the breast in a state where the breast 1 is inserted, the force toward the center of the opening is greater when the light-shielding member is farther from the vicinity of the opening center. More preferably it is strong. In the configuration using the expansion / contraction member 610, the force toward the center of the opening becomes stronger as the opening S is expanded in accordance with the spring constant of the expansion / contraction member 610.

  FIG. 4D and FIG. 4E are side views showing an example of the elastic member 610 having an inclination. The elastic member 610 may be arranged in a shape that increases in inclination in the direction in which the breast 1 is inserted toward the center of the opening. In FIG. 4D, an inclination is provided from the fixing member 611 to the center of the opening. In FIG. 4E, an inclination is provided only in the vicinity of the opening. As described above, it is possible to easily insert the breast 1 into the opening S by providing an inclination in a region where the breast 1 contacts at least when the breast 1 spreads the opening S.

  FIG. 5 is a diagram illustrating a state in which the detector 220 is scanned in the Y direction. When the detector 220 is scanned, the light irradiation unit 210 provided in the detector 220 also moves in the Y direction, so that the region A of the gap between the breast 1 and the opening is included in the light irradiation range indicated by the broken line. However, since the gap is reduced by the light shielding member 600, it is possible to reduce light leakage to the subject side.

<Another configuration example>
Next, another configuration example will be described. FIG. 6 is a schematic diagram of a light shielding member 600 that drives a plurality of (here, eight) blades 622 to deform the opening area. The light shielding member 600 includes a fixing member 621 for fixing to the bed 110, a blade 622 that forms the opening S, and a drive ring 623 for driving the blade 622.
The blade 622 may be a member that does not transmit light or a member that attenuates and transmits light. When a member that does not transmit light is used as the light shielding member, if the light that has been shielded is reflected and irradiated to a member other than the breast 1, an acoustic signal is generated therefrom, resulting in an artifact in the image. Therefore, it is preferable that the surface on the laser emission side of the light shielding member is processed so that light is not reflected.

The drive ring 623 is configured to rotate about the same center X as the fixed member 621. The blade 622 rotates around the fulcrum 622a with respect to the fixed member 621. The blade 622 is provided with a long hole 622b, and a shaft 623a provided on the drive ring 623 is fitted into the long hole 622b. The drive ring 623 is provided with an urging spring 624 for urging the force so as to rotate in the direction in which the opening S becomes narrower. As a result, the bias is applied in the direction in which the area of the opening is reduced. The biasing spring 624 always applies a force in the direction of arrow a. As a result, the drive ring 623 and the shaft 623a rotate in the direction of the arrow b. Further, the rotation of the shaft 623a moves the blade 622 in the arrow c direction.
As the biasing spring, a constant load spring may be used so that a change in load is reduced in the rotation region of the drive ring 623. By reducing the change in the load, the same load can always be applied to the breast 1 regardless of the area of the opening S, that is, regardless of the insertion depth and size of the breast 1.

  An elastic material such as rubber is preferably formed on the tip 622c of the blade 622 that is in contact with the breast 1 in order to reduce pain to the breast 1 when in contact with the breast 1. The blade 622 may have a shape that is inclined in the direction in which the breast 1 is inserted toward the center of the opening.

  Also in this configuration, when the breast 1 is inserted, the breast 1 expands the opening S formed by the blades 622. A force is applied to the expanded opening S in the direction of closing the opening S by the biasing spring 624, and the gap between the opening S and the breast can be reduced. Even if such a rigid member is used, the shape of the opening S can be changed. Further, by using the biasing spring 624, it is possible to follow the shape of the breast and reduce the gap between the opening S and the breast 1.

FIG. 7A is a schematic diagram of a configuration in which the shape of the opening S is deformed by linearly moving the eight light shielding plates 629. Each light shielding plate 629 moves linearly as indicated by an arrow. The light shielding plate 629 is provided with an urging spring 641 and urged in a direction to close the opening S. FIG. 7B and FIG. 7C are side views of the light shielding plate 629. The light shielding member 629 is provided with an inclined portion 629a. For this reason, when the breast 1 is inserted into the opening, the force applied to the light shielding plate 629 by the breast 1 acts in a direction to widen the opening S, so that the opening S can be easily widened.
In this embodiment, eight blades 622 or light shielding plates 629 are configured, but the number is not limited to this. Further, the shape of the blade 622 or the light shielding plate 629, the driving method, the biasing method, and the like are not limited thereto.

In the configuration using the above-described expansion / contraction member 610 and the configuration in which the blade 622 is urged by the urging spring 624, the area of the opening S is minimized before the breast 1 is inserted. Therefore, when the subject inserts the breast 1 into the opening S, it is possible to suppress the positional deviation between the breast 1 and the center of the opening S. By making the center of the opening S and the center of the cup 310 coincide with each other, there is an effect that the alignment of the breast 1 with respect to the cup 310 is facilitated.
Further, since the force in the direction in which the opening S becomes narrower is only applied to the breast 1 by the expansion member 610 and the biasing spring 624, it is possible to prevent the force from being applied to the breast 1 more than necessary.

<Example 2>
The light shielding member 600 of this embodiment is characterized in that it has a control mechanism for controlling the shape of the opening S and an input unit for the user to manually perform the control.

  FIG. 8 is a schematic view of a light shielding member 600 in which a wire 612 for controlling the shape of the opening S is provided on the expandable member 610 of FIG. The wire 612 is fixed to the elastic member 610 via a wire fixing member 613. Wire 612 is coupled to control mechanism 614. The wire fixing member 613, the wire 612, and the control mechanism 614 are provided at eight locations around the opening S of the elastic member 610. In this embodiment, eight control mechanisms 614 are provided, but the number is not limited to this. It is also possible to simplify the mechanism by combining a plurality of wires 612 with one control mechanism 614 and controlling them simultaneously.

  The control mechanism 614 includes a fixed portion 614a for the bed 110 and a movable portion 614b, and the movable portion 614b moves straight in the direction of the arrow. When the opening S is widened, the movable portion 614b moves in a direction in which the elastic member 610 is pulled. When the movable portion 614b moves in the opposite direction, the elastic member 610 acts in the direction of narrowing the opening S, so that the opening S can be narrowed. The control mechanism 614 includes an encoder (not shown) that detects the position of the movable portion 614b. By calculating from the position of the movable portion 614b, the shape of the opening S of the expansion / contraction member 610 can be detected.

Control of the control mechanism 614 is performed by a user operation from the monitor 900. FIG. 9 is a schematic view of a screen displayed on the monitor. On the monitor 900, a button for operating the control mechanism 614 and images of the breast 1 and the expansion / contraction member 610 by the camera 270 provided in the detector 220 are displayed. The user can check the gap between the breast 1 and the opening S of the expansion / contraction member 610 on the monitor screen. The user touches the button 911 to open the opening S and touches the button 912 to close it. The control mechanism 614 is driven only while the buttons 911 and 912 are touched. Accordingly, the user can control the opening of the light shielding member 600 while checking the presence or absence of a gap on the monitor 900.
Furthermore, the shape information of the opening of the expansion / contraction member 610 by the encoder provided in the control mechanism 614 may be displayed on the monitor 900 to support the operation by the user input unit. At this time, the camera is a shape acquisition unit that acquires the shape of the subject, and the monitor is a display unit.

Further, the shape information of the breast 1 acquired by the shape information acquisition unit 400 and the opening information of the expansion / contraction member 610 by the encoder provided in the control mechanism 614 are displayed on the monitor, and the opening shape is adjusted to the breast 1 from the information. May be performed. For example, a method in which numerical values of the positions of the opening S and the breast 1 are displayed and the opening shape is manipulated so that the numerical values match can be applied.
Further, a procedure window may be provided so that the user can operate the input unit while viewing the positions of the breast 1 and the light shielding member 600.

When the breast 1 is inserted, the opening S of the expansion / contraction member 610 is first expanded more than the breast 1. After the breast is inserted, the opening S is controlled to become narrower.
In this configuration, since the opening S is preliminarily widened when the breast is inserted, there is no need to push and widen the opening S by the breast 1 of the subject. Therefore, it is easy to insert the breast 1 into the opening S, and it is possible to eliminate the feeling of pressure and pain at the time of insertion.
Further, in the operation from the monitor 900, the plurality of control mechanisms 614 may be controlled independently. In this case, it is possible to more freely control the opening shape of the elastic member 610 according to the shape of the breast 1 or a place where it is not desired to tighten it. For this reason, it is possible to further reduce discomfort due to the fastening of the elastic member 610 to the breast.

<Another configuration example>
The light shielding member 600 also has an input unit for the user to control the shape of the opening S.
FIG. 10 is a plan view of a light shielding member 600 provided with a gear 623b in the drive ring 623 of FIG. The gear 623b meshes with the transmission gear 625. Transmission gear 625 is coupled to a motor (not shown). When the transmission gear 625 is driven in the direction of the arrow d, the drive ring 623 rotates in the direction of the arrow e, and the blade 622 is driven in the direction to close the opening S. If the transmission gear 625 is rotated in the reverse direction, the opening S is widened. That is, the opening shape can be controlled by controlling the driving of the motor. Control is performed from the monitor 900 by the user.

  In the configuration of FIG. 10, a biasing force by a biasing spring 626 is applied to the drive ring 623 in the direction of the arrow f. The biasing spring 626 provides an action of automatically opening the opening S when the motor is de-energized. By adopting a configuration in which the opening S is automatically opened in this manner, an operation for separating the breast 1 from the opening becomes easy.

<Another configuration example>
FIG. 11A is a schematic diagram of a light shielding member 600 in which a linear member 631 having a spring property is disposed on a stretchable member 630 having an opening S so as to surround the periphery of the opening S. The linear member 631 is provided so as to have an urging force in a direction in which a ring portion formed so as to surround the opening S expands. In addition, the tip of the linear member 631 is coupled to a drive mechanism (not shown). The member 630 is coupled so that the shape of the opening S changes according to the change in the shape of the ring portion of the linear member 631. The shape of the ring portion of the linear member 631 is changed by driving of the driving mechanism.

When the tip of the linear member 631 moves in the direction of arrow h by the drive mechanism, the shape of the ring portion changes in the direction of arrow i, so that the opening S can be closed. If the drive mechanism is controlled in reverse, the opening S can be opened. Further, since the urging force is exerted in the direction in which the ring portion expands, the opening S can be automatically opened by shutting off the energization of the drive mechanism even in this configuration. FIG. 11B shows another configuration example, and the tip 631a of the linear member 631 may be driven in a direction substantially along the circumference of the ring portion to change the shape of the ring portion. One end 631b may be driven or fixed.
In the above control, after the user manually controls the opening, the opening S may be controlled by a method as described in Examples 3 to 4 described later.

<Example 3>
In the present embodiment, a detection unit (detection unit) that detects the distance between the breast 1 and the opening S is provided, and the driving of the light shielding member is controlled based on the detection information.

FIG. 12 is a schematic view of a light shielding member 600 in which a distance sensor 642 is provided on a fixing member 641, FIG. 12 (a) is a plan view, and FIG. 12 (b) is a side view. The distance sensor 642 evaluates and calculates the light reflected by irradiating the breast with the light 642a, and converts the light into a distance for output. As shown in FIG. 12A, it is preferable to provide a plurality of distance sensors 642 for the opening S in order to detect the shape of the breast 1 in more detail.
Further, the light shielding member 600 preferably has a configuration in which the opening shape can be deformed by a control mechanism corresponding to the plurality of distance sensors 642. For example, a configuration in which the shape of the expansion / contraction member of Example 2 is controlled by a plurality of control mechanisms can be applied. The opening shape of the expansion / contraction member 610 can be obtained by calculation from the position of the encoder provided in the control mechanism of the expansion / contraction member 610. Therefore, the distance between the breast 1 and the opening S can be calculated from the distance obtained by the distance sensor 642 and the opening shape of the expansion / contraction member 610.

  The driving of the telescopic member 610 is started by a user operation from the monitor 900. When the user touches the drive start button, the calculation unit 710 automatically drives based on the information of the distance sensor 642 and the position information of the expansion / contraction member 610. At this time, it is preferable that the driving of the expansion / contraction member 610 be controlled such that the calculated distance is 0, that is, the expansion / contraction member 610 is driven until it contacts. By driving until contact, the gap between the breast 1 and the opening S can be further reduced, and light leakage can be reduced.

  As another driving example of the expansion / contraction member 610, the driving may be stopped before the distance between the breast 1 and the opening S becomes 0, that is, before the expansion / contraction member 610 contacts the breast 1. In this case, for example, it is effective when the region to be measured such as cancer is in the vicinity of the place where the stretchable member 610 comes into contact. Thus, when performing control to stop driving before the breast 1 expansion and contraction member 610 contacts, it is preferable that the sensor be able to acquire the absolute value of the distance.

The detecting means for detecting the distance between the breast 1 and the opening S may be configured so that the distance is not directly output but can be converted into a distance by calculation. For example, a proximity sensor, a load sensor, a camera, etc. can be applied.
In the case of a proximity sensor, a method of detecting that the breast 1 and the opening S are close to a desired distance and stopping driving there can be considered.
In the case of a load sensor, since the load by the breast 1 and the expansion / contraction member can be detected, it can be determined that the state in which the load is greater than 0 is in contact with the breast and the opening S. When it is desired to make the breast and the expansion / contraction member not in contact with each other, a method of detecting a state in which the load is greater than zero and then opening the opening S and detecting a state in which the load is zero can be considered. A strain sensor may be used as means for detecting the load.
In the case of a camera, the position of the breast can be detected from the captured image by image processing. The camera may use a temperature camera to detect the position of the breast based on the temperature, or may calculate the position using a camera that can be measured as three-dimensional data.
The shading member 600 may be driven such that the opening S can be controlled by a user operation after the opening S is automatically controlled, or the shape of the breast 1 is always detected and feedback controlled. Also good.

  As described above, by including the detection unit that detects the distance between the breast 1 and the opening S, the gap between the breast 1 and the opening S can be quantitatively adjusted. Further, by automatically adjusting the opening S, the user's operation is simplified. In particular, even when the opening shape is controlled by a plurality of control mechanisms, each can be automatically adjusted, so that the operation can be simplified. Further, by always performing feedback control, even when the breast 1 is moved, the shape of the opening S is deformed following the movement, so that the state in which the gap is reduced can be maintained.

<Example 4>
In this embodiment, there is a detection means for detecting the load of the light shielding member added to the breast 1, and the drive of the light shielding member is controlled based on the detection information.

FIG. 13 is a view showing a light shielding member 600 provided with a strain gauge 627 as a load detecting means. The strain gauge 627 is provided on a shaft 628 that couples the transmission gear 625 and a motor (not shown). The rotational torque when driving the blade 622 of the light shielding member 600 is calculated from the strain detected by the strain gauge 627. The correlation formula between the rotational torque and the load applied to the breast 1 is obtained in advance using a tool capable of measuring the load in the opening S and stored in the storage unit 720 of the computer 700. Therefore, the strain of the strain gauge 627 is always read from the storage unit 720 and is calculated by the calculation unit 710.
A threshold value of a load that can be applied to the breast 1 is stored in the storage unit 720. The threshold is preferably a load that does not cause discomfort to the subject even when the light shielding member 600 contacts the breast 1.

The light shielding member 600 is automatically controlled from the calculated load. The drive is started by an operation from the monitor 900 by the user. When the driving operation is started, the opening S is closed and comes into contact with the breast 1. After the contact, the driving continues until the threshold load is reached. When it exceeds the threshold value, it is driven in the direction to open the opening S, and feedback control is performed so that it is below the threshold value.
The load detecting means may be any place where the load on the breast 1 can be calculated by calculation, and a load sensor can be applied in addition to a strain gauge. Further, when the opening S is constituted by a plurality of members, each may be provided with means capable of detecting a load and controlled individually.

  According to this configuration, the light shielding member 600 can be controlled with a stable load without causing discomfort to the subject.

<Embodiment 2>
In the present embodiment, an example of an apparatus that irradiates a subject with light and detects the scattered light within the subject with a photodetector to acquire subject information (DOT device) will be described.

FIG. 14 is an internal configuration diagram of the present embodiment. Members having the same configurations as those of the first embodiment have the same reference numerals. The measurement unit 800 includes a photodetector 820 that detects scattered light from the breast 1 after the light is irradiated onto the breast 1 by the irradiation unit 210.
When the photo detector 820 is driven in the Y direction when the breast 1 is irradiated with light, the area of the gap A is also irradiated with light. Also in this embodiment, the light shielding member 600 of any of the examples described in the first embodiment is applicable. Therefore, light leakage from the gap A between the breast 1 and the opening can be reduced.

  In each of the above embodiments, the opening shape defining portion that defines the shape of the periphery (edge) of the opening has been described as being a light shielding member that mainly blocks light. However, as described in some examples, in order to achieve the purpose of preventing the subject or doctor from irradiating light with high energy, a method other than blocking light can be employed. For example, instead of the light blocking member of each embodiment, a light diffusing member that diffuses light to reduce the amount of light per unit area or a light absorbing member that absorbs part of the light may be used. Further, even when a light shielding member is used, a light shielding effect that attenuates light leaking to the outside to some extent may be used instead of shielding all of the light.

  Moreover, in some examples, it described about performing the process which suppresses reflection of light inside a light-shielding member. However, from the viewpoint of preventing leakage light to the outside, a reflective member that reflects light back into the bed unit may be provided inside the opening shape defining portion. In this case, when the characteristic information is obtained by calculation, a change in the amount of light applied to the subject is considered.

  In addition, the aperture shape defining part can block a part of the optical path of the leaked light as long as it covers at least a part of the gap between the subject and the periphery (edge) of the opening, thereby reducing the light quantity to the outside. The effect of doing.

  100: bed unit, 110: bed, 200: measurement unit, 210: light irradiation unit, 220: detector, 600: light shielding member

Claims (16)

A light source;
A support member for supporting the subject, and a support member having an opening for inserting a subject that is a part of the subject; and
A detection unit that detects an acoustic wave generated from the subject irradiated with light from the light source and outputs an electrical signal;
A processing unit that acquires characteristic information in the subject based on the electrical signal;
Have
The object information acquiring apparatus according to claim 1, wherein the support member includes an opening shape defining portion that defines the shape of the opening around the opening. The subject according to claim 1, wherein the opening shape defining portion closes at least a part of a gap between the subject and the periphery of the opening when the subject is inserted into the opening. Information acquisition device. The opening shape defining portion is at least a part of an optical path of light leaking from a gap between the subject and the periphery of the opening when light is emitted from the light source in a state where the subject is inserted into the opening. The subject information acquiring apparatus according to claim 1, wherein: The object information acquiring apparatus according to claim 1, wherein the opening shape defining portion is a light blocking member that blocks light from the light source. The object information acquiring apparatus according to claim 1, wherein the opening shape defining unit reduces the amount of light per unit area of the light. The object information acquiring apparatus according to claim 1, wherein the opening shape defining portion changes in shape according to the shape of the object. The object information acquiring apparatus according to claim 6, wherein the opening shape defining portion is an elastic member.   The subject information acquiring apparatus according to claim 7, wherein the elastic member is arranged around the opening so as to cover a portion other than a central portion of the opening. The subject information acquiring apparatus according to claim 8, wherein the stretchable member is inclined in a direction in which the subject is inserted toward the center of the opening. The object information acquiring apparatus according to claim 6, wherein the opening shape defining unit changes the opening area by driving a plurality of blades. The object information acquiring apparatus according to claim 10, wherein the plurality of blades are biased in a direction of reducing the area of the opening. The object information acquiring apparatus according to claim 6, further comprising an input unit for a user to control the opening shape defining unit. The object information acquiring apparatus according to claim 12, further comprising: a shape acquiring unit that acquires the shape of the object; and a display unit that displays the shape of the object. The subject information acquiring apparatus according to claim 12, further comprising a detection unit configured to detect a distance between the subject and the opening shape defining unit. The object information acquiring apparatus according to claim 1, further comprising a holding unit that holds the object inside the opening. The object information acquiring apparatus according to claim 1, wherein a process of suppressing reflection of light is performed on a side of the opening shape defining portion that is irradiated with the light. .

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