JP5654364B2 - Photoacoustic diagnostic imaging equipment - Google Patents

Description

  The present invention relates to a photoacoustic image diagnostic apparatus, and more particularly to a photoacoustic image diagnostic apparatus that irradiates a subject with laser light and detects ultrasonic waves generated in the subject due to laser light irradiation.

  An ultrasonic inspection method is known as a kind of image inspection method capable of non-invasively examining the state inside a living body. In the ultrasonic inspection, an ultrasonic probe capable of transmitting and receiving ultrasonic waves is used. When ultrasonic waves are transmitted from the ultrasonic probe to the subject (living body), the ultrasonic waves travel inside the living body and are reflected at the tissue interface. By receiving the reflected sound wave with the ultrasonic probe and calculating the distance based on the time until the reflected ultrasonic wave returns to the ultrasonic probe, the internal state can be imaged.

  In addition, photoacoustic imaging is known in which the inside of a living body is imaged using a photoacoustic effect. In general, in photoacoustic imaging, a living body is irradiated with pulsed laser light such as a laser pulse. Inside the living body, the living tissue absorbs the energy of the pulsed laser light, and ultrasonic waves (photoacoustic signals) are generated by adiabatic expansion due to the energy. By detecting this photoacoustic signal with an ultrasonic probe or the like and constructing a photoacoustic image based on the detection signal, in-vivo visualization based on the photoacoustic signal is possible.

  Here, in photoacoustic imaging, it is necessary to irradiate a living body with laser light having a relatively high output. From the viewpoint of safety, it is preferable to suppress emission of pulsed laser light when the probe is not in contact with the living body. In this regard, Patent Document 1 includes a contact pressure detection unit that detects contact pressure on the probe, and prevents the laser light from being emitted from the probe when the contact pressure detection unit does not detect the pressure of an object that contacts the probe. It is described.

JP-A-2005-13597

  However, since Patent Document 1 only determines contact with a living body based on contact pressure, it is possible to prevent laser light from being emitted to the outside at an unintended timing by an operator such as a doctor. Can not. For example, when the operator is touching the tip of the probe with his / her finger near the face, there may be a situation where the contact pressure detection unit detects contact with the living body and laser light is emitted.

  In view of the above, an object of the present invention is to provide a photoacoustic image diagnostic apparatus that can effectively prevent laser light from being emitted to the outside at a timing that is not intended by an operator.

  In order to achieve the above object, the present invention provides a laser light source, a probe for irradiating a laser beam guided from the laser light source and receiving at least an ultrasonic wave, and a tomography based on the ultrasonic wave received by the probe. A photoacoustic comprising: an image generating means for generating an image; a switch provided in the probe; and a control means for allowing laser light to be emitted from the probe when the switch is operated. An image diagnostic apparatus is provided.

  In the photoacoustic image diagnostic apparatus of the present invention, the probe further transmits ultrasonic waves, and the control means causes the probe to transmit ultrasonic waves into the subject when the switch is not operated, so that the image The generation unit can employ a configuration for generating the tomographic image based on the ultrasonic wave received by the probe.

  The control means causes the probe to emit laser light and transmit ultrasonic waves from the probe when the switch is operated, and the image generating means receives the laser light received by the probe. A first tomographic image is generated based on an ultrasonic wave generated in a living body, and a second tomographic image is generated based on a reflected ultrasonic wave received by the probe and transmitted from the probe. Also good.

  The control means may output a trigger signal for causing the laser light source to emit laser light when the switch is operated.

  The light source may include a light irradiation suppression circuit that masks the trigger signal when the switch is not operated.

  In the present invention, a momentary push switch can be used as the switch.

  In the present invention, the switch is provided on each of two opposite side surfaces of the probe, and the control means is configured to allow the probe to emit laser light when both switches are operated. May be adopted.

  In the photoacoustic image diagnostic apparatus of the present invention, a switch is provided in a probe, and laser light can be emitted from the probe when the switch is operated. By doing in this way, it can prevent that a laser beam is radiated | emitted from a probe at the timing which an operator does not intend, and can improve safety | security.

The block diagram which shows the photoacoustic image diagnostic apparatus of one Embodiment of this invention. The figure which shows the external appearance of a probe. The flowchart which shows an operation | movement procedure. (A) is a figure which illustrates an ultrasonic image, (b) is a figure which illustrates the image which superimposed the ultrasonic image and the photoacoustic image.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a photoacoustic image diagnostic apparatus according to an embodiment of the present invention. The photoacoustic image diagnostic apparatus 10 includes an ultrasonic probe (probe) 11, an ultrasonic unit 12, and a laser light source (laser unit) 13. The photoacoustic image diagnostic apparatus 10 can generate both an ultrasonic image and a photoacoustic image. The laser unit 13 generates laser light that irradiates a subject when generating a photoacoustic image. What is necessary is just to set the wavelength of a laser beam suitably according to an observation target object. The laser light emitted from the laser unit 13 is guided to the probe 11 using light guide means such as an optical fiber.

  The probe 11 irradiates the subject with the laser light guided from the laser unit 13. The probe 11 also outputs (transmits) ultrasonic waves to the subject and detects (receives) ultrasonic waves from the subject. The probe 11 has, for example, a plurality of ultrasonic transducers arranged one-dimensionally. For example, when generating an ultrasonic image, the probe 11 outputs ultrasonic waves from a plurality of ultrasonic transducers, and detects reflected ultrasonic waves (hereinafter also referred to as reflected acoustic signals) with respect to the output ultrasonic waves. When the photoacoustic image is generated, the probe 11 detects an ultrasonic wave (hereinafter also referred to as a photoacoustic signal) generated when the measurement target in the subject absorbs the laser light from the laser unit 13.

  The probe 11 is provided with a switch 15. For example, a momentary operation push switch can be used as the switch 15. The switch 15 is used for switching ON / OFF of laser irradiation. When an operator such as a doctor desires to generate a photoacoustic image, the operator presses the switch 15 to set the operation state. When the switch 15 is in the operating state, the laser unit 13 performs laser emission, and the ultrasonic unit 12 generates a photoacoustic image. On the other hand, when the switch 15 is in a non-operating state (a state in which the hand is separated from the switch 15), the laser unit 13 does not emit laser light, and the ultrasonic unit 12 generates an ultrasonic image.

  The ultrasonic unit 12 includes a reception circuit 16, an AD conversion unit 17, an image reconstruction unit 18, a detection unit 19, a logarithmic conversion unit 20, an image construction unit 21, a control unit 22, and a transmission control circuit 23. The receiving circuit 16 receives ultrasonic waves (photoacoustic signals or reflected acoustic signals) detected by a plurality of ultrasonic transducers included in the probe 11. The AD conversion means 17 converts the ultrasonic signal received by the receiving circuit 16 into a digital signal. The AD conversion means 17 samples an ultrasonic signal with a predetermined sampling period, for example.

  The image reconstruction unit 18, the detection unit 19, the logarithmic conversion unit 20, and the image construction unit 21 correspond to an image generation unit that generates a tomographic image based on the ultrasonic waves detected by the probe 11. The function of the image generation means can be realized by a computer operating a process according to a predetermined program. The image generating means generates a first tomographic image (photoacoustic image) based on the photoacoustic signal received by the probe 11 and also generates a second tomographic image (ultrasonic wave) based on the reflected acoustic signal received by the probe 11. Image).

  The image reconstruction unit 18 generates data for each line of the tomographic image based on the ultrasonic signals detected by the plurality of ultrasonic transducers of the probe 11. For example, the image reconstruction unit 18 adds data from 64 ultrasonic transducers of the probe 11 with a delay time corresponding to the position of the ultrasonic transducer to generate data for one line (delay addition method). ). The image reconstruction means 18 may perform reconstruction by the CBP method (Circular Back Projection) instead of the delay addition method. Alternatively, the image reconstruction unit 18 may perform reconstruction using the Hough transform method or the Fourier transform method.

  The detection means 19 outputs an envelope of the data of each line output from the image reconstruction means 18. The logarithmic conversion means 20 logarithmically transforms the envelope output from the detection means 19 to widen the dynamic range. The image construction unit 21 generates a tomographic image based on the data of each line subjected to logarithmic transformation. For example, the image construction unit 21 converts a position in the time axis direction of the ultrasonic signal (peak part) into a position in the depth direction in the tomographic image to generate a tomographic image. The image display unit 14 displays the tomographic image generated by the image construction unit 21 on a display monitor or the like.

  The control means 22 controls each part in the ultrasonic unit 12. The control means 22 determines whether or not the switch 15 is in an operating state. The control means 22 enables laser emission from the probe 11 when the switch 15 is in the operating state. More specifically, the control means 22 sends a laser oscillation trigger signal to the laser unit 13 when the switch 15 is in the operating state. The laser unit 13 receives the trigger signal, performs laser oscillation, and emits laser light. On the other hand, the control means 22 sends an ultrasonic transmission trigger signal to the transmission control circuit 23 when the switch 15 is not in the operating state. When receiving the trigger signal, the transmission control circuit 23 transmits an ultrasonic wave from the probe 11.

  The laser unit 13 includes a light irradiation suppression circuit 24. The light irradiation suppression circuit 24 is configured by, for example, an AND circuit that takes a logical product of a laser oscillation trigger signal and an output signal of the switch 15. The light irradiation suppression circuit 24 masks the laser oscillation trigger signal when the switch 15 is not in the operating state. For example, when the laser oscillation trigger signal is a pulse signal that becomes H level only for a predetermined period, the light irradiation suppression circuit 24 holds the output at L level even when the laser oscillation trigger signal becomes H level. Even when the control unit 22 outputs a laser oscillation trigger signal to the laser unit 13 when the switch 15 is not in the operating state, the light irradiation suppression circuit 24 masks the trigger signal so that the laser unit 13 performs laser output. Absent. On the other hand, when the switch 15 is in the operating state, the light irradiation suppression circuit 24 passes the laser oscillation trigger signal, and the laser unit 13 emits laser light in response to the trigger signal.

  FIG. 2 shows the appearance of the probe. The operator touches the surface on which the ultrasonic transducers are arranged at a place to be observed by grasping the probe 11 by hand. The switch 15 is provided, for example, in a portion where the thumb is located when the probe 11 is grasped by hand. When the operator desires to observe the photoacoustic image, the operator keeps pressing the switch 15. When the switch 15 is in the operating state, a laser oscillation trigger signal is output from the ultrasonic unit 12 to the laser unit 13, and the trigger signal passes through the light irradiation suppression circuit 24 and is irradiated with laser light. A switch 15 may be provided on each of the two side surfaces of the probe 11 facing each other, and laser light may be emitted from the probe when both the switches 15 are operated. When the operator desires observation with an ultrasonic image, the operator removes his / her hand from the switch 15 and brings the probe 11 into contact with the place to be observed.

  FIG. 3 shows an operation procedure. When generating an image, the control means 22 determines whether or not the switch 15 is pressed (step S1). When determining that the switch 15 is pressed, the control means 22 outputs a laser oscillation trigger signal to the laser unit 13 (step S2). The laser unit 13 emits pulsed laser light on condition that the switch 15 is pressed. The pulse laser beam emitted from the laser unit 13 is irradiated to the subject from the probe 11 (step S3). The probe 11 receives the photoacoustic signal generated in the living body by the irradiation of the laser light (step S4). The control means 22 controls the sampling start timing of the photoacoustic signal in the AD conversion means 17 in synchronization with the laser oscillation trigger signal. The image generation means in the ultrasonic unit 12 generates a photoacoustic image based on the photoacoustic signal (step S5).

  Subsequently, the control means 22 outputs an ultrasonic transmission trigger signal to the transmission control circuit 23 (step S6). The probe 11 transmits an ultrasonic wave into the subject (step S7). The probe 11 receives the reflected acoustic signal reflected within the subject (step S8). The control means 22 controls the sampling start timing of the reflected acoustic signal in the AD conversion means 17 in synchronization with the ultrasonic transmission trigger signal. The image generation means in the ultrasonic unit 12 generates an ultrasonic image based on the reflected acoustic signal (step S9). The image display unit 14 displays the photoacoustic image and the ultrasonic image generated by the ultrasonic unit 12 on the display screen (step S10). The image display means 14 superimposes and displays a photoacoustic image and an ultrasonic image, for example. Either the photoacoustic image generation or the ultrasonic image generation may be performed first. Further, only the photoacoustic image may be generated when the switch 15 is operated.

  If the control means 22 determines that the switch 15 is not pressed in step S1, the control means 22 proceeds to step S6 and outputs an ultrasonic transmission trigger signal. Thereafter, an ultrasonic wave is transmitted in step S7, a reflected acoustic signal is received in step S8, and an ultrasonic image is generated in step S9. The image display means 14 displays an ultrasonic image on a display screen at step S10.

  FIG. 4A shows an ultrasonic image, and FIG. 4B shows an image obtained by superimposing an ultrasonic image and a photoacoustic image. The horizontal direction of the paper corresponds to the direction in which the ultrasonic transducers are arranged, and the vertical direction corresponds to the depth direction. When the operator generates an image without pressing the switch 15, the subject is not irradiated with laser light, and the image display unit 14 displays an ultrasonic image. On the other hand, when the operator generates an image while pressing the switch 15, laser light irradiation is performed on the condition that the switch 15 is pressed when the laser oscillation trigger signal is output, and a photoacoustic image is generated. Is done. The image display means 14 displays a photoacoustic image or an image obtained by superimposing an ultrasonic image on the photoacoustic image.

  In the present embodiment, the control means 22 does not output a laser oscillation trigger signal to the laser unit 13 when the switch 15 provided in the probe 11 is not pressed. By doing in this way, it can prevent effectively that a laser beam is emitted outside at the timing which an operator does not intend. In the present embodiment, the generation of an ultrasonic image without laser light irradiation and the generation of a photoacoustic image with laser light irradiation are switched according to the operation state of the switch 15. By doing in this way, the operator can switch a display image easily.

  In the present embodiment, a light irradiation suppression circuit 24 is provided in the laser unit 13, and the light irradiation suppression circuit 24 masks the laser oscillation trigger signal when the switch 15 is not pressed. By providing such a circuit, it is possible to more effectively prevent the subject from being irradiated with laser light when the switch 15 is not pressed, and safety can be improved. Further, even if the ultrasonic unit 12 breaks down and the laser oscillation trigger signal continues to be output, the laser oscillation trigger signal can be masked by releasing the switch 15, and there is a risk that laser light will continue to be output. It can be avoided.

  As mentioned above, although this invention was demonstrated based on the suitable embodiment, the photoacoustic image diagnostic apparatus of this invention is not limited only to the said embodiment, A various correction and change from the structure of the said embodiment. Those subjected to are also included in the scope of the present invention.

10: Photoacoustic image diagnosis apparatus 11: Probe 12: Ultrasonic unit 13: Laser unit 14: Image display means 15: Switch 16: Reception circuit 17: AD conversion means 18: Image reconstruction means 19: Detection means 20: Logarithmic conversion Means 21: Image construction means 22: Control means 23: Transmission control circuit 24: Light irradiation suppression circuit

Claims (6)

A light source unit including a laser light source;
A probe for irradiating laser light guided from the laser light source and receiving at least ultrasonic waves;
A signal processing unit including image generating means for generating a tomographic image based on the ultrasonic wave received by the probe;
A switch provided on the probe,
When the switch is operated, the signal processing unit is a control means that enables laser light to be emitted from the probe, and is connected to the switch. When the switch is in an operating state, the signal processing unit is connected to the light source unit. And a control means for outputting a signal for instructing laser emission.
When the light source unit is connected to the switch, the switch is in an operating state, and the control means outputs a signal instructing laser emission, light is emitted from the light source, and the switch is not in an operating state. In some cases, the photoacoustic image diagnostic apparatus further includes a light irradiation suppression circuit that masks a signal that instructs the laser emission.   The probe further transmits ultrasonic waves, and the control means transmits ultrasonic waves from the probe into the subject when the switch is not operated, and the image generation means transmits the ultrasonic waves received by the probe. The photoacoustic image diagnostic apparatus according to claim 1, wherein the tomographic image is generated based on a sound wave.   The control means causes the probe to emit laser light and transmit ultrasonic waves from the probe when the switch is operated, and the image generation means transmits the laser light received by the probe. A first tomographic image is generated based on an ultrasonic wave generated in the living body by irradiation, and a second tomographic image is generated based on a reflected ultrasonic wave received by the probe and transmitted from the probe. The photoacoustic image diagnostic apparatus according to claim 2, wherein the photoacoustic image diagnostic apparatus is generated.   The photoacoustic image diagnostic apparatus according to claim 1, wherein the switch is a momentary push switch.   The switch is provided on each of two opposing side surfaces of the probe, and the control means enables emission of laser light from the probe when both switches are operated. The photoacoustic image diagnostic apparatus in any one of Claim 1 to 4. The photoacoustic image diagnosis apparatus according to claim 1, wherein an output signal of the switch is branched and transmitted to the control unit and the light irradiation suppression circuit.