WO2014056134A1

WO2014056134A1 - Imaging method combining ultrasound with photoacoustic image, and imaging device

Info

Publication number: WO2014056134A1
Application number: PCT/CN2012/082567
Authority: WO
Inventors: 吕委整; 吴国瑞; 刁国栋
Original assignee: 财团法人工业技术研究院
Priority date: 2012-10-08
Filing date: 2012-10-08
Publication date: 2014-04-17
Also published as: TW201415020A

Abstract

An imaging method combining ultrasound with a photoacoustic image, and an imaging device. The imaging device (100) comprises a pulse laser generating unit (130), a pulse laser scanning unit (140), an ultrasound generating unit (110), an ultrasound imaging processing unit (120), and a focus calculating unit (150). The pulse laser scanning unit (140) is used to control an irradiation position of a pulse laser (L). The ultrasound generating unit (110) is used to emit ultrasound (U). The ultrasound imaging processing unit (120) is used to detect a photoacoustic signal (PA) emitted by an irradiation point (R) of the pulse laser (L) and receive an echo of ultrasound (U) and a beam generated by the photoacoustic signal (PA) to convert to a two-dimensional image. The focus calculating unit (150) is used to calculate a focus (F) coordinate of ultrasound (U) and send a single of the focus (F) coordinate to the pulse laser scanning unit (140) and the ultrasound imaging processing unit (120), thereby adjusting the irradiation position of the pulse laser (L).

Description

Imaging method and imaging device combining ultrasonic and photoacoustic images

The present invention relates to an imaging method and an imaging apparatus, and more particularly to an imaging method and imaging apparatus that combines ultrasonic and photoacoustic images. Background technique

Ultrasound imaging principle is to use a transducer to receive the emitted sound waves, and then use the difference in reflection characteristics between different tissues to convert the received sound wave signals into two-dimensional images. In addition, the imaging principle of photoacoustic ultrasound is to emit pulsed laser light waves, not sound waves, unlike conventional ultrasonic systems. Therefore, when the pulsed laser penetrates the tissue, part of the energy is absorbed and converted into thermal energy, which further causes a very small thermal expansion. When the fluctuations caused by thermal expansion are detected by the ultrasonic probe, the resulting two-dimensional image can reflect the distribution of specific molecules and substances in the local tissue.

However, the illumination range of the conventional laser light wave generator and laser light wave is fixed. When the photoacoustic signal emitted by the laser-irradiated tissue is a point source, the sound wave emitted by it is diverged by the spherical wave. Since the difference in sound path is different, the magnification of the center and the edge on the same plane after transmission will be different. Therefore, when the sound signal received by the ultrasonic probe is different from the sound field emitted when the object is subjected to laser stimulation, the computer needs to perform rear-end recombination of the information and adjust the magnification and the sound path difference to generate a two-dimensional image, so that it is difficult to improve the final imaging. The quality makes the resolution of photoacoustic images slightly worse than the resolution of traditional ultrasonic images. Summary of the invention

According to an aspect of the present invention, an imaging apparatus combining an ultrasonic wave and a photoacoustic image is provided, comprising a pulse laser generating unit, a pulse laser scanning unit, an ultrasonic generating unit, an ultrasonic imaging processing unit, and a pair of focal points. Calculation unit. The pulsed laser generating unit is configured to emit a pulsed laser. The pulse laser scanning unit is used to control the irradiation position of the pulsed laser. The ultrasonic generating unit is configured to emit an ultrasonic wave. The ultrasonic imaging processing unit is configured to detect a photoacoustic signal emitted by the irradiation point of the pulsed laser, and receive the echo generated by the ultrasonic wave and the beam generated by the photoacoustic signal to be converted into a two-dimensional image. The focus calculation unit is configured to calculate the focus coordinates of the ultrasonic wave, and transmit the signal of the focus coordinate to the pulse laser scanning unit and the ultrasonic imaging processing unit to synchronously adjust the irradiation position of the pulse laser. According to another aspect of the present invention, an imaging method combining ultrasonic and photoacoustic images is proposed, comprising the following steps. Launch a supersonic wave. The echo of the ultrasonic wave is received for imaging processing of the ultrasonic wave. The focus coordinates of the ultrasonic waves are calculated to simultaneously calculate the illumination point of a pulsed laser. Corresponding to the adjustment of the irradiation position of the pulsed laser. The pulsed laser is emitted to detect a photoacoustic signal emitted by the irradiation point of the pulsed laser, and receive a beam generated by the photoacoustic signal to obtain a two-dimensional image.

For a better understanding of the above and other aspects of the present invention, the following detailed description of the embodiments of the invention

1 is a schematic diagram of an imaging device combining ultrasonic waves and photoacoustic images according to an embodiment of the present invention; FIG. 2 is a schematic diagram of a probe placed on an object to be tested;

3A and 3B are two embodiments for controlling the irradiation position of the pulsed laser;

FIG. 4 is a schematic flow chart of an imaging method combining ultrasonic waves and photoacoustic images according to an embodiment of the present invention. Main component symbol description

10: DUT

100 Imaging device combining ultrasonic and photoacoustic images

110 ultrasonic generating unit

112 transmit beamformer

114 pulser

120 ultrasonic imaging processing unit

122 Receive Beamformer

123 imaging unit

124 analog front end components

126 send / receive switch

128 probe

130 pulse laser generating unit

132 laser head

140 pulse laser scanning unit

142 drive 144: Mirror group

150: focus point calculation unit

160: Image Analysis Unit

L: pulsed laser

R: irradiation point

PA: Photoacoustic signal

U: Ultrasonic

υ': Acoustic signal

F: focus point

The imaging method and imaging apparatus combining the ultrasonic wave and the photoacoustic image disclosed in the embodiment control the irradiation position of the pulse laser to obtain an emission focusing effect close to that of the conventional ultrasonic wave. That is to say, the ultrasonic wave is first transmitted to set the coordinate of the ultrasonic receiving point of the focus point, and then the signal of the focus coordinate is simultaneously transmitted to the pulse laser scanning unit and the ultrasonic imaging processing unit to adjust the irradiation position of the pulse laser correspondingly. . Therefore, the acoustic signal received by the ultrasonic probe is the photoacoustic signal emitted when the focus is subjected to laser stimulation, which is very close to the emission focusing effect of the conventional ultrasonic wave, so that the imaging quality of the photoacoustic image can be improved.

The following is a detailed description of various embodiments, which are intended to be illustrative only and not intended to limit the scope of the invention. First embodiment

Referring to FIG. 1, a schematic diagram of an imaging device 100 incorporating ultrasonic and photoacoustic images is illustrated in accordance with an embodiment of the present invention. The image forming apparatus 100 may include an ultrasonic generating unit 110, an ultrasonic imaging processing unit 120, a pulse laser generating unit 130, a pulse laser scanning unit 140, a pair of focus calculating units 150, and an image analyzing unit 160.

The ultrasonic generating unit 110 includes a transmit beamformer 112 and a pulser 114. The ultrasonic imaging processing unit 120 includes a receive beamformer 122, an imaging unit 123, an analog front end component 124, a transmit/receive switch 126, and a probe 128. As shown in FIG. 2, the probe 128 is placed on the object to be tested 10 to transmit an ultrasonic wave U emitted by the ultrasonic generating unit 110 to the object to be tested 10, and receives a return sound from the focus point F of the ultrasonic wave U. Wave signal U,. This acoustic signal U can be passed through an analog front end component The signal processing of 124 is transmitted to the receive beamformer 122, which is then beamformed by the receive beamformer 122 to obtain an echo image. The echo image can be represented by the imaging unit 123 of the bright spot mode (B-mode) to indicate the intensity of the returned sound wave to a brightness level to be converted into a two-dimensional image having a grayscale effect.

In one embodiment, the image analysis unit 160 analyzes the echo image of the ultrasonic U for the user to select a Region of interest to illuminate the pulsed laser light on the region of interest. That is to say, the region of interest can be determined by the image analysis unit 160 based on the system preset value, or can be determined by the user input. In Fig. 1 of the present embodiment, the region of interest and the focus point calculation unit 150 can be separated or combined into one unit.

The focus calculation unit 150 is configured to calculate the focus F coordinate of the ultrasonic wave U, and simultaneously transmit the signal of the focus F coordinate to the pulse laser scanning unit 140 and the ultrasonic imaging processing unit 120.

Referring to FIG. 3A, in one embodiment, the pulsed laser scanning unit 140 has, for example, a driver 142, and the pulsed laser generating unit 130 has a laser head 132 for emitting a pulsed laser light L. The driver 142 drives the laser head 132 to move to control the irradiation position of the pulsed laser light L. Referring to FIG. 3B, in another embodiment, the pulsed laser scanning unit 140 has, for example, a movable or rotatable mirror group 144 that allows the pulsed laser light L to adjust its illumination position via the mirror group 144. That is to say, the irradiation position of the pulsed laser light L can be adjusted in synchronization according to the focus F coordinate of the ultrasonic wave U. In addition, the ultrasonic imaging processing unit 120 can also calculate the sound path difference based on the focus F coordinate to perform beamforming calculation.

Referring to FIG. 1, the probe 128 of the ultrasonic imaging processing unit 120 is configured to detect a photoacoustic signal PA emitted by the irradiation point R of the pulsed laser light L, and receive a beam generated by the photoacoustic signal PA. The photoacoustic signal PA is a point source that can be transmitted to the receive beamformer 122 via signal processing of the analog front end component 124, and then beamformed by the receive beamformer 122 to obtain a photoacoustic image. The photoacoustic image can be converted into a two-dimensional image having a false color effect by the imaging unit 123 to reflect the distribution of specific molecules and substances in the object to be tested 10.

Please refer to FIG. 4 , which is a flow chart of an imaging method combining ultrasonic and photoacoustic images according to an embodiment of the invention. Please refer to the description of FIGS. 1 and 2 for the following component numbers. First, in step S11, an ultrasonic wave U is transmitted. In step S12, an echo of the ultrasonic wave U is received to perform imaging processing of the ultrasonic wave. That is, the probe 128 transmits the ultrasonic wave U to the object to be tested 10, and receives a sound wave signal U returned by the focus point F of the ultrasonic wave U. In steps S13 and S14, an echo image of the ultrasonic wave U is subjected to imaging analysis to determine an area of interest. The area of interest may be automatically determined according to the preset value of the system, as shown in step S15; or the area of interest may be determined by the user to input it, as shown in step S16. Next, in step S17, the coordinates of the focus point F of the ultrasonic wave U are calculated, and the irradiation point R of the pulse laser light L is calculated in synchronization with the coordinates of the focus point F of the ultrasonic wave U. In step S18, after the irradiation position of the pulsed laser light L is adjusted, for example, the laser head 132, the moving mirror group 144, or the rotating mirror group 144 is moved, step S19 is performed to emit the pulsed laser light L on the object to be tested 10. In step S20, the probe 128 detects a photoacoustic signal PA emitted by the irradiation point R of the pulsed laser light L, and receives the beam generated by the photoacoustic signal PA to obtain a two-dimensional image.

In the above steps S17 to S20, when the position of the probe 128 is fixed and the irradiation position of the pulsed laser light L is moved, a two-dimensional image of different irradiation positions can be obtained. Preferably, but not limited to, the pulsed laser L is moved at a distance equal to the spacing between the sensing elements in the probe 128, which provides optimized beamforming accuracy.

As can be seen from the above description, the present invention improves the imaging quality of the photoacoustic image by controlling the irradiation position of the pulsed laser to obtain an emission focusing effect close to the conventional ultrasonic wave, and can reduce the laser energy requirement.

In conclusion, although the invention has been disclosed in connection with the preferred embodiments described above, it is not intended to limit the invention. A person skilled in the art to which the invention pertains can make various changes and modifications without departing from the spirit and scope of the invention. Therefore, the scope of the invention should be determined by the appended claims.

Claims

Claim

1. An imaging device that combines ultrasonic and photoacoustic images, including:

a pulsed laser generating unit for emitting a pulsed laser;

a pulse laser scanning unit for controlling an irradiation position of the pulsed laser;

An ultrasonic generating unit for transmitting an ultrasonic wave;

The ultrasonic imaging processing unit is configured to detect a photoacoustic signal emitted by the irradiation point of the pulsed laser, and receive the echo of the ultrasonic wave and the beam generated by the photoacoustic signal to be converted into a two-dimensional image;

The focus calculation unit is configured to calculate a focus coordinate of the ultrasonic wave, and transmit the signal of the focus coordinate to the pulse laser scanning unit and the ultrasonic imaging processing unit to synchronously adjust the irradiation position of the pulse laser.

2. The imaging apparatus according to claim 1, further comprising an image analyzing unit configured to analyze the echo image of the ultrasonic wave for the user to select an area of interest to cause the pulsed laser to illuminate the area of interest.

3. The imaging apparatus according to claim 1, wherein the pulse laser generating unit comprises a laser head that moves the laser head to control an irradiation position of the pulsed laser.

4. The imaging apparatus according to claim 1, wherein the pulsed laser scanning unit comprises a movable or rotatable mirror group that adjusts the irradiation position of the pulsed laser light via the mirror group.

5. An imaging method that combines ultrasonic and photoacoustic images, including:

Transmitting an ultrasonic wave;

Receiving an echo of the ultrasonic wave to perform an imaging process of the ultrasonic wave;

Calculating a focus coordinate of the ultrasonic wave to synchronously calculate an irradiation point of a pulsed laser;

Corresponding to adjusting the irradiation position of the pulsed laser;

The pulsed laser is emitted, and a photoacoustic signal emitted by the irradiation point of the pulsed laser is detected, and a beam generated by the photoacoustic signal is received to obtain a two-dimensional image.

6. The imaging method according to claim 5, further comprising selecting a region of interest based on the echo image of the ultrasonic wave, and adjusting an irradiation position of the pulsed laser light to illuminate the pulsed region on the region of interest.

The image forming method according to claim 5, wherein the step of adjusting the irradiation position of the pulsed laser light comprises moving a laser head to adjust an irradiation position of the pulsed laser light.

8. The image forming method according to claim 5, wherein the step of adjusting the irradiation position of the pulsed laser light comprises providing a movable or rotatable mirror group, the pulsed laser light being adjusted in its irradiation position via the mirror group.