Patent Description:
Ultrasound signals may be used in the treatment of biological tissues, such as cancer, tumors, lesions, and the like. Treatment with ultrasound is a method of treating a lesion by emitting ultrasound signals to the lesion of the human body. Ultrasound treatment may cause less trauma of a patient, compared to general surgical treatment or chemotherapy, and realize non-invasive treatment. Examples of the application of ultrasound treatment include liver cancer, bone sarcoma, breast cancer, pancreatic cancer, kidney cancer, soft tissue tumors, pelvic tumors, and the like.

<CIT> describes an ultrasound transducer assembly and methods of using.

<CIT> describes an ultrasound guided opening of blood-brain barrier.

<CIT> describes transducers, systems, and manufacturing techniques for focused ultrasound therapies.

<NPL> describes a large improvement of the electrical impedance of imaging and high-intensity focused ultrasound (HIFU) phased arrays using multilayer piezoelectric ceramics coupled in lateral mode.

According to an embodiment, a focused ultrasound device capable of protecting an image transducer from a therapeutic focused ultrasound (FUS) signal and removing image artifact and an image transducer protection method are proposed.

A focused ultrasound device according to an embodiment includes: an ultrasound probe structure including a treatment transducer for transmitting a focused ultrasound signal and an image transducer for transmitting and receiving an ultrasonic image signal, a reception switch for selecting a plurality of first elements among elements of the image transducer as a protection area and deactivating the same, and selecting a plurality of second other elements among the elements of the image transducer as a reception area and activating the same, an image beamformer for forming a reception beam signal by focusing ultrasonic echo signals received from the plurality of second elements, an image generation unit for generating an image for a target area in an object on the basis of the reception beam signal, and a control unit for controlling the selection of the protection area and reception area by means of a reception switch, wherein the plurality of first elements are in a central area of the image transducer in which the focused ultrasound signal reflected from an interface of the ultrasound probe structure to the image transducer is concentrated and the plurality of second elements may be in a peripheral area of the image transducer.

The protection area may include N elements located at the center of the entire scan lines, and the reception areas may include (the total number of channels-N)/<NUM> elements on each of the left and right sides with respect to a center position of the entire scan lines.

The focused ultrasound device may further include a control unit configured to select the reception area by means of the reception switch on the basis of the image generated by the image generation unit.

The control unit may select and combine at least one from four methods including a first method of activating (the total number of channels-N)/<NUM> elements on each of the left and right sides with respect to the center position of the entire scan lines, a second method of activating (the total number of channels-N)/<NUM> elements on each of the left and right sides with respect to the center position of the entire scan lines and controlling a focusing angle, a third method of activating the total number of channels/<NUM> elements on each of the left and right sides with respect to the center position of the entire scan lines, or a fourth method of activating the total number of channels/<NUM> elements on each of the left and right sides with respect to the center position of the entire scan lines and controlling a focusing angle.

The image transducer may include a protective film configured to protect the protection area of the image transducer, the protective film may include any one of a diffuse reflection material, a reflective material, and an attenuating material, the diffuse reflection material or the reflective material may be any one of a copper foil, an aluminum foil, and a reflective plate made of plastic, and the attenuating material may be any one of natural rubber, latex, and silicone rubber.

The ultrasound probe structure may further include a column-shaped case and a membrane filled with an ultrasonic transmission medium along the shape of the case.

The ultrasound probe structure may further include a height adjustment unit configured to adjust a height of the case of the ultrasound probe structure. The height adjustment unit may adjust the height to satisfy H'=LcosΘ-D, where L denotes a FUS signal length of the outermost channel of the treatment transducer to the target area of the object, H denotes a vertical distance from the treatment transducer to the target area of the object, Θ denotes an angle between L and H, D denotes a vertical distance from the target area of the object to a skin surface of the object, and H' denotes the height of the case of the ultrasound probe structure.

The ultrasound probe structure may further include a plurality of contact sensors configured to detect contact between the ultrasound probe structure and the target object.

The focused ultrasound device may further include a noise filter configured to filter noise from signals generated from each of the contact sensors, a contact switch configured to select a predetermined contact signal from among a plurality of contact signals from which the noise has been filtered, a signal processing unit configured to perform signal processing on the selected contact signal, and a control unit configured to determine a contact state at each position from the contact signal received from the signal processing unit and control the treatment transducer to transmit a FUS signal on the basis of the contact state.

The focused ultrasound device may further include an output unit configured to output a contact state and a contact instruction message to the outside.

According to a focused ultrasound device and an image transducer protection method in accordance with an embodiment, an image transducer may be protected from a therapeutic focused ultrasound (FUS) signal, thereby minimizing damage to the image transducer and image artifact may be removed.

The advantages and features of the present invention and the manner of achieving the advantages and features will become apparent with reference to embodiments described in detail below together with the accompanying drawings. The same reference numerals refer to the same components throughout this disclosure.

The terms described below are defined in consideration of the functions in the embodiments of the present invention, and these terms may be varied according to the intent or custom of a user or an operator. Therefore, the definitions of the terms used herein should follow contexts disclosed herein.

The embodiments of the present invention are provided to aid those skilled in the art in the explanation and the understanding of the present invention.

<FIG> is a diagram for explaining a principle in which an image transducer is damaged by a focused ultrasound (FUS) signal in a FUS device according to an embodiment of the present invention.

Referring to <FIG>, a FUS device <NUM> includes an image transducer <NUM> and a treatment transducer <NUM>. The structure of the image transducer <NUM> and the treatment transducer <NUM> may vary. For example, as shown in <FIG>, the treatment transducer <NUM> may be formed around the image transducer <NUM> and the image transducer <NUM> may be formed in the center of the treatment transducer <NUM>. However, the structure of the image transducer <NUM> and the treatment transducer <NUM> is not limited to this, and may be modified in various ways.

The image transducer <NUM> transmits an image ultrasound signal and an image ultrasonic echo signal reflected from a target area of an object. The FUS device <NUM> generates an image of the target area using the received ultrasonic echo signal, and uses the generated image to monitor the state of the object.

The treatment transducer <NUM> generates a thermal lesion by focusing a therapeutic FUS signal to the target area of the object and performs FUS treatment. The location of the target area may be identified through monitoring of the image transducer <NUM>.

When the FUS signal transmitted through the treatment transducer <NUM> is reflected at the interface of an ultrasonic transmission medium (e.g., water) and a reflected FUS signal <NUM> is directed to the image transducer <NUM>, the image transducer <NUM> may be thermally/mechanically damaged. As a result, an image obtained through the image transducer may have artifacts and thus reduced quality, which may cause a problem in diagnosis. The present invention proposes a technique for minimizing thermal/mechanical damage to and protecting the image transducer <NUM> from the FUS signal <NUM> reflected from the image transducer <NUM> among the FUS signals transmitted from the treatment transducer <NUM>.

<FIG> is a diagram illustrating the configuration of a FUS device according to an embodiment of the present invention.

Referring to <FIG>, a FUS device <NUM> includes an ultrasound probe structure <NUM>, an image transmission/reception unit <NUM>, a treatment transmission unit <NUM>, a control unit <NUM>, an image generation unit <NUM>, a storage unit <NUM>, an input unit <NUM>, and an output unit <NUM>.

The ultrasound probe structure <NUM> includes an ultrasound probe configured to transmit an ultrasound signal to the object, receive an ultrasonic echo signal from the object, and convert the received ultrasonic echo signal into an electrical signal. The ultrasound probe is a combination of the image transducer <NUM> and the treatment transducer <NUM>.

A transducer array is provided at an end of the ultrasound probe. The transducer array refers to a plurality of elements arranged in an array. The transducer array generates an ultrasound signal while vibrating by an applied pulse signal or alternating current. The generated ultrasound signal is transmitted to the target area inside the object. The ultrasound signal generated by the transducer array is reflected from the target area inside the object, returning to the transducer array. The transducer array receives an ultrasonic echo signal reflected and returning from the target area and converts the received ultrasonic echo signal into an electrical signal. Each element in the transducer array may transmit and receive the ultrasound signal through each channel. The number of channels may be the same as the number of elements constituting the transducer array. Each element may include a piezoelectric vibrator or a thin film.

The ultrasound probe structure <NUM> may include a column-shaped case and a membrane filled with an ultrasonic transmission medium along the shape of the case so that the FUS signal is not reflected to the image transducer <NUM>. An embodiment of this will be described below with reference to <FIG>.

The image transmission/reception unit <NUM> includes a reception switch <NUM> and an image beamformer <NUM>.

The reception switch <NUM> selects a plurality of fist elements among elements constituting the image transducer <NUM> as a protection area and deactivates the same, and selects a plurality of second elements as a reception area and activates the same. The protection area is an area of the image transducer <NUM> expected to be thermally/mechanically damaged by the FUS signal. The plurality of first elements may be in the central area of the image transducer <NUM>, and the plurality of second elements may be in the peripheral area of the image transducer <NUM>. For example, when the image transducer <NUM> has a 1D transducer array structure, the protection area includes N elements located at the center of the entire scan line, and the reception area includes (the total number of channels-N)/<NUM> elements on each of the left and right sides with respect to a center position of the entire scan lines. The protection area of the image transducer <NUM> corresponds to the central part, where the FUS signal reflected from the interface of the ultrasonic transmission medium of the ultrasound probe structure <NUM> to the image transducer <NUM> is concentrated. The control unit <NUM> may intentionally deactivate the second elements of the protection area selected by means of the reception switch <NUM> to block the reception of the FUS signal reflected to the image transducer <NUM>, thereby protecting the second elements from the FUS signal and increasing the resolution of an ultrasound image.

The image beamformer <NUM> generates a transmission beam signal in response to a control signal of the control unit <NUM> and transmits the same to the image transducer <NUM>, and when receiving an ultrasonic echo signal from the image transducer <NUM>, generates a reception beam signal and transmits the same to the control unit <NUM>. The image beamformer <NUM> may generates the reception beam signal by focusing the ultrasonic echo signals received from the plurality of second elements of the image transducer.

The treatment transmission unit <NUM> includes a treatment beamformer <NUM>. The treatment beamformer <NUM> generates a FUS signal toward the target area of the object in response to the control signal of the control unit <NUM>, and transmits the same to the treatment transducer <NUM>.

The control unit <NUM> controls the overall operation of the FUS device <NUM>. In particular, the control unit <NUM> calculates a delay profile for the plurality of elements constituting the image transducer <NUM>, and calculates a time delay value according to the distance difference between the plurality of elements and a focal point of the object, on the basis of the calculated delay profile. In addition, the control unit <NUM> accordingly controls the image beamformer <NUM> to generate transmission/reception beam signals, and controls the treatment beamformer <NUM> to generate a FUS signal. The control unit <NUM> may generate a control command for each component of the FUS device <NUM> and control the FUS device <NUM>, in response to an instruction or command of a user input through the input unit <NUM>.

The control unit <NUM> may select the reception area by means of the reception switch <NUM> on the basis of the image generated by the image generation unit <NUM>. An embodiment of this will be described below with reference to <FIG>.

The control unit <NUM> may determine a contact state between the ultrasound probe structure <NUM> and the object from contact signals detected from a plurality of contact sensors, and control the treatment transducer <NUM> to transmit the FUS signal on the basis of the contact state. An embodiment of this will be described below with reference to <FIG> and <FIG>.

The image generation unit <NUM> generates an ultrasound image of the target area inside the object on the basis of the reception beam signal focused through the image transmission/reception unit <NUM>.

The storage unit <NUM> temporarily or non-temporarily stores the ultrasound image generated by the image generation unit <NUM>.

The input unit <NUM> is provided for the user to input a command for an operation of the FUS device <NUM>. The user may input or set a diagnosis mode selection command, such as an ultrasound diagnosis start command, amplitude mode (A-mode), brightness mode (B-mode), color mode, Doppler mode (D-mode), and motion mode (M-mode), region of interest (ROI) setting information including the size and location of an ROI, and the like through the input unit <NUM>.

The output unit <NUM> displays menus or information required for ultrasound diagnosis and ultrasound images obtained in the process of ultrasound diagnosis. The output unit <NUM> displays the ultrasound image of the target area inside the object generated by the image generation unit <NUM>. The ultrasound image displayed on the output unit <NUM> may be an A-mode ultrasound image, a B-mode ultrasound image, or a three-dimensional (3D) stereoscopic ultrasound image. The output unit <NUM> may output a contact state between the ultrasound probe structure <NUM> and the object and a contact instruction message to the outside.

<FIG> is a view illustrating a protection area located in the center of an image transducer according to an embodiment of the present invention.

Referring to <FIG> and <FIG>, when the treatment transducer <NUM> focuses an FUS signal to the target area <NUM> of the object, part of the FUS signal <NUM> is reflected from the interface of the ultrasound probe structure <NUM> and concentrated at the center of the image transducer <NUM>. Thus, the FUS device <NUM> sets the central part of the image transducer <NUM> as the protection area <NUM>. Reference numeral <NUM> denotes an image range of the image transducer <NUM>.

<FIG> is a view illustrating an example of channel activation for protecting a protection area on an entire scan line of an image transducer according to an embodiment of the present invention.

Referring to <FIG> and <FIG>, a transducer array is composed of a plurality of elements. In order to obtain an ultrasound image, a plurality of scan lines are required, and the FUS device <NUM> may perform beamforming of the focal point from the first scan line to the last scan line. The FUS device <NUM> transmits an ultrasound signal for each scan line, and generates an ultrasound image by receiving an ultrasonic echo signal reflected and returning from the target area of the object.

The FUS device <NUM> according to an embodiment may intentionally deactivate a predetermined scan line and activate only a predetermined scan line, rather than receiving ultrasound echo signals for all scan lines.

More specifically, the control unit <NUM> may select the reception area by means of the reception switch on the basis of the image generated by the image generation unit <NUM>, and control a focusing angle of the reception beam signal. For example, when the image transducer <NUM> has a 1D transducer array structure, the control unit <NUM> may select and combine at least one from four methods. The four methods include a first method of activating (Ch#-N)/<NUM> elements on each of the left and right sides with respect to the center position of the entire scan lines, a second method of activating (Ch#-N)/<NUM> elements on each of the left and right sides with respect to the center position of the entire scan lines and controlling a focusing angle, a third method of activating Ch#/<NUM> elements on each of the left and right sides with respect to the center position of the entire scan lines, and a fourth method of activating Ch#/<NUM> elements on each of the left and right sides with respect to the center position of the entire scan lines and controlling a focusing angle. Here, Ch# represents the total number of channels.

When the image transducer <NUM> is damaged by an FUS signal, the resolution of the central part of an ultrasound image deteriorates. The control unit <NUM> may check the resolution of the ultrasound image generated by the image generation unit <NUM> to determine whether the image transducer <NUM> is damaged. In this case, when it is determined that the image transducer <NUM> is damaged based on the deteriorated resolution, the control unit <NUM> may control the reception switch <NUM> to select the first method of activating (Ch#-N)/<NUM> elements on each of the left and right sides with respect to the center position of the entire scan lines. Further, the second method of controlling a focusing angle of the reception beam signal may be additionally combined to increase the resolution of the ultrasound image. For example, the control unit <NUM> may perform spatial compound for focusing the reception beam at different angles, rather than focusing the reception beam in a linear direction. In this case, image noise may be reduced, achieving good contrast and resolution.

<FIG> is a view illustrating a FUS device for protecting a protection area of an image transducer using a protective film according to an embodiment of the present invention.

Referring to <FIG> and <FIG>, the ultrasound probe structure <NUM> includes a protective film <NUM> mounted on the protection area of the image transducer <NUM>, causing the direction of the FUS signal to move away from the protection area of the image transducer <NUM>. The protective film <NUM> may include any one of a diffuse reflection material, a reflective material, and an attenuating material.

The diffuse reflection material/reflective material may be, for example, a copper foil made of metal, an aluminum foil, a reflective plate such as an acrylic plate made of plastic, or the like. The thickness and material of the diffuse reflection material/reflective material may be selected to reduce the magnitude of the FUS signal incident to the image transducer to a predetermined value (e.g., -<NUM> dB). However, if the thickness of the diffuse reflection material/reflective material is too thick, it affects the ultrasound signal of the adjacent image channel and the FUS signal of the treatment transducer, and hence, the thickness is limited within the allowable range. In this case, as the diffuse reflection material/reflective material, a material with a difference in impedance from the ultrasonic transmission medium (e.g., water) greater than a predetermined value may be used.

The attenuating material may be, for example, natural rubber, latex, silicone rubber, or the like such that it has a small difference in acoustic impedance from the ultrasonic transmission medium (e.g., water) and can attenuate ultrasound energy. The thickness and substance of the attenuating material may be selected in the same way as for the reflective material.

<FIG> is a view illustrating an ultrasound probe structure for protecting an image transducer according to an embodiment of the present invention.

Referring to <FIG> and <FIG>, the ultrasound probe structure <NUM> may include a column-shaped case <NUM> and a membrane <NUM> filled with an ultrasonic transmission medium along the shape of the case <NUM>. The case <NUM> is formed in a vertical direction with respect to a skin surface <NUM> of the object so that a FUS signal is not reflected. The case <NUM> may be in the form of a sound-absorbing plate.

The membrane <NUM> has a structure mounted inside the case <NUM> to block an ultrasound radiation surface. An accommodation space <NUM> is formed between a focused ultrasound radiation surface and the membrane <NUM> for accommodating the ultrasonic transmission medium, and the membrane <NUM> is made of an elastic material. In general, when the accommodation space <NUM> is filled with a set amount of ultrasonic transmission medium, the membrane <NUM> forms a hemispherical shape that is convex downward by an elastic force. In this case, the FUS signal may not reach the target area <NUM> of the object but may be reflected in an air layer <NUM> between the membrane <NUM> and the skin surface <NUM> of the object along the hemispherical shape of the membrane <NUM>, and directed toward an intermediate element of the image transducer <NUM>. In this case, the image transducer <NUM> may degrade.

In the FUS device <NUM> according to an embodiment, the case <NUM> of the ultrasound probe structure <NUM> is provided in the shape of a vertical column with respect to the skin surface <NUM> of the object so that the membrane <NUM> does not form a hemispherical shape when the accommodation space <NUM> is filled with the ultrasonic transmission medium. When the accommodation space <NUM> is filled with a set amount of the ultrasonic transmission medium, the membrane <NUM> tightly fits along the vertical shape of the case <NUM>. Accordingly, the membrane <NUM> is formed in the shape of a column, rather than in the shape of a hemisphere, through the column-shaped case <NUM>, so that the direction of the FUS signal is not formed in the air layer <NUM> outside the case <NUM>, but in the target area <NUM> of the object. The height of the case <NUM> is adjustable. An embodiment of this will be described below with reference to <FIG>.

The ultrasound probe structure <NUM> according to an embodiment includes a plurality of contact sensors <NUM>. The plurality of contact sensors <NUM> detect whether the ultrasound probe structure <NUM> is in contact with the object. The plurality of contact sensors <NUM> may be formed along the periphery of the lower surface of the ultrasound probe structure <NUM> in contact with the object.

In order to prevent the air layer <NUM> from being generated due to lifting occurring when the ultrasound probe structure <NUM> is in contact with the object, the FUS device <NUM> detects the contact with the object using the plurality of contact sensors <NUM>. The FUS device <NUM> determines the contact state at each position from contact signals detected by means of the plurality of contact sensors <NUM>, and controls the treatment transducer to transmit a FUS signal on the basis of the contact states. In this case, the FUS device <NUM> blocks the transmission of the FUS signal of the treatment transducer in the case of incomplete contact, and transmits the FUS signal through the treatment transducer only in the case of complete contact. For example, contact signals are detected from a predetermined number or more of the plurality of contact sensors <NUM>, the FUS device <NUM> determines that the ultrasound probe structure <NUM> is in contact with the skin surface of the object, and at this time, transmits the FUS signal through the treatment transducer. A device configuration for this will be described below with reference to <FIG>.

<FIG> is a top view of an ultrasound probe structure including a case and a membrane according to an embodiment of the present invention.

Referring to <FIG> and <FIG>, the ultrasound probe structure <NUM> includes a column-shaped case <NUM> and a membrane <NUM> filled with an ultrasonic transmission medium along the shape of the case <NUM>, and may solve a problem in which a FUS signal is reflected to the image transducer <NUM> by the case <NUM>.

<FIG> is a bottom view of an ultrasonic probe structure including a plurality of contact sensors according to an embodiment of the present invention.

Referring to <FIG> and <FIG>, the ultrasound probe structure <NUM> includes a plurality of contact sensors <NUM>. The FUS device <NUM> uses the plurality of contact sensors <NUM> to determine whether the ultrasound probe structure <NUM> is in contact with the object, and controls the treatment transducer <NUM> to transmit a FUS signal only in the case of contact with the object.

<FIG> is a diagram illustrating the configuration of a FUS device including a plurality of contact sensors according to an embodiment of the present invention.

Referring to <FIG> and <FIG>, the FUS device <NUM> may include a plurality of contact sensors 70a, 70b, 70c, and 70d, a plurality of noise filters <NUM>, a contact switch <NUM>, a signal processing unit, a control unit <NUM>, and an output unit <NUM>. The signal processing unit may include an analog-to-digital (A/D) converter <NUM> and an amplification unit <NUM>. The plurality of noise filters <NUM>, the contact switch <NUM>, and the signal processing unit may be located in the image transmission/reception unit <NUM> of <FIG>.

The plurality of noise filters <NUM> filter noise by distinguishing a contact signal and a noise signal from signals generated from each of the contact sensors 70a, 70b, 70c, and 70d.

The contact switch <NUM> selects a predetermined contact signal from among a plurality of contact signals from which noise has been filtered by the plurality of noise filters <NUM> and transmits the selected contact signal to the A/D converter <NUM>.

The signal processing unit performs signal processing on the contact signal. For example, the A/D converter <NUM> converts an analog signal into a digital signal, and the amplification unit <NUM> amplifies the digital signal.

The control unit <NUM> determines a contact state at each position from the contact signal received from the signal processing unit, and controls the treatment transducer <NUM> to transmit the FUS signal on the basis of the contact state. For example, as shown in <FIG>, when the control unit <NUM> detects contact signals from three or more (contact rate of <NUM>%) among the four contact sensors 70a, 70b, 70c, and 70d, the control unit <NUM> determines that the ultrasound probe structure <NUM> is in contact with the skin surface of the object, and at this time, controls the treatment transducer <NUM> to transmit the FUS signal. Further, when all four contact sensors 70a, 70b, 70c, and 70d detect contact, the control unit <NUM> may determine complete contact (contact rate of <NUM>%), and control the treatment transducer <NUM> to transmit the FUS signal only in the case of complete contact.

The control unit <NUM> outputs the contact state to the outside through the output unit <NUM> when the contact state satisfies a predetermined condition. At this time, a contact instruction message may be output through the output unit <NUM> together. For example, a contact instruction message may be output through a light-emitting diode (LED), voice, screen, or the like.

<FIG> is a view illustrating an example of adjusting the height of a case of an ultrasound probe structure according to an embodiment of the present invention.

Referring to <FIG> and <FIG>, a height adjustment unit of the FUS device <NUM> adjusts the height H' of the case <NUM> of the ultrasound probe structure <NUM> to LcosΘ-D. Here, L denotes a FUS signal length of the outermost channel of the treatment transducer <NUM> to the target area <NUM> of the object, H denotes a vertical distance from the treatment transducer <NUM> to the target area <NUM> of the object, Θ denotes an angle between L and H, D denotes a vertical distance from the target area <NUM> of the object to the skin surface <NUM> of the object, and H' denotes the height of the case <NUM> of the ultrasound probe structure <NUM>.

Claim 1:
A focused ultrasound device (<NUM>) comprising:
an ultrasound probe structure (<NUM>) comprising a treatment transducer (<NUM>) for transmitting a focused ultrasound signal and an image transducer (<NUM>) for transmitting and receiving an ultrasonic image signal;
a reception switch (<NUM>) for selecting a plurality of first elements among elements of the image transducer (<NUM>) as a protection area (<NUM>) and deactivating same, and selecting a plurality of second other elements among the elements of the image transducer (<NUM>) as a reception area and activating same;
an image beamformer (<NUM>) for forming a reception beam signal by focusing ultrasonic echo signals received from the plurality of second elements;
an image generation unit (<NUM>) for generating an image for a target area (<NUM>) in an object on the basis of the reception beam signal; and
a control unit (<NUM>) for controlling the selection of the protection area (<NUM>) and reception area by means of a reception switch (<NUM>),
characterized in that the plurality of first elements are in a central area of the image transducer (<NUM>) in which the focused ultrasound signal reflected from an interface of the ultrasound probe structure (<NUM>) to the image transducer (<NUM>) is concentrated and the plurality of second elements are in a peripheral area of the image transducer (<NUM>).