Patent Application
20100076352
The present invention relates, in general, to an extracorporeal High Intensity Focused Ultrasound (HIFU) necrosis apparatus through the control of an electronic signal, and more particularly, to a method of forming a focus using an electronic signal in a planar type array of an ultrasonic oscillator that is an ultrasonic source.
In general, extracorporeal HIFU refers to ultrasonic wave that is obtained by focusing ultrasonic wave, generated outside a human body, on a target tissue (for example, tumor) within a life. Today, extracorporeal HIFU has been in the spotlight in the medical field because of its non-invasive characteristic.
A basic principle of HIFU, of selectively breaking tissues, such as tumor, by using a conventional ultrasonic wave is illustrated in
The HIFU necrosis apparatus has been used to treat prostate tumor and hypertrophia in Korea since several years ago, and recently finds increasing application fields in various solid cancer treatments, including hepatoma. However, if a target tissue is eliminated using the conventional ultrasonic oscillator of the geometric form, there is a problem in that even normal tissues not having tumor are broken due to a limit accompanied by the geometric shape of the ultrasonic oscillator. A problem also arises in spatial limit for installation because the geometric curve of the ultrasonic oscillator is used.
Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide an extracorporeal HIFU necrosis apparatus through the control of an electronic signal and a method of using the same, in which an ultrasonic oscillator is constructed to have a planar shape not a geometric shape, so that convenience in installing the apparatus can be improved, an electrical signal can be controlled easily and precisely, and target tissues can be eliminated without damage to normal tissues.
The above object of the present invention is accomplished by an extracorporeal HIFU necrosis apparatus through the control of an electronic signal, including oscillation elements for generating ultrasonic beams; an ultrasonic oscillator array having the oscillation elements fixed on a plane and oriented toward a life; delay circuits respectively connected to the oscillation elements for delaying ultrasonic oscillation by a delay time; and control means for controlling the delay time so that the ultrasonic beams are focused.
The shape of the ultrasonic oscillator array 100 in which the oscillation elements 110 are arranged may be circular or square.
A length of a diameter or one side of the ultrasonic oscillator array 100 may be in the range of 15 to 30 cm.
The ultrasonic oscillation elements 110 may be ring-shaped, and a plurality of the ring-shaped ultrasonic oscillation elements 110 having different sizes may be disposed on a concentric circle.
The oscillation elements 110 may include piezoelectric material, a magnetostrictive transducer or a Capacitive Micromachined Ultrasonic Transducer (CMUT).
Furthermore, the above object of the present invention is accomplished by an extracorporeal HIFU necrosis apparatus through the control of an electronic signal, including an ultrasonic oscillator array 100 having ultrasonic oscillation elements 110 fixed on a plane and oriented toward a life; delay circuits 120 respectively connected to the oscillation elements 110 for delaying ultrasonic oscillation by a delay time; an ultrasonic oscillator including control means 150 for controlling the delay time so that the ultrasonic beams are focused; and 3-D image diagnosis means 170 for measuring the shape of a target tissue 30 within the life and outputting the measured shape as a 3-D image, wherein the control means 150 controls the delay time of the delay circuits 120 based on a positional data of the 3-D image in order to focus the ultrasonic beams on the target tissue 30.
The image diagnosis means 170 may include one of Magnetic Resonance Imaging (MRI), Computed Tomography (CT), and ultrasonic image diagnosis means.
Meanwhile, the extracorporeal HIFU necrosis apparatus may further include amplification means 140 for amplifying a signal applied to the ultrasonic oscillator array 100.
Furthermore, the extracorporeal HIFU necrosis apparatus may further include a multiplexer 130 for selectively applying a signal to the ultrasonic oscillator array 100.
The extracorporeal HIFU necrosis apparatus may further include necrosis design means 160 for designating a necrosis sequence based on the 3-D image between the image diagnosis means 170 and the control means 150. The control means 150 may control the delay time of the delay circuit 120 based on a necrosis sequence designated by the necrosis design means 160 in order to focus the ultrasonic waves on the target tissue 30.
Furthermore, the above object of the present invention is accomplished by a method of employing an extracorporeal HIFU necrosis apparatus through the control of an electronic signal, including a step (S100) of allowing 3-D image diagnosis means 170 to measure a shape of a target tissue 30 within a life and output a measured shape as a 3-D image; a step (S140) of allowing control means 150 to control delay time of each of delay circuits 120 connected to an ultrasonic oscillator array 100 based on a positional data of the 3-D image; a step (S180) of allowing the control means 150 to oscillate the ultrasonic oscillator array 100; and a step (S200) of making the target tissue 30 necrotized by focusing an oscillated ultrasonic wave on the target tissue 30 depending on a difference of the delay time.
Meanwhile, the method may further include a design step (S120) of specifying a necrosis sequence of the target tissue 30 and an intensity of an ultrasonic beam based on the 3-D image, after the step of outputting the 3-D image (S100).
Furthermore, the method may further include a step (S150) of amplifying a signal of the control means 150 and controlling ultrasonic sound power by controlling an amplification ratio, after the step (S140) of controlling the delay time.
Furthermore, the method may further include a step (S160) of selecting an oscillation element from which an ultrasonic beam is radiated and controlling a sound intensity I of an ultrasonic wave at a focus through the control of the amplification ratio, after the step (S150) of controlling the ultrasonic sound power.
The above object, and further objects and merits and characteristics of the present invention will become more apparent from the following detailed description and preferred embodiments taken in conjunction with the accompanying drawings.
According to the present invention, a waved surface having a variety of directions and curvatures can be formed using several oscillation elements and delay circuits existing on a plane. In other words, if an ultrasonic oscillator array having a predetermined shape upon fabrication is used, an installation position of an apparatus has to be changed, posing a limit to a focus brought in a desired place. If an electronic signal is used, however, there is an advantage in that a focus can be brought in any desired place without changing an installation position.
Accordingly, there is an advantage in that a tissue, such as tumor, which is a target tissue, can be necrotized without damage to normal tissues. Furthermore, if an extracorporeal HIFU necrosis apparatus through the control of an electronic signal according to the present invention is employed, there are advantages in that the recovery of a patient can quicken, a symptom after recovery can be mitigated, and so on because there is no damage to normal tissues other than target tissues.
The present invention will now be described in detail in connection with preferred embodiments with reference to the accompanying drawings.
The extracorporeal HIFU necrosis apparatus through the control of an electronic signal according to the present invention has the same basic principle as that of the conventional geometrical ultrasonic oscillator array 10 in that an ultrasonic beam is focused on a target tissue 30 in order to induce a temperature rise of a critical temperature (for example, 60 degrees Celsius) or more, and the target tissue 30 is necrotized. However, the extracorporeal HIFU necrosis apparatus of the present invention differs from the conventional geometrical ultrasonic oscillator array 10 in that an ultrasonic oscillator array 100 is formed on a plane. The planar ultrasonic oscillator array 100 has several ultrasonic oscillation elements 110 mounted therein. Ultrasonic waves are radiated from the respective ultrasonic oscillation elements 110 with a time lag and are then focused on the target tissue 30. As the ultrasonic waves are radiated with a time lag, a focus can be formed in the same manner as that a focus is formed by the geometric type ultrasonic oscillator.
The front shape of the planar ultrasonic oscillator array 100 in which the oscillation elements 110 are arranged may be preferably isotropic, circular or square, as shown in
Furthermore, when considering the size of the target tissue 30 (for example, tumor) to be eliminated, the size of a life, etc., the length of a diameter or one side of the planar ultrasonic oscillator array 100 may be preferably in the range of 15 to 30 cm. When the length of a diameter or one side of the planar ultrasonic oscillator array 100 is 15 cm or less, it is difficult to expect a sufficient temperature rise in the target tissue 30 during a predetermined time since the number of the ultrasonic oscillation elements 110 from which ultrasonic waves are generated is less. When the length of a diameter or one side of the planar ultrasonic oscillator array 100 is 30 cm or more, there is a problem in that efficiency is low, such as that the intensity of an ultrasonic beam is weak and time taken for temperature to rise is long, because a focus distance is lengthened.
The oscillation elements 110 forming the planar ultrasonic oscillator array 100 can be disposed in matrix form, as shown in
In this case, the oscillation elements 110 forming a circular ultrasonic oscillator array 100 can be disposed in a ring shape and the oscillation elements 110 with different radii can be disposed on a concentric circle, as shown in
The shape of one of several ultrasonic oscillation elements 110 existing in the planar ultrasonic oscillator array 100 can be rectangular, circular, elliptical, fan-shaped, ring-shaped and so on as well as square shown in
An oscillator that can be used as the ultrasonic oscillation element 110 can be formed from a piezoelectric material employing the piezoelectric effect, such as PZT-based material with a high electro-mechanical coupling coefficient, PMN-PT-based material with a good piezoelectric characteristic or LiNb-based material. A magnetostrictive transducer that varies according to a magnetization state can be used as the oscillator. A Capacitive Micromachined Ultrasonic Transducer (CMUT) can also be used as the oscillator. The CMUT is advantageous in that the same transducer can be fabricated and it can be directly applied to an electronic circuit because a semiconductor process is introduced.
As another embodiment of the extracorporeal HIFU necrosis apparatus through the control of an electronic signal, there is an extracorporeal HIFU necrosis apparatus through the control of an electronic signal, including the ultrasonic oscillator array 100 having the ultrasonic oscillation elements 110 fixed on a plane and oriented toward a life; the delay circuits 120 respectively connected to the oscillation elements 110 for delaying ultrasonic oscillation by a delay time; an ultrasonic oscillator including the control means 150 for controlling the delay time so that the ultrasonic beams are focused; and 3-dimensional (3-D) image diagnosis means 170 for measuring the shape of the target tissue 30 within the life and outputting the measured shape as a 3-D image. The control means 150 controls the delay time of the delay circuit 120 based on a positional data of the 3-D image in order to focus the ultrasonic beams on the target tissue 30.
It is preferred that the image diagnosis means 170 generally employ Magnetic Resonance Imaging (MRI), Computed Tomography (CT), ultrasonic image diagnosis means or the like.
It is preferred that amplification means 140 for amplifying a signal applied to the ultrasonic oscillator array 100 be further included.
It is preferred that a multiplexer 130 for selectively applying a signal to the ultrasonic oscillator array 100 be further included.
Furthermore, it is preferred that necrosis design means 160 for designating a necrosis sequence based on the 3-D image acquired by the 3-D image diagnosis means be further included between the image diagnosis means 170 and the control means 150.
The role and use method of each means, as a preferred embodiment of the extracorporeal HIFU necrosis apparatus through the control of an electronic signal, including the above means, is described below.
A 3-D image of the target tissue 30, which is acquired by the image diagnosis means 170, is sent to the necrosis design means 160.
The necrosis design means 160 establishes a plan for a sequence for breaking the target tissue 30, the intensity of an ultrasonic beam, etc. based on the 3-D image. It is intended not to give much burden on a life in which the target tissue 30 exists when the size of the target tissue 30 is small and is not simple in structure.
The control means 150 controls a delay time given to each delay circuit 120 based on a positional data of the 3-D image and the designed plan. Ultrasonic beams are radiated according to the delay time and are focused on the target tissue 30.
The amplification means 140 amplifies an electrical signal received from the control means 150. The signal amplified in the amplification means 140 is related to the intensity of the ultrasonic beams radiated from the oscillation elements 110. In other words, the output (that is, sound power P) of a desired ultrasonic beam can be controlled by controlling the amplification ratio (gain) of the amplification means 140. In this case, a total sound power P is decided depending on voltage Vi applied to each of the oscillation elements 110 and radiation conductance Gi of each oscillation element, and can be expressed in the following [Equation 1].
The multiplexer 130 selects one of several oscillation elements 110 at a location where the ultrasonic beam has to be radiated, and sends the amplified electrical signal to one of the delay circuits 120 connected to the selected oscillation element 110. That is, it is not necessary to apply signals to the several delay circuits 120, respectively, using the multiplexer 130.
The plurality of delay circuits 120 are connected to the plurality of oscillation elements 110, respectively. The delay circuits 120 delay the signal received from the multiplexer 130 by a specific time, and induce the radiation of the ultrasonic beam. The plurality of delay circuits 120 cause a variety of delay times so that the radiated ultrasonic beams have various waved surfaces.
That is, by using the delay circuit 120 and the planar ultrasonic oscillator array 100, the same focus as that, which could be obtained in the conventional geometric ultrasonic oscillator array 10, can be obtained. Furthermore, the geometric ultrasonic oscillator array 100 is problematic in accurate control since spatial movement is required in the ultrasonic oscillator when the location of the focus is to be changed. However, in the extracorporeal focus type necrosis apparatus through the control of an electronic signal, a focus location can be changed accurately and easily through the use of only a delay time without spatial movement.
A method of controlling a focus location by employing a time delay of several ultrasonic oscillation elements 110 and several delay circuits 120 disposed in the ultrasonic oscillator array 100 is described in detail below.
Referring to
Referring to
Furthermore, by selecting an oscillation element through the multiplexer 130 and controlling the amplification ratio (gain) of the amplification means 140, a sound intensity I at the focus can be controlled.
At this time, the sound intensity I can be expressed in the following [Equation 2].
where, di is a distance from each element to a focus distance, α is sound attenuation in a medium, A is a beam cross section in a focus, and Vi is voltage applied to each oscillation element. Ns is the number of oscillation elements, which are selected by the multiplexer 130.
The method includes a step (S100) of allowing the 3-D image diagnosis means 170 to measure the shape of the target tissue 30 within a life and output a measured shape as a 3-D image, a step (S140) of allowing the control means 150 to control delay time of each of the delay circuits 120 connected to the ultrasonic oscillator array 100 based on a positional data of the 3-D image, a step (S180) of allowing the control means 150 to oscillate the ultrasonic oscillator array 100, and a step (S200) of causing the target tissue 30 to be necrotized by focusing the oscillated ultrasonic wave on the target tissue 30 depending on a difference of the delay time.
It is preferred that after the 3-D image output step (S100), a design step (S120) of designating a necrosis sequence of the target tissue 30 and the intensity of an ultrasonic beam based on the 3-D image be further included. This is because a plan for the intensity of ultrasonic beams, a focus sequence, etc. for making a tissue necrotized when the target tissue 30 has a complicated structure or shape is required as mentioned earlier.
It is preferred that a step (S150) of amplifying signal of the control means 150 and controlling ultrasonic sound power by controlling an amplification ratio be further included, after the step (S140) of controlling the delay time. The ultrasonic sound power can be controlled by controlling the parameter values in [Equation 1], as mentioned earlier. This is because the ultrasonic sound power is concerned with the intensity of the ultrasonic beams radiated from the ultrasonic oscillation elements 110. In the method of amplifying the signal, it would be economical to amplify the signal at the control means 150 before the signal reaches the delay circuit 120 in terms of the manufacturing cost. However, a method of amplifying the signal at the control means 150 after the signal reaches the delay circuit 120, that is, when the signal reaches from the delay circuit 120 to the oscillation elements 110 may be used.
Furthermore, it is preferred that a step (S160) of selecting an oscillation element from which an ultrasonic beam is radiated and controlling the sound intensity I of an ultrasonic wave at a focus through the control of the amplification ratio be further includes, after the step (S150) of controlling the ultrasonic sound power. It is possible to predict the sound intensity at a point at which the focus of an ultrasonic beam is formed based on the above-mentioned [Equation 2] by controlling the sound power according to the step (S140) of controlling the ultrasonic sound power and selecting the oscillation element 110 from which the ultrasonic beam is radiated (in this case, the number of selected oscillation elements is indicated by Ns).
As described above, an optimal state for making the target tissue 30 necrotized within a life can be used safely for necrosis of the target tissue 30 without damage to normal tissues by predicting and controlling a focus location of an ultrasonic beam, the sound power P, and the sound intensity I at the focus.
As described above, according to the present invention, waved surfaces with a variety of directions and curvatures can be formed using several oscillation elements and several delay circuits disposed on a plane. It is therefore possible to form a focus at any desired place without change of an installation position of an ultrasonic oscillator array. Furthermore, a tissue, such as tumor, which is a target tissue, can be necrotized without damage to normal tissues necrosis.
Further, if an extracorporeal HIFU necrosis apparatus through the control of an electronic signal according to the present invention is used, there is no damage to normal tissues other than a target tissue. Accordingly, there are advantages in that a recovery speed of a patient can quicken, a symptom after recovery can be mitigated, and so on.
Although the specific embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2006-0116052 | Nov 2006 | KR | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/KR06/05178 | 12/4/2006 | WO | 00 | 5/1/2009 |
