Patent Publication Number: US-8973443-B2

Title: Ultrasound probe

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims the priority of Korean Patent Application No. 10-2010-0004543, filed on Jan. 18, 2010 in the KIPO (Korean Intellectual Property Office). Further, this application is the National Phase application of International Application No. PCT/KR2010/004603 filed Jul. 15, 2010, which designates the United States and was published in Korean. 
     TECHNICAL FIELD 
     The present invention relates to an ultrasound treatment system using high-intensity focused ultrasound and, more particularly, to an ultrasound probe of the ultrasound treatment system which easily performs manufacturing and maintenance processes. 
     BACKGROUND ART 
     Recently, ultrasound treatment has increased the range of use. With the growth of ultrasound treatment, a specific ultrasound treatment, especially high-intensity focused ultrasound (HIFU), is applied to damaging dose in order to effectively cure many types of disease, especially tumor. In comparison with conventional surgical operation and chemotherapy, HIFU treatment may hardly traumatize patients and also realize non-invasive treatment. Therefore, HIFU treatment is increasing in clinical applications. For example, HIFU treatment are being used for liver cancer, bone sarcoma, breast cancer, pancreas cancer, kidney cancer, soft tissue tumor, pelvic tumor, and the like. 
     Such an ultrasound treatment apparatus employs in general an ultrasound probe using a sphere focusing. Ultrasound emitted from all points of the ultrasound probe proceeds toward the center of a sphere, thus forming focused ultrasound. An emitter of the ultrasound treatment apparatus emits ultrasound from the outside to the inside of a body, and this forms a high-energy focused point by being focused during emission and transmission. Highly intensive and continuous ultrasound energy is applied to a target region of a treatment subject. Excessively high temperature (65˜100° C.), cavitation effect, mechanical effect and acoustic-chemical effect may selectively cause coagulative necrosis of ailing organization and also prevent proliferation, invasion and metastasis of tumors. 
     This ultrasound treatment apparatus requires more exact, safer, and more effective localization of a focused point during HIFU treatment and also requires more convenient operability for locating the target. 
     DETAILED DESCRIPTION OF THE INVENTION 
     Technical Problems 
     Accordingly, an object of the present invention is to provide an ultrasound probe with improved ultrasound and heat dissipation characteristics. 
     Another object of the present invention is to provide an ultrasound probe which can easily perform manufacturing and maintenance processes. 
     Technical Solutions 
     In order to accomplish the above objects, the present invention provides an ultrasound probe that comprises a housing, a plurality of probe units, and a grounding film. The housing is recessed inward from edges at an upper part thereof and has a plurality of mounting holes formed apart from a center and to the edges. The plurality of probe units are installed in the mounting holes, respectively, so that a spherical surface for a spherical focusing is formed at the upper part of the housing. The grounding film covers the spherical surface formed by the plurality of probe units. 
     In the ultrasound probe of the present invention, each of the probe units may include a connection bar having electric and thermal conductivity, a first connection pin formed on a lower surface of the connection bar and protruded from a lower part of the housing through the mounting hole of the housing, a rear block formed on an upper surface of the connection bar and having an inclined plane for forming the spherical surface, a piezoelectric wafer formed on the inclined plane of the rear block, and a plurality of acoustic matching layers formed on an upper surface of the piezoelectric wafer. 
     In the ultrasound probe of the present invention, the mounting holes may be arranged in a radial form in the housing. 
     In the ultrasound probe of the present invention, the mounting holes may be arranged along ring-shaped coaxial regions which are disposed beyond a certain radius from the center of the spherical surface and to the edges of the spherical surface. 
     In the ultrasound probe of the present invention, stacks of the rear block, the piezoelectric wafer and the acoustic matching layer formed on the first connection pin may have a first length at a first region toward the center of the housing and a second length at a second region toward the edges of the housing, the first length being shorter than the second length. 
     In the ultrasound probe of the present invention, the probe units arranged along the same ring-shaped region may have the same shape. 
     In the ultrasound probe of the present invention, the probe units may have increasing length according as positions thereof become more distant from the center of the housing, and the first connection pins protruded from the lower part of the housing may be all the same length. 
     In the ultrasound probe of the present invention, the connection bars located at different ring-shaped regions may have different lengths which increase according as positions thereof become closer to the edges and become more distant from the center of the housing. 
     In the ultrasound probe of the present invention, the connection bar of the probe unit may have at a lower part thereof a first pin hole into which the first connection pin is inserted. 
     In the ultrasound probe of the present invention, the rear block may have a second connection pin extruded from a lower surface thereof, and the connection bar of the probe unit may have at an upper part thereof a second pin hole into which the second connection pin is inserted. 
     In the ultrasound probe of the present invention, the mounting hole may include a first mounting hole formed at the lower part of the housing such that the first connection pin is inserted into the first mounting hole and protruded from the first mounting hole, a second mounting hole vertically connected to the first mounting hole such that the connection bar is inserted into the second mounting hole, and a third mounting hole vertically connected to the second mounting hole such that the rear block is inserted into the third mounting hole. 
     In the ultrasound probe of the present invention, the connection bar of the probe unit may be formed of copper. 
     In the ultrasound probe of the present invention, the rear block of the probe unit may be formed of graphite, the piezoelectric wafer may be formed of PZT or PMN-PT, and the grounding film may be formed of polyimide film. 
     The ultrasound probe of the present invention may further comprise a cover layer covering the grounding film. 
     Advantageous Effects 
     Since a plurality of probe units are installed in the housing and further a spherical surface is formed at the upper part of the housing, the ultrasound probe according to the present invention may enhance ultrasound characteristics (acoustic characteristics) through the control of the plurality of probe units. Also, since the probe units are arranged along a plurality of ring-shaped coaxial regions which are disposed beyond a certain radius from the center of the spherical surface and to the edges of the spherical surface, and since each ring-shaped region has a plurality of divided sections, acoustic loss caused by empty spaces between the probe units may be prevented and thus ultrasound characteristics may be enhanced. And also, since the probe units located at adjacent ring-shaped regions are arranged differently in zigzags, ultrasound characteristics may be enhanced and further a unifying force between the probe units may be improved. 
     The probe unit has at the lower part thereof the connection pin and has at the upper part thereof a stack structure of the rear block, the piezoelectric wafer, and the acoustic matching layer via the connection bar of copper. Therefore, heat dissipation efficiency may be enhanced through the connection bar. 
     Since the grounding film covers and protects the entire upper surface of the probe units inserted into the housing, a manufacturing process of the ultrasound probe may be simplified. Also, acoustic loss caused by empty spaces between the probe units may be prevented and thus ultrasound characteristics may be enhanced. 
     The ultrasound probe according to this invention is manufactured by inserting the probe unit into the mounting hole formed in the housing, so a manufacturing process is simplified. Also, since the probe unit is detachable from the housing, a maintenance process is allowed for each of the probe units. Therefore, when some parts of the ultrasound probe are defective, there is no need to replace the entire ultrasound probe and hence unnecessary cost loss may be prevented. 
     Since the connection pins are extruded from the lower part of the housing, the ultrasound probe according to this invention can be connected to the main body of the ultrasound treatment system using the connector cable of a connector coupling manner rather than a wiring manner. Therefore, the ultrasound treatment system has an advantage of simply performing a maintenance process for the ultrasound probe by detaching the ultrasound probe from the connector cable. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         FIG. 1  is a perspective view illustrating a state in which a connector cable is connected to an ultrasound probe in accordance with an embodiment of the present invention. 
         FIG. 2  is a perspective view illustrating the ultrasound probe in accordance with an embodiment of the present invention. 
         FIG. 3  is a cross-sectional view illustrating the ultrasound probe shown in  FIG. 2 . 
         FIG. 4  is a perspective view illustrating a probe unit shown in  FIG. 2 . 
         FIG. 5  is a perspective view illustrating the probe unit shown in  FIG. 4 . 
         FIG. 6  is a cross-sectional view illustrating the probe unit shown in  FIG. 5 . 
     
    
    
     BEST MODE FOR CARRYING OUT THE INVENTION 
     Embodiments of the present invention will now be described more fully with reference to the accompanying drawings. 
     As shown in  FIGS. 1 to 3 , an ultrasound probe  100  according to an embodiment of the present invention is connected to a main body of an ultrasound treatment system in a connector coupling manner using a connector cable  200 . 
     The ultrasound probe  100  includes a housing  10 , a plurality of probe units  20  installed in the housing  10  to form a spherical surface at the upper part of the housing  10 , a grounding film  30  covering the spherical surface formed by the plurality of probe units  20 , and a cover layer covering the grounding film  30 . Namely, the upper surface of the ultrasound probe  100  is formed with a bowl-shaped spherical surface in order to offer a spherical focusing. In the ultrasound probe  100 , first connection pins  22  of the probe unit  20  are uniformly extruded from the lower surface of the housing  10 . A through hole  14  is formed at the central part of the housing  10 . The grounding film  30  is formed on the upper surface of the plurality of probe units  20 , namely, on the upper surface of the acoustic matching layer  27 , and forms a spherical surface. A polyimide film may be used for the grounding film  30 . The cover layer  40  covers and protects the grounding film  30 . Silicone material may be used for the cover layer  40 . 
     Additionally, the connector cable  200  includes a connector  110  having connection holes  112  which correspond to the first connection pins  22 , and a cable  120  which electrically couples the first connection pins  22  inserted into the connector  110  to the main body of the ultrasound treatment system. The main body of the ultrasound treatment system applies a driving signal to the ultrasound probe  100  through the connector cable  200 , and in response to the driving signal the ultrasound probe  100  generates high-intensity focused ultrasound required for ultrasound treatment. 
     As shown, the connector  110  of the connector cable  200  has, at the central part thereof, a through hole  114  which corresponds to a through hole  14  of the housing  10 . However, instead of the through hole, any hole with a limited depth may be formed or no hole may be formed. 
     Since the first connection pins  22  are extruded from the lower part of the housing  10 , the ultrasound probe  100  according to an embodiment of this invention can be connected to the main body of the ultrasound treatment system using the connector cable  200  of a connector coupling manner rather than a wiring manner. Therefore, the ultrasound treatment system has an advantage of simply performing a maintenance process for the ultrasound probe  100  by detaching the ultrasound probe  100  from the connector cable  200 . 
     Furthermore, since the grounding film  30  covers and protects the entire upper surface of the probe units  20  inserted into the housing  10 , a manufacturing process of the ultrasound probe  100  may be simplified. Also, acoustic loss caused by empty spaces between the probe units  20  may be prevented and thus ultrasound characteristics may be enhanced. 
     As shown in  FIGS. 1 to 6 , the ultrasound probe  100  according to an embodiment of this invention includes the housing  10 , the probe unit  20  and the grounding film  30  and may further include the cover layer  40 . The housing  10  is recessed inward from edges at the upper part thereof, and a plurality of mounting holes  12  are formed apart from the center and to the edges. Additionally, the probe units  20  are installed in the mounting holes  12 , respectively, so that a spherical surface for a spherical focusing is formed at the upper part of the housing  10 . 
     Particularly, the housing  10  has a cylindrical shape, has the through hole  14  formed at the central part thereof, and has the spherical upper part around the central part. The housing  10  may be formed of rigid plastic material such as polyethylene (PE), polypropylene (PP), polystyrene (PS), polyethylene-terephthalate (PET), acrylonitrile-butandiene-styrene (ABS), or the like. 
     The mounting holes  12  are arranged in a radial form in the housing  10 . Specifically, the mounting holes  12  may be arranged along ring-shaped coaxial regions which are disposed beyond a certain radius from the center of the spherical surface and to the edges of the spherical surface. Each mounting hole  12  is parallel to the central axis of the housing  10  and has the first mounting hole  12   a , the second mounting hole  12   b , and the third mounting hole  12   c . From the first mounting hole  12   a  to the third mounting hole  12   c , the diameter of hole is gradually increased. A related description will be described later. 
     The probe units  20  are inserted into the mounting holes  12  of the housing  10 , respectively. In each of the probe units  20 , the lower end is protruded from the lower part of the housing  10 , and the upper end is protruded from the upper part of the housing  10 , forming the spherical surface. The probe unit  20  has a connection bar  21 , the first connection pin  22 , a rear block  23 , a piezoelectric wafer  25 , and an acoustic matching layer  27 . A second connection pin  28  is formed on the lower surface of the rear block  23 . 
     The connection bar  21  is formed of electrically and thermally conductive material and has a pole shape. Copper or any other metal having good electric and thermal conductivity may be used for the connection bar  21 . 
     The first connection pin  22  is formed on the lower surface of the connection bar  21  and protruded from the lower part of the housing  10  through the mounting hole  12  of the housing  10 . The connection bar  21  has the first pin hole  24  which is formed in the lower surface thereof and into which the first connection pin  22  is partially inserted. Alternatively, the first connection pin  22  may be integrated with the connection bar  21 . 
     The rear block  23  is formed on the upper surface of the connection bar  21 , and the upper part of the rear block  23  forms an inclined plane so as to ultimately form the spherical surface. The rear block  23  absorbs unnecessary ultrasound signals which travel from the piezoelectric wafer  25  to the rear block  23 . The rear block  23  may be formed of rubber or graphite which has a good sound absorption property. As shown in  FIG. 6 , the rear block  23  has a form partially removed from a rectangular parallelepiped and thus has a cross section of trapezoid form. A removed surface forms the inclined plane of the rear block  23 . 
     The second connection pin  28  integrated with the rear block  23  is extruded from the lower surface of the rear block  23 . The second pin hole  26  is formed in the upper surface of the connection bar  21 , so that the second connection pin  28  can be inserted into the second pin hole  26 . Therefore, the rear block  23  is joined to the connection bar  21  via the second connection pin  28  inserted into the second pin hole  26 . The lower surface of the rear block  23  adheres closely to the upper surface of the connection bar  21 . 
     The first and second connection pins  22  and  28  may be fixedly inserted into the first and second pin holes  24  and  26  in a forced insertion manner or using electrically conductive adhesive. 
     The piezoelectric wafer  25  and the acoustic matching layer  27  are sequentially formed on the inclined plane of the rear block  23  so as to be parallel to the inclined plane. Namely, each of the piezoelectric wafer  25  and the acoustic matching layer  27  has a rectangular parallelepiped form having upper and lower surfaces corresponding to the inclined plane of the rear block  23  and is sequentially stacked. Therefore, in an embodiment, a stack of the piezoelectric wafer  25  and the acoustic matching layer  27  is laterally protruded from the lower end of the inclined plane as shown. Alternatively, the stack may be formed so as not to exceed the lateral surface of the rear block  23 . In this case, each of the piezoelectric wafer  25  and the acoustic matching layer  27  has upper and lower surfaces corresponding to the inclined plane of the rear block  23  and has a cross section of trapezoid form. 
     The piezoelectric wafer  25  is formed on the inclined plane of the rear block  23  and generates ultrasound. The piezoelectric wafer  25  is divided into a plurality of devices in a scan direction. Ceramic material such as PZT or PMN-PT may be used for the piezoelectric wafer  25 . 
     The acoustic matching layer  27  is formed on the upper surface of the piezoelectric wafer  25  and performs an acoustic matching function for the ultrasound generated from the piezoelectric wafer  25 . The acoustic matching layer  27  may be composed of at least one layer. Also, the acoustic matching layer  27  may be formed of metal powder, ceramic powder, silicon wafer, and the like. 
     Particularly, the probe unit  20  is installed in each mounting hole  12  of the housing  10 , and the probe units  20  arranged along the same ring-shaped region have the same shape. The mounting holes  12  have increasing length according as their positions become more distant from the center of the housing  10 . The probe units  20  have also increasing length as shown in  FIG. 3 , but the first connection pins  22  protruded from the lower part of the housing  10  are all the same length. In the probe units  20 , the connection bars  21  located at different ring-shaped regions have different lengths which increase according as their positions become closer to the edges, namely, become more distant from the center of the housing  10 . 
     As discussed above and shown in  FIG. 3 , the mounting hole  12  of the housing  10  into which the probe unit  20  is fixedly installed includes the first to third mounting holes  12   a ,  12   b  and  12   c . The first mounting hole  12   a  is formed at the lower part of the housing  10 , and the first connection pin  22  is inserted thereinto and protruded therefrom. The second mounting hole  12   b  is vertically connected to the first mounting hole  12   a , and the connection bar  21  is inserted thereinto. The lower surface of the connection bar  21  is mounted on the bottom of the second mounting hole  12   b  communicating with the first mounting hole  12   a . The third mounting hole  12   c  is vertically connected to the second mounting hole  12   b , and the rear block  23  is inserted thereinto. The third mounting hole  12   c  accommodates a part of the rear block  23  of the probe unit  20 , so that the piezoelectric wafer  25  and the acoustic matching layer  27  stacked on the rear block  23  are located out of the third mounting hole  12   c.    
     In order that the probe unit  20  can be stably inserted and fixed, the mounting hole  12  of the housing  10  is formed to be adapted for the shape of the probe unit  20 . For example, if each of the first connection pin  22  and the connection bar  21  of the probe unit  20  has a circular cross section in a plan view, each of the first and second mounting holes  12   a  and  12   b  is formed to have a circular cross section in a plan view. Also, if the rear block  23  has a rectangular cross section in a plan view, the third mounting hole  12   c  is formed to have a rectangular cross section in a plan view. 
     The probe unit  20  may be fixedly inserted into the mounting hole  12  of the housing  10  through adhesive or in a forced insertion manner. Also, the probe unit  20  may be installed in the mounting hole  12  of the housing  10  in a screw coupling manner. And also, any other well known manners may be used for installing the probe unit  20  into the mounting hole  12  of the housing  10 . 
     As discussed above, since a plurality of probe units  20  are installed in the housing  10  and further a spherical surface is formed at the upper part of the housing  10 , the ultrasound probe  100  according to an embodiment may enhance ultrasound characteristics (acoustic characteristics) through the control of the plurality of probe units  20 . Also, since the probe units  20  are arranged along a plurality of ring-shaped coaxial regions which are disposed beyond a certain radius from the center of the spherical surface and to the edges of the spherical surface, and since each ring-shaped region has a plurality of divided sections, acoustic loss caused by empty spaces between the probe units  20  may be prevented and thus ultrasound characteristics may be enhanced. And also, since the probe units  20  located at adjacent ring-shaped regions are arranged differently in zigzags, ultrasound characteristics may be enhanced and further a unifying force between the probe units  20  may be improved. 
     The probe unit  20  of the ultrasound probe  100  according to an embodiment has at the lower part thereof the first connection pin  22  and has at the upper part thereof a stack structure of the rear block  23 , the piezoelectric wafer  25 , and the acoustic matching layer  27  via the connection bar  22  of copper. Therefore, heat dissipation efficiency may be enhanced through the connection bar  22 . 
     The ultrasound probe  100  according to an embodiment is manufactured by inserting the probe unit  20  into the mounting hole  12  formed in the housing  10 , so a manufacturing process is simplified. Also, since the probe unit  20  is detachable from the housing  10 , a maintenance process is allowed for each of the probe units  20 . Therefore, when some parts of the ultrasound probe  100  are defective, there is no need to replace the entire ultrasound probe  100  and hence unnecessary cost loss may be prevented. 
     Now, a method for manufacturing the ultrasound probe  100  according to an embodiment will be described. At the outset, the housing  10  and the plurality of probe units  20  to be inserted into the mounting holes  12  of the housing  10  are prepared. 
     Next, the probe units  20  are inserted into the mounting holes  12  located near the through hole  14  of the housing  10  and fixedly installed through adhesive. At this time, the inserted probe units  20  form a ring shape. Then, in the same manner, other probe units  20  are inserted and fixedly installed in the next mounting holes  12  which are outwardly adjacent to the previously inserted probe units  20 . In this manner, the probe units  20  are inserted and fixedly installed in all the mounting holes  12  of the housing  10  sequentially from the near side of the through hole  14  to the far side. 
     Next, the grounding film  30  is formed on a spherical surface formed by the plurality of probe units  20 . The grounding film  30  may be adhered to the acoustic matching layers  27  of the probe units  20  via adhesive. 
     Also, the cover layer  40  is covered on the grounding film  30 , and thus a manufacturing process of the ultrasound probe  100  is completed. The cover layer  40  may be formed in an adhering or coating manner to cover the grounding film  30 . 
     In the above-discussed manufacturing process, the reason the probe units  20  are installed from the inner side of the housing  10  is that a stack of the piezoelectric wafer  25  and the acoustic matching layer  27  is laterally protruded from the lower end of the inclined plane of the rear block  23 . 
     Alternatively, if used is the probe unit having the stack of the piezoelectric wafer and the acoustic matching layer without exceeding the lateral surface of the rear block, there is no need to install the probe units in a sequential manner discussed above. Namely, since the probe unit has the stack which is not protruded from the lateral surface of the rear block, the probe units may be inserted and installed in the housing regardless of the order if only the same probe units are arranged in the same ring-shaped region. 
     While this invention has been particularly shown and described with reference to an exemplary embodiment thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.