Patent Document

FIELD OF THE INVENTION 
       [0001]    The present invention pertains to the field of medical equipment, relates to an ultrasonic therapeutic system, and specifically to a MRI guided high-intensity focused ultrasonic therapeutic system. 
       BACKGROUND OF THE INVENTION 
       [0002]    The existing focused ultrasound therapies mainly use B-mode ultrasonic diagnostic apparatus to perform location and to monitor the therapy. Such B-mode ultrasonic diagnostic apparatus adopted in monitoring and treating has the following disadvantages: 1) Because B-mode ultrasound image is only a plane image with a certain angle and even though a 3-D ultrasound system is used, the visible area is still limited. 2) The ultrasound image is limited in the observation depth. The bone substances influence the image greatly and the tissue behind the bone almost cannot be displayed and the artifacts are existed. 3) Ultrasound images have poor capacity to identify the tissue boundary and particularly it is more difficult to identify small tumors and deep-bedded tumors. 
         [0003]    Otherwise, a MRI (Magnetic Resonance Imaging) device is an important application in biological and medical fields. It may apply appropriate gradients to the magnetic field so that the magnetic resonance signals can be acquired selectively. The information is processed to gain the tissue characteristics of each point and further the tissue can be imaged. The acquired magnetic resonance images have a great ability to identify different tissues and are able to distinguish the normal tissue and tumor tissue easily. What we obtained are stereoscopic data within a certain volume and a part of human body or full body can be imaged, therefore MRI is very suitable to monitor the high-intensity focused ultrasound therapeutic procedure. 
         [0004]    Japanese Patent JP3322649 discloses a therapy system combining a MRI device with an ultrasonic therapeutic equipment. Normally, the vertical moving distance under the treatment bed in the bore of MRI device is about 140 mm, therefore, the ultrasonic therapy equipment moves upward and downward for treatment in a quite limited space. Therefore, this therapy system employs MRI device to determine the location of a tumor firstly, and then the patient is moved out from the magnetic field of the MRI device and then treated by ultrasound. This kind of therapy system needs repeated moving of patient and needs location for many times. The locating system is complex and a long time is needed to make locations. 
         [0005]    U.S. Pat. No. 5,275,165 provides a MRI surgery system, which facilitates surgery with a focused ultrasound transducer that selectively destroys tissues in a region within a patient. The focused ultrasound transducer focalizes energy at a focal point within the region of tissue to be destroyed. A non-magnetic moving and positioning device, whose moving mechanism is small enough to fit easily within the bore of the magnetic field of the MRI device, moves in a vertical direction. The moving and positioning device employs a plurality of hydraulic moving positioners and an inclined plane to drive the ultrasound transducer in a limited vertical space and positions the ultrasound focal point under the control of an operator. A MRI system employing a temperature sensitive pulse sequence creates an image of the tissue and the region being heated to allow the operator to adjust the position of the ultrasonic transducer so as to direct ultrasonic energy to the appropriate location. But the ultrasound transducer equipped in this moving and positioning device can not rotate and can only move from the bottom up for ultrasound treatment, therefore it can not meet the requirements of treating tumors in multiple orientations. 
         [0006]    Another U.S. Pat. No. 5,443,068 similarly discloses a non-magnetic positioning device of an ultrasound energy applicator, which is operated within the bore of a MRI magnetic field. The purpose of this invention is to provide a simplified positioner, which is operated within the magnetic filed. And also the interference to the magnetic field of MRI system due to a moving means is avoided. 
         [0007]    U.S. Pat. No. 6,148,225 with assignee of Siemens AG discloses an ultrasonic therapeutic apparatus, which adopts a high-frequency generator to generate discrete electrical signals with different frequency which developed within a frequency band in the order of time. Integral multiples of the discrete frequency values do not lie in a second frequency band that corresponds to the reception band of a simultaneously operated diagnostic MRI apparatus. In this way, the ultrasonic therapeutic apparatus does not interfere the magnetic field of the MRI apparatus when the ultrasound treatment is carried out during MRI monitoring. 
         [0008]    All of above mentioned patents are directed to a therapy system combining a MRI device with an ultrasonic therapeutic equipment. These therapy systems mainly have the following disadvantages: 1) Because the vertical moving distance under the treatment bed in the bore of MRI is quite limited, it is very difficult to place an ultrasound transducer requiring a multiple-dimensional movement under the treatment bed and it is more difficult to place a complex moving and positioning mechanism. And the moving and positioning mechanism placed under the treatment bed in the bore of MRI occupies the limited space for moving an ultrasound transducer, accordingly the treatment procedure is affected; 2) The requirement of non-magnetic designs and treatment on the ultrasound transducer and its moving and positioning means for these systems are higher, therefore, the technical complexity and the cost of these systems are increased; 3) The ultrasound transducer driven by the moving and positioning mechanism can only move in a limited space and can not meet the multiple orientation requirement in treating diseases, like tumor. Because the ultrasound transducer can not rotate, it can only move from the bottom up for ultrasound treatment under the treatment bed. It can not work when ultrasound treatment need to be done both by side and from the top down; 4) It is difficult to perform assistant manual operations by an operator and also it is inconvenient for an operator to make clinical observations. 
       SUMMARY OF THE INVENTION 
       [0009]    In view of the disadvantages of the related art as above mentioned, the technical problem to be solved by the present invention are to provide a MRI guided high-intensity focused ultrasonic therapeutic system, in which an ultrasound transducer moves in multiple orientations, freely moves without any limitation of space under the treatment bed, and brings less interference to a MRI apparatus. 
         [0010]    The technical solution proposed by the present invention is: the MRI guided high-intensity focused ultrasonic therapeutic system includes a MRI apparatus and a high-intensity focused ultrasonic therapeutic apparatus. Said MRI apparatus includes the first treatment bed and said high-intensity focused ultrasonic therapeutic apparatus includes an ultrasound transducer and a moving and positioning means, which drives said transducer move in all directions. Wherein, said moving and positioning means is placed outside of the bore of the MRI apparatus during treatment and a supporting rod, which can extend into the bore of the MRI apparatus, is connected to said moving and positioning means at one end and is connected to said ultrasound transducer at the other end. Said moving and positioning means includes a control means, which drives said supporting rod to move in X, Y and Z-directions and rotate around X-direction. Driving by said control means, the supporting rod moves along X, Y and Z-directions and rotate around X-direction. Because said ultrasound transducer is connected to the supporting rod, the ultrasound transducer can be positioned precisely. 
         [0011]    During the whole treatment procedure, said moving and positioning means isn&#39;t located in the bore of the MRI apparatus and is placed outside of the bore. Only through said supporting rod, said moving and positioning means is connected to said ultrasound transducer. In this way, the space under the treatment bed in the bore of the MRI apparatus is extended and the interference from the ultrasonic therapeutic apparatus to the magnetic field of MRI apparatus is decreased extremely. Taking full advantage of the structure and the function of the MRI apparatus, the present invention makes the area to be applied with energy by the ultrasound transducer intercross with the imaging and monitoring area of the MRI apparatus at the target area to be treated and achieves excellent therapeutic effects. 
         [0012]    In present invention, said moving and positioning means may comprise an adjusting device for moving said moving and positioning means upward and downward. By adjusting that adjusting device, the supporting rod drives the ultrasound transducer to move in Z-direction in the bore of the MRI apparatus. 
         [0013]    Said moving and positioning means may comprise a sliding device at its bottom for moving said moving and positioning means horizontally. The sliding device includes a pulley and a slide rail. The pulley is installed at the bottom of the moving and positioning means and is placed in the slide rail. When an operator applies force to the moving and positioning means in X-direction, the whole moving and positioning means driven by the pulley can move on the slide rail forward and backward and accordingly the ultrasound transducer driven by the supporting rod can move in X-direction in the bore of the MRI apparatus. 
         [0014]    Said moving and positioning means may further comprise a rotating device for driving the supporting rod to rotate around the axis of MRI or the parallel lines of the axis. Thus, the ultrasound transducer can rotate around the axis of MRI or the parallel lines of the axis in the bore of MRI apparatus and variable and agile movement manners of the ultrasound transducer can be achieved for more appropriately meeting the needs of treatment. 
         [0015]    In one preferable embodiment, the first treatment bed may be connected to the second treatment bed. The first treatment bed is connected to the second one by an adjustable fastening device. The adjustable fastening device can adjust the distance and angle between the two treatment beds freely and can drive the treatment beds to move in X-direction. 
         [0016]    In another preferable embodiment, the MRI apparatus further comprises the second treatment bed and the moving and positioning means comprises a bed moving means for driving said second treatment bed to move rightward and leftward and forward and backward. The second treatment bed is connected to the bed moving means. Driven by the bed moving means, the second treatment bed may move rightward and leftward and forward and backward. 
         [0017]    These additional devices mentioned as above facilitate an operator to assistantly manually operate the ultrasound transducer during treatment and are more helpful for an operator to make clinical observations during treatment. 
         [0018]    Preferably, the supporting rod is made of non-magnetic material or non-metal material and accordingly the interference from the ultrasonic therapeutic apparatus to the magnetic field of the MRI apparatus is decreased further. 
         [0019]    The ultrasound transducer can be placed within a container containing fluid. When the container connected to the supporting rod is placed under the first treatment bed or the second treatment bed, the first treatment bed or the second treatment bed has an aperture thereon and the ultrasound transducer can be placed in the appropriate position corresponding to the aperture of the first treatment bed or the second treatment bed. The container is an open one, which is open at the end faced to the aperture of the treatment bed and enables a patient to directly contact with the fluid in the container. When the container is placed above the first treatment bed, the container is a close one. The open end of the container is closed by an acoustically transparent membrane adapted to be in direct contact with the patient. Wherein, said fluid may be degassed water. 
         [0020]    Because said moving and positioning means is placed outside of the bore of the MRI apparatus, the MRI guided high-intensity focused ultrasonic therapeutic system of the present invention minimizes the limitation on moving space of the ultrasound transducer and greatly reduces the non-magnetic requirements of the moving and positioning means of the ultrasound transducer and accordingly the most precise treatment on the nidus of the patient may be ensured. Meanwhile, the present invention integrates the MRI apparatus with the ultrasonic therapeutic apparatus better and increases the utilization rate of equipment. The present invention provides multiple movement manners for treatment and enables the medical personnel to treat the patient in various postures. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0021]      FIG. 1  is a schematic structural diagram of the embodiment 1 according to the present invention. 
           [0022]      FIG. 2  is a schematic structural diagram of a high-intensity focused ultrasonic therapeutic apparatus in the embodiment 1 according to the present invention. 
           [0023]      FIG. 3  is a schematic structural diagram of the embodiment 2 according to the present invention. 
           [0024]      FIG. 4  is a schematic structural diagram of a second treatment bed in the embodiment 3 according to the present invention, which is placed outside of the MRI apparatus. 
           [0025]      FIG. 5  is a schematic structural diagram of a second treatment bed in the embodiment 3 according to the present invention, which is placed in the MRI apparatus. 
           [0026]      FIG. 6  is a schematic structural diagram of an adjustable fastening device in the embodiment 1 according to the present invention. 
       
    
    
       [0027]    Wherein:  1 —MRI apparatus  2 —first treatment bed  3 —supporting means  4 —supporting rod  5 —container  6 —ultrasound transducer  7 —flexible matter  8 —rotating device  9 —control means  10 —adjusting device  11 ,  31 ,  42 ,  43 —pulley  12 ,  20 —slide rail  13 —second treatment bed  14 —adjustable fastening device  15 —acoustically transparent membrane  16 —aperture  17 ,  23 ,  26 ,  41 —slide rail  18 ,  21 ,  24 ,  27 ,  36 ,  39 —motor  19 —screw rod  22 ,  25 ,  40 —screw rod  28 ,  37 —synchronization belt  29 ,  38 —synchronization belt-wheel  30 —transition piece  32 —pulley support  33 —bolt  34 —nut  35 —compressible spring 
       DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0028]    As shown in  FIGS. 1-5 , a MRI guided high-intensity focused ultrasonic therapeutic system of the present invention comprises a MRI apparatus  1  and a high-intensity focused ultrasonic therapeutic apparatus. 
         [0029]    A first treatment bed  2  in the bore of the MRI apparatus  1  is supported by a supporting means  3 , which is fixed on the MRI apparatus  1 . The high-intensity focused ultrasonic therapeutic apparatus comprises an ultrasound transducer  6  and a moving and positioning means for driving ultrasound transducer  6  to move in multiple-orientations and the moving and positioning means is placed outside of the bore of the MRI apparatus  1  and is connected to a supporting rod  4 , which may extend into the bore of the MRI apparatus and is connected to the ultrasound transducer  6  at the other end. 
         [0030]    The moving and positioning means comprises a control means  9  for driving supporting rod  4  to move in X, Y and Z-directions and rotate around X-direction. The moving and positioning means may comprise an adjusting device  10  for moving said moving and positioning means upward and downward. The moving and positioning means may comprise a sliding device at the bottom for moving the moving and positioning means horizontally. The sliding device includes a pulley  11  and a slide rail  12 . The pulley  11  is installed at the bottom of moving and positioning means and the pulley  11  is placed on the slide rail  12 . Said moving and positioning means may further comprise a rotating device  8  for driving the supporting rod to rotate around the axis of MRI or the parallel lines of the axis. 
         [0031]    Preferably, supporting rod  4  is made of non-magnetic material or non-metal material. 
         [0032]    The MRI guided high-intensity focused ultrasonic therapeutic system of the present invention further comprises the second treatment bed  13 . The ultrasound transducer  6  is placed within a container  5 , which is full of fluid and connected to the supporting rod  4 . When the container  5  is placed under the treatment bed used by a patient (the first treatment bed or the second treatment bed), this treatment bed has an aperture  16  thereon. The position of the ultrasound transducer  6  corresponds to that of the aperture  16  of that treatment bed. The container  5  is an open one, which is open at the end faced to the aperture  16  and enables a patient to directly contact with the fluid in the container  5 . When the container  5  is placed above the treatment bed used by a patient (the first treatment bed or the second treatment bed), the container is a close one. The open end of container  5  is closed by a flexible acoustically transparent membrane  15  adapted to be in direct contact with the patient. Wherein, the fluid may be degassed water. 
         [0033]    The present invention is further described in detail taking in conjunction with the following embodiments and accompanying drawings. 
       Embodiment 1 
       [0034]    As shown in  FIG. 1 , the system in this embodiment comprises a MRI apparatus  1  and a high-intensity focused ultrasonic therapeutic apparatus. Wherein, the high-intensity focused ultrasonic therapeutic apparatus comprises an ultrasound transducer  6 , a moving and positioning means, which is located behind the MRI apparatus and is connected to a supporting rod  4 . The supporting rod  4  is connected to a control means  9  of the moving and positioning means at its one end and is connected to ultrasound transducer  6  at the other end. The moving and positioning means comprises the control means  9 , which drives the supporting rod  4  to move in X, Y and Z-directions and rotate around X-direction. 
         [0035]    As shown in  FIG. 1  and  FIG. 2 , each motion structure for movement in X, Y and Z directions of the control means  9  comprises a motor, a screw rod, a sliding block and a slide rail, which are integrated with the supporting rod. The screw rod is connected to the motor and the sliding block on the slide rail engages with the screw rod. Driven by a motor  18 , a screw rod  19  drives the supporting rod  4  to move along a slide rail  20  in X-direction. Driven by a motor  21 , a screw rod  22  drives the supporting rod  4  to move along a slide rail  23  in Y-direction. As shown in  FIG. 1 , driven by a motor  24 , a screw rod  25  drives the supporting rod  4  to move along a slide rail  26  in Z-direction. The structure for rotating around X-direction of the control means  9  comprises a motor  27 , a synchronization belt  28  and a synchronization belt-wheel  29 . The synchronization belt-wheel  29  is integrated with the supporting rod  4 . Through the synchronization belt  28 , an output shaft of motor  27  is connected to the synchronization belt-wheel  29 . Under the drive of the motor  27  and the force of the synchronization belt  28  and synchronization belt-wheel  29 , the supporting rod  4  can rotate 0-360° around X-axis. 
         [0036]    In this embodiment, the supporting rod  4  adopts a nickel-zinc-copper alloy in order to minimize the interference to the magnetic field of MRI apparatus  1 . 
         [0037]    As shown in  FIG. 1 , there is a first treatment bed  2  and a second treatment bed  13  in the bore of the MRI apparatus  1  and the second one  13  is placed above the first one  2 . The first treatment bed  2  is connected to the second one  13  by an adjustable fastening device  14 , which can be used to adjust the position between the first treatment bed  2  and the second treatment bed  13 . The first treatment bed  2  is fixed on a supporting means  3 , which is fixed on the MRI apparatus  1 . Wherein, there is an aperture on a section of the second treatment bed  13 , which doesn&#39;t overlap with the first treatment bed  2 . 
         [0038]      FIG. 6  is a schematic structural diagram of adjustable fastening device  14 . The adjustable fastening device  14  comprises a transition piece  30 , a pulley  31 , a pulley support  32 , a bolt  33 , a nut  34  and a compressible spring  35 . The transition piece  30  is embedded in the first treatment bed  2  and the pulley  31  is installed on the transition piece  30 . The pulley support  32  is connected to a pulley shaft. The bolt  33  passes through the second treatment bed  13  and the pulley support  32  and is connected to the nut  34 . The compressible spring  35  encases the bolt  33  and is sandwiched between the second treatment bed  13  and the pulley support  32 . The transition piece  30  is embedded in the first treatment bed  2  so that the pulley  31  can move thereon. There are the bolt  33 , the nut  34  and the compressible spring  35  installed between the pulley support  32  and the second treatment bed  13 . When the second treatment bed  13  is pushed, under that pushing force, the second treatment bed  13  is driven by the pulley  31  and moves in X-direction. By adjusting the bolt  33  and the nut  34 , the compressible spring  35  deforms and accordingly the distance between the two beds changes. Multiple sets of devices which include the bolt  33 , the nut  34  and the compressible spring  35  can be installed between the two beds and by adjusting different bolts  33  and nuts  34 , the compressible springs deform to different extents and accordingly the different angles can be formed between the two beds. 
         [0039]    As shown in  FIG. 1  and  FIG. 2 , the moving and positioning means further comprises a sliding device, which facilitates an operator to manually operate the ultrasound transducer during treatment. Said sliding device comprises a pulley  11  and a slide rail  12  for the pulley  11  sliding on. 
         [0040]    As shown in  FIG. 1 , a rotating device  8  is connected to the control means  9  by a screw thread and the like. Under the drive of a motor  36  and the force of a synchronization belt  37  and a synchronization belt-wheel  38 , the rotating device  8  drives the whole control means  9  to be rotatable 0-360° around the axis of MRI apparatus  1  or the parallel lines of the axis. Because the supporting rod  4  is connected to the control means  9 , under the drive of the control means  9 , the supporting rod  4  can also rotate 0-360° around the axis of MRI apparatus  1  or the parallel lines of the axis. 
         [0041]    As shown in  FIG. 2 , the adjusting device  10  comprises a motor  39 , a screw rod  40  and a slide rail  41 . Under the drive of motor  39 , the screw rod  40  drives the rotating device  8  to move upward and downward along the slide rail  41  in Z-direction. Because the control means  9  is connected to the rotating device  8  and the supporting rod  4  is connected to the control means  9 , under the movement transmission, the supporting rod  4  can also move upward and downward in Z-direction. 
         [0042]    The sliding device is located under the moving and positioning means and comprises the pulley  11  installed under the moving and positioning means and the slide rail  12  for the pulley  11  sliding on. When the force is applied to the moving and positioning means in X-direction, the whole moving and positioning means will move in X-direction. 
         [0043]    After the ultrasound transducer  6  is positioned under the second treatment bed  13 , the ultrasonic therapy can be applied to the nidus of the patient from the bottom up. 
         [0044]    In this embodiment, the ultrasound transducer  6  is placed into a container  5 , which contains fluid. The container  5  is a water bag, which is open at the end faced to the aperture  16  of the treatment bed  13 . The container is full of degassed water. The degassed water is used as ultrasound propagation medium with a controlled temperature of about 25° C. Because the ultrasound transducer  6  is placed in the water bag, the water bag is connected to the supporting rod  4  through a flexible matter  7 . Wherein, ultrasound transducer  6  adopts spherical shell focusing piezoelectric transducer with a focal distance ranging from 80 mm to 200 mm, a diameter ranging from 80 mm to 300 mm and a working frequency ranging from 0.5 MHz to 2 MHz. 
         [0045]    The work process of the therapy system in the present embodiment is: firstly, placing the patient on the second treatment bed  13  of the MRI apparatus  1 , adjusting the supporting means  3  and/or the adjustable fastening device  14  to position the nidus of the patient within the magnet resonance volume and using the MRI apparatus  1  to image the nidus of the patient. Then, driving the supporting rod  4  by the moving and positioning means to move the ultrasound transducer  6  in the space under the second treatment bed  13 , moving the ultrasound transducer  6  until it aims at the aperture  16  of the second treatment bed  13 , and overlapping the focus of the ultrasound transducer  6  with the nidus of the target area to be treated within the magnetic resonance volume. Finally, transmitting the therapeutic ultrasonic waves and applying therapy to the patient. 
       Embodiment 2 
       [0046]    As shown in  FIG. 3 , in this embodiment, the moving and positioning means is located behind the MRI apparatus  1 . It is different from the embodiment  1  that in this embodiment, there is only the first treatment bed  2  in the bore of the MRI apparatus  1  and the ultrasound transducer  6  is located above the first treatment bed  2  to apply the ultrasonic waves to the nidus of the patient from the top down. Because the ultrasound transducer  6  is located above the first treatment bed  2  to apply the ultrasonic waves to the nidus of the patient from the top down, the first treatment bed  2  in the MRI apparatus  1  may not have an aperture and it may be used for performing normal treatment. 
         [0047]    The container  5  adopts a water bag, which is full of degassed water. In order to avoid the overflow of the degassed water in that bag, a flexible acoustically transparent membrane  15  is used to seal the open end of the water bag and that membrane can be in direct contact with the patient. 
         [0048]    Other components in this embodiment are the same as those in the embodiment 1. 
       Embodiment 3 
       [0049]    As shown in  FIG. 4  and  FIG. 5 , in this embodiment, the moving and positioning means is in front of the MRI apparatus  1  during treatment. The MRI apparatus comprises a first treatment bed  2  and a second treatment bed  13 . The moving and positioning means comprises a bed moving means for moving the second treatment bed  13  and a control means  9  for driving an ultrasound transducer to move in X, Y and Z-directions and rotate around X-direction. The second treatment bed  13  is connected to the moving and positioning means through the bed moving means. 
         [0050]    Wherein, the structure of the control means  9  is the same as that in the embodiment 1. 
         [0051]    The bed moving means comprises a structure of pulley and slide rail for moving the second treatment bed  13  rightward and leftward and a structure of pulley and slide rail for moving the second treatment bed  13  forward and backward. 
         [0052]    As shown in  FIG. 4 , a slide rail  17  is fixed on the control means  9  and a fluid container  5  is placed in an aperture of the second treatment bed  13 . When the whole high-intensity focused ultrasonic therapeutic apparatus is pushed by hand, under the driving of a pulley  43 , the whole apparatus moves rightward and leftward along a slide rail  12  horizontally and is located in front of the MRI apparatus  1 . As shown in  FIG. 5 , when the second treatment bed  13  is pushed by hand, the pulley  42  moves along the slide rail  17  forward and backward. Because the second treatment bed  13  is connected to the moving and positioning means, the whole moving and positioning means also moves along the slide rail  12  forward and backward by this force. And finally, the second treatment bed  13  enters into the bore of the MRI apparatus  1  and is positioned in the optimal position for treatment on the patient. 
         [0053]    After the ultrasound transducer  6  is positioned under the second treatment bed  13 , the ultrasonic therapy can be applied to the nidus of the patient from the bottom up. 
         [0054]    Other components and functions in this embodiment are the same as those in the embodiment 1.

Technology Category: 1