Abstract:
A therapy head for use in HIFU procedures is described. The therapy head has an enclosure with a window, an energy applicator and a means of moving the energy applicator within the enclosure. The therapy head uses motors and actuators to move the energy applicator, usually an ultrasound transducer, inside the enclosure. A controller is provided either internally or externally that allows the therapy head to identify and distinguish locations where the therapy head should be to radiate energy into a patient. The controller uses the motors and actuators to move the energy applicator into the desired locations.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     This application claims the benefit of provisional application No. 60/534,036, filed on Dec. 30, 2003, the full disclosure of which is incorporated herein by reference. 
     The subject matter of the present application is related to that of the following applications: Ser. No. 10/750,370, entitled “Medical Device Inline Degasser”; Ser. No. 10/751,344, entitled “Articulating Arm for Medical Procedures”; Ser. No. 10/750,369, entitled “Disposable Transducer Seal”; 60/533,528, entitled “Position Tracking Device”; 60/533,988, entitled “Method for Planning and Performing Ultrasound Therapy”; 60/533,958, entitled “Systems and Methods for the Destruction of Adipose Tissue”; 60/534,034, entitled “Component Ultrasound Transducer”; the full disclosure of each of these applications are incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a handheld medical device for delivering energy in precise locations into the human body. The device is principally for non-invasive therapies. 
     2. Background of the Present Invention 
     A general problem in the application of high intensity focused ultrasound (HIFU) for therapeutic purposes is that it is often necessary to hold the therapeutic means stationary for some significant amount of time over the tissue to be treated. Alternatively, it may be necessary to scan the therapy beam at a slow, constant rate through the tissue to be treated. Both of these requirements present a barrier to a hand-held therapeutic device, as it is often difficult or impossible for a person to either hold the device steady, or to scan at an acceptably slow and steady rate for the desired therapeutic effect. 
     A HIFU procedure may require that the ultrasound beam be scanned over the treatment volume at a constant rate (e.g. 5 mm/sec +/−1 mm/sec) to achieve the desired therapeutic effect. Additionally, the treatment volume must be scanned so that there is never more than a 2 mm spacing between adjacent focal lines of treatment. These requirements are beyond the capabilities of human beings. The solution in the past has been to incorporate a computer controlled motion device rigidly mounted to something that is stationary with respect to the patient (e.g. the floor, wall or bed). Such a device is either absolutely stationary, or is able to scan at a precise rate in a precise pattern without any human intervention. Such an arrangement has the disadvantages of size and bulk, complexity and reliability of the overall device. 
     Thus there remains a need in the art for a HIFU applicator that can be easily manipulated by a user while still providing reliable and uniform treatment. 
     There is also a need for a HIFU transducer that can keep track of the tissue volumes treated so as to prevent re-treatment of those same volumes. 
     There is still further a need for a therapy device that can assist the operator in identifying regions of tissue to be treated. 
     BRIEF SUMMARY OF THE INVENTION 
     It is an objective of the present invention to provide for a therapy head usable in HIFU procedures that can be easily manipulated and provide reliable and uniform treatment. 
     It is another object of the presenting invention to track tissue in a library or map of the tissue to be treated. 
     It is still further an objective of the present invention to provide a means for alerting a physician to any problems or difficulties associated with a procedure using a HIFU generator of the present invention. 
     At least some of the objectives of the present invention are realized through an ultrasound therapy head comprising an enclosure having a window, at least one energy applicator suspended within the enclosure and a means for maneuvering the energy applicator within the enclosure such that the energy applicator radiates energy through the window. 
     Preferably the energy applicator is an ultrasound transducer however a variety of other energy applicator may be used in combination with an ultrasound transducer. 
     The means for maneuvering the energy applicator preferably includes a means for determining the position of the energy applicator within the enclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a therapy head. 
         FIG. 2  shows a therapy head on an articulating arm with external control elements. 
         FIGS. 3A-B  show internal views of actuators and motors in the therapy head. 
         FIG. 4  provides a schematic of the elements of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Described herein is a device for use primarily in high intensity ultrasound procedures. A therapy head is disclosed having an enclosure with a window. The enclosure contains one or more energy applicators, and a means of moving the energy applicators within the enclosure. The energy applicators are positioned so the radiant energy passes through the window to a patient. 
     The enclosure is preferably small enough to be manipulated by hand. It can be operated by itself with a physician carrying the load of the therapy head, or it can be supported by an articulating arm or other mechanical device. The enclosure has a window that is oriented toward a patient. The window may be made from any material so long as it is essentially transparent to the energy applicator. The window may be incorporated into the enclosure, or it may be a removable device. If the window is a removable device, then the window will cover an access port through which the interior components of the enclosure may be accessed. The window may also be a disposable device, such as a disposable transducer seal. 
     Within the enclosure is at least one energy applicator. Preferably this energy applicator is an ultrasound transducer. More preferably the ultrasound transducer is a high intensity focused ultrasound transducer. However the transducer may be a component transducer assembly, or a device that incorporates multiple energy applicators, some of which may not be ultrasound transducers. 
     There is a positioner or other means for maneuvering the energy applicator within the enclosure. The means for maneuvering the energy applicator requires two components. A first component is one or more actuators. The energy applicator is attached to the actuators. The attachment may be a slidable engagement, rotational engagement or through a series of traveler rods. The actuators are driven by a force generating device, like an electric motor or the equivalent. Electric motors are preferred for their small size and reliability. One or more position sensing devices, such as rotational or optical encoders, are built into either the motor assembly, or the actuators, so the movement of the energy applicator within the enclosure is known. Alternatively the energy applicator may also contain a miniature location device (e.g. like mini-GPS system) that an external sensor can identify to determine the location of the energy applicator within the enclosure. 
     The second component of the maneuvering means is a driver or controller. The driver or controller directs the movement of the motors, and thus the movement of the actuators and the maneuvering of the energy applicator. The controller may be a medical appliance, a computer, or a specialized medical procedure controller. The controller may be positioned within the enclosure, or it may be a device outside the enclosure providing signal to the motors. 
     In operation, the controller has a library of data used to coordinate the movement of the energy applicator and the dosage of the radiant energy into the patient. By controlling the movement of the energy applicator while radiant energy is emitted through the window, a precise energy dosage may be delivered into the patient. The controller can be programmed with the parameters needed to perform the task. Parameters may include the type of therapy to be administered and the maximum safe dosage that may be applied to a patient for a given area, volume or mass of tissue. 
     Once the therapy head has been completely prepared for a procedure, a physician can place the therapy head on a patient. The therapy head can move the energy applicator within the enclosure to treat the patient according to the procedure parameters programmed into the controller. If the procedure area is small, then the controller can move and activate the energy emitter without any additional input from a user. 
     If the treatment area exceeds the window of the enclosure, or exceeds the range of motion of the energy applicator within the enclosure, the therapy head must be moved to cover as much area as needed. Movement of the therapy head can be done manually, or through a mechanical device. Data from the encoders is relayed to the controller so that the controller can identify the position of the energy applicator within the confines of the enclosure. This position information can be combined with a Position Tracking Device (Co-pending application, Ser. No. 11/027,911), and an Articulating Arm (Co-pending application, Ser. No. 11/751,344). The controller can utilize position data from the present invention, combined with the data derived from the two aforementioned co-pending applications, to produce precise position data for the energy applicator with respect to the enclosure, the patient and a fixed external reference point. During the procedure if the controller reads the position or motion information from the encoders and other sensors and determines the energy applicator is not in the proper position, the controller can use the means for maneuvering the applicator, to correct the energy applicator&#39;s position. 
     Similarly the controller can identify the dosage of energy delivered with great precision to any particular area. The controller can track the amount of energy transmitted into the patient through out the treatment area and can cause the energy applicator to radiate or not radiate depending on the amount of energy already deposited into the patient at the particular place in the procedure. 
     Turning now to the drawings, in  FIG. 1  there is shown a therapy head  500  having an enclosure. The enclosure has a partition  505  and divides the enclosure into an upper chamber  504 , and a lower chamber  502 . Contained within the lower chamber  502  is an energy applicator  600 . The energy applicator  600  is preferably one or more ultrasound transducer(s). The upper chamber  504  contains a motor assembly. There are one or more pass through ports in the partition  505  allowing position control of the energy applicator from the motor assembly. The pass through ports may also be used for electronic communication between the transducer(s) and a computer  400  and/or therapy controller  250 . Electronic communication between the therapy head  500  and the computer  400  and/or therapy controller  250  is achieved through an electronic link  572 . 
     The therapy head  500  may be mounted ( FIG. 2 ) on an articulated arm  200  supported by a base  100 . The articulating arm  200  would also have its movements and functions monitored or controlled by a computer  400  or therapy controller  250 . 
     Positioning of the energy applicator  600  may be achieved through various different means. A generic representation of a mechanical solution is shown in  Fig. 3A . The schematic is a bottom view of the lower chamber  502  without the confining walls of the body of the therapy head. The motors previously described are not shown in this view. A mechanical connection between the motors and the energy applicator can be achieved through a gear assembly or mechanical linkage (referred to hereinafter as a gear linkage). The gear linkages  514 ,  518  are connected to a pair of travelers rods  520 ,  528 . The traveler rods may act as drive screws for a pair of slotted actuators  520 ′,  528 ′. Rotation of the traveler rods will cause the corresponding slotted actuator to move, with the energy applicator moving with the intersection of the two slotted actuators. The energy applicator  600  can be positioned anywhere the intersection of the two slotted actuators can be moved. A rotational encoder  530  is attached to each of the traveler rods  520 ,  528  so the amount of motion can be determined. The data from the rotational encoders is used by a computer to determine and plan the movement and energy transmission into the patient. 
     In the preferred embodiment  FIG. 3B ), motor drives  508 ,  510  are connected to direct couplers  520   a ,  528   a  instead of a pair of traveler rods  520 ,  528  as previously described. The direct couplers  520   a ,  528   a  are connected to a pair of pivoting sliders  520   b ,  528   b . A transducer carriage  516  is mounted with a plurality of angular joint receptacles allowing the transducer carriage  516  to move with the pivoting slides  520   b ,  528   b . In this manner as the pivoting slides change the angle of intersection relative to each other, the transducer carriage is able to move with the intersection of the sliders, thus providing movement control of the transducer carriage  516  in the lower chamber. A transducer  600  or other radiant energy device is mounted on the transducer carriage  516 . A rotational encoder  530  is mounted on each of the motors  508 ,  510  to measure the true rotation of each of the direct couplers  520   a ,  528   a . The encoders  530 , motors  508 ,  510 , and transducer  600  are all in electronic communication with the computer  400  and/or therapy processor  250  so the precise location of the transducer within the lower chamber  502  can be determined at any time. 
       FIG. 4  illustrates a schematic of the present invention. The enclosure defined by the interior of the therapy head  500  is separated into an upper chamber  504  and a lower chamber  502 . The partition  505  between the upper chamber  504  and lower chamber  502  has a plurality of pass through ports for the mechanical connections  520 ,  528  between the motors  508 ,  510  and the transducer  600 . Fluid flows through a fluid circuit  712  and electronic communication is provided through an electronic communication link  531 . The therapy head  500  is closed off with a transmissible window  590 .