Abstract:
Devices for use in medical imaging can include a robotic arm ( 220 ) having multiple degrees-of-freedom movement capability, a scanning transducer ( 230 ) coupled in proximity to an end of the robotic arm, and a haptic interface ( 250 ) having one or more mechanical linkages and being in communication with the robotic arm, and adapted to issue command signals to move the robotic arm in one or more directions or angles and to receive feedback signals from the robotic arm.

Description:
BACKGROUND 
       [0001]    There are a variety of medical imaging technologies used in modern medicine including X-ray photography, linear-tomography, poly-tomography, Computerized Axial Tomography (CAT/CT), NucleoMagnetic Resonance (NMR) and ultrasonic imaging. Of all these technologies, only ultrasonic imaging requires the direct hands-on attention of a medical professional often referred to as a “sonographer”. For example, while technicians routinely take X-ray images of a patient from the vantage of a completely different room in order to avoid radiation exposure, a sonographer must physically hold and subtly manipulate an ultrasonic transducer against a patient&#39;s skin in order to get meaningful images. 
         [0002]    While the known manual methods of ultrasonic imaging are generally safe and work well for most situations, there are a number of scenarios where these traditional methods pose uncomfortable or potentially dangerous situations for the sonographer. For instance, during surgery it may be necessary for a sonographer to provide constant image feedback for the surgeon, but doing so requires that the sonographer pose in highly contorted and uncomfortable positions for long periods of time—a practice that over time can result in a long-term disability of the sonographer. Also, in situations where the patient is located in a physically hazardous environment, such as in an X-ray laboratory, simultaneously taking X-ray and ultrasonic images can be both difficult and hazardous for the sonographer. Accordingly, new methods and systems relating to ultrasonic imaging are desirable. 
       SUMMARY 
       [0003]    In an illustrative embodiment, a haptic system for use in medical imaging includes a robotic arm having multiple degrees-of-freedom movement capability, a scanning transducer coupled in proximity to an end of the robotic arm, and a haptic interface having one or more mechanical linkages and being in communication with the robotic arm, and adapted to issue command signals to move the robotic arm in one or more directions or angles and to receive feedback signals from the robotic arm. 
         [0004]    In another illustrative embodiment, haptic system configured to enable an operator to remotely perform a medical scanning procedure on a patient includes a scanning transducer having one or more force sensors coupled thereto, and a haptic control means for issuing command signals capable of controlling the position and angle of the scanning transducer relative to a patient, and for receiving feedback signals for providing tactile feedback to an operator handling the haptic control means. 
         [0005]    In yet another illustrative embodiment, a method for enabling an operator to perform an ultrasonic medical image scan on a patient from a remote position includes generating command signals by a haptic device in response to mechanical manipulation by an operator, positioning a robotic arm having an ultrasonic transducer coupled thereto in response to the generated command signals such that the ultrasonic transducer makes physical contact with the patient, sensing at least one of position and force feedback signals from the robotic arm and causing the haptic device to conform to the feedback signals. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0006]    The illustrative embodiments are best understood from the following detailed description when read with the accompanying drawing figures. It is emphasized that the various features are not necessarily drawn to scale. In fact, the dimensions may be arbitrarily increased or decreased for clarity of discussion. Wherever applicable and practical, like reference numerals refer to like elements. 
           [0007]      FIG. 1  depicts an illustrative block diagram of a networked medical imaging system using haptic feedback technology; 
           [0008]      FIG. 2  depicts an exemplary ultrasonic imaging device used in conjunction with a robotic arm; 
           [0009]      FIG. 3  depicts an exemplary ultrasonic transducer with various force vectors of interest acting upon it; 
           [0010]      FIG. 4  depicts an exemplary haptic controller; 
           [0011]      FIG. 5  is a block diagram of an exemplary control system useable with a hapticly controlled imaging system; 
           [0012]      FIG. 6  is an exemplary control model for use with a hapticly controlled ultrasonic imaging system; and 
           [0013]      FIG. 7  is a block diagram outlining various exemplary operations directed to the haptic control of a medical imaging device. 
       
    
    
     DETAILED DESCRIPTION 
       [0014]    In the following detailed description, for purposes of explanation and not limitation, illustrative embodiments disclosing specific details are set forth in order to provide a thorough understanding of an embodiment according to the present teachings. However, it will be apparent to one having ordinary skill in the art having had the benefit of the present disclosure that other embodiments according to the present teachings that depart from the specific details disclosed herein remain within the scope of the appended claims. Moreover, descriptions of well-known apparatus and methods may be omitted so as to not obscure the description of the illustrative embodiments. Such methods and apparatus are clearly within the scope of the present teachings. 
         [0015]      FIG. 1  depicts an illustrative embodiment of a medical imaging system  100  using haptic feedback technology. As shown in  FIG. 1 , the medical imaging system  100  includes a remote haptic controller  130  and a medical instrument  120  connected to a common network  110  via links  112 . 
         [0016]    In operation, an operator/sonographer located at the haptic controller  130  can manipulate a specially-configured control mechanism in order to define the spatial and angular positions of a hand-held “reference wand”. In various embodiments, the haptic controller  130  can be used to define 6 degrees-of-freedom (DOF) including the X, Y and Z positions of the reference wand (relative to some reference point) as well as the X, Y and Z angles at which the reference wand is positioned. Note that the position and angle of the reference wand can be used to define the spatial position and angle of an ultrasonic transducer (relative to a patient) located at the medical instrument  120 . 
         [0017]    While the exemplary haptic controller  130  is a 6-DOF system, in other embodiments a 7-DOF haptic controller can be used that further includes a rotational degree of freedom about the central-axis of the reference wand thus allowing the sonographer to spin the wand (and by default an ultrasonic transducer) on its central-axis. In other embodiments, however, fewer than six degrees of freedom can be used. For example, in one embodiment a 4-DOF system using a single linear direction control and three dimensional angular control can be used, while in other embodiments a 1-DOF system capable of being manipulated along a single linear direction may be used. Notably, there are comparatively few cases where rotation would be required. 
         [0018]    During operation, as the sonographer manipulates the haptic controller&#39;s reference wand, the exemplary haptic controller  130  can send some form of control signals representing the position and angles of the reference wand, and/or control signals representing the forces that the sonographer applies to the reference wand, to the medical instrument  120  via the network  110  and links  112 . 
         [0019]    In turn, a robotic arm carrying the aforementioned ultrasonic transducer at the medical instrument  120  can react to the control signals, i.e., change the position and angle of the ultrasonic transducer in a manner that would be consistent/conform with the position and angles of the haptic controller&#39;s reference wand—or otherwise mimic those forces that the sonographer applies to the reference wand. 
         [0020]    As the robotic arm reacts to conform with the control signals, various position and force sensors located in the robotic arm and/or coupled to the ultrasonic transducer can provide various feedback signals to the haptic controller  130 . For example, by coupling one or more force sensors to the ultrasonic transducer to detect forces applied to the transducer, the medical instrument  120  can provide feedback signals to the haptic controller  130  that can be used to create analogous forces against the hand of the sonographer to effectively simulate the tactile feel that the sonographer would experience as if he were directly manipulating the transducer at the medical instrument  120 . 
         [0021]    In addition to a haptic interface, the haptic-controller  130  and medical instrument  120  can optionally include some form of system to remotely control the “back end” of the ultrasonic instrumentation supporting the ultrasonic transducer. For example, by providing a personal computer at the haptic controller  130  containing a specially designed software package, the sonographer can change any number of the ultrasonic instrument&#39;s settings, such as its frequency and power settings, that the sonographer would otherwise need direct access to the ultrasonic instrument&#39;s front panel. Additionally, any image that might be generated at the ultrasonic instrument&#39;s display can be optionally sent to the personal computer for more convenient display to the sonographer. 
         [0022]    The illustrative network  110  is an Ethernet communication system capable of passing IEEE1588 compliant signals. However, in other embodiments the network  110  can be any viable combination of devices and systems capable of linking computer-based systems. The network  110  may include, but is not limited to: a wide area network (WAN), a local area network (LAN), a connection over an intranet or extranet, a connection over any number of distributed processing networks or systems, a virtual private network, the Internet, a private network, a public network, a value-added network, an Ethernet-based system, a Token Ring, a Fiber Distributed Datalink Interface (FDDI), an Asynchronous Transfer Mode (ATM) based system, a telephony-based system including T1 and E1 devices, a wired system, an optical system, or a wireless system. Known protocols for each of the noted networks are included and are not detailed here. 
         [0023]    The various links  112  of the present embodiment are a combination of devices and software/firmware configured to couple computer-based systems to an Ethernet-based network. However, it should be appreciated that, in differing embodiments, the links  112  can take the forms of Ethernet links, modems, networks interface card, serial buses, parallel busses, WAN or LAN interfaces, wireless or optical interfaces and the like as may be desired or otherwise dictated by design choice. 
         [0024]      FIG. 2  depicts an ultrasonic imaging system  120  used in conjunction a CT scanning system  210  in accordance with an illustrative embodiment. As shown in  FIG. 2 , the CT scanning system  210  is accompanied by a bed  212  upon which a patient might rest. A 6-DOF robotic arm  220  is attached to the CT scanning system  210 , and an ultrasonic transducer  230  is coupled at the end of the robotic arm  220 . A remote interface  250  is further coupled to the robotic arm  220 , and a back-end ultrasonic module  240  is coupled to the ultrasonic transducer  230 . Notably, the bed  212  may be any structure adapted to translate a patient through the CT scanning system  210 . Also, it may be useful to couple the translation of the bed  212  to the control robotic arm thereby allowing the arm to move in ‘lock-step’ with the bed  212 . 
         [0025]    In operation, control signals sent by an external device, such as a haptic controller, can be received by the remote interface  250 . The remote interface  250  can condition, e.g., scale, the received control signals and forward the conditioned control signals to the robotic arm  220 . In turn, the robotic arm  220  can change the position and angle of the transducer  230  to conform with the conditioned control signals. 
         [0026]    As the robotic arm reacts to conform with the control signals, various position sensors within the robotic arm (not shown) and force sensors coupled to the transducer (also not shown) can be used to provide tactile feedback to a remotely positioned sonographer using a haptic controller via the remote interface  250 . For example, assuming that the robotic arm  220  positions the face of the transducer  230  against a patient&#39;s abdomen, the force sensors can detect the forces between the transducer  230  and the patient. The detected forces, in turn, can be used to generate an analogous set of forces against the sonographer&#39;s hand using a haptic controller. Accordingly, the sonographer can benefit from an extremely accurate tactile feel without needing to be exposed to any radiation produced by the CT device  210 . 
         [0027]    As the ultrasonic transducer  230  is advantageously positioned against a patient, the ultrasound module  240  can receive those ultrasonic reflection signals sensed by the ultrasonic transducer  230 , generate the appropriate images using a local display and/or optionally provide any available image to the sonographer via the remote interface  250 . Additionally, the sonographer can change various settings of the ultrasound module  240  via the remote interface  250  as would any sonographer in the direct presence of such an ultrasonic imaging instrument. 
         [0028]      FIG. 3  depicts the ultrasonic transducer  230  of  FIG. 2  along with various force vectors of interest that may be used to provide tactile feedback to a sonographer. As shown in  FIG. 3  the ultrasonic transducer  230  has a central axis running along the length of the ultrasonic transducer  230  upon which a first force vector F Z  representing a force applied against the front tip/face (at point A) of the ultrasonic transducer  230  is shown. 
         [0029]    In addition to the force vector F Z  along the central axis, it can be advantageous to measure forces applied laterally to the transducer&#39;s front face, such as those represented by force vectors F X  and F Y  that can exist in a plane normal to force vector F Z  and normal to one another. Sensing forces along vectors F X  and F Y  can provide an enhanced tactile feedback to the sonographer, such as the tactile feel of the friction and pressure that occur when a transducer&#39;s face is dragged along the surface of a patient&#39;s skin. 
         [0030]    Still further, in order to provide tactile feedback in situations where a sonographer might wish to rotate the transducer  230  while in contact with a patient&#39;s skin, a rotational force about the central axis of the transducer  230 , represented by force vector F θ , can be optionally detected. 
         [0031]    Continuing to  FIG. 4 , a haptic controller  130  of an illustrative embodiment is shown. The haptic controller  130  includes a base  400  having a mechanical armature/linkage  410  onto which a reference wand  420  is appended. The exemplary reference wand  420  is shaped like the transducer  230  of  FIGS. 2 and 3 , but of course the particular configuration of the reference wand  420  can change from embodiment to embodiment. 
         [0032]    The haptic controller  130  of the illustrative can be configured to sense the position of the tip of the reference wand  420  in three dimensions, as well as the angle of the reference wand  420  in three dimensions, relative to the base  400  using a number of position sensors (not shown). In some embodiments, the reference wand  420  can additionally be equipped to sense a rotation (or rotational force) about the central axis of the reference wand, while in other embodiments the haptic controller  130  as a whole may have less than 6 degrees-of-freedom. 
         [0033]    Further, in order for the haptic device  130  to provide an appropriate tactile feedback to a sonographer&#39;s hand  430 , a number of force sensors and drive motors (not shown) can be installed. Thus, when the proper controls and interfaces are applied to the haptic device  130  and a respective robotic arm and transducer, any force applied to the reference wand  420  by the sonographer&#39;s hand  430  can be countered by tactile feedback provided by the respective robotic arm and transducer. 
         [0034]    Examples of various haptic controllers useable for some embodiments include the PHAMTOM® Omni device, the PHAMTOM® Desktop device, the PHAMTOM® Premium device, and the PHAMTOM® Premium 6DOF device made by SensAble Technologies, Inc. located at 15 Constitution Way, Woburn, Mass. 
         [0035]      FIG. 5  is a block diagram of a remote interface  250  of an illustrative embodiment that is adapted for use with a haptic controlled imaging system. The remote interface  250  can include a controller  510 , a memory  520 , a first set of instrumentation  530  having a first set of drivers  532  and first data acquisition device  534 , a second set of instrumentation  540  having a second set of drivers  542  and second data acquisition device  544 , a control-loop modeling device  550 , an operator interface  560  and an input/output device  590 . The controller  510  does not necessarily, mimic the coarse movements of the robotic arm, but rather the pressure applied by the robotic arm in 3D space. If there is no resistance (i.e. no force) applied in response to force applied by the controller, a coarse motion of the robotic arm results in response to the force applied to the controller. 
         [0036]    Although the remote interface  250  of  FIG. 5  uses a bussed architecture, many other architectures contemplated for use as would be appreciated by one of ordinary skill in the art. For example, in various embodiments, the various components  510 - 590  can take the form of separate electronic components coupled together via a series of separate busses or a collection of dedicated logic arranged in a highly specialized architecture. 
         [0037]    It also should be appreciated that portions or all of some of the above-listed components  530 - 590  can take the form of software/firmware routines residing in memory  520  and be capable of being executed by the controller  510 , or even software/firmware routines residing in separate memories in separate servers/computers being executed by different controllers. 
         [0038]    In operation, the remote interface  250  can receive control signals from a haptic controller, such as that shown in  FIG. 4 , via the second data acquisition device  544 , then process the control signals using the control-loop modeling device  550 . Various processing for the received control signals can include changing the gain of the control signals to increase or decrease sensitivity, adding a governor/limiter on the control signals to limit a maximum position or force that the respective robotic arm should be capable of exhibiting and so on. In an embodiment, a “deadman” safety is provided to the robotic arm via the control signals. Such a feature is useful, for example, if the network communication link is disrupted, the applied pressure is zeroed. 
         [0039]    Once the control signals have been conditioned, the control signals can be fed to the respective robotic arm (via drivers  532 ) while bring further processed according to a complex control loop in the control-loop modeling device  550  using optional feed-forward and feedback compensation. 
         [0040]    Simultaneously, the first data acquisition device  534  can receive position and/or force feedback information from the respective robotic arm, and optionally condition the feedback information in much the same way as the control information, e.g., by changing gain or imposing a more complex transfer function. The conditioned feedback information can then be provided to the haptic controller (via drivers  542 ) while being processed according to the control loop processes modeled in the control-loop modeling device  550 . 
         [0041]      FIG. 6  depicts a control model  600  for use with a haptic controlled imaging system in accordance with an illustrative embodiment. As shown in  FIG. 6 , a first scaling module  610  can receive control signals, typically position or force data, from a haptic controller  130  where it can then be processed according to a control loop involving a first feed-forward compensation module  612 , the mechanics of the robot arm  220  and a first feedback compensation module  614 . 
         [0042]    Similarly, a second scaling module  620  can receive position and/or force feedback signals from the robotic arm  220  and transducer  230  where the feedback signals can then be processed according to a second control loop involving a second feed-forward compensation module  622 , the mechanics of the haptic controller  130  and a second feedback compensation module  624 . 
         [0043]    Note that when the control signals provided by the haptic controller  130  primarily consist of position information, the subsequent (upper) control loop will be a position control loop, the feedback signals will primarily consist of force information and the subsequent (lower) control loop will be a force control loop. Conversely, when the control signals provided by the haptic controller  130  primarily consist of force information, the upper control loop will be a force control loop, the feedback signals will primarily consist of position information and the lower control loop will be a position control loop. 
         [0044]    Also note that the particular control model portrayed in  FIG. 6  is purely exemplary, and practical control models should not be limited to the sole embodiment illustrated of  FIG. 6 . 
         [0045]    Returning to  FIG. 5 , as the various instrumentation  530  and  540  and control-loop modeling device  550  enable a sonographer to remotely position an ultrasonic transducer with tactile feedback, the operator interface  560  and input/output device  590  optionally can be used to remotely configure the back-end of the ultrasonic instrumentation connected to an ultrasonic transducer in much the same fashion as a sonographer having hands-on access might do. Additionally, the operator interface  560  and input/output device  590  may be used to convey ultrasonic image data from the ultrasonic instrumentation to the sonographer. 
         [0046]    Note that in various embodiments the remote interface  250  can be divided into two or more portions, which may be advantageous when a haptic control device and a robotic arm are separated by appreciable distances. For example, two separate interfaces  250 A and  250 B might be used with remote interface  250 A located by a haptic controller and remote interface  250 B located by the respective robotic arm. In this example, remote interface  250 A can drive the servo-mechanisms and collect transducer data of the haptic controller, and remote interface  250 B can drive the servo-mechanisms and collect transducer data of the robotic arm and ultrasonic transducer. Control and feedback data can be exchanged via the respective input/output devices, and overall control may be delegated to one of the two remote interfaces  250 A and  250 B. 
         [0047]      FIG. 7  is a block diagram outlining various exemplary operations directed to the haptic control of a medical imaging device. The process starts in step  702  where an ultrasonic imaging instrument (or similarly situated medical device) is set up along with a robotic arm coupled to the ultrasonic imaging instrument&#39;s transducer plus a number of force sensors. Next, in step  704 , a haptic controller is similarly set up and communicatively connected to the robotic arm and transducer of step  702 . Control continues to step  706 . 
         [0048]    In step  706 , an operator, such as a trained sonographer, can move a control surface (e.g., a reference wand) of the haptic controller to generate force or position control signals. Next, in step  708 , the control signals can be optionally scaled or otherwise processed, and then sent to the robotic arm of step  702 . Control continues to step  710 . 
         [0049]    In step  710 , the robotic arm can react to the scaled/processed control signals, and during the reaction process generate position and/or force feedback signals. Next, in step  712 , the feedback signals can be optionally scaled/processed and then sent to the haptic controller. Then, in step  714 , the haptic controller can respond to the feedback signals to give the sonographer a tactile feel of the ultrasonic transducer. Control continues to step  720 . 
         [0050]    In step  720 , a determination is made as to whether to continue to operate the controlled haptic feedback process described in steps  706 - 714 . If the haptic feedback processes to continue, control jumps back to step  706 ; otherwise, control continues to step  750  where the process stops. 
         [0051]    In various embodiments where the above-described systems and/or methods are implemented using a programmable device, such as a computer-based system or programmable logic, it should be appreciated that the above-described systems and methods can be implemented using any of various known or later developed programming languages, such as “C”, “C++”, “FORTRAN”, Pascal”, “VHDL” and the like. 
         [0052]    Accordingly, various storage media, such as magnetic computer disks, optical disks, electronic memories and the like, can be prepared that can contain information that can direct a device, such as a computer, to implement the above-described systems and/or methods. Once an appropriate device has access to the information and programs contained on the storage media, the storage media can provide the information and programs to the device, thus enabling the device to perform the above-described systems and/or methods. 
         [0053]    For example, if a computer disk containing appropriate materials, such as a source file, an object file, an executable file or the like, were provided to a computer, the computer could receive the information, appropriately configure itself and perform the functions of the various systems and methods outlined in the diagrams and flowcharts above to implement the various functions. That is, the computer could receive various portions of information from the disk relating to different elements of the above-described systems and/or methods, implement the individual systems and/or methods and coordinate the functions of the individual systems and/or methods described above. 
         [0054]    In view of this disclosure it is noted that the various methods and devices described herein can be implemented in hardware, software and firmware. Further, the various methods and parameters are included by way of example only and not in any limiting sense. In view of this disclosure, those of ordinary skill in the art can implement the present teachings in determining their own techniques and needed equipment to effect these techniques, while remaining within the scope of the appended claims.