Abstract:
A guide plate for inserting, into a body, instruments, such as needles, used for medical purposes, comprising a plurality of openings for receiving an instrument; for each of the openings, a sensor arrangement for detecting presence of an instrument when an instrument is received in an opening; and reporting apparatus for reporting sensing of an instrument by each respective sensor arrangement. Use may be with an imaging system, including a display for an image of a portion of the body into which instruments are inserted. The imaging system can superimpose on the image an array corresponding to openings in the guide plate; a signal transmission means responsive to reports from respective reporting apparatus transmit output of the reporting apparatus to the imaging system. A display modification arrangement can modify elements of the array to indicate that an instrument has been inserted into a respective opening.

Description:
This application claims priority under 35 U.S.C. §119 (e) from U.S. provisional patent application Ser. No. 60/689,654, filed on Jun. 11, 2005, which is incorporated herein by reference, in its entirety. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   This invention relates generally to an active template grid system. More particularly, it relates to an active template system for positioning medical implants. Still more particularly this invention relates to a template grid system for use with transrectal ultrasound imaging probes in brachytherapy and cryosurgery for cancerous prostate and related surgeries, where the template has sensors embedded in it to detect the presence of the seed-delivering, or freezing needles. 
   2. Background Art 
   As illustrated in FIG. 1 of U.S. Pat. No. 6,422,997, and in FIG. 1 of United States Patent Publication 20040152986 (the entire contents of which are incorporated by reference herein), brachytherapy is performed with the patient in the lithotomy position, using an ultrasound imaging probe placed in the rectum to monitor seed placement. A template grid arrangement or guide plate having openings at predefined positions of a coordinate grid thereon, of the general type illustrated in FIG. 3 of U.S. Pat. No. 6,387,034, which is kept in precise linear orientation with the ultrasound probe, must be accurately oriented adjacent the perineum in relation to the prostate, and locked in position throughout the procedure to achieve optimum seed placement. A cradle of the type illustrated in FIG. 17 of U.S. Pat. No. 6,752,753 is helpful in this regard. Precise and reproducible orientation and positioning of the ultrasound imaging probe in the rectum is a key element in both the calculations required for determining the number and distribution of radioactive seeds required for treatment and their subsequent placement using preloaded needles guided by the peritoneal template and real time ultrasound imaging. 
   Even with proper probe positioning, placement of the needles using the template grid needs to be accurate and precisely coordinated with the images from the probe and the patient&#39;s anatomy to have effective therapy. Keeping track of the actual needles inserted can also be problematic during the procedure. 
   SUMMARY OF THE INVENTION 
   It is an object of the invention to provide an apparatus and a method for using the apparatus, which keeps track of the actual insertions performed during a procedure. 
   It is a further object of the invention to keep track of the insertions automatically. 
   It is yet another object of the invention to assure that all of the insertions are at correct locations. 
   These objects and others are achieved in accordance with the invention by adding sensors to a template grid or guide plate to detect the presence of an insertion needle at each location. Indications of what locations, out of a multitude of locations, are to be used for insertion are provided. When an insertion has taken place, a change in the indication, or a further indication, is provided until the entire procedure has been completed. 
   In accordance with a first aspect, the invention is directed to a guide plate for inserting, into a body, needles used for medical purposes. The guide plate comprises a plurality of openings, each opening being for receiving a needle; for each of the openings, a sensor arrangement for detecting presence of a needle when a needle is received in an opening; and for each of the openings, reporting apparatus for reporting sensing of a needle by each a respective sensor arrangement. 
   Each of the sensors can comprise an electromagnetic source and an electromagnetic detector responsive to energy from the source, the source and the detector being disposed so that insertion of a needle into a respective opening blocks at least a portion of energy traveling from the light source to the detector. Alternatively, each of the sensors can comprise an inductor, and means for detecting a change in inductance of the inductor, the inductor being disposed so that insertion of a needle into a respective opening changes inductance of the inductor. 
   The guide plate can comprise a first wall and a second wall, which are generally parallel to one another, the openings being defined by tubes extending from the first wall to the second wall, and a respective sensor arrangement being disposed about respective ones of the tubes. 
   In accordance with the invention, the guide plate can be combined with an imaging system, the imaging system including a display for displaying an image of a portion of the body into which needles are to be inserted, the imaging system having means for superimposing on the image on the display an array corresponding to openings in the guide plate; signal transmission means responsive to reports from respective reporting apparatus for transmitting an output of the reporting apparatus to the imaging system; and a display modification arrangement responsive to signals from the signal transmission means for modifying elements of the array to indicate that a needle has been inserted into a respective opening in the guide plate. The imaging system can be an ultrasonic imaging system, the ultrasonic imaging system comprising an ultrasonic probe for contacting the body to display the portion of the body where the needles are inserted. The probe can be a transrectal probe, and the portion of the body that is imaged can include the prostate. 
   The signal transmission means can include at least one selected from the group consisting of an electrical cable, a radio link and an infrared link. The display modification arrangement can change color of a respective element of the array when a needle has been inserted into a respective opening in the guide plate. 
   A dosage calculation means for assisting in determining through which of the openings in the guide plate a needle should be placed for insertion into the body may also be provided. 
   The guide plate can be shaped with a portion for receiving a transrectal probe associated with an ultrasonic imaging system. Preferably, a cradle for carrying the transrectal probe and the guide plate is included. 
   The invention is also directed to a method for using the apparatus comprising the steps of connecting the apparatus to an imaging system having a capability for superimposing an array corresponding to the openings on an image of a portion of the body generated by the imaging system; inserting successive needles in indicated ones of the openings; and viewing modification of elements of the array as the needles are inserted to monitor which of the openings and corresponding locations in the body have needles inserted therein. 
   Another aspect of the invention is directed to an imaging system for a portion of a body, comprising an array generator for generating an array of symbols superimposed on an image of the portion of the body; an input for receiving data concerning which locations in the body corresponding to symbols of the array have undergone a change in status; and means for changing an indication associated with the symbols in the array to indicate which locations in the body have undergone a change in status. The system can further comprise a guide plate having an array of openings corresponding to the array of symbols; and a sensor arrangement for sensing insertion of an element into one of the openings and for providing an output indicative of the insertion; and means for changing the indication in response to the output. The system can be an ultrasonic imaging system. 
   The system can further comprise a transrectal probe for imaging a prostate; the guide plate being disposed to guide treatment needles into the prostate. 
   In accordance with yet another aspect, the invention is directed to a combination of components for operation with an imaging system, comprising a guide plate for inserting, into a body, needles used for medical purposes, the guide plate including a plurality of openings, each opening being for receiving a needle; for each of the openings, a sensor arrangement for detecting presence of a needle when a needle is received in an opening; and for each of the openings, reporting apparatus for reporting sensing of a needle by each a respective sensor arrangement; and a sensor reading module, responsive to the reporting apparatus for providing to the imaging system, data concerning which of the openings has a needle disposed therein. The data can be provided to the imaging system to change an indication representative of one of the openings on a display of the imaging system, when a needle is disposed in the one of the openings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The foregoing aspects and other features of the present invention are explained in the following description, taken in connection with the accompanying drawing, wherein: 
       FIG. 1  is a plan view of a brachytherapy template or guide plate in accordance with the invention. 
       FIG. 2  is a partial sectional view of  FIG. 1  illustrating a first embodiment of a sensor arrangement used in accordance with the invention. 
       FIG. 2A  is a partial sectional view of  FIG. 1  illustrating a second embodiment of a sensor arrangement used in accordance with the invention. 
       FIG. 3  is a diagram of a system which utilizes the present invention. 
       FIG. 3A  is a view of the display of the system of  FIG. 3 . 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring to  FIG. 1 , there is shown a plan view of a template or guide plate  10  incorporating features of the present invention. Although the present invention will be described with reference to the single embodiment shown in the drawings, it should be understood that the present invention can be embodied in many alternate forms of embodiments. In addition, any suitable size, shape or type of elements or materials could be used. In view of the need for sterilization, guide plate  10  should be formed of a disposable material such as, for example, a plastic, or a metal or other material which can be sterilized. 
   As more fully described below with respect to  FIG. 3 , the ultrasound system used to guide the needles has a grid on the screen representing the locations of openings or through apertures  12  in guide plate  10  in  FIG. 1 . The ultrasound system can be associated with or contain a dosimetry program used to calculate the location of the radioactive seeds to be placed in the prostate, as is known in the art. The locations where needles are to be inserted are identified with a first color, preferably green. All other locations are identified by a second color, preferably red. The first location for the needle to be inserted blinks on the screen. After the system detects that a needle is inserted, the color of that location on the screen changes from green to red, indicating that a needle is already placed at that location. The next location that requires a needle insertion will flash green, until the next needle is inserted. When all the required needles are inserted, all the locations will have turned red. 
   Referring to  FIG. 2  and  FIG. 2A , the detection of a needle, which has been positioned in an opening or aperture  12 , can be accomplished in several ways. In the embodiment of  FIG. 2 , the guide plate  10  may be comprised of a first wall  202  and a second wall  204 , which are generally parallel to one another, with a space  206  between the walls. The openings  12  may be defined by tubes  208  extending from the first wall to the second wall. One approach is to have a photoelectric pair, including a light emitting diode (LED)  210 , and a photoreceptor  212 , located at each aperture  12  (at openings on opposite sides of the tube  208 ) in the grid of guide plate  10 , so that the needle will block the light flow, and the system can then detect its presence. 
   In  FIG. 2A , another embodiment uses a magnetic pickup. A coil  201  around each tube  208  senses the change in inductance of the coil as the needle passes through a aperture  12  in the guide plate  10 . 
   Whatever their nature, the sensors associated with the apertures  12  may be electronically scanned, and the location of each needle passing through openings or apertures  12  in the guide plate  10  is easily detected. 
   Guide plate  10  has a curved cut out portion  18  through which the transrectal ultrasound probe extends in a direction generally perpendicular to the plane of guide plate  10 . Both the transrectal ultrasound probe and the guide plate  10  are carried by a cradle, a pair of posts  58  extending from guide plate  10  being received in suitable openings in the cradle, as more fully illustrated in  FIG. 3 , below. 
   Referring to  FIG. 3 , and as discussed in U.S. Pat. No. 6,752,753, a conventional brachytherapy system including a cradle  300 , has a stepping unit  302 , one or more needles  306  and a corresponding number of stylets  303 . Another example of a conventional stepping unit is disclosed in U.S. Pat. No. 5,871,448. The manner in which seeds are placed using this type of apparatus is discussed in detail in U.S. Pat. No. 6,752,753, and is incorporated herein by reference. 
   The guide plate  10  of the present invention may be supported by the stepping unit  302  at a position adjacent but spaced from the patient&#39;s body. The guide plate  10  having its array of openings or apertures  12 , defining an x-y array, each of which openings or apertures  12  is sized to receive one of the needles  306 . The apertures  12  extend in rows oriented in the x direction (i.e., perpendicular to the drawing page) and in columns oriented in the y direction (i.e., in or parallel to the  15  plane guide plate  10 ). Thus, each aperture  12  corresponds to a precise location in the x and y directions on a cross section of the prostate  321  parallel to the guide plate  10 . Accordingly, for any specific aperture, a particular configuration of seeds for treating a portion of the prostate  321  at a position corresponding to that aperture can be used. 
   An ultrasound probe  310  coupled to the stepping unit  302  is inserted rectally to a depth adjacent a portion of a patient&#39;s prostate  321 . The ultrasound probe  310  emits waves directed through the adjacent portion of the prostate  321  from which an ultrasonic cross-sectional image of that portion of the prostate  321  can be obtained. The stepping unit  302  incrementally moves the ultrasound probe to obtain ultrasound images of successive planes of the prostate or other organ or tissue. The stepper unit  302  includes a scale  311  oriented in the z direction that shows the depth of the ultrasonic probe  310  relative to a predetermined datum. 
   Ultrasound probe  310  is coupled to an ultrasonic imaging system  309  by a cable  313 . System  309  and probe  310  may be of the kind described in United States Patent Publication 20040152986. System  309  includes an electronics module, the module having: excitation circuitry for exciting probe  310 , receiving circuitry for processing signals received from probe  310 , signal processing circuitry for processing signals from the receiving circuitry to produced processed image signals; and a display  307  for displaying the processed image signals. 
   In accordance with the invention, a cable  314  connects the sensors of guide plate  10  (described above with respect to  FIG. 2  and  FIG. 2A ) with a sensor reading module  316 , which monitors or scans the outputs of the sensors. Module  316  is in turn connected to system  309  by a cable  315 , which supplies data concerning which apertures  12  have needles therein. This data is supplied to an array generating program, which superimposes an array of points, as illustrated in  FIG. 3A , on the display  307 . The program will change the color of the indicator for the apertures from, for example, green to red, indicating that the needle has already been placed. 
   While cable  314  connects the sensors of guide plate  10  to sensor reading module  316 , it will be recognized that other signal transmission techniques, such as a radio or an infrared link may also be used. 
   The guide plate  10  and the sensor reading module  316  may be added to a standard ultrasonic imaging system, which has a software array generator added thereto, and input for receiving data from sensor reading module  316 , to assemble a system in accordance with the invention. Thus, existing imaging systems may readily be adapted to implement the present invention, as described herein. 
   Referring to  FIG. 3A , as noted above, the locations corresponding to the outline of the prostate  301  where needles are to be inserted are identified with a first color, preferably green (shown as gray  308  in  Fig. 3A ). All other locations are identified by a second color, preferably red (shown as black  305  in  FIG. 3A ). The first location for the needle to be inserted blinks on the screen. After the system detects that a needle is inserted, the color of that location on the screen changes from green to red, indicating that a needle is already placed at that location. The next location that requires a needle insertion will flash green, until the next needle is inserted. When all the required needles are inserted, all the locations will have turned red. 
   Thus, using the apparatus and method of the invention, the treating physician is immediately, continuously and accurately informed of which needles (and corresponding seeds in the case of brachytherapy) have been placed, and at which additional locations needles still need to be placed. 
   As noted above, imaging system  309  may have a software module  320  which assists in determining where needles are to be place in order to provide the proper treatment for a particular patient. Such software is described in U.S. Pat. No. 6,539,247. 
   While the present invention has been described with respect to an ultrasonic imaging system and apparatus used to treat the prostate, it will be understood that different types of imaging systems, such as, for example, x-ray systems may be used. Other procedures, on other parts of the body, which require accurate placement of instruments or sensors may be advantageously preformed with the apparatus and methods of the invention. Further, although the apertures in the guide plate, and corresponding display indicators have been shown to be arranged in a rectangular X-Y coordinate system, it will be understood that other coordinate systems may be useful for various portions of the body being treated, and the invention, as described herein, can be modified for use with such coordinate systems. 
   It should be understood that the foregoing description is only illustrative of the invention. Various alternatives and modifications can be devised by those skilled in the art without departing from the invention, which embraces all such alternatives, modifications and variances.