Abstract:
A neurosurgical instrument includes a radiation detecting sensor adjustably positioned proximate a distal end of an arm of the instrument. A controller is programmed to receive and process electrical signals from the sensor. The controller operates to control an audio tone generator to emit a tone of higher intensity as the surgeon moves the sensor and its associated coagulator closer to radioactively tagged malignant tissue or a brain tumor of a patient, and of lower intensity as the coagulator moves away from the tissue or tumor, thereby permitting the surgeon to accurately locate and remove the malignant tissue or brain tumor. Also, in place of or in combination with the audio tone generator, a light emitter provides for emitting light of intensity directly related to the distance the sensor is from the malignant tissue or brain tumor tagged with a radioactive isotope.

Description:
RELATED APPLICATION  
       [0001]     The present invention is related to and takes priority from U.S. Provisional Patent Application Ser. No. 60/551,582, filed on Mar. 9, 2004, for “COAGULATOR WITH GAMMA RAY DETECTOR,” the teachings of which are incorporated herein by reference to the extent that they do not conflict herewith. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The present invention relates generally to neurological instruments, and more particularly to such instruments that include mechanisms for permitting a surgeon to more readily locate and remove malignant brain tissue and/or brain tumors from a patient.  
       BACKGROUND OF THE INVENTION  
       [0003]     It is important for surgeons to have the ability to remove the maximum amount, and preferably all of a malignant tumor or cancerous tissue. It is known in the art to inject patients with a radioactive isotope prior to cancer surgery, whereafter a radiation detection device can be utilized by the surgeon in order to locate cancerous tissue or tumors where the isotope tends to accumulate. Use of radioactive isotopes, such as thallium, along with radiation detectors has successfully been used in surgically removing cancerous lymph nodes from various areas of a patient&#39;s body. However, because of the restricted space available to a surgeon for operating on malignant brain tissue or tumors, the present apparatus available for radioactive isotope assisted surgery is not readily useable in neurosurgery. Yet, in order to improve a patient&#39;s chances of survival, and reducing the recurrence of a cancerous brain tumor, it is particularly important that a neurosurgeon have the ability to preferably completely remove the brain tumor, and to at least have the ability to locate and remove major portions of malignant brain tissue.  
       SUMMARY OF THE INVENTION  
       [0004]     In one embodiment of the present invention, a standard neurosurgical instrument, such as a coagulator, forceps, or cavitational ultrasonic surgical aspirator, for example, is modified to incorporate therewith a gamma ray detector, or other useable radiation detector. During surgery, a patient is injected with a known radioactive isotope that tends to accumulate in malignant brain tissue or tumors, for permitting a neurosurgeon to expose the affected area of the brain, and thereafter position the instrument, having a radiation sensor attached to and in close proximity to an extended arm thereof, for example, for permitting the surgeon to quickly locate the radioactive isotope infiltrated tissue or tumor for removal.  
         [0005]     In another embodiment of the invention, a radiation sensor is mounted proximate the distal end of an arm of an associated neurosurgical instrument, such as a coagulator electrode arm, for example. The other end of the arm is secured to a lower portion/of the coagulator main frame. Note that for purposes of example, the invention is described in association with a coagulator, but is not meant to be limited thereto. This arrangement permits a surgeon to position the radiation detector tip close to one of the electrodes of the coagulator. An electrical cable has one end run through the associated arm and electrically connected to the radiation sensor, a portion of the cable being attached to the associated coagulator arm. The other end of the cable is electrically connected to electronic processing equipment, a controller, for receiving signals from the radiation sensor, and processing the same. When the radiation sensor receives radiation signals above a predetermined level, the controller will trigger a sound and/or light emitting device to indicate to the surgeon that the coagulator is in the vicinity of a brain tumor and/or malignant brain tissue that has absorbed a radioactive isotope. In another embodiment, the controller adjusts the intensity of the audible alarm or light indicator to increase as the sensor approaches radioactively tagged tissue, and decrease as the sensor moves away from the tissue. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0006]     Various embodiments of the present invention are described below in detail with reference to the drawings, in which like items are identified by the same reference designation, wherein:  
         [0007]      FIG. 1  is a pictorial view of a standard type of coagulator used in neurosurgery to which a radiation sensor has been added for one embodiment of the invention;  
         [0008]      FIG. 2  shows an embodiment of the invention for including a radiation sensor on a neurosurgical instrument, such as a coagulator, in a substantially fixed manner for permitting sterilization of the assembly after each use;  
         [0009]      FIG. 3  is a pictorial view of a mechanical attachment device for use in the embodiment of the invention of  FIG. 2 , whereby the attachment device itself represents another embodiment of the invention;  
         [0010]      FIG. 4  is a cross-sectional view taken along  4 - 4  of  FIG. 3  with an associated cap screw shown in an exploded assembly view configuration;  
         [0011]      FIG. 5  shows another embodiment of the invention for removably attaching a radiation detector to a neurosurgical instrument, such as a coagulator, for providing an easily disposable configuration for the radiation sensor;  
         [0012]      FIG. 6  shows a cross-sectional view taken along  6 - 6  of  FIG. 5 , modified for purposes of illustration to be an exploded assembly view configuration; and  
         [0013]      FIG. 7  shows a pictorial view of the clip configuration of  FIGS. 5 and 6 , for the disposable embodiment of the invention.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0014]     With reference to  FIG. 1 , a standard coagulator  2  for use in neurological surgery is shown modified for one embodiment of the invention. As previously mentioned, the various embodiments of the invention, for ease of illustration, are described in association with a neurosurgical coagulator  2 , but the invention is not meant to be so limited, in that it can be applied for use with other neurosurgical instruments. Note the coagulator  2  includes two arm extensions  5  terminated to a plug  3 , to permit the coagulator to be disconnected from its power source and controller (not shown) for purposes of sterilization after use. Coagulator  2  also includes two arms  6  formed as part of and protruding from respective arm extensions  5 , as shown. Individual electrodes are connected to the free ends of each protruding arm  6 . The modifications include, in this example, using an electrically insulated sheath  4  to hold tightly against a lower portion of one arm  6  of the coagulator  2 , a lower portion of a tubular flexible arm  8 , and a portion of an electrical cable  10 , as shown. One end of the cable  10  is threaded through the center of the flexible arm  8  for electrical connection to the radiation sensor  12 . The other end of the cable  10  is connected to a controller  16 . In this example, the radiation sensor  12  is a gamma ray sensor. However, depending upon the type of radioactive isotope used in the surgical procedure, the radiation sensor  12  can be other than a gamma ray sensor, for example, a beta ray sensor. Accordingly, the various embodiments of the invention are not meant to be limited to only a gamma ray sensor  12 , or sensing gamma rays, or neurosurgical coagulators.  
         [0015]     Certain radiation sensors are capable of sensing both beta and gamma rays to given degrees of sensitivity. The insulated sheath  4  can be provided by shrink wrap tubing, for example, or other suitable dielectric material, in one embodiment of the invention. Note also that in another embodiment of the invention the radiation sensor can be incorporated into one arm  6  of a coagulator, with the radiation detecting tip or element  12  being electrically and thermally insulated from the associated electrode operating element  14  of the coagulator  2 .  
         [0016]     The electrical cable  10  has its other end electrically connected to an electronic control device or controller  16  that processes signals from the sensor  12  via an included programmable microprocessor (not shown), for example, and also includes an output signal generator  17  for providing a surgeon with either an acoustical alarm and/or light emitter of varying intensity depending upon whether the radiation sensor  12  is being moved closer to (increasing intensity) or further from (decreasing intensity) malignant brain tissue or a brain tumor, in this example, that has absorbed the aforesaid radioactive isotope. The cable  10  may include coaxial cable to conduct signals from sensor  12  to the controller  16 , and shield such signals from electrical interference. Note also that the signal generator  17  can be provided as either a separate module, or in a module also including controller  16 .  
         [0017]     In another embodiment of the invention, the radiation sensor  12  is no larger than one-quarter inch in diameter for insuring its easy affixation to a desired neurological instrument such as a coagulator  2 , as shown. It is expected that the electronic controller  16 , in a preferred embodiment, will incorporate wireless features, such as battery backup, low battery alert, adjustment of the sensitivity of the device, and adjustment of the acoustical sound alerting portion of the system. Note that presently available coagulators typically include foot pedal controllers for operating the coagulator device. Also, the present controller  16  may be completely self powered, and attached to the surgeon&#39;s operating uniform or garb.  
         [0018]     In another embodiment of the invention, the controller  16  and signal generator  17  can be contained in a single module for belt mounting to the surgeon in a sterile manner. Also, wireless foot or hand controllers  18 ,  20 , respectively, may be included for permitting the surgeon to control the main controller  16  of the radiation detector without the encumbrance of control cables around the surgical table. To avoid false readings, the controller  16  can be selectively turned on or off to avoid false readings.  
         [0019]     It should be noted that presently available coagulator apparatus provide for both a cutting mode for removing tissue, and a coagulation mode for closing off blood vessels at the surgical site. An example of presently available neurosurgical coagulators is the “IsoCool” line of Codman, Raynham, Mass. 02767, which includes both bipolar forceps, and electrical bipolar generators, and controllers. As previously indicated, the present radiation detection system can be added to such standard coagulator devices or apparatus  2 , or can be incorporated into a newly designed coagulator device, or incorporated into other neurosurgical instruments.  
         [0020]     In one embodiment of the invention, the radiation sensor  12  is likely to be provided by a 716 Gamma Detector of LND, Inc., Oceanside, N.Y. Also, the flexible arm  8  is likely to be provided by a “flexible arm” of Uniprize International, Terryville, Conn.  
         [0021]     In another embodiment of the invention, as shown in  FIG. 2 , a radiation sensor  12  having its electrical cable  10  enclosed within a flexible arm  8 , is semipermanently attached to an arm of a neurosurgical instrument, such as arm  6  of a coagulator, for example. The mechanical attachment is provided by an attachment device  22 , which will be described in greater detail below. Also, the electrical cable  10  of the radiation sensor  12  is moveably attached via the use of a known plug-in connector  24 , suitable for such use. In this embodiment of the invention, the cable  10  can be unplugged via the connector  2 , and the assembly of the radiation sensor  12 , with flexible arm  8 , and coagulator&#39;s arms  6 , can be sterilized for reuse.  
         [0022]      FIG. 3  shows a pictorial view of the mechanical attachment device  22 . The device  22  can be made from a number of materials, including but not limited to aluminum, stainless steel, and appropriate plastic materials. As shown, the attachment device  22  includes a pair of spaced apart open slotways  26 ,  28 , respectively. The bottom of slotway  26  terminates into a cylindrical cavity  30  dimensioned for snugly carrying therein the flexible arm  8 . The open slotway  28  is configured for snugly receiving and retaining a portion of an arm of an associated neurological instrument, such as coagulator arm  6 , in this example, as shown. A cross section of the attachment device  22  taken along  4 - 4  is shown in  FIG. 4 . As shown, a cap screw  39  is inserted through the successive holes  36 ,  38 , and into threaded hole  34 , for permitting the cap screw  39  to have its threaded end  41  screwed into threaded hole  34  for causing the circular cavity  30 , and slotways  26  and  28  to be dimensionally reduced for squeezing or compressing against the portion of the flexible arm  8 , and the portion of the instrument arm  6 , for rigidly retaining the two within the attachment device  22 . In this manner, the flexible sheet or arm  8  and the arm  6  of a coagulator, in this example, are rigidly secured together. After use of the coagulator  2  in combination with the radiation sensor  12  and tubular flexible arm  8 , the cable  10  is disconnected from the assembly via connector  24 , and the opposing coagulator arms  6 , in this example, are unplugged from their main coagulator body  2 , for permitting sterilization of the detached elements for later reuse.  
         [0023]     In another embodiment of the invention, the radiation sensor  12  and associated tubular flexible arm  8 , and cable  10  are removably attached to a neurosurgical instrument such as to a coagulator arm  6 , in this example, as shown in  FIG. 5 . In this embodiment, two clips  40  are used for removably attaching the sensor assembly  8 ,  10 ,  12  to the coagulator arm  6 . In  FIG. 6 , a cross section of a clip  40  taken along  6 - 6  of  FIG. 5  is shown in an exploded assembly view configuration with a tubular flexible arm  8  and coagulator arm  6  portion. The clip  40  includes opposing flexible fingers  42  for permitting a portion of a coagulator arm  6  or other neurosurgical instrument portion to be snapped into the receiving area  44  thereof, for securely retaining the coagulator arm  6  portion, in this example. The other end of the clip  40  includes a pair of opposing flexible fingers  46  for permitting a portion of the tubular flexible arm or shaft  8  to be snapped into a receiving area  48  of a clip  40 , and securely held therein.  FIG. 7  shows a pictorial view of the clip  40 . It is expected that typically two or more such clips  40  will be utilized for securing the radiation sensor assembly  8 ,  10 ,  12  to a portion of a neurosurgical instrument, such as coagulator  2 . Note that the clip  40  can be fabricated from any suitable material, including polycarbonate, nylon, and so forth.  
         [0024]     Prior to using a neurosurgical instrument fitted with the radiation sensor assembly  8 ,  10 ,  12  of the present invention, a patient being prepared for brain surgery to remove a malignant or cancerous tumor, must first typically have the patient injected with an appropriate radioactive tracer that after injection will travel to and accumulate in the malignant tumor. Thallium 201 has been used for a number of years in nuclear medicine. Thallium is known to emit gamma rays. Accordingly, when this radioactive isotope is utilized, the radiation sensor  12  must be capable of detecting gamma rays. The method of administration of Thallium 201, and other radioactive isotopes, is well known by anesthesiologists. Accordingly, for the sake of brevity, a description of a typical procedure for targeting brain tumors with a radioactive tracer, such as Thallium 201, will not be described herein. After the radioactive tracer has had sufficient time to accumulate in the brain tumor, the surgeon can then begin use of the present invention in association with a neurosurgical instrument for assisting in the removal of the malignant tissue. Thallium  201  is produced by Amersham located in Livingston, N.J.  
         [0025]     Although various embodiments of the invention have been shown and described above, they are not meant to be limiting. As previously indicated, for purposes of illustration various embodiments of the invention have been described in association with a neurosurgical coagulator, whereas the invention can also be practiced in association with other neurosurgical instruments, such as forceps, ultrasonic surgical aspirators, and rongeurs, for example. Those of skill in the art may recognize certain modifications to these embodiments, which modifications are meant to be covered by the spirit and scope of the appended claims.