Abstract:
A method and apparatus for identifying and tracking surgical objects is disclosed. More specifically, a method and apparatus for identifying and tracking surgical objects such as needles, scalpels, blades, sponges and instruments in a medical industry using an identifier encoded on a fluorescent paint attached to the surgical object combined with detectors and software capable of retrieving the identifying information on the identifier.

Description:
RELATED APPLICATIONS 
     This application claims the benefit of priority from and incorporates by reference herein, U.S. Provisional Application No. 61/093,770, filed Sep. 3, 2008. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention generally relates to an apparatus and a method for identifying and tracking disposable objects and surgical instruments in surgical operating rooms. More specifically, the present invention relates to a system and method to identify and count surgical objects such as needles, scalpels, blades have long been used in the medical profession to help and assist doctors and nurses with their medical needs. In some instances, these types of surgical objects have been left unaccounted for and to the detriment of those within an operating theatre, have caused serious injury. Some current methods of manually counting and tracking these potentially dangerous items include utilizing the nurses within the hospitals. 
     Moreover, other objects such as sponges may be heavily used during surgery and some of these can easily be left behind unaccounted for. Some conventional techniques for tracking sponges have used radio frequency identification (RFID). 
     A wide array of surgical instruments may be employed during a surgery and these can be left behind in the patient, creating a serious health hazard. One other known technique uses a bar code system on instruments but this may impose tedium as the barcode can sometimes only be read by the detection system if the labeled object is held at a certain angle, and effective detection of the barcode may require more than one pass. 
     Hence, it can be seen that a need exists for a system and method of for automated tracking of surgical objects used in a surgical theatre. 
     SUMMARY OF THE INVENTION 
     In one aspect of the present invention a system for identifying and tracking a surgical object comprises a tag identifier including object information encoded on a fluorescent paint coating attached to a surgical object; a detector disposed to receive a reflection of the fluorescent paint from the tag identifier; and a receiver in communication with the detector receiving a signal transmitted by the detector wherein the signal is generated by the reflection of the tag identifier. 
     In another aspect of the present invention a tag identifier comprises one or more quantum dots arranged to define a spectral signature; and a layer coating comprising the one or more quantum dots, wherein the layer coating is attached to an object. 
     In still yet another aspect of the present invention a method of tracking surgical objects comprises steps including passing a surgical object including a fluorescent tag identifier by a detector; logging a first signal generated by the detector detecting the fluorescent tag identifier; generating an event marking an introduction of the surgical object into an operation area based on the logged signal; passing the surgical object after use back through the detector; logging a second signal generated by the detector detecting the fluorescent tag identifier of the surgical object; and determining that the surgical object is accounted for based on the logged second signal. 
     These and other features, aspects and advantages of the present invention will become better understood with reference to the following drawings, description and claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  depicts a tracking system according to an exemplary embodiment of the present invention; 
         FIGS. 1B and 1C  show a top view and a front view respectively of an exemplary setup according to the tracking system shown in  FIG. 1A ; 
         FIG. 2  depicts a surgical object being tracked and disposed of in accordance with the exemplary embodiment of the present invention shown in  FIG. 1 ; 
         FIG. 3  is a front view of a surgical object including an identifier in accordance with another exemplary embodiment of the present invention; 
         FIG. 4  is a magnified cross-sectional side view of an identifier field shown in  FIG. 1 ; 
         FIG. 5  is a magnified top view of a bead and quantum dots according to another exemplary embodiment of the present invention; and 
         FIG. 6  is a series of steps illustrating a method in accordance with another exemplary embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The following detailed description is one of the best currently contemplated modes of carrying out the invention. The description is not to be taken in a limiting sense, but is made merely for the purpose of illustrating the general principles of the invention, since the scope of the invention is best defined by the appended claims. 
     Various inventive features are described below that can each be used independently of one another or in combination with other features. 
     Referring to  FIG. 1A , a system  10  in accordance with one exemplary embodiment may generally include an identifier tag  20 , a detector  50 , an amplifier-digitizer  88 , and a computer  80 . The system  10  may further include a light source  40 , and a motion detector  60 . A surgical object  30  may be a sharp instrument such as a scalpel that is coated with an identifier tag  20 . Other exemplary surgical objects  30  usable according to exemplary embodiments of the present invention may include a needle, a blade, or any other sharp object (“sharps”), a blunt surgical instrument, or a surgical sponge. Tag identifier  20  may be used for identifying the type of object to which it is attached and counting the number of same type objects having passed by or through the detector  50 . In addition to the classification information, other information could also be embedded in the tag identifier such as an object length, an object gauge, a batch number, an instrument type, or any other information that could be of interest in identifying the surgical object  30 . 
     Referring to  FIGS. 1B and 1C , an exemplary set up of the elements illustrated in  FIG. 1A  are shown with the exception of the amplifier-digitizer  88 , and the computer  80 . As depicted in one exemplary embodiment in  FIGS. 1B and 1C , the detector  50  may be a CCD camera. The light source  40  may be positioned near or attached to the detector  50 . The detector  50  may be surrounded by one or more motion detectors  60 . In one exemplary embodiment, a bandpass filter  53  may be disposed in front of the detector  50  for filtering out unwanted low or high wavelength emissions being detected by the detector  50 . 
     Referring to  FIGS. 3 and 5 , the identifier tag  20  may for example, comprise a fluorescent quantum dot deposit of cadmium based quantum dots  25  or organic quantum dots  25 . The identifier tag  20  may contain identifying information regarding the surgical object  30 . In one exemplary embodiment, the quantum dots may be arranged next to each other in a non-linear formation. 
     One example of materials used in constructing the tag identifier  20  may be quantum dots  25  made from small, colloidal fluorescent nanocrystals. The quantum dots  25  may be assembled into combinations and adhered to quantum beads  26 . A quantum dot  25  may represent one of multiple types as depicted where quantum bead  26  includes quantum dots  25   a ,  25   b , and  25   c  that may work in combination to provide, for example, at least 400 different specific spectra in the form of a spectral signature  29 . The quantum dots  25  can be mixed into liquid solutions and blended with polymer coating materials such as adhesives to be applied as a mechanically resilient coating layer  28  on solid surfaces of surgical objects  30  such as sharps or used in coating formulations on fibrous materials such as in surgical sponges. The coated surgical objects  30  can then be used for fluorescent tagging by optical methods. Some exemplary materials used for producing the quantum dots  25  may include cadmium selenide, cadmium sulfide, indium arsenite, indium phospites of the inorganic type and some quantum dots  25  may be based on organic fluorescent dyes. One exemplary advantage of the quantum dots  25  in accordance with the present invention over other traditional fluorescence organic dyes is their high quantum yield. Thus a very small amount of material may be used to obtain a strong spectral signature  29  signal. For example, the quantum dots  25  may vary in size from 5-100 nm and an exemplary quantum bead  26  may measure up to 1 uM. 
     Each type of quantum dot ( 25   a ,  25   b , and  25   c ) can be produced to obtain a specific signal depending on the frequency of detection desired for an application. 
     When used in various combinations, quantum dots  25  can be formed into the quantum beads  26 , which can be formulated to produce a specific spectral signature  29  identifying a particular surgical object  30  and differentiating the spectral signature  29  from other types. Thus formulation of these quantum beads  26  can be used to tag a specific surgical object  30  and properly identify it. 
     One exemplary manner of producing coatings may produce both inorganic and organic quantum dots  25  by first dissolving dots in an organic solvent such as toluene, decane, acetone, ethyl acetate or ethylalcohol and then blending these solutions with various resins such as polycyanoacrylates, polymethylmethacrylate, polyurethane or epoxy resins to produce paints which upon solvent evaporation and/or curing yield abrasion resistant coatings on metal objects such as sharps and sponge materials. 
     Alternatively the quantum dots  25  can be formulated into aqueous dispersions using surfactants and blended with various polymers to obtain latex paints, for coating with surgical objects. 
     The preparation of coating layer  28  of the tag identifier  20  applied to surgical objects  30  such as sharps, may be radiation resistant, but not resistant to autoclaving as the sharps are not reused; these criteria may be satisfied for example, by using a cadmium based coating. The levels of cadmium can be well below toxic levels. The cadmium-based quantum dots  25  may be extremely fluorescent so they can be applied in minute quantities. The coating layer  28  of the tag identifier  20  may be designed so that it will not rub off the surgical object  30 . 
     In one exemplary embodiment, referring specifically to  FIG. 4 , the coating layer  28  may be covered by an additional, optically transparent sealant  22 . The tag identifier  20  may be covered with a thin layer, for example 1 um to 100 um thick of resistant, inert material to prevent interaction with bodily fluids. This inert material serves to protect the tag identifier  20  as well as the doctors and patients who utilize various surgical objects. 
     Referring back to  FIGS. 1A and 2 , detector  50  may be an optical detector such as a CCD camera or a substantially cylindrical array of light detectors, which may within nanoseconds, interrogate a tag identifier  20  of a surgical object  30  passing by CCD camera or through the detector array. As surgical objects  30  pass by or through the detector  50 , light shined on the tag identifier  20  may be reflected onto and sensed by the detector  50  thus, producing a signal from the reflection of the tag identifier  20 . The detector  50  may also include a wireless antenna  55  for transmitting signals wirelessly. In another exemplary embodiment, the detector  50  may also be connected to a motion detector  60  also including a wireless antenna  65 . The detector  50  may have an optical filter  53  to remove non-relevant light wavelengths. It will be understood that the detector array  50  may also use other identifying technologies such as infrared technology, laser scanning technology, or any other types of technology that may be capable of detecting the information embedded within the tag identifier  20 . 
     Motion detector  60  may utilize high frequency, short range waves to detect passage of the surgical object  30  in front of the optical detector  50 , thereby triggering the detector  50  to acquire spectral information from the tag identifier  20 . The motion detector  60  may operate optically or via sound waves. The motion detector  60  may send information either via cable or through a wireless connection using wireless antenna  65 . 
     The computer system  80  may serve as a receiver for receipt of the information detected and transmitted by the detector  50 . A computer system  80  may include a display  85  and be connected an amplifier-digitizer  88  including a wireless antenna  87  receiving signals transmitted from the detector array  50  and motion detector  60 . The amplifier-digitizer  88  may acquire via wireless antenna  87  from the detector  50 , a signal including information identifying the identifier tag  20  passed through the detector  50 . The amplifier-digitizer  88  may amplify the optical spectral signature  29  embedded in the surgical object  30  and may then send the information for analysis in the computer  80  which may then be displayed on the display  85 . 
     The computer system  80  may in one exemplary embodiment, be connected by wireless antenna  86  to amplifier-digitizer  88  in order to analyze, count and display the information gathered from the tag identifier  20  of surgical object  30 . 
     It will also be understood that computer software (not shown) to analyze the fluorescent spectra of the tagged surgical objects  30 , count them, display the counts on a screen, and save the count data to a spreadsheet file has been developed by the inventors using the Labview® programming language. The programming in this invention may be extended to include other languages such as C, Pascal, assembler and Java. 
     In one exemplary use, referring to  FIGS. 1B ,  2 ,  4  and  6 , a surgical object  30  may be tracked both as it is introduced into an operating area and when it is disposed after use into a disposal container  90 . A surgical object  30  should include an identifier tag  20  coated with, for example, a cadmium-based layer of quantum dots  25 , (Step  610 ) sealed by an optically transparent sealant (Step  620 ). The disposal container  90  may be a disposal receiving container that is generally used in the hospital for disposal or holding of surgical objects  30 . It will be understood that one or more detectors  50  may be used simultaneously to identify and track surgical objects  30  being introduced and surgical objects  30  that are being disposed. Thus, one detector array  50  used to track which surgical objects are introduced into an operations table area may be freestanding and separate while another detector array  50  may be attached to the disposal container  90  and may allow an operator to track which surgical objects  30  are being disposed of after use. Thus, surgical objects  30  being introduced during a particular procedure should match up with the type and number of surgical objects  30  disposed of in the disposal container  90 . 
     One or more surgical objects  30  may be prepared for the procedure by being organized together for an inventory check (Step  630 ). Each surgical object  30  containing the tag identifier  20  may be passed through the detector array  50  wherein the detector array  50  may be activated by movement of the surgical object  30  detected by the motion sensor  60  (Step  640 ). A light source  40 , may be shone upon the tag identifier  20  which may cause the quantum dots  25  to emit a spectral signature  29 . The spectral signature  29  ( FIG. 5 ) detected by the detector  50  may be transmitted as a signal via the wireless antenna  55  to the amplifier-digitizer  88 . The amplifier-digitizer  88  may filter the transmitted signal including the spectral signature  29  and transform the signal into a readable digital format wherein the signal may be transmitted in turn to the computer system  80 . The signal including the spectral signature  29  may be digitally logged (Step  650 ) and counted (Step  660 ). Similarly, used surgical objects  30  may be passed by the detector array  50  after use and signals generated by their detection may be logged (Step  670 ). Thus, a check may be performed to see if each surgical object  30  that was introduced is matched by a surgical object  30  disposed (Step  680 ). This may include matching a number of the same type of surgical objects  30  sharing a common spectral signature  29  at both the introduction and disposal stages. 
     Although the current exemplary embodiment utilizes a wireless connection, any other sort of connection that may or may not utilize wires could also be used to connect the various components of the current invention without departing from the scope of the present invention. 
     While exemplary embodiment of the present invention have been described as employing a tag identifier  20  using quantum dots  25 , it may be understood that other embodiments may employ tag identifiers using a barcode, a scanner, a modified radio frequency identification tag able to operate in aqueous environments, or any other identifiable object may be used all without departing from the scope of the present invention; so long as it serves the purpose of embedding the information necessary in an identifiable format. 
     It should be understood, of course, that the foregoing relates to exemplary embodiments of the invention and that modifications may be made without departing form the spirit and scope of the invention as set forth in the following claims.