Techniques, products and methods of use supporting radio frequency identification

Abstract

The present invention relates to technical improvements, use of these improvements, and data analysis to provide improved surgical procedure efficiency, efficacy, and safety. In particular, using improved support for radio frequency identification (RFID), through improved surgical instrument tracking in both time and space, and data analysis for collecting, tracking, and analyzing instrument usage individually and in combination, to discover and correct significant inefficiencies, safety concerns, and risks associated with surgical procedures.

Description

TECHNICAL FIELD

[0001] The present invention relates generally to the integration of technology radio frequency identification (RFID) interrogation improvements, the use of these improvements, and data analysis to provide increased surgical efficiency, efficacy, and patient safety. Specifically, advances made in technology supporting RFID are used to discover and correct significant deviations and inefficiencies, safety concerns and risks associated with surgical procedures through improved surgical instrument tracking and related data analysis used to collect, track, and evaluate individualized instruments and their use, and combinations of the instruments in actual use. BACKGROUND

[0002] Enhanced RFID technology with the ability to increase the safety and improved statistics achieved by surgical instruments through enhanced detection mechanisms, where technology advances allow for identification, tracking, and monitoring through systems that more accurately and effectively, individually and in combination, detect and track the precise location of hundreds of surgical tools. Moreover, this same RFID technology can be used to analyze the movement of discrete instruments, especially those in close proximity, to describe and depict spatial placement and movement, by discretely and collectively monitoring the frequency and duration of use, to "map out" implementation patterns that directly and precisely lead to their more efficient and more economical use. Ultimately, however, in addition to advances in surgical instrument tracking, patients benefit through enhanced accountability and increased safety by monitoring and avoiding the adverse consequences of surgical subjects retained due to human error. (See Retained Surgical Foreign Bodies after Surgery, Open Access Maced J Med Sci . 2017 Feb 15; 5(1): 97-100.

[0003] In essence, RFID technology can be divided into two types: the first type is "active" RFID technology, in which a radio frequency ID (RFID) tag or label contains an integrated power source (i.e., a battery), which allows a signal and data to be transmitted to a radio frequency antenna / reader; and the second type is "passive" RFID technology, in which the RF tag does not have an integrated or embedded power source, but rather relies on electromagnetic coupling from the antenna / reader, in which the reader transfers power from the reader to the RFID tag through the antenna. The tag is then activated (i.e., "energized") by the electromagnetic field dispersion, and in this enhanced state, can then relay information back to the same reader (also known as an "interrogator"). However, it is also within the inventor's contemplation to separate the activation of one or more tags and the reading / interrogation of those same tags into two separate devices. And, while by definition the tags are mobile, the reader or "interrogator" itself can be either fixed or mobile, with a fixed reader being set up to create a particular "interrogation zone" that surveys a predetermined space or area, as opposed to a mobile reader, which is characterized by being hand-held or mounted on a mobile conveyance.

[0004] It is the "passive" RFID technology that provides the most utility for the purposes of the present invention. In contrast to "active" RFID technology, true "passive" RFID technology (such as those that use active readers and passive tags) requires only two components: an integrated circuit (i.e., a microchip) and a transmitting and receiving antenna. This combination constitutes what is more commonly known as an "inlay." To activate an RFID tag, a reader transmits an interrogation signal to the tag or group of tags within its "read frequency range." The tags receive the signal through their respective antennas and use the received radio wave energy of the reader to power the integrated circuit. The tags then use inductive coupling for near field effects and backscatter coupling for far field effects to transmit a signal back to the reader through the same antenna. The signal transmitted back to the interrogator (here via the principle of backscatter) can be made to include a range of information from very simple information (such as a unique identification number, tag serial number, batch number, and / or date of manufacture) to complex information (such as environmental information and relationship to space), thereby distinguishing even physically identical instruments by spatial position, orientation, and location in space (via received signal strength, time of arrival, and angle of arrival). This allows the reader to determine not only the identity, age, grade, and origin of the instrument, but also its position in 2D and even 3D space relative to the interrogator (and other instruments).

[0005] Generally, RFID systems operating at 125-135 kHz and 13.56 MHz operate in the near field and use inductive coupling, while RFID systems operating above 100 MHz, such as 860-960 MHz and 2400 and 5800 MHz, operate in the far field and use backscatter (radiated) coupling, where the transmitter and receiver are coupled via load modulation or backscatter, depending on whether the tag is operating in the near or far field of the interrogator.

[0006] And, while passive RFID tags exhibit the disadvantages of high energy requirements (and thus potential increased interference), short range, and limited (small) to no memory or power storage, the advantages of "passive" RFID technology generally outweigh these disadvantages to include low cost, robust and simplified construction, light weight, and relatively long life (compared to battery operated devices) and low environmental noise.

[0007] However, the most attractive use of passive RFID is AIDC (Automatic Identification and Data Capture), where external data is converted into digital information that can be stored, processed, and compared to previously recorded information - retroactively, in real time, or prospectively - without human intervention. This information can then be monitored and analyzed to determine the location of "tagged" items in space, and more efficiently track and systematically trace surgical items to incorporate the various efficiencies discussed herein, which form the basis of the present invention.

[0008] Among the many versions of antenna architecture in "passive" systems, common forms include (1) linear polarized (vertical or horizontal) antennas and (2) circularly polarized antennas, where the amplitude of the wave is constant but rotates over time. Linearly polarized antennas communicate best with RFID tags if the electric field orientation of the transmitting and receiving antennas are similar, however the interrogator must "know" the orientation of the tag in space. Conversely, circularly polarized antennas have a rotating electric field and thus can communicate with RFID tags in any direction perpendicular to the wave propagation direction, where the tag and reader can be on different planes, and the interrogator does not need to "know" the orientation of the tag. Clearly, as is the case with surgical instruments, where specific orientation cannot be controlled and the distance between instruments is extremely short, circularly polarized antennas are clearly preferred for such tag interrogation.

[0009] While historically the main technical limitation of simple static tag systems with linear or circular polarized antennas is the electromagnetic shadowing of the field generated by the antenna / reader, where RFID enabled items in close proximity to each other cause incomplete reads of the RFID tags (e.g., ten items are read as only one tag, individual tags are not read at all, or a combination thereof). In essence, the greater the distance of each tag from each other, added to the increased distance from the reader (further considering the range and sensitivity of the incorporated tags and reader), results in an increased bias in the instrument statistics that deviates from the instrument tracking. Obviously, RF tags in close relationship and those closer to the excitation source (i.e., those RF tags that capture more energy than those further away in proximity from the reader) cause omissions and inconsistencies in the instrument tracking and monitoring. Inadequate tracking and statistics directly increase the safety risk for the patient and ultimately lead to flawed data and subsequent inaccurate conclusions, which in the best case give measurements of no utility, and in the worst case, draw conclusions of opposite utility based on "bad data", and even and including risks to patient safety. In the context of healthcare, this technical challenge is a significant limitation to the efficient use of existing products used in the operating room, to the detriment of both the patient and the physician.

[0010] With the above in mind, in addition to the main drawback of effectively capturing data from RFID enabled items (extremely limited and generally ineffective in current RFID enabled products), current systems are also bulky, occupying valuable space in the operating room, and these systems require a great deal of manual effort and human intervention and input in their operation.

[0011] The system itself requires the user to manually create proximity (spacing) between the items, where the instruments need to be arranged in a forward-facing manner for interrogation, or where a handheld device must be used to "scan" on the RFID enabled items, in order to record each instrument and consider each surgical tool individually. In terms of detection, passive UHF (Ultra High Frequency) systems (where the higher frequency band is preferred to provide faster detection speeds) operate according to the principle of backscatter communication, where the RFID tag antenna collects energy from the electromagnetic waves emitted by the reader and then uses the same energy to power the (IC) microchip. This then changes the load on the antenna to enable backscatter modulation, which is then transmitted back to the reader, allowing the RFID tagged items to be interrogated and information to be captured from the "energized" tags, all without the need for the reader operator to participate, tool manipulation, or a movable "scan" interrogation.

[0012] In terms of spacing, current recommendations suggest that RFID tags need to be spaced approximately 10 cm in order to be reliably detected without significantly increasing the required RF power. Unfortunately, given (a) the number of instruments in inventory, (b) the inherent spatial proximity of instruments, and (c) the limited available space provided - each of these attendant factors require multiple "workarounds" with existing technology to accommodate the above-mentioned weaknesses, such a spatial arrangement is not practical in a typical surgical tray.

[0013] While the deficiencies in accurately and efficiently tracking and monitoring surgical instruments are numerous, some of the primary examples of the problems historically and currently faced are described above and below. The first of the technical obstacles to be realized is tag desense, more specifically defined as follows:

[0014] Tag detuning, re-radiation cancellation, and tag shadowing:

[0015] Label Mismatch

[0016] Tag detuning is caused by power loss due to a mismatch between a tag antenna and an integrated circuit (IC) because of a change in impedance from the tag antenna when one tag is in close proximity to another tag, where it has been shown that tag detuning has a significant impact when RFID tags are in close juxtaposition (and conversely, tag detuning has a lesser impact when tags are placed at a 1 cm spacing). In essence, tags in close relationship can absorb each other's energy and "detune" each other's antennas, thereby impeding the ability of the tag to receive a signal from an interrogator. This problem is further compounded in that most surgical surface and instrument trays (e.g., mayo trays) are of a metallic composition, where the introduction of the metallic instrument surface inherently impedes the original RF wave, further complicating tag detuning (in addition to the adverse effects of signal reflection off the metallic surface). Greater Than

[0017] Label Re-Emission Elimination

[0018] Additionally, the combination of the two electromagnetic signals (generated by both the tag and the reader) has the potential to at least partially cancel each other's signal in the form of "tag re-radiation cancellation," where the "re-radiated" wave from the RF tag couples with the resulting RF wave from the reader to combine in an interfering manner. In certain instances and locations, this combined signal interference is destructive, rather than constructive, and can completely impede accurate instrument detection or tag detection.

[0019] Label Occlusion

[0020] ​Complicating proper detection is that "tag shadowing" can also occur, where tags closer to the energizing source (the RF reader) are disproportionately affected by the electromagnetic waves generated from the RF reader and capture more energy due to the close proximity to the reader. Tags at a distance further from the reader's energizing pulse (electromagnetic energy) can be shadowed and less efficiently read (or completely ignored at extended distances), essentially "shadowed" by the closer tags, while those tags closer to the reader's pulse are more clearly received.

[0021] The prior art must recognize and account for all of the limitations in this field (e.g., tag detuning, re-radiation cancellation, and tag shadowing). One way to consider these systems is to implement artificial "workarounds," which means that the user must manually turn the reader-generated RF field in multiple directions to avoid creating disruptive interference to backscatter communications, so that the distance from the reader to the tag can be varied to the same rate and same degree as other, closer tags Artificial energizing the further tags (shadowed by another tag), thus physically aiding in the proper interrogation. For example, if the reader is generating a field in an omni-directional manner, accuracy can be degraded due to one or more of the issues. Most commonly, however, the interference due to tag shadowing and re-radiation cancellation still has the most detrimental impact. When a wave that is traveling in all directions interrogates a tag, backscatter communications cause disruptive interference that cancels out the normally transmitted RF signal; and tags that are far from the wave either do not capture enough energy for a return transmission due to tag shadowing and are either poorly activated or never activated. This results in insufficient (i.e., weak) or no re-communication with the reader. Intuitively, to account for and accommodate tag detuning, an increase in the RF power generated at the reader and / or an omni-directional projection of the RF wave can seem like an appropriate solution by transmitting (1) an extended wave propagation and (2) enabling interrogation of all tags at near and far proximities, thus capturing both strong signals and attenuated signals. However, as the increase in power and the extended wave propagation of the multi-path wave brings an increase in the rate of re-radiation cancellation—especially at greater distances—this offsets the gains and appeal of increasing the power and the multi-path wave transmission rate.

[0022] Furthermore, the inventors have recognized that in order to seek higher detection accuracy, extending the radio frequency in several planes and in various directions makes it more likely to "spill over" or "bleed" into adjacent areas. "Spill over" is defined here as the RF waves extending beyond the intended area, thereby interfering with another adjacent antenna system (i.e., destructing the signal of the adjacent system and / or causing a reduction in the saturation of the waves, which can further exacerbate the electromagnetic shadowing of the tag). The individual "spill over" combined with the enhanced tag mis-tuning, re-radiation cancellation and tag shadowing add to the myriad of problems that have not been solved in RFID technology to date, resulting in adverse consequences of increased power generation, adding to the list of continuing unmet needs.

[0023] While progress has been made in overcoming the deficiencies in tracking and monitoring surgical tools, it is apparent that there are still considerable deficiencies in this area. It is therefore an object of the present invention and methods of use thereof to redress these deficiencies to provide increased patient safety and efficient surgical instrument tracking and monitoring.

[0024] Notably, while the inventors have set forth what the inventors believe to be the best modes contemplated by the inventors of carrying out the present invention to enable any person skilled in the art to practice the invention, the preferred embodiments are not intended to be limiting, but rather, are to be included in a non-limiting sense to be readily altered and modified herein, within the scope and spirit of the disclosure and the appended claims. SUMMARY

[0025] The present invention, in certain but not necessarily all aspects and features, discloses a new and novel RFID monitoring and tracking system (including configuration and use) that strives to (1) an invention that directs wave signals in such a way that it captures items even when they are shielded by another item or in close contact or proximity to each other (i.e. shielded), (2) reduce or eliminate the current disparity experienced in reading closely proximate items, as well as the bias due to tag detuning, re-radiation cancellation, and tag reader system overflow, (3) reduce the size of the monitoring system, where the current system is compact compared to existing systems, but retains (and even details) all original functionality, and (4) add flexibility in element configuration by adding and subtracting modular elements. Finally, while developing the antenna architecture, the inventors recognized the shortcomings of some of the most pressing technical constraints and set out to build a system that (1) produces an RF field in the 20"-30" range, (2) interrogates RFID-enabled items with up to 99.9% accuracy (regardless of orientation or proximity), (3) "reads" up to 300 items (depicting even one item placed on top of another or in an overlapping manner) in density, (4) scans items placed in the RF field generated by the system continuously and passively, and the system (5) works both autonomously and instantaneously to interrogate RFID tags within a sub-second timeframe.

[0026] In particular, the present invention produces an RF field that operates between 902-928 MHz frequencies (according to the North American Industrial Scientific Medical (ISM) band), as defined by ISO / IEC 18000-6:2013 for RFID devices operating in the 860 to 960 mHz ISM band, with an effective range of at least 24 inches (typically 3 to 39 feet), which is able to interrogate (read) up to and including 300 RFID-enabled items with 99.9% accuracy, regardless of item orientation or proximity to other items.

[0027] The present invention also utilizes an algorithmic assistance platform with which (a) tracks and (b) assesses the duration of use of surgical instruments, which then classifies the surgical instruments according to time and spatial utilization. The former (a) tracks the instruments individually, speaking to the safe use and recycling of surgical instruments, and the latter (b) relates to efficiency, use, and effective inventory control. However, these two are not mutually exclusive, where strict inventory requirements are directly related to the safe use and recycling of surgical tools, and the safe utilization of instruments must be highly monitored and managed. However, the study and analysis of tool movement and placement is much more detailed and worthy of description than simple inventory.

[0028] Correspondingly, it can be observed that surgical instruments meet the following criteria that characterize instrument utilization, where:

[0029] (1) "Rarely used" is defined by an instrument utilized within 30 consecutive surgeries;

[0030] (2) "Least used" is defined by an instrument utilized within 20 consecutive surgeries;

[0031] (3) "Moderately used" is defined by an instrument utilized within 10 consecutive surgeries; and

[0032] (4) "Not used" results in the instrument being removed from the surgical set.

[0033] And, although 30, 20, and 10 consecutive surgeries are used above, these criteria are easily revisable and can be modified according to a particular surgery or subset of surgeries, type of operating room, type of facility, or any other user-defined parameter.

[0034] Furthermore, the same algorithmic parameters can be established to equate tracked individual instrument movements to necessitate adoption, modification, and / or removal from inventory based on temporal and spatial location, where movement of an instrument from a primary storage location to a receiving station (e.g., a mayo tray) constitutes a "movement," movement of an instrument to a patient constitutes another "movement," and movement of an instrument to any other field constitutes a third "movement" (e.g., back to a surgical tray, to another storage library, or back office). In short, movement from a storage area (or second operating table) to a "mayo tray" can result in satisfaction of a number of subsequent conditions for advancement: (1) the instrument can be moved from the mayo tray and placed back in the storage area, (2) the instrument can be used and then placed back on the mayo tray, (3) the instrument can be used in or on the patient, (4) the instrument can be placed in an auxiliary container, or (5) the instrument can simply be dropped - all resulting in informative placement and replacement that can be monitored, analyzed, quantified, and used for instrument regulation, safety, and efficient inclusion or exclusion from an instrument inventory.

[0035] Furthermore, the third condition (i.e., use of the instrument in or on the patient) can be further dissected to determine the time of use in operation, where not only is the location of the instrument determinable, but also the duration of use is determinable. As a function of time, if the instrument is placed on or in the field of the patient for a specified period of time, this can prove informative "length of use" in addition to frequency of use, where:

[0036] (1) "Least used" is defined by an instrument utilized for 15 seconds or less;

[0037] (2) "Moderately used" is defined by an instrument utilized for more than 15 seconds but less than or equal to 60 seconds;

[0038] (3) "High use" is defined by instrument use that exceeds 60 seconds but is less than or equal to 300 seconds; and

[0039] (4) "Very high use" is defined by instrument use that is 300 seconds or more.

[0040] It should be understood that these parameters are merely exemplary and can be modified according to user determinations of the length of use time without departing from the contemplated purpose of determining instrument use, frequency, and duration.

[0041] Brief Description of Several Views of the Drawings

[0042] Certain embodiments of the application, both as to its organization and manner of operation, together with further objects and advantages thereof, can be more fully understood with reference to the following description, taken in conjunction with the accompanying drawings in which preferred embodiments of the application are illustrated by way of example. It is expressly understood that such drawings are for illustrative purposes only and do not purport to be

[0043] These drawings illustrate embodiments contemplated at the time of filing this patent and are not intended to unjustifiably limit the scope of the application, which can have other equally effective or equivalent embodiments.

[0044] Figure 1a Depicts a front view of a low profile patch antenna.

[0045] Figure 1b Depicts a 90 degree rotated view of a low profile patch antenna. Figure 1a

[0046] Figure 2 is a model of the patch antenna element (PAE) depicted in Figure 1 scaled to a series of eight PAEs.

[0047] Figure 3 is an RF simulation model containing four PAEs in various modes of antenna element activation.

[0048] Figure 4 represents eight PAEs consisting of a top row of four PAEs and a bottom row of four PAEs.

[0049] Figure 5 Depicts the ability to switch the angle of RF waves within a set of elements.

[0050] Figure 6 is a schematic representation of the operable components of the application.

[0051] Figure 7 Illustrates a classification and regression algorithm to determine instrument use.

[0052] Figure 8 Depicts an RF multiplexer.

[0053] ​Certain embodiments of the present application are illustrated in the above identified figures, and various aspects and features of embodiments of the present application are described below. Any combination of the above identified or described aspects and / or features can be used, unless such aspects and / or features are mutually exclusive, incompatible, or contradictory.

[0054] It is to be understood that the figures and descriptions of the present application herein are intended to be illustrative only and are not intended to limit the present application or cover every possible variation of the present application. Rather, the present application is intended to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present application as defined by the appended claims. In showing and describing the figures of the preferred embodiments, the figures are not necessarily to scale and certain features and certain views of the figures can be exaggerated in scale or in proportions for the sake of clarity.

[0055] As used herein and throughout all portions of this patent (and headings), the terms "application," "the application," and variants thereof mean one or more embodiments, and are not intended to mean the claimed application of any single particular embodiment. Any aspect or feature or combination of aspects or features of any embodiment disclosed herein can be used in conjunction with any other compatible embodiment disclosed herein. The present application includes multiple aspects that can be combined in different ways as can be desired to achieve certain particular results.

[0056] The following description is provided to list elements and describe some embodiments of the application and various examples and embodiments of the described are not to be construed as limiting the application to only the explicitly described systems, techniques, methods, and applications.

[0057] Although operations (or portions thereof) can be described as a sequential process, many of the operations can be performed in parallel or concurrently, and / or the order of the operations can be rearranged. Further, not all operations or steps listed in any particular method or process need necessarily be performed in all embodiments. DETAILED DESCRIPTION

[0058] Accordingly, Figure 1a A front view of a low profile patch antenna is shown in detail, and Figure 1b A front view of a low profile patch antenna is shown in detail, and Figure 1aa 90 degree rotation of the front view of a low profile patch antenna, wherein each antenna contains four individual elements (A, B, C, D) in a 2x2 pattern, referred to as a patch antenna element (PAE) array 10. The design of the PAE 10 provides the present invention with the ability to fire RF waves (i.e. "excite") from any individual element (A, B, C, D) within the patch antenna element array 10 at one time. This flexibility allows the RF waves generated from the PAE 10 as a whole to have more coverage. The dynamic nature of the present invention allows for the ability to provide significant coverage by orienting the PAE 10 into a series, a quadrant, or other form factor, whereby the RFID tags are actuated differentially, allowing for the electronic manipulation of the phase shift or phased array (creation of a radio beam) of the RF waves by the antenna elements (A, B, C, D) to be activated (as opposed to manual "hand" manipulation) without the need for movement in the transmitter (interrogator). Thus, the phased array antenna can provide constructive or destructive interference based on a particular spatial angle, thereby directing or "steering" the RF beam in a particular direction. Separately, the transmitter provides power to the discrete antenna elements (A, B, C, D) through a phase shifter, which electronically alters the phase to steer the RF waves. In a dynamic phased array, a variable phase shifter array is used to move the beam, and adjustable phase shifters are used collectively to move the beam relative to the array face. The use of this "dynamic" phased array is particularly desirable because it allows the present invention to simultaneously monitor multiple targets while continuing to search for new targets in a given field. Furthermore, the ability of the present invention to precisely interrogate different tags selectively through directional signal processing (via the directed RF waves) to achieve spatial selectivity (a process more commonly referred to as "beamforming") is further enhanced by the manipulation of the phase and / or amplitude to inform precise positioning accuracy. Thus, by correctly receiving (amplifying) the tag signal and minimizing tag interference (discussed above) by angle (angle of arrival of the received), the transmit side from the interrogator can generate a more accurate weighted antenna array signal. This allows for subsequent improvement in signal-to-noise ratio and enhanced tag readability in a 3-dimensional (3D) environment.

[0059] Furthermore, FIG. 1 depicts the key components (2x2 element configuration) that provide the PAE 10, which can scale up (and down) into various form factors with multiple 2x2 (PAE) element 10 arrays (as Figure 2 illustrated in FIG. 2) up (and down). This scalability of the PAE 10 design improves additional capabilities related to the present invention as a whole in the ability to retrofit the present invention to various applications and a wide variety of specific environmental orientations.

[0060] Figure 2Model representing the PAE 10 depicted in Figure 1, scaled into a series of eight antennas - 4 upper patch antenna elements (PAEs) (set 30) consisting of PA, P2, P3, and P4, and 4 lower patch antenna elements (PAEs) (set 40) consisting of P5, P6, P7, and P8. Each individual PAE contains its own four elements (A, B, C, D), where PI will consist of PI-A, PI-B, PI-C, and PI-D, P2 will consist of P2-A, P2-B, P2-C, and P2-D, and so on for P3 through P8. This preferred embodiment of the present invention shows the scalability allowed in the present invention, which is strictly exemplary and can be modified to support any configuration and size that will support the four (4) element PAE 10 design of Figure 1. Through the RF multiplexer (RFMUX), one element can be excited at any given time. Additionally, two to four elements can be excited simultaneously, but only one element per PAE at a time. For example, in the case of four PAEs constructed in a 2x2 quadrant, with a total of 16 elements (four antenna elements (A, B, C, D) per PAE 10), the RFMUX can excite one antenna element (A, B, C, or D) at a time for each of the four PAEs (30, 40), such that all 16 elements are excited over an extended period of time. Additionally, the RFMUX can excite two elements simultaneously or delayed, as long as those two elements do not belong within the same PAE 10. For example, two adjacent elements can be activated from two different PAEs (e.g. PI-D and P2-C or P6-B and P7-A). Finally, the RFMUX can excite four elements simultaneously or delayed, as long as those four antenna elements (A, B, C, D) do not belong within the same PAE 10. Within a PAE 10, the four elements that can be excited will be all the adjacent elements centered on the quadrant (e.g. PI-D, P2-C, P5-B, and P6-A or P3-D, P4-C, P7-D, and P8-A).

[0061] Figure 3 Illustrates an RF simulation module containing four PAEs, each PAE containing 4 individual antenna elements, oriented in a square, whereby each PAE illustrates 4 antenna elements, each in a 2x2 array. This figure illustrates the ability of the array to activate or "fire" four elements (i.e. RF wave interrogation) in sequence from left to right across the top two adjacent PAEs. This PAE layout is similar in design to the first four PAE 10 array in Figure 2 , while Figure 3is half of the eight PAE configuration (30, 40). As an example, four adjacent PAEs 10 can fire one antenna element at the same time, or with a slight delay relative to other antenna elements: however, not all four elements within one PAE fire at the same time. The ability to fire two to four elements between two to four adjacent PAEs allows for phase shifting, and ultimately beamforming spatial directionality, where a tag residing above the PAE 10 can be identified by a reader inquiry regardless of orientation or proximity in a defined 3D space. Figure 3 The upper left PAE P1 antenna element P1-A is shown firing, the upper left PAE P1 antenna element P1-B, the upper right PAE P2 antenna element P2-A, and the upper right PAE P2 antenna element P2-B are sequentially "firing".

[0062] Figure 4 is shown in FIG. 1 1. Figure 2eight PAE configurations (P1, P2, P3, P4, P5, P6, P7, and P8) in which each corresponding antenna element is labeled (A, B, C, and D). This means there are eight A antenna elements, eight B antenna elements, eight C antenna elements, and eight D antenna elements, for a total of 32 elements (each PAE 10 (P1, P2, P3, P4, P5, P6, P7, and P8) has four elements, with each PAE 10 having one A antenna element, one B antenna element, one C antenna element, and one D antenna element). When two to four elements are excited from each selected PAE (P1, P2, P3, P4, P5, P6, P7, and P8), a phase shift occurs relative to the delay of the element excitation based on prior reflection data of the received RF wave, causing the generated RF wave (50, 52, 54, and 56) to tilt to a newly calculated direction. Controlling the element excitation delay means controlling the phase shift. This means that the angle of beamforming can be controlled, creating new dimensions for the system. Controlling the direction of RF wave propagation, which would otherwise be upwards, can illuminate RFID-enabled items that are otherwise obscured by other items. This ability removes the need for traditional human intervention to direct the RF wave to alternative angles, allowing for directional interrogation, shortening the required wavelength, and thus reducing the power required for tag localization. This phase-shift array and directional spatial positioning, in addition to reducing power requirements, avoids the weaknesses of tag detuning, re-radiation cancellation, tag obscuring, and spillage described above, while providing higher accuracy even for those appliances that are placed in close proximity to one another. As yet another example, exciting element D in P2, element C in P3, element B in P6, and element A in P7 (where element D in P2 and element A in P7 are delayed) form a beam that provides a new angle to illuminate tags that would otherwise be hidden by other RFID-enabled items or metallic appliances. This is critical because, without this ability, attempted tag interrogation can result in a reading error by the system, or, when in fact the item cannot be interrogated, indicate that the item is lost. Historically, this would force the user to intervene in the process, either by scanning the area with a handheld item, which creates a different angle for the penetration of the RF wave.

[0063] Additionally, where as Figure 2 and Figure 4 RF multiplexer hardware elements can provide RF paths via activation of the selected antenna element(s) in the array according to the following schedule table, including the phase of the RF to and from each antenna element:

[0064] 1. Any individual antenna element (i.e., PAE) in a 4-element cluster;

[0065] 2. An array of any of the antenna elements (A, B, C or D) on any of the PAE P1, P2, P3, P4, P5, P6, P7 and P8 either sequentially, simultaneously or a combination thereof to adequately interrogate individual tags (via received angle of arrival and subsequent beamformed transmission;

[0066] 3. An array of any of the A and B elements either sequentially, simultaneously or a combination thereof to adequately interrogate individual tags (via received angle of arrival and subsequent beamformed transmission;

[0067] 4. An array of any of the A and C elements either sequentially, simultaneously or a combination thereof to adequately interrogate individual tags (via received angle of arrival and subsequent beamformed transmission;

[0068] 5. An array of any of the A and D elements either sequentially, simultaneously or a combination thereof to adequately interrogate individual tags (via received angle of arrival and subsequent beamformed transmission;

[0069] 6. An array of any of the B and C elements either sequentially, simultaneously or a combination thereof to adequately interrogate individual tags (via received angle of arrival and subsequent beamformed transmission;

[0070] 7. An array of any of the B and D elements either sequentially, simultaneously or a combination thereof to adequately interrogate individual tags (via received angle of arrival and subsequent beamformed transmission;

[0071] 8. An array of any of the A and D elements either sequentially, simultaneously or a combination thereof to adequately interrogate individual tags (via received angle of arrival and subsequent beamformed transmission;

[0072] 9. An array of any of the foregoing schedules above either sequentially, simultaneously or a combination thereof.

[0073] Figure 5 The results of the phase shifting and the ability of the present invention to change the angular direction of the RF waves within a set of elements (per the above schedule) to control the phase shifting and beamforming, direct and steer the angle of the beamformed by relative delay and sequential and / or simultaneous activation and delay activation. From Figure 4 Continuing with the above example, the resulting beam is formed in the Y+ direction by the reflection of the RF waves propagating from element C in P3 (beamformed) and element B in P6, and the slight excitation delay from element D in P2 and element A in P7.

[0074] Conversely, delaying element B in P6 and element C in P3 will direct the RF waves in the Y direction by the reflection of the RF waves propagating from element D in P2 and element A in P7, and the slight excitation delay from element B in P6 and element C in P3.

[0075] Thus, by controlling the order and sequence of activated antenna(s) via a programmable next compute unit 60 (NUC) (see Figure 6 ) the NUC 60 is a single board computer that facilitates system logic. While most systems are forced to run static wave propagation from the RFID / antenna array, the NUC 60 allows for much greater flexibility. This flexibility allows the system to run many different excitation sequences across the 32 elements within each PAE 10. The NUC 60 runs a preprogrammed command protocol that instructs the reader to activate a specific port. Depending on which port is activated, the corresponding elements will be excited individually, two at a time, or four at a time. The RFID reader 62 has eight ports, seven of which are connected to RF coaxial cables that are connected to an RF splitter 64. The remaining port is connected to an RF coaxial cable that is directly connected to an RF multiplexer (RFMUX) 66. The RFMUX 66 itself includes four sets of SMA input connections (eight total per set) that correspond to the A, B, C, and D elements of each PAE 10. Additionally, there are four sets of output SMA connections that will connect to the 32 elements among the eight PAE 10s.

[0076] The seven ports from the RFID reader 60 are connected to the RF splitter 64 (six two-way splitters and one four-way splitter), where they split one connection into two RF connections that are directly connected to the RFMUX 66 inputs. These inputs correspond to the elements they intend to excite (A, B, C, D). The six two-way splitters will connect in combinations of (A, B), (A, C), (B, D), (C, D), etc. to two inputs from one splitter and a total of 12 to the four element inputs (A, B, C, D). One four-way splitter connects to all A, B, C, and D inputs. The preprogrammed protocol of the NUC 60 instructs the RFID reader 62 of a specific excitation command sequence, which in turn energizes the ports that send signals to the (RFMUX) 66 to actuate, either simultaneously or sequentially, to indicate one to many elements in order to create a phase shift between the elements, thereby beamforming the RF wave to interrogate RFID-enabled items and receive the activated RFID tag information from the reader electromagnetic induction.

[0077] As Figure 6As detailed and depicted, the present application can operate through the combination of the components depicted. These components are used to integrate and control the PAE 10 and its corresponding individual elements in order to interrogate RFID-enabled surgical elements regardless of orientation or proximity. Specifically, the RFID reader 62, the NUC 60, and the multiplexer (RFMUX) 66 direct the phase shifting and beamforming through the power 68 that activates the RFID reader 62 and the NUC 60. Once the RFID reader 62 is activated along with the NUC 60, a preprogrammed command protocol is activated that instructs the RFID reader 62 to fire a specific port that is connected to one of the inputs on the RFMUX 66 to actuate, one to multiple antenna elements (A, B, C, D) can be instructed simultaneously or sequentially in order to create a phase shift between the elements, thus beamforming the RF waves to interrogate the RFID-enabled items and receive the reader electromagnetically induced, activated RFID tag information by establishing a command protocol that fires the elements from the PAE 10 in a specific pattern. This sequence can change continuously, thus optimizing accuracy in the case of a given technical embodiment. The power 68 activated on the NUC 60 and the RFID reader 62 will remain consistent. The system provides flexibility by having multiple connection options from the station base 65 including USB 70, HDMI 72, or Ethernet 74. The 24 V power supply 78 turns on the RFID reader 62 and the NUC 60. This power 68 translates into a signal sent by the RFID reader 62 that is controlled by the preprogrammed commands from the NUC 60. The signal comes from one of the eight ports connected to the RF splitter 64. The RF splitter 64 then communicates with one or more inputs on the RFMUX 66, which then controls the firing of one, two, or four of the 32 antenna elements (A, B, C, D) within one or more PAE 10.

[0078] Furthermore, this configuration allows maximum flexibility in creating phase shifts among the antenna elements. This phase shift allows for beamforming and subsequently control of the beam direction. Having the ability to continuously change the order of element firing means that you can continuously shape the beam to illuminate all RFID-tagged items regardless of their proximity or whether they are hidden / shielded by metal or other RFID-enabled items.

[0079] Figure 7 Classification and regression algorithms are depicted for movement of instruments from back table to Mayo tray, from Mayo tray to patient, from patient back to Mayo tray, and from patient to another field (back table or Mayo tray). Furthermore, Figure 7 Duration of instrument utilization (i.e., minimal, moderate, high use) and instrument use in successive procedures (e.g., moderate, minimal, very minimal, and no use) are indicated.

[0080] Figure 8 One embodiment of the RF multiplexer (RFMUX) 66 is illustrated. The RF multiplexer 66 is created to excite individual elements, between two and four elements at a time, while also being able to excite each element correctly based on the sequence received from the NUC 60. This is accomplished by the RFID reader 62 and the RF splitter 64, which connects the eight ports from the RFID reader 62 to the RFMUX 66. As shown, there are a total of 61 SMA connections on the multiplexer. Of these, 28 eight SMA connections correspond to the A, B, C, and D inputs, which are designated as IN A, IN B, IN C, and IN D. This means that A, B, C, and D have seven input connections.

[0081] 32 SMA connections correspond to the A, B, C, and D outputs. They are designated as OUT A, OUT B, OUT C, and OUT D. This means that A, B, C, and D have eight output connections:

[0082] Eight of the outputs correspond to the eight A elements, with one A element in each of the eight PAEs.

[0083] Eight of the outputs correspond to the eight B elements, with one B element in each of the eight PAEs.

[0084] Eight of the outputs correspond to the eight C elements, with one C element in each of the eight PAEs.

[0085] Eight of the outputs correspond to the eight D elements, with one D element in each of the eight PAEs.

[0086] The last SMA connection is a direct connection from the RFID reader.

[0087] The RFID reader 62 has eight ports, seven of which are connected to an RF splitter 64 (six two-way splitters and one four-way splitter). The RF splitter 64 splits one connection into two RF connections that are connected directly to the inputs of an RF MUX 66. These RF MUX 66 inputs correspond to the elements (A, B, C, D) that they are designated to excite. When the RFID reader 62 generates a signal, the RFID reader 62 carries the signal from its port through an RF coaxial cable to the RF splitter 64, which sends its signal through RF coaxial cables. The signal can be carried through two RF coaxial cables for a two-way splitter or through four RF coaxial cables for a four-way splitter connected to an input SMA. The six two-way splitters will connect in combinations of [A, B], [A, C], [B, D], and [C, D] from one splitter to two inputs, for a total of 12 connections to the four element inputs (A, B, C, D). One four-way splitter connects to all A, B, C, and D inputs.

[0088] The RF MUX 66 then takes the single, two, or four signals sent to one of the A, B, C, or D inputs and routes that energy to one, two, or four of the corresponding A, B, C, or D outputs. For example, depending on the NUC 60 program, a signal sent to the A input will be routed to one of the eight A elements. This multiplexing of signals provides the ability to adjust the timing of each element excitation, which subsequently allows the assembly to create a phase shift. This phase shift occurs when the signals of two port excitations are slightly delayed relative to the other A, B, C, or D inputs. The RF MUX then delays the corresponding elements of the excitation to create the phase shift. Ultimately, the logic and order of excitation is controlled by the NUC 60, but the RF MUX 66 allows one, two, or four elements to be excited in sequence or with a delay.

[0089] Preferred Embodiments

[0090] The drawings and the embodiments described below are exemplary and are not intended to limit the all versions of the invention described, claimed, and disclosed herein. However, the inventors have set forth the best mode contemplated by the inventors as the best representatives of the invention shown and described.

[0091] The invention uses a "patch antenna stack", which means that each individual antenna has a 2x2 element cluster pattern. (Figure 1) This constitutes a patch antenna element (PAE) array. This 2x2 PAE can be scaled to any size as long as it maintains the minimum 2x2 element architecture, i.e. one PAE has 4 elements, eight PAEs have 32 elements.

[0092] The RF power to the element is multiplexed between elements via a radio frequency multiplexer (RFMUX). Combined with a single-board computer, the RFMUX can call any element from any series of PAEs. Conversely, it can call two elements from two PAEs or four elements from four different PAEs at a time. This series can be represented by PAEs (P1-P8) and each element within that antenna (A, B, C, or D). Due to this flexibility, the system can continuously and passively call any antenna element array, allowing for dynamic phase shifting. Figure 4 .

[0093] Dynamic phase shifting provides the ability to create beamforming within the element. Figure 5 As briefly described in the detailed description, the excitation of four antenna elements in a manner that delays each other relative to provide the ability to shape the beam in various directions. In this sense, excitation means generating RF waves. This allows RF waves to travel across the plane in a non-perpendicular direction. As shown above, a dynamic system implies control over the propagation of RF waves from one, two, to four elements, where the invention can take into account the cancellation of re-radiation that could potentially disrupt the signal. Thus, the RF field propagates along the X, Y, and Z axes without requiring the field (e.g., the RF field) to be "guided" via movement of the reader / interrogator. The result is tag illumination of previously restricted tags that might be obscured (or blocked) by other tags, as the wave (as is common in the art) propagates in a single direction.

[0094] Without beamforming between two to four elements, the propagation of RF waves would be static and generated in an inefficient omnidirectional manner. The omnidirectional output of RF waves would be equivalent to the RF waves generated in a handheld barcode scanner, forcing the user to provide movement in order to detect / interrogate RFID-enabled items. In contrast, by generating dynamic wave phase shifts through beamforming, this device systematically and selectively delivers radio frequency waves to overcome the aforementioned weaknesses (such as tag detuning, re-radiation cancellation, spillover, and masking), thereby enabling better detection, cataloging, and monitoring of the location and use of surgical tools.

[0095] The combination of dynamically formed arrays of individual components and beamforming of the signal provides the system with the ability to guide signals from a source (i.e., without any manual movement of the equipment), thus eliminating the need for manual RF wave manipulation or directional control. Furthermore, the patch antenna stack allows the antenna / reader architecture and electronics to be packaged in a 3”–5” enclosure, which can be located on top of a surface or adapted to a pre-existing space in an operating room.

[0096] The novelty and utility of the antenna stack system of the present invention lies in the following capabilities of the current system: (1) to produce circularly polarized fields, (2) to control the direction of wave propagation, (3) to direct the efficient and effective generation and focusing of the RF field signaling without signal spillage or leakage, (4) to provide scalability to different sizes to retrofit / replace pre-existing spaces in operating rooms, and (5) to switch between antenna elements on sub-second time frames, thereby allowing the present invention to produce a continuous field that captures 99.9% of items regardless of orientation and item density (see generally Figure 2 and Figure 3 ) where instantaneous transmission of data can occur to data collection devices (e.g., external computers or wireless tablet computers) for sub-second data collection, data storage, and data analysis.

[0097] As can be readily appreciated from the foregoing, the basic concepts of the present invention can be embodied in various ways as pertain to structures, devices, method steps and techniques, and equipment to achieve the appropriate inventive creation(s).

[0098] Moreover, while some devices and structures are disclosed, it is to be understood that these devices and structures not only implement certain methods, but can also vary in a wide variety of ways. Importantly, with respect to all of the foregoing, all such aspects are to be understood as being encompassed by the present disclosure.

[0099] It is also to be understood that various alterations can be made without departing from the scope of the present invention. Such alterations are implicitly contemplated as would be apparent to one of ordinary skill in the art. It is intended to be covered by the following claims.

[0100] Thus, in summary, it can be seen that the present invention and embodiments disclosed herein, as well as the embodiments covered by the appended claims, are well adapted to carry out the abovementioned objects and to attain the ends and advantages mentioned as desirable, without undergoing departures in spirit and scope.

Claims

1. A radio frequency antenna system utilizing 2 or more patch antenna elements PAEs, wherein each PAE consists of a configuration of 4 antenna elements assembled to selectively interrogate passive radio frequency RF tags with dynamic phase shifting and beam forming to more accurately and precisely detect and monitor individual and group radio frequency RF tags in 2D or 3D space regardless of occlusion, orientation or proximity to one another, wherein the group of 2 or more patch antenna elements PAEs are combined in succession and each PAE consists of: two to many 2x2 antenna patch stacks; wherein each 2x2 antenna patch stack is coplanar with all other antenna patch stacks; wherein each 2x2 patch stack consists of 4 antenna elements in a 2x2 pattern, wherein: each antenna element is selectively activated individually; and a group of adjacent 2x2 antenna patch stacks can simultaneously or sequentially excite one of each of their elements in conjunction with the excitation of successive antenna elements to manipulate the weighted RF wave in a local spatial direction via dynamic phase shifting through the effect of activation and deactivation of each element.

2. The radio frequency antenna system of claim 1, wherein interrogation occurs on or near the surface of the device.

3. The radio frequency antenna system of claim 1, which generates an RF field operating between UHF frequencies of 902-928 MHz.

4. The radio frequency antenna system of claim 1, wherein, The RF wave is generated by a circularly polarized field.

5. The radio frequency antenna system of claim 1, wherein, The system is configured to continuously and passively scan items placed in the RF field generated by the system.

6. The radio frequency antenna system of claim 1, wherein, The system is capable of individually tracking instruments to provide instrument tracking, movement monitoring, patient safety, and determination of instrument usage duration.

7. The radio frequency antenna system of claim 4, wherein, Instrument tracking and movement monitoring is used to: implement accountability and patient safety; implement movement monitoring; implement duration monitoring; and implement utilization monitoring.

8. The radio frequency antenna system of claim 6, wherein movement monitoring can include: movement from a primary storage location to a receiving station; instrument movement from a Mayo tray to a patient; instrument movement from a patient to a Mayo tray; and and instrument movement to other fields.

9. The radio frequency antenna system of claim 7, wherein, Duration is measured when in use in or on a patient and can include: (1) "Minimal use" defined by 15 seconds or less of instrument utilization; (2) "Moderate use" defined by more than 15 seconds but less than or equal to 60 seconds of utilization; (3) "High use" defined by more than 60 seconds but less than or equal to 300 seconds of instrument use; and (4) "Extremely high use" defined by 300 seconds or more of instrument utilization.

10. The radio frequency antenna system of claim 7, wherein, Utilization is measured when in use in or on a patient and can include: (1) "Extremely low use" defined by an instrument utilized within 30 consecutive surgeries; (2) "Minimal use" defined by an instrument utilized within 20 consecutive surgeries; (3) "Moderate use" defined by an instrument utilized within 10 consecutive surgeries; and (4) "No use" resulting in an instrument removed from a surgical set.

11. A method of selectively interrogating passive radio frequency (RF) tags with dynamic phase shifting and beam forming to more accurately and precisely detect and monitor individual and group radio frequency (RF) tags, whereby: a radio frequency (RF) reader transmits UHF radio waves to passive RFID tagged instruments via dynamic phase shifting and beam forming; the RF reader utilizes a patch antenna element (PAE) configuration consisting of two to multiple 2x2 antenna patch stacks, where each 2x2 patch stack consists of 4 antenna elements in a 2x2 pattern to manipulate and direct beam formed waves through dynamic phase shifting; one element within the 2x2 antenna patch stack can be selectively individually actuated on each of the multiple PAEs; where each PAE element of the multiple PAEs can each activate one element; where multiple can activate multiple adjacent elements in order to direct RF waves; a passive radio frequency antenna receives and transmits radio waves from the RF reader; and a passive radio frequency tag microchip receives the radio waves transmitted by the RF reader, the microchip is activated, and the microchip transmits tag specific information back to the RF reader.

12. The method of claim 11, wherein the created RF waves are produced by a circular polarized field in the 902-928 MHz range.

13. The method of claim 11, wherein, Dynamic phase shifting is implemented where RF waves are beam formed based on specific spatial angles, thereby electronically altering the phase through directional signal processing to precisely selectively interrogate different tags in order to achieve spatial selectivity in a 3D environment without causing tag detuning, re-radiation cancellation, tag shadowing, or spillage.

14. The method of claim 11, wherein, Dynamic phase shifting and beam forming are used to control the formation and direction of RF wave propagation through simultaneous or sequential antenna element activation, which is used to selectively track, assess, and monitor the combination of instruments and instrument locations in space in order to accurately account for instrument location, usage, and duration of usage, thereby ensuring (1) patient safety, (2) proper inventory and statistics, and (3) efficient instrument usage.

15. The method of claim 11, wherein a next unit of computation (NUC) is utilized to implement a preprogrammed protocol that instructs the RF reader to activate specific antenna elements in a specific pattern through an RF multiplexer to direct phase shifting and beam forming through power activation of the RFID reader to continuously alter the firing sequence and, therefore, shape the direction of RF wave propagation to interrogate all RFID tags regardless of location in space or proximity to one another.

16. The method of claim 15, wherein spatial location can be accurately determined, monitored, and analyzed through dynamic phase arrays and RF wave beam forming.

17. The method of claim 15, wherein instrument usage can be accurately determined, monitored, and analyzed through dynamic phase arrays and RF wave beam forming spatial selectivity within a specified area.

18. The method of claim 15, wherein the duration of use of the implement can be accurately determined, monitored and analyzed through dynamic phased array and RF wave beamforming spatial selectivity within a specified area over a determinable amount of time.

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