Surgical Instrument RFID Tag Reading Apparatus and Method, and Surgical Instrument Tracking System

Abstract

Surgical instrument RFID tag reading apparatus (10) comprises an interrogation zone (12) for receiving a surgical instrument set (14) comprising: a plurality of surgical instruments, each having a respective RFID tag containing identification information; an RFID tag reader (16); RF antenna (18) arranged to transmit an RF signal (20) and arranged to receive RF return signals from at least some of the RFID tags; guidance apparatus (22) arranged to cause predetermined relative movement between the RFID tags on the surgical instruments and the RF signal; and a controller (24) arranged to: receive the surgical instrument identification information from the RFID tag reader for each RFID tag from which an RF return signal is received; compare the received surgical instrument identification information with a surgical instrument list of the set; and; determine whether surgical instrument identification information has been received for each of the surgical instruments on the surgical instrument list, and if not, generate an incomplete list alert.

Claims

1. Surgical instrument radio frequency identification, RFID, tag reading apparatus comprising: an interrogation zone arranged to receive a surgical instrument set comprising a plurality of surgical instruments, each surgical instrument comprising a respective RFID tag containing identification information for the surgical instrument; an RFID tag reader; a first radio frequency, RF, antenna coupled to the RFID tag reader and arranged to transmit an RF signal having a signal field at least part of which extends within the interrogation zone and arranged to receive RF return signals from at least some of the RFID tags, each RF return signal containing the identification information of the respective RFID tag; guidance apparatus arranged to cause a predetermined relative movement between the RFID tags on the surgical instruments and the RF signal; and a controller arranged to: a. receive the surgical instrument identification information from the RFID tag reader for each RFID tag from which an RF return signal is received; b. compare the received surgical instrument identification information with a surgical instrument list of the surgical instrument set; and c. determine whether surgical instrument identification information has been received for each of the surgical instruments on the surgical instrument list, and if not, generate an incomplete list alert.

2. Surgical instrument RFID tag reading apparatus as claimed in claim 1, wherein the controller is further arranged to, in response to an incomplete list alert: d. transmit a control signal to the guidance apparatus comprising instructions arranged to cause a further predetermined relative movement between the RFID tags on the surgical instruments and the RF signal, the further predetermined relative movement being different to said predetermined relative movement; and e. repeat steps a to c recited in claim 1.

3. Surgical instrument RFID tag reading apparatus as claimed in claim 1, wherein the guidance apparatus is arranged to guide movement of the surgical instrument set through the RF signal along a predetermined path.

4. Surgical instrument RFID tag reading apparatus as claimed in claim 3, wherein the controller is arranged to generate and transmit a control signal to the guidance apparatus comprising instructions to cause the guidance apparatus to guide movement of the surgical instrument set along the predetermined path at a speed which varies along said path, and wherein the speed varies according to a predetermined speed profile.

5. Surgical instrument RFID tag reading apparatus as claimed in claim 1, wherein the guidance apparatus is movably mounted and is arranged to perform at least one of rotation and tilting, such that a predetermined rotational or tilting relative movement is caused between the RF signal and the surgical instrument set, and shaking, such that the position of at least some of the surgical instruments is changed.

6. Surgical instrument RFID tag reading apparatus as claimed in claim 1, wherein the guidance apparatus comprises weighing apparatus and the controller is further arranged to: receive a weight of the surgical instrument set from the weighing apparatus; compare the weight with a reference weight associated with the surgical instrument list; and determine whether the received weight is substantially equal to the reference weight, and if not, generate an incomplete list alert.

7. Surgical instrument RFID tag reading apparatus as claimed in claim 1, wherein the guidance apparatus comprises an antenna carrier on which the first RF antenna is mounted, the antenna carrier being movably mounted and arranged to undergo at least one of a predetermined linear movement, rotation and tilting such that at least one of a predetermined linear, rotational and tilting relative movement is caused between the RF signal and the surgical instrument set.

8. Surgical instrument RFID tag reading apparatus as claimed in claim 1, wherein the system comprises a second RF antenna coupled to an RFID tag reader and wherein the first and second RF antennas are arranged in a spaced relationship generally opposing each other such that the interrogation zone is located generally between the first and second RF antennas.

9. A surgical instrument RFID tag reading system comprising: surgical instrument RFID tag reading apparatus as claimed in claim 1; and an instrument carrier comprising: a base which is reflective to RF signals; and an instrument platform which is at least partially transparent to RF signals, the instrument platform being mounted within the instrument carrier raised above the base.

10. A surgical instrument tracking system comprising: a surgical instrument set comprising a plurality of surgical instruments each comprising a respective RFID tag containing identification information for the surgical instrument; and a plurality of surgical instrument RFID tag reading apparatus as claimed in claim 1, each apparatus arranged to receive the surgical instrument set.

11. A method of reading RFID tags on a plurality of surgical instruments of a surgical instrument set, each RFID tag containing identification information for the respective surgical instrument, the method comprising steps: a. transmitting an RF signal having a signal field; b. locating the RFID tags within the RF signal field; c. causing a predetermined relative movement between the RF signal and the RFID tags; d. receiving a RF return signal from at least some of the RFID tags, each RF return signal containing the identification information of the respective RFID tag; e. obtaining the surgical instrument identification information from each RF return signal; f. comparing the received surgical instrument identification information with a surgical instrument list of the surgical instrument set; and g. determining whether surgical instrument identification information has been received for each of the surgical instruments on the surgical instrument list, and if not, generating an incomplete list alert.

12. A method as claimed in claim 11, further comprising, in response to an incomplete list alert, steps: h. causing a further predetermined relative movement between the RF signal and the RFID tags, the further relative movement being different to said predetermined relative movement; and i. repeating steps a. to g recited in claim 11.

13. A method as claimed in claim 11, wherein the predetermined relative movement comprises movement along a predetermined path.

14. A method as claimed in claim 13, wherein the predetermined relative movement comprises movement along the predetermined path at a speed which varies along said path, and wherein the speed is varied along said path according to a predetermined speed profile.

15. A method as claimed in claim 12, wherein in step c. the predetermined relative movement comprises one of linear movement in a first direction, rotation by a first angle, and tilting in a first plane and by a first angle.

16. A method as claimed in claim 15, wherein in step h. the further relative movement is one of movement in a second direction, different to the first direction, rotation by a second angle different to the first angle, tilting in a second plane different to the first plane, tilting by a second angle different to the first angle, or a different one of linear movement in a first direction, rotation by a first angle, and tilting in a first plane and by a first angle.

17. A method as claimed in claim 12, wherein step h. additionally comprises shaking the surgical instrument set prior to the further relative movement, such that the position of at least some of the surgical instruments is changed.

18. A method as claimed in claim 12, wherein the relative movement between the RF signal and the RFID tags comprises movement of the surgical instruments through the RF signal.

19. A method as claimed in claim 11, wherein the relative movement between the RF signal and the RFID tags comprises movement of the RF signal across the surgical instruments.

20. A computer program, comprising instructions which, when executed on at least one processor, cause the at least one processor to carry out the method according to claim 11.

21. A carrier containing the computer program of claim 20, wherein the carrier is one of an electronic signal, optical signal, radio signal, or computer readable storage medium.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0089] FIG. 1 is a diagrammatic representation of surgical instrument RFID tag reading apparatus according to a first embodiment of the invention;

[0090] FIG. 2 is a diagrammatic representation of surgical instrument RFID tag reading apparatus according to a second embodiment of the invention;

[0091] FIG. 3 is a diagrammatic representation of surgical instrument RFID tag reading apparatus according to a fourth embodiment of the invention;

[0092] FIG. 4 is a diagrammatic representation of surgical instrument RFID tag reading apparatus according to a sixth embodiment of the invention;

[0093] FIG. 5 is a diagrammatic representation of surgical instrument RFID tag reading apparatus according to a embodiment of the invention;

[0094] FIG. 6 is a diagrammatic side view of surgical instrument RFID tag reading apparatus according to an eleventh embodiment of the invention;

[0095] FIG. 7 is a diagrammatic end view of the surgical instrument RFID tag reading apparatus of FIG. 6;

[0096] FIG. 8 is a diagrammatic representation of surgical instrument RFID tag reading apparatus according to a twelfth embodiment of the invention;

[0097] FIG. 9 is a diagrammatic representation of surgical instrument RFID tag reading apparatus according to a thirteenth embodiment of the invention;

[0098] FIG. 10 is a diagrammatic representation of surgical instrument RFID tag reading apparatus according to a fourteenth embodiment of the invention;

[0099] FIG. 11 is a diagrammatic representation of a surgical instrument tracking system according to a fifteenth embodiment of the invention;

[0100] FIG. 12 is a diagrammatic representation of a surgical instrument tracking system according to a sixteenth embodiment of the invention;

[0101] FIG. 13 shows the steps of a method according to a seventeenth embodiment of the invention of reading RFID tags on a plurality of surgical instruments of a surgical instrument set;

[0102] FIG. 14 shows the steps of a method according to a nineteenth embodiment of the invention of reading RFID tags on a plurality of surgical instruments of a surgical instrument set;

[0103] FIG. 15 shows the steps of a method according to a twentieth embodiment of the invention of reading RFID tags on a plurality of surgical instruments of a surgical instrument set;

[0104] FIG. 16 shows the steps of a method according to a twenty-first embodiment of the invention of reading RFID tags on a plurality of surgical instruments of a surgical instrument set;

[0105] FIG. 17 shows the steps of a method according to a twenty-second embodiment of the invention of reading RFID tags on a plurality of surgical instruments of a surgical instrument set;

[0106] FIG. 18 shows the steps of a method according to a twenty-third embodiment of the invention of reading RFID tags on a plurality of surgical instruments of a surgical instrument set;

[0107] FIG. 19 is a diagrammatic representation of a surgical instrument RFID tag reading system according to a twenty-fourth embodiment of the invention; and

[0108] FIG. 20 is a part cut-away view of the instrument tray of FIG. 19.

DETAILED DESCRIPTION

[0109] Referring to FIG. 1, a first embodiment of the invention provides surgical instrument radio frequency identification, RFID, tag reading apparatus 10. The apparatus 10 comprises an interrogation zone 12, an RFID tag reader 14, a radio frequency, RF, antenna 18, guidance apparatus 22 and a controller 24.

[0110] The interrogation zone 12 is arranged to receive a surgical instrument set 14 (shown for clarity in FIG. 1 but not forming part of this embodiment). The surgical instrument set comprises a plurality of surgical instruments, each of which has a respective RFID tag provided on it. Each RFID tag contains identification information for its surgical instrument.

[0111] The RF antenna 18 is coupled to the RFID tag reader 16. The RF antenna 18 is arranged to transmit an RF signal 20 having a signal field at least part of which extends within the interrogation zone. The RF signal field is also arranged to receive RF return signals from the RFID tags on the surgical instruments. Each RF return signal will contain the identification information of the respective RFID tag. RFID tags, RF antennas and RFID tag readers will be well known to the skilled person, so their structure, signalling and operation will not be described in further detail here.

[0112] The guidance apparatus of this embodiment takes the form of a guide rail 22 which is arranged such that the surgical instrument set 14 can move along the guide rail, in the direction indicated by the arrow, along a predetermined path. The movement of the surgical instrument set along the guide rail causes predetermined relative movement between the RFID tags on the surgical instruments and the RF signal 20.

[0113] The controller 24 is arranged to receive the surgical instrument identification information from the RFID tag reader for each of the RFID tags from which an RF return signal has been received. The controller is arranged to compare the received surgical instrument identification information with a surgical instrument list of the surgical instrument set. The surgical instrument list specifies each surgical instrument which should be present within the surgical instrument set. The controller is arranged to determine whether surgical instrument identification information has been received for each of the surgical instruments on the surgical instrument list. If surgical instrument identification information has not been received for each of the surgical instruments on the surgical instrument list, the controller generates an incomplete list alert. Missing surgical instrument identification information for a surgical instrument on the instrument list indicates that an RFID tag has not been read for that surgical instrument. This may be because the RFID tag did not see the RF signal, the RF antenna did not see the return RF signal transmitted by the RFID tag, or the surgical instrument is missing from the set. The apparatus 10 may therefore generate a false negative due to signalling error but it cannot generate a false positive, since a return RF signal will not be received if a surgical instrument RFID tag is not present.

[0114] A second embodiment of the invention provides surgical instrument radio frequency identification, RFID, tag reading apparatus 30 as shown in FIG. 2. The apparatus 30 of this embodiment is similar to the apparatus 10 of FIG. 1, with the following modifications. The same reference number are retained for corresponding features.

[0115] In this embodiment, the guidance apparatus takes the form of a conveyor 32, which may be a belt conveyor or a roller conveyor. The conveyor 32 is arranged to transport the surgical instrument set 14 into and through the RF signal in the direction of the arrow, along a predetermined path. It will be appreciated however that the conveyor 32 could equally be arranged to transport the surgical instrument set in the opposite direction.

[0116] A third embodiment of the invention provides surgical instrument radio frequency identification, RFID, tag reading apparatus having the same general structure as the apparatus shown in FIG. 2. In this embodiment, the conveyor is arranged to guide movement of the surgical instrument set along the predetermined path at a speed which varies along the path. The speed varies according to a preselected speed profile. The speed profile may be a linearly increasing or decreasing speed or may be a nonlinear profile, for example with the speed increasing or decreasing along one or more sections of the path and remaining constant along one or more other sections.

[0117] FIG. 3 shows surgical instrument radio frequency identification, RFID, tag reading apparatus 40 according to a fourth embodiment of the invention. The apparatus of this embodiment is similar to the apparatus 10 of FIG. 1, with the following modifications. The same reference number are retained for corresponding features.

[0118] In this embodiment, the guidance apparatus comprises an interrogation platform 42 which is arranged to receive the surgical instrument set 14. The guidance apparatus is movably mounted and is arranged to rotate, as indicated by the arrow, to rotate the surgical instrument set within the RF signal 20. This causes a predetermined rotational relative movement between the RF signal and the RFID tags on the surgical instruments in the surgical instrument set.

[0119] A fifth embodiment provides surgical instrument radio frequency identification, RFID, tag reading apparatus having the same general structure as the apparatus 40 shown in FIG. 3. In this embodiment, the guidance apparatus additionally comprises weighing apparatus, which in this embodiment is incorporated into the interrogation platform 42. The weighing apparatus is arranged to generate an instrument set weight signal containing the weight measured by the weighing apparatus.

[0120] The controller is arranged to receive the weight of the surgical instrument set from the weighing apparatus and to compare the weight with a reference weight associated with the surgical instrument list. The controller is arranged to determine whether the received weight is substantially equal to the reference weight, indicating that all of the surgical instruments on the instrument list are present. It will be appreciated that the reference weight will in practice be a weight range, to allow for differences in the actual weight of each surgical instrument, within a known manufacturing tolerance. If the received weight is not equal to the reference weight, within the weight range, this indicates that one or more surgical instruments are missing, and the controller is arranged to generate an incomplete list alert when this occurs.

[0121] FIG. 4 shows surgical instrument radio frequency identification, RFID, tag reading apparatus 50 according to a sixth embodiment of the invention. The apparatus of this embodiment is similar to the apparatus 10 of FIG. 1, with the following modifications. The same reference number are retained for corresponding features.

[0122] In this embodiment, the guidance apparatus comprises an interrogation platform 52 which is arranged to receive the surgical instrument set 14. The guidance apparatus is movably mounted and is arranged to tilt, as indicated by the arrow, to tilt the surgical instrument set within the RF signal 20. This causes tilting relative movement between the RF signal and the RFID tags on the surgical instruments in the surgical instrument set.

[0123] A seventh embodiment of the invention provides surgical instrument radio frequency identification, RFID, tag reading apparatus 60 as shown in FIG. 5. The apparatus 60 of this embodiment is similar to the apparatus 30 of FIG. 2 and the apparatus 40 of FIG. 3, with the following modifications. The same reference number are retained for corresponding features.

[0124] In this embodiment, the guidance apparatus comprises both conveyor apparatus 62 and an interrogation platform 42. The surgical instrument set additionally comprises an instrument carrier, this example a metal instrument tray 69, in which the surgical instruments are carried. The interrogation zone is arranged to receive the instrument tray carrying the surgical instruments. The conveyors 64a, 64b are arranged to transport the instrument tray, and thus the surgical instruments into and through the RF signal. It will be appreciated that a plastic instrument tray may alternatively by used, and the instrument tray will typically of the type known as an autoclavable instrument tray.

[0125] The conveyor 62 comprises two conveyor belts 64a, 64b, provided on opposing sides of the interrogation platform. The interrogation platform 62 is movably mounted and is arranged to rotate, as indicated by the arrow, to rotate the surgical instrument set 14, 69 within the RF signal 20. It will be appreciated that the interrogation platform 52, arranged to tilt the surgical instrument set within the RF signal, may alternatively be used, as may an interrogation platform configured for both rotational and tilting movement.

[0126] Each conveyor belt 64a, 64b is arranged to transport the surgical instrument tray 69 along a predetermined path in two opposing linear directions, so that the surgical instrument set may be moved into, through and out of the RF signal 20 in either direction.

[0127] The controller 66 of this embodiment is arranged to transmit a first control signal 68 to the guidance apparatus 42, 63 comprising instructions arranged to cause an initial predetermined relative movement between the RFID tags on the surgical instruments and the RF signal. The controller 66 is additionally arranged, in response to an incomplete list alert, after the initial relative movement has been completed, to generate a second control signal 68 to the guidance apparatus 42, 63 comprising instructions arranged to cause further predetermined relative movement between the RFID tags on the surgical instruments and the RF signal. The further relative movement is different to the initial relative movement.

[0128] For example, the first control signal may comprise instructions arranged to cause the conveyor apparatus 62 to transport the surgical instrument tray 69 into the interrogation zone 12 and to deliver the surgical instrument tray onto the interrogation platform 42. If an incomplete list alert is generated, a second control signal is transmitted comprising instructions to cause the interrogation platform to rotate, thereby rotating the surgical instrument tray. It will be appreciated that when the interrogation platform 52, arranged to tilt, is used or an interrogation platform configured to both rotate and tilt, the second control signal will comprise instructions arranged to cause the interrogation platform to rotate, tilt or rotate and tilt.

[0129] An initial substantially linear predetermined relative movement between the RFID tags on the surgical instruments and the RF signal is thereby followed by a rotational and/or tilting predetermined relative movement between the RFID tags on the surgical instruments and the

[0130] RF signal. The second control signal may, for example, cause the interrogation platform to rotate by 180° or 360°, or may cause the interrogation platform to rotate by +θ and then by −θ, to return the interrogation platform to its starting position. θ may be any angle up to 180°, although it is most preferably any angle up to 45°.

[0131] Alternatively, the first control signal may comprise instructions arranged to cause the conveyor apparatus to transport the surgical instrument set at a first speed, or with a first speed profile, and the second control signal may comprise instructions arranged to cause the conveyor apparatus to reverse direction and transport the surgical instrument set back through the RF signal in the opposite direction. This may be done at a second speed, or with a second speed profile, different to the first.

[0132] The following combinations of speed, reversing movement and rotation may, for example, be implemented:

TABLE-US-00001 No. of passes through RF Signal Speed Rotation Direction 1 Fast nil 1 Slow nil 1 Profile nil 2 1 fast 2nd Fast nil 2 1 Fast 2nd Slow nil 2 1 Fast 2nd Profile nil 2 1 Slow 2nd Slow nil 2 1 Profile 2nd Profile nil 1 Fast 180° Clockwise 1 Slow 180° Clockwise 1 Profile 180° Clockwise 2 1 fast 2nd Fast 180° Clockwise 2 1 Fast 2nd Slow 180° Clockwise 2 1 Fast 2nd Profile 180° Clockwise 2 1 Slow 2nd Slow 180° Clockwise 2 1 Profile 2nd Profile 180° Clockwise 1 Fast 180° Anti-clockwise 1 Slow 180° Anti-clockwise 1 Profile 180° Anti-clockwise 2 1 fast 2nd Fast 180° Anti-clockwise 2 1 Fast 2nd Slow 180° Anti-clockwise 2 1 Fast 2nd Profile 180° Anti-clockwise 2 1 Slow 2nd Slow 180° Anti-clockwise 2 1 Profile 2nd Profile 180° Anti-clockwise

[0133] As a result of the further predetermined relative movement, the controller again receives surgical instrument identification information. The controller is arranged to compare this surgical instrument identification information with the surgical instrument list and determine whether surgical instrument identification information has now been received for each of the surgical instruments on the surgical instrument list. The comparison is a cumulative comparison of the received surgical instrument identification information with the surgical instrument list. Performing a cumulative comparison when repeating the comparison means that only those surgical instruments for which identification information has not previously been received are considered the second time round. Because the instruments are checked off the instrument list cumulatively it is not necessary to receive identification information for each surgical instrument in the set during either relative movement alone.

[0134] If surgical instrument identification information has still not been received for each of the surgical instruments on the surgical instrument list, the controller generates a fail alert.

[0135] In an eighth embodiment, again described with reference to FIG. 5, the controller is additionally arranged to generate a third control signal 68 comprising instructions to cause the conveyor apparatus 62 to move the surgical instrument tray 69 out of the RF signal, which may be done at a third speed or with a third speed profile. The apparatus 60 of this embodiment is therefore able to process a plurality of surgical instrument sets 14 in series, the surgical instrument trays 69 moving through the apparatus on the conveyor belts 64, one after another.

[0136] In a ninth embodiment, again described with reference to FIG. 5, the second control signal 68 additionally comprises instructions to cause the conveyor apparatus 62 to move the surgical instrument tray 69 rapidly back and forth, thereby shaking the surgical instrument set. This causes the position of at least some of the surgical instruments to change within the tray prior to the further predetermined relative movement being performed.

[0137] In a tenth embodiment, again described with reference to FIG. 5, the conveyors 64a, 64b are arranged to transport the surgical instrument set at a speed which varies along the path of the conveyors. The speed varies according to a preselected speed profile. The speed profile may be a linearly increasing or decreasing speed or may be a nonlinear profile, for example with the speed increasing or decreasing along one or more sections of the path and remaining constant along one or more other sections.

[0138] FIGS. 6 and 7 show surgical instrument radio frequency identification, RFID, tag reading apparatus 70 according to an eleventh embodiment of the invention. The apparatus of this embodiment is similar to the apparatus 60 of FIG. 5, with the following modifications. The same reference number are retained for corresponding features. In this embodiment, the apparatus 70 comprises four RF antennas 18a, 18b, 18c, 18d arranged as two opposing pairs 18a, 18c and 18b, 18d above the interrogation platform 42. Each of the antennas is coupled to the RFID tag reader 16. It will be appreciated that each antenna may alternatively be coupled to a respective RFID tag reader, and the controller 66 is arranged to receive surgical instrument identification information from each RFID tag reader. The surgical instrument set 74 comprises a plurality of surgical instruments provided within an instrument tray, as described above. The surgical instrument tray is loaded onto the interrogation platform in the direction indicated by the arrow, thereby causing substantially linear relative movement between the RFID tags on the surgical instruments and the RF signal.

[0139] FIG. 8 shows surgical instrument radio frequency identification, RFID, tag reading apparatus 80 according to a twelfth embodiment of the invention. The apparatus of this embodiment is similar to the apparatus 70 of FIGS. 6 and 7, with the following modifications. The same reference number are retained for corresponding features.

[0140] In this embodiment, the interrogation platform 82 is movably mounted and is arranged to rotate, tilt and shake, as indicated by the arrows, to rotate and tilt the surgical instrument set 74 within the RF signal 20, and the shake the surgical instruments within the tray.

[0141] A thirteenth embodiment of the invention provides surgical instrument radio frequency identification, RFID, tag reading apparatus 90 as shown in FIG. 9. The apparatus 90 of this embodiment is similar to the apparatus 10 of FIG. 1, with the following modifications. The same reference number are retained for corresponding features.

[0142] In this embodiment, the guidance apparatus comprises an antenna carrier 92 on which the RF antenna 18 is mounted. The antenna carrier is movably mounted and is arranged for linear movement, rotation and tilting. The controller 94 is arranged to generate a control signal 98 comprising instructions to cause the antenna carrier 92 to undergo at least one of a predetermined linear movement, a predetermined rotation, and a predetermined tilting movement. The RF signal can therefore be moved linearly relative to the surgical instrument set, may be rotated about the instrument set or may be tilted about the instrument set 14, or any combination of these, to cause a predetermined relative movement between the RF signal and the surgical instrument RFID tags.

[0143] A fourteenth embodiment of the invention provides surgical instrument radio frequency identification, RFID, tag reading apparatus 100 as shown in FIG. 10. The apparatus 100 of this embodiment is similar to the apparatus 30 of FIG. 2, with the following modifications. The same reference number are retained for corresponding features.

[0144] In this embodiment, a second RF antenna 102 is provided, generally opposite the RF antenna 18 and underneath the conveyor apparatus 32, such that the interrogation zone is located generally between the RF antennas. The second antenna is coupled to the RFID tag reader 16 and its RF signal 104 extends into the interrogation zone and partially overlaps with the RF signal 20 of the RF antenna 18.

[0145] Referring to FIG. 11, a fifteenth embodiment of the invention provides a surgical instrument tracking system 200. The system 200 comprises a surgical instrument set, IS, 202 and a plurality, two in this example, of surgical instrument RFID tag reading apparatus 10, as described above with reference to FIG. 1. It will be appreciated that any of the above described surgical instrument RFID tag reading apparatus 30, 40, 50, 60, 70, 80, 90, 100 described with reference to FIGS. 2 to 10 may alternatively be used.

[0146] The instrument set 202 comprises a plurality of surgical instruments each comprising a respective RFID tag containing identification information for the surgical instrument.

[0147] Each surgical instrument RFID tag reading apparatus is arranged to receive the surgical instrument set at a respective location.

[0148] For example, the system 200 may be used within an operating theatre of a hospital. The surgical instrument RFID tag reading apparatus 10 provided at location 1 may be used to check that the instrument set IS 202 is complete before an operation is commenced, and the apparatus at location 2 may be used to check that the instrument set IS 202 is complete once the operation is completed. The surgical instruments can therefore be tracked over the course of an operation, to ensure that all of the surgical instruments required to perform the operation are present before starting the operation and to ensure that all of the surgical instruments are accounted for after the operation.

[0149] Alternatively, the system 200 may be used within the CSSD of a hospital. The surgical instrument RFID tag reading apparatus 10 provided at location 1 may be used to inspect the instrument set IS 202 before commencing the autoclave sterilisation and decontamination, and the apparatus at location 2 may be used to check that the instrument set IS 202 is complete once sterilisation and decontamination is completed. The surgical instruments can therefore be tracked over the sterilisation and decontamination process, to ensure that all of the surgical instruments are accounted for and the instrument set is complete and ready for use.

[0150] A sixteenth embodiment of the invention provides a surgical instrument tracking system 210 as shown in FIG. 12. The system 210 of this embodiment is similar to the system 200 of the previous embodiment, with the following modifications. The same reference numbers are retained for corresponding features.

[0151] In this embodiment, the system 210 comprises two surgical instrument RFID tag reading apparatus 10, as described above with reference to FIG. 1, and two surgical instrument RFID tag reading apparatus 60, as described above with reference to FIG. 5.

[0152] This system 210 may be used within a hospital to track a surgical instrument set during the sterilisation and decontamination process and during use to perform an operation. The first two surgical instrument RFID tag reading apparatus 60 may be provided within the CSSD, as described above, and the second two surgical instrument RFID tag reading apparatus 10 may be provided in an operating theatre, as described above.

[0153] Referring to FIG. 13, a seventeenth embodiment of the invention provides a method 300 of reading RFID tags on a plurality of surgical instruments of a surgical instrument set. Each RFID tag contains identification information for the respective surgical instrument.

[0154] The method 300 comprises the following steps:

[0155] a. transmitting an RF signal having a signal field 302;

[0156] b. locating the RFID tags within the RF signal field 304;

[0157] c. causing a predetermined relative movement between the RF signal and the RFID tags 306;

[0158] d. receiving a RF return signal from at least some of the RFID tags 308, each RF signal return containing the identification information of the respective RFID tag;

[0159] e. obtaining the surgical instrument identification information from each RF return signal 310;

[0160] f. comparing the received surgical instrument identification information with a surgical instrument list of the surgical instrument set 312; and

[0161] g. determining whether surgical instrument identification information has been received for each of the surgical instruments on the surgical instrument list 314, and if not, generating an incomplete list alert 316.

[0162] Referring to FIG. 14, an eighteenth embodiment of the invention provides a method 320 of reading RFID tags on a plurality of surgical instruments of a surgical instrument set. The method 320 of this embodiment is similar to the method 300 of the previous embodiment, with the following modifications. The same reference numbers are retained for corresponding steps.

[0163] In this embodiment, the method 320 comprises, in response to an incomplete list alert 316, the following additional steps:

[0164] h. causing further predetermined relative movement between the RF signal and the

[0165] RFID tags 322, the further predetermined relative movement being different to said predetermined relative movement; and

[0166] i. repeating steps a. 302 to g. 314.

[0167] If after repeating step g., surgical instrument identification information has still not been cumulatively received for all of the surgical instruments on the surgical instrument list, the method proceeds to generate a fail alert 324.

[0168] The predetermined relative movement performed in step c. 306 comprises one of linear movement in a first direction, rotation by a first angle, and tilting in a first plane and by a first angle. The further predetermined relative movement performed in step h. 322 comprises one of linear movement in a second direction, different to the first direction, rotation by a second angle different to the first angle, tilting in a second plane different to the first plane, tilting by a second angle different to the first angle, or a different one of linear movement in a first direction, rotation by a first angle, and tilting in a first plane and by a first angle.

[0169] In a nineteenth embodiment, also described with reference to FIG. 14, in step c.

[0170] 306 the predetermined relative movement is movement along a predetermined path at a first speed and in step h. 322 the further predetermined relative movement is movement along the predetermined path at a second speed, different to the first. Each linear movement may be at a constant speed or may follow a speed profile, in which the speed of movement is varied. The further predetermined movement may alternatively be along a different predetermined path.

[0171] Referring to FIG. 15, a twentieth embodiment of the invention provides a method 330 of reading RFID tags on a plurality of surgical instruments of a surgical instrument set. The method 330 of this embodiment is similar to the method 320 of the previous embodiment, with the following modifications. The same reference numbers are retained for corresponding steps.

[0172] In this embodiment, the method 330 additionally comprises shaking the surgical instrument set 332 such that the position of at least some of the surgical instruments is changed. The shaking is performed before the further relative movement 322.

[0173] Referring to FIG. 16, a twenty-first embodiment of the invention provides a method 340 of reading RFID tags on a plurality of surgical instruments of a surgical instrument set. The method 340 of this embodiment is similar to the method 300 described with reference to FIG. 13, with the following modifications. The same reference numbers are retained for corresponding steps.

[0174] In this embodiment, the surgical instrument set, and thus the RFID tags on the surgical instruments, is moved through the RF signal 342.

[0175] Referring to FIG. 17, a twenty-second embodiment of the invention provides a method 350 of reading RFID tags on a plurality of surgical instruments of a surgical instrument set. The method 350 of this embodiment is similar to the method 300 described with reference to FIG. 13, with the following modifications. The same reference numbers are retained for corresponding steps.

[0176] In this embodiment, the RF signal is moved across the surgical instruments, and thus across the RFID tags on the surgical instruments.

[0177] Referring to FIG. 18, a twenty-third embodiment of the invention provides a method 360 of reading RFID tags on a plurality of surgical instruments of a surgical instrument set.

[0178] The method 360 is implemented using the apparatus 60 shown in FIG. 5. The instrument set 14 of this embodiment additionally has an RFID tag on the instrument tray.

[0179] The method comprises:

[0180] placing the instrument tray containing the surgical instruments on the conveyor apparatus 362;

[0181] turning on the RFID reader and the RF antenna to transmit an RF signal and searching for identification, ID, information for the RFID tags on the surgical instruments 364;

[0182] receiving ID information for the tray 366;

[0183] retrieving the instrument list for the tray 380;

[0184] receiving surgical instrument ID information from at least some of the RFID tags on the surgical instruments 368;

[0185] comparing the received surgical instrument ID information with the surgical instrument list and determining whether ID information has been received for each of the surgical instruments on the list 370;

[0186] if ID information has been received for each of the surgical instruments on the list, displaying a ‘tray positive’ status 372 and exiting the tray from the apparatus 374; and

[0187] if ID information has not been received for each of the surgical instruments on the list, causing further relative movement between the RF signal and the RFID tags, by repeating the scan by at least one of: moving the conveyor apparatus in the opposite direction; moving the conveyor apparatus at a different speed; rotating the interrogation platform; tilting the interrogation platform; and shaking the interrogation platform or moving the conveyor apparatus backwards and forwards to shake the instrument tray;

[0188] comparing all the received surgical instrument ID information with the surgical instrument list and determining whether ID information has been received for each of the surgical instruments on the list 370; and

[0189] if ID information has been received for each of the surgical instruments on the list, displaying a ‘tray positive’ status 372 and exiting the tray from the apparatus 374; and

[0190] if ID information has still not been received for each of the surgical instruments on the list, transmitting a fail alert 378.

[0191] Referring to FIGS. 19 and 20, a twenty-fourth embodiment of the invention provides a surgical instrument RFID tag reading system 400 comprising a surgical instrument RFID tag reading apparatus 10 and an instrument carrier, in the form of an instrument tray 402. The instrument tray comprises a base 404 and an instrument platform 406. The instrument platform is mounted within the instrument tray raised above the base. The base is reflective to RF signals and the instrument platform is at least partially transparent to RF signals.

[0192] It will be appreciated that any of the above described surgical instrument RFID tag reading apparatus 10, 30, 50, 60, 70, 80, 90, 100 described with reference to FIGS. 2 to 10 may alternatively be used.