IDENTIFICATION AND CALIBRATION METHOD

Abstract

The invention relates to a data processing method for identifying a medical instrument (5) which is configured to be tracked by means of a medical tracking system (4), wherein the method is designed to be executed by a computer and comprises the following steps:acquiring relative position and/or movement data which comprise relative position and/or movement information describing a relative position and/or movement between a calibration tool (1), which comprises at least one supporting surface (2), and the medical instrument (5) which is in contact with the side or edge of the at least one supporting surface (2), respectively;acquiring geometry data which comprise geometry information describing at least one geometrical feature for a plurality of candidate instruments;determining, on the basis of the relative position and/or movement data and the geometry data, candidate data which comprise candidate information describing at least one candidate instrument from the plurality of candidate instruments, the at least one geometrical feature of which would allow the relative position and/or movement between the medical instrument (5) and the calibration tool (1).

Claims

1-15. (canceled)

16. A data processing system comprising a computer having a processor configured to execute a computer-implemented medical method for identifying a medical instrument that is tracked by a medical tracking system, the method comprising the steps of: acquiring, at the processor, relative position and/or movement data which comprise relative position and/or movement information describing a relative position and/or movement between a calibration tool that is tracked by the medical tracking system, which comprises at least one supporting surface, and the medical instrument which is in contact with a side or edge of the at least one supporting surface, respectively; acquiring, at the processor and from a database comprising datasets containing information about geometry of each of a plurality of candidate instruments, geometry data which comprise geometry information describing at least one geometrical feature for each of the plurality of candidate instruments; determining, by the processor and on the basis of the relative position and/or movement data and the geometry data, candidate data which comprise candidate information describing at least one candidate instrument from the plurality of candidate instruments, the at least one geometrical feature of which would allow the relative position and/or movement between the medical instrument and the calibration tool.

17. A computer-implemented medical method for identifying a medical instrument that is tracked by a medical tracking system, the method comprising executing, on a processor of a computer, the steps of: acquiring, at the processor, relative position and/or movement data which comprise relative position and/or movement information describing a relative position and/or movement between a calibration tool that is tracked by the medical tracking system, which comprises at least one supporting surface, and the medical instrument which is in contact with a side or edge of the at least one supporting surface, respectively; acquiring, at the processor and from a database comprising datasets containing information about geometry of each of a plurality of candidate instruments, geometry data which comprise geometry information describing at least one geometrical feature for each of the plurality of candidate instruments; determining, by the processor and on the basis of the relative position and/or movement data and the geometry data, candidate data which comprise candidate information describing at least one candidate instrument from the plurality of candidate instruments, the at least one geometrical feature of which would allow the relative position and/or movement between the medical instrument and the calibration tool.

18. The method according to claim 17, wherein the at least one supporting surface restricts the relative position and/or relative movement between the calibration tool and the medical instrument contacting the at least one supporting surface.

19. The method according to claim 17, wherein the medical instrument is moved relative to the calibration tool during the step of acquiring the relative position and/or movement data, and wherein physical contact between the medical instrument and the at least one supporting surface is maintained.

20. The method according to claim 17, wherein the medical instrument is held in a substantially invariant position relative to the calibration tool during the step of acquiring relative position and/or movement data, and wherein physical contact between the medical instrument and the at least one supporting surface is maintained.

21. The method according to claim 17, wherein the step of acquiring the relative position and/or movement data is performed several times.

22. The method according to of claim 21, wherein the step of acquiring the relative position and/or movement data is/are performed until only one candidate instrument from the plurality of candidate instruments remains, the at least one geometrical feature of which would allow all of the relative positions and/or movements performed up until that point.

23. The method according to claim 22, further comprising the step of indicating the at least one candidate instrument for which the at least one geometrical feature which would allow all of the relative positions and/or movements performed up until that point.

24. The method according to claim 22, wherein the method is discontinued as soon as only one candidate instrument from the plurality of candidate instruments remains and/or wherein a signal is outputted which indicates that only one candidate instrument from the plurality of candidate instruments remains, the at least one geometrical feature of which would allow all of the relative positions and/or movements performed up until that point.

25. The method according to claim 22, further comprising the step of identifying the one remaining candidate instrument as the medical instrument on the basis of the candidate data.

26. The method according to claim 17, wherein on the basis of the candidate data, tracking data which comprise tracking information describing features of the medical instrument which would allow the medical instrument to be navigated in a surgical environment are transmitted to a navigation system.

27. The method according to claim 17, wherein the step of acquiring the geometry data involves providing a directory which comprises said geometry data.

28. The method according to claim 17, wherein the at least one relative movement comprises a substantially translational movement.

29. The method according to claim 17, wherein the at least one relative movement comprises a rotational movement.

30. A non-transitory computer-readable program storage medium storing a computer program which, when executed on a processor of a computer or loaded into the memory of a computer, causes the computer to perform a computer-implemented medical method for identifying a medical instrument that is tracked by a medical tracking system, the method comprising the steps of: acquiring, at the processor, relative position and/or movement data which comprise relative position and/or movement information describing a relative position and/or movement between a calibration tool that is tracked by the medical tracking system, which comprises at least one supporting surface, and the medical instrument which is in contact with a side or edge of the at least one supporting surface, respectively; acquiring, at the processor and from a database comprising datasets containing information about geometry of each of a plurality of candidate instruments, geometry data which comprise geometry information describing at least one geometrical feature for each of the plurality of candidate instruments; determining, by the processor and on the basis of the relative position and/or movement data and the geometry data, candidate data which comprise candidate information describing at least one candidate instrument from the plurality of candidate instruments, the at least one geometrical feature of which would allow the relative position and/or movement between the medical instrument and the calibration tool.

31. A computer comprising the non-transitory computer-readable program storage medium according to claim 30.

32. A medical instrument identification system comprising: the computer according to claim 31; a medical tracking system; and a calibration tool that is tracked by the medical tracking system and comprises at least one supporting surface which restricts the relative position and/or the relative movement between the calibration tool and a medical instrument contacting the at least one supporting surface of the calibration tool.

Description

[0029] In the following, the invention is described with reference to the enclosed figures which represent preferred embodiments of the invention. The scope of the invention is not however limited to the specific features shown in the figures.

[0030] FIG. 1 schematically shows a calibration tool such as can be used in connection with the present invention.

[0031] FIG. 2 shows a sequence of relative positions of a medical instrument as it is moved relative to a calibration tool.

[0032] FIG. 3 shows another embodiment of a calibration tool such as can be used in connection with the present invention.

[0033] FIG. 1 shows a calibration tool 1, comprising: two angled supporting surfaces 2 which form a V-shaped notch; and an array 3 which comprises three tracking markers and is rigidly attached to the calibration tool 1. The spatial position of each of the three tracking markers is determined by means of a medical tracking system 4 comprising two cameras which are sensitive to infrared light. Once the spatial position of each of the tracking markers has been determined, the spatial position of the calibration tool 1 and consequently also the spatial position of each of the two supporting surfaces 2 is known.

[0034] As shown in FIG. 2, an elongated distal section 7 of a medical instrument 5 can be inserted into the notch formed by the supporting surfaces 2 of the calibration tool 1 shown in FIG. 1. Once the distal section 7 has been inserted into the notch, the instrument 5 is moved in a distal direction (indicated by arrows in FIG. 2), during which physical contact between the distal section 7 and each of the supporting surfaces 2 is maintained.

[0035] The instrument 5 also has an array 6 comprising three tracking markers (which, for the sake of illustrative clarity, is only shown in the first image of the instrument 5 and not in any of the subsequent images in the sequence shown in FIG. 2) which are fixedly attached to the instrument 5, such that the spatial position of the instrument 5 can be determined by means of the tracking system 4.

[0036] Assuming the shape of the distal section 7 is initially unknown, relative position and/or movement data will be obtained as the instrument 5 is moved relative to the calibration tool 1. Initially, only the position of the proximal section of the instrument 5 and the position of the supporting surfaces 2 will be known. As soon as the distal section 7 is inserted into the notch, the spatial position of the part of the distal section 7 which is in contact with the supporting surfaces 2 will also be known. Therefore, each part of the distal section 7 which is moved through the notch, and therefore the relative position of each such part of the distal section 7 relative to the proximal section comprising the tracking marker array 6, will be known to the tracking system 4. The acquired data concerning the shape of the distal section 7 are then compared with the data stored in a database for a plurality of candidate instruments. The greater the geometric data acquired for the instrument 5, the more candidate instruments can be excluded, until eventually only one candidate instrument remains, which represents the actual instrument 5 which has been moved through the notch.

[0037] It is then possible to transmit data describing the precalibrated instrument, which are necessary for performing computer-assisted surgery, to the navigation system.

[0038] The procedure shown in FIG. 2 can be initiated by pressing a start button 10 (see FIG. 1) before the instrument 5 is inserted into the notch of the calibration tool 1, and is completed as soon as there is only one candidate dataset remaining from a plurality of candidate datasets stored in a database on the computer 8.

[0039] The movement of the instrument 5 relative to the calibration tool 1 need not of course necessarily be a translational movement, but can instead also be a rotational movement. The distal tip of the distal section 7 could for example be inserted into a tapered recess 9 (shown in an enlarged representation in FIG. 1) and rotated about the point at which the tip is in contact with the recess 9.

[0040] As shown in FIG. 3, a calibration tool 1 which is provided can comprise a plurality of supporting surfaces 2 which are configured to abut against the tip of a hollow distal section 7 of a medical instrument 5. Since the calibration tool 1 and the proximal section of the instrument 5 are tracked, geometrical data regarding the diameter of the instrument tip can be obtained by measuring the distance between the tracking marker array 3 on the calibration tool 1 and the tracking marker array 6 on the proximal section of the instrument 5. If the inner diameter of the hollow tip exceeds a predetermined value, the tip will fit over the upper cylindrical section of the calibration tool 1 and abut against the circular supporting surface 2. If the inner diameter of the hollow tip of the instrument 5 does not exceed said predetermined value, the tip will abut against the tapered supporting surface 2 provided within the upper cylindrical section of the calibration tool 1. The lower the value of the outer diameter of the instrument tip, the further down the instrument tip can be inserted onto the tapered supporting surface 2, such that geometrical data regarding the outer diameter of the instrument tip can be obtained by measuring the distance between the tracking reference array 3 and the tracking reference array 6. No relative movement between the instrument 5 and the calibration tool 1 is performed, since the instrument 5 is merely held in a position relative to the calibration tool 1 in which the instrument tip abuts one of the supporting surfaces 2. This enables data regarding both the inner diameter and outer diameter of the hollow tip 7 to be obtained, in order to perform the method of the invention.