METHOD AND SYSTEM FOR PROJECTING AN INCISION MARKER ONTO A PATIENT

Abstract

This document relates to technologies of projecting an incision marker onto a patient using a movable gantry carrying a medical imaging system and at least one laser which is adjustable relative to the gantry. The medical imaging system is used for capturing a fluoroscopic or x-ray image of at least a part of the patient from a viewing direction. Then a virtual marker is set in the captured image in order to indicate a point or region of interest, for example as a point or at least one line of an incision. Then the laser is used to indicate, from a projection direction different from the viewing direction, the point or region of interest onto the surface of the patient, thus making the point or region of interest visible from the outside.

Claims

1. A method of projecting an incision marker onto a patient using an associated medical imaging system comprising a gantry and at least one laser that is adjustable relative to the gantry, the method comprising: capturing a fluoroscopic image of at least a part of the bony structure of the patient from a viewing direction onto the patient; setting a virtual marker in the fluoroscopic image; controlling the at least one laser to project the incision marker in accordance with the virtual marker onto the patient from a projection direction different from the viewing direction; projecting by the at least one laser an imaging marker onto the patient, wherein the imaging marker indicates a position of the fluoroscopic image on the patient when the fluoroscopic image is captured; and overlying an initial virtual marker over the fluoroscopic image, wherein a position of the initial virtual marker in the fluoroscopic image corresponds with a position of the imaging marker projected onto the patient.

2. The method of claim 1, wherein an angle between the viewing direction and the projection direction lies between 85° and 95°.

3. (canceled)

4. (canceled)

5. The method of claim 1, further comprising changing the position of the initial virtual marker to obtain the virtual marker.

6. The method of claim 1, wherein the virtual marker comprises a point.

7. The method of claim 6, wherein the at least one laser projects a point or a crosshair as the incision marker.

8. The method of claim 1, wherein: the capturing the fluoroscopic image of the at least a part of the bony structure of the patient comprises capturing a fluoroscopic image of at least a part of the spine of the patient; and the setting the virtual marker comprises setting a virtual marker that indicates a vertical position on the spine.

9. The method of claim 8, wherein the projecting by the laser comprises projecting a line as the incision marker.

10. The method of claim 1, further comprising: setting a second virtual marker in the fluoroscopic image; and controlling the at least one laser to project a second incision marker in accordance with the second virtual marker.

11. The method of claim 1, further comprising: changing the position of a virtual marker in the fluoroscopic image; and controlling the at least one laser according to the changed position of the virtual marker to adapt the position of the corresponding incision marker in real time.

12. A non-transitory computer readable storage medium storing a program that, when running on a computer that is connected with an associated medical imaging system comprising a gantry and at least one laser that is adjustable relative to the gantry, causes the computer to perform steps comprising: acquiring a fluoroscopic image of at least a part of the bony structure of a patient from a viewing direction onto a patient; receiving user input representing a virtual marker in the fluoroscopic image; outputting control parameters for controlling the at least one laser to project an incision marker onto the patient in accordance with the virtual marker from a projection direction different from the viewing direction; instructing the at least one laser to project an imaging marker onto the patient, wherein the imaging marker indicates a position of the fluoroscopic image on the patient when the fluoroscopic image is captured; and overlying an initial virtual marker over the fluoroscopic image, wherein a position of the initial virtual marker in the fluoroscopic image corresponds with a position of the imaging marker projected onto the patient.

13. A computer comprising a processor and a non-transitory computer readable storage medium storing a program executable by the processor to: control an associated medical imaging system comprising a gantry and at least one laser that is adjustable relative to the gantry to capture a fluoroscopic image of at least a part of a bony structure of an associated patient from a viewing direction onto the associated patient; control the associated medical imaging system to set a virtual marker in the fluoroscopic image; control the at least one laser to project the incision marker in accordance with the virtual marker onto the associated patient from a projection direction different from the viewing direction; control the at least one laser to project an imaging marker onto the patient, wherein the imaging marker indicates a position of the fluoroscopic image on the patient when the fluoroscopic image is captured; and control the associated medical imaging system to overly an initial virtual marker over the fluoroscopic image, wherein a position of the initial virtual marker in the fluoroscopic image corresponds with a position of the imaging marker projected onto the patient.

14. A system comprising: a medical imaging system comprising a gantry and at least one laser that is adjustable relative to the gantry; and a computer comprising: a processor; and a non-transitory computer readable storage medium storing a program executable by the processor to: control the medical imaging system to capture a fluoroscopic image of at least a part of a bony structure of an associated patient from a viewing direction onto the associated patient; control the medical imaging system to set a virtual marker in the fluoroscopic image; control the at least one laser to project the incision marker in accordance with the virtual marker onto the associated patient from a projection direction different from the viewing direction; control the at least one laser to project an imaging marker onto the patient, wherein the imaging marker indicates a position of the fluoroscopic image on the patient when the fluoroscopic image is captured; and control the medical imaging system to overly an initial virtual marker over the fluoroscopic image, wherein a position of the initial virtual marker in the fluoroscopic image corresponds with a position of the imaging marker projected onto the patient.

15. (canceled)

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0058] In the following, the invention is described with reference to the appended figures which give background explanations and represent specific embodiments of the invention.

[0059] The scope of the invention is however not limited to the specific features disclosed in the context of the figures, wherein

[0060] FIG. 1 illustrates a medical imaging system;

[0061] FIG. 2 shows details of the detector including lasers;

[0062] FIG. 3 is a schematic illustration of a computer for implementing the method;

[0063] FIG. 4 shows a workflow of the method;

[0064] FIG. 5a shows a fluoroscopic image with two virtual markers; and

[0065] FIG. 5b shows a side view of the patient with two incision markers.

DESCRIPTION OF EMBODIMENTS

[0066] FIG. 1 schematically shows a medical imaging system 1 comprising a gantry 2 carrying an x-ray source 3 and carrying an x-ray detector 4. The gantry 2 comprises a base and a ring, wherein at least the x-ray detector 4, but optionally also the x-ray source 3, is rotatable in the ring. The base 2 comprises wheels (not shown) with which the medical imaging system 1 can be positioned, for example in an operating room. The ring might be tiltable relative to the base.

[0067] The x-ray source 3 emits x-ray beam which radiographs a patient (not shown) and is then detected using the detector 4 and converted into a displayable image which is recognizable by a human being.

[0068] FIG. 2 shows an exploded view of the x-ray detector 4. It comprises a detector panel 7 which is two-dimensional defined by an X direction and an Y direction which are orthogonal to each other. Adjacent to the detector panel 7, there are guide rails 6a, 6b and 6c, wherein guide rail 6a carries lasers 5a and 5b, guide rail 6b carries laser 5c and guide rail 6c carries laser 5d. Each laser 5 emits a laser beam. In the present embodiment, each laser beam is a fan beam lying in a particular plane. This plane is typically perpendicular to the direction in which the corresponding guide rail 6 extends. This means that the fan beam emitted by the lasers 5a and 5b typically lies in a plane spanned by the Y direction and a Z direction perpendicular to both the Y direction and the X direction, and the laser beams emitted by the lasers 5c and 5d typically lie in a plane spanned by the X direction and Z direction. However, in the present embodiment, the laser beams can be tilted relative to said planes, for example using a pivotable mirror. The laser beams emitted by the lasers 5a and 5b can be rotated about the Y direction and the beams emitted by the lasers 5c and 5d can be rotated about the X direction.

[0069] When capturing a fluoroscopic image using the medical imaging system 1, the lasers 5 can be used to indicate the field of view of the medical imaging system. In one embodiment, two lasers project a crosshair indicating the central beam of the medical imaging system 1. In another embodiments, the lasers 5 are controlled to emit their beams towards the x-ray source 3, such that the beams indicate the boundaries of the x-ray beam.

[0070] FIG. 3 schematically shows a computer 8 connectable to the medical imaging system 1. The computer 8 comprises a central processing unit 9, a memory 10 and an interface 11 for connecting the computer 8 to the medical imaging system 1. The computer 8 is connected to an input device 12 such as a keyboard and/or a mouse, and an output device 13, such as a monitor. The memory 10 stores instructions which, when carried out by the central processing unit 9, implement the claimed method. The memory 10 may further store working data, such as a fluoroscopic image obtained from the medical imaging system 1. The computer 8 is further configured to control the imaging device 1 via the interface 11, for example to control one or more of the lasers 5 or to activate actuators of the medical imaging system, for example for moving the base of the gantry 2 or rotating the x-ray source and/or the x-ray detector 4 within the ring of the gantry 2.

[0071] FIG. 4 shows the general structure of the claimed method.

[0072] Step S01 involves capturing an image of at least a part of a patient using the medical imaging system 1. The fluoroscopic image is transferred to the computer 8 and displayed on the output device 13. Using the input device 12, a user can set one or more virtual markers in the fluoroscopic image in step S02.

[0073] In step S03, the computer 8 controls at least one of the lasers 5 to project an incision marker in accordance with the virtual markers set in step S02.

[0074] FIG. 5a shows an exemplary lateral fluoroscopic image of a part of the spine of a patient taken from a lateral direction. Arrow A indicates the longitudinal direction of the patient and Arrow B indicates the anterior-posterior direction of the patient. The lateral direction is perpendicular both to the longitudinal direction and the anterior-posterior direction.

[0075] In the example of FIG. 5a, two virtual markers V1 and V2 in terms of vertical lines are set in the lateral fluoroscopic image. The two virtual markers V1 and V2 mark the beginning and the end of a region extending in the longitudinal direction of the patient which shall be accessed by an incision. It shall be noted that the two end points could also be indicated by virtual markers in the shape of points or any other suitable shape.

[0076] In the example shown in FIG. 5a, the computer 8 controls the lasers 5a and 5b to project two parallel lines onto the back of the patient corresponding to the positions of the virtual markers V1 and V2 in the fluoroscopic image. The two parallel lines are shown as incision markers 11 and 12 in FIG. 5b, which is a schematic rear view of the patient. The incision markers can have other shapes, such as points, dots, crosshairs or any other suitable shape. If necessary, the computer 8 instructs the medical navigation system to rotate the ring of the gantry 2 together with the x-ray detector 4, or the x-ray detector 4 along the gantry 2, such that the lasers 5A and 5B are in a position from which they can emit their laser beams onto the back of the patient. It is possible to project only one or more than two incision markers onto the back, or rear side, of the patient, based on the position of a corresponding number of virtual markers set in the lateral fluoroscopic image.

[0077] Since the viewing direction of the fluoroscopic image onto the patient is known (in this case, the lateral direction), and the lasers 5 are calibrated with respect to the gantry 2, the computer 8 can calculate the position of the lasers 5 along the guide rails 6 and the angle at which the lasers must emit the laser beams such that the laser lines are projected onto the correct positions on the surface of a patient.

[0078] In a modification or extension of the embodiments, it is possible to move a virtual marker V1 or V2 in the corresponding fluoroscopic image using the input device 12. If the position of the virtual marker in the fluoroscopic image is changed, the computer 8 instructs the lasers 5 in real time to adapt the positions of the laser lines of the surface of the patient.