Method for Optimising the Position of a Patient's Body Part Relative to an Irradiation Source

Abstract

The present invention relates to a method for positioning a patient's body part including a target to be irradiated relative to an irradiation source of a radiation imaging device, that generates a radiation beam directed towards the target, the method being constituted to be executed by a processor of a computer and comprising the following steps: receiving, at the processor, geometry data describing the geometry of at least one structure located in the field of view of the radiation imaging device; receiving, at the processor, tracking data describing the spatial position of the at least one structure within the field of view of the radiation imaging device; determining, with the processor, position data incorporating the geometry data and the tracking data, describing whether a position of the at least one structure lies within a radiation beam trajectory through the target; determining, with the processor, repositioning data describing a position of the at least one structure away from the radiation beam trajectory through the target; outputing, from the processor, the repositioning data allowing for repositioning of the at least one structure. The present invention further relates to a corresponding computer program and system.

Claims

1.-15. (canceled)

16. A method for positioning a patient's body part including a target to be irradiated relative to an irradiation source of a radiation imaging device, that generates a radiation beam directed towards the target, the method executed by one or more processors and comprising the following steps: receiving, by one or more of the processors, geometry data describing the geometry of at least one structure located in the field of view of the radiation imaging device; receiving, by one or more of the processors, tracking data describing the spatial position of the at least one structure within the field of view of the radiation imaging device; determining, by one or more of the processors, position data incorporating the geometry data and the tracking data, describing whether a position of the at least one structure lies within a radiation beam trajectory through the target; determining, by one or more of the processors, repositioning data describing a position of the at least one structure away from the radiation beam trajectory through the target; outputting, from one or more of the processors, the repositioning data allowing for repositioning of the at least one structure.

17. The method according to claim 16, wherein the at least one structure is: an anatomical structure having a high sensitivity to radiation damage; and/or a medical installation which may interfere with the radiation beam.

18. The method according to claim 16, wherein the spatial position of at least one structure is obtained: via a marker device attached to said structure, which is detectable by a medical tracking system; and/or via a position transmission device transmitting the spatial position of said structure to a medical navigation system; and/or from at least one registered cross-sectional image showing the structure; and/or from an anatomical atlas indicating the spatial position of the anatomical structure relative to the patient's body part.

19. The method according to claim 16, wherein the geometry of at least one structure is obtained: from a database; and/or from at least one registered cross-sectional image showing the structure from an anatomical atlas indicating the geometry of the anatomical structure relative to the patient's body part.

20. The method according to claim 16, wherein the patient's body part is immobilized via. an immobilization structure relative to a support structure.

21. The method according to claim 16, wherein said repositioning data output is used to automatically reposition the patient's body part and/or at least one structure relative to said irradiation source, and to output instructions to manually reposition the patient's body part and/or at least one structure relative to said irradiation source.

22. The method according to claim 16, wherein the position of the patient's body part together with at least one structure positionally fixed to the patient's body part is altered relative to the radiation imaging device to obtain a position of the at least one structure away from the radiation beam trajectory through the target.

23. The method according to claim 16, wherein the position of at least one structure is altered relative to the patient's body part to obtain a position of the at least one structure away from the radiation beam trajectory through the target.

24. The method according to claim 16, wherein a threshold value is set for the distance of at least one structure from the radiation beam trajectory through the target.

25. The method according to claim 16, wherein at least one structure is selected from the group of: an immobilization device for immobilizing the patient's body part; a headring fixed to the patients head; an articulated support structure for a biopsy device.

26. The method according to claim 16, wherein the position of the target is determined automatically or manually from at least one registered cross-sectional image showing the target; and/or automatically or manually from at least one registered 2D transmission image, and/or automatically or manually from a registered anatomic atlas, and/or manually by the use of a tracked pointer instrument.

27. The method according to claim 16, wherein a radiation intensity of the radiation beam is reduced for an anatomical structure having a high sensitivity to radiation damage and lying within the radiation beam trajectory.

28. The method according to claim 16, wherein an orientation of a biopsy device is considered when determining the repositioning data.

29. At least one non-transitory computer storage medium storing instructions for positioning a patient's body, the instructions comprising: a plurality of instructions which, when executed by one or more processors, causes the one or more processors to: receive, by one or more of the processors, geometry data describing the geometry of at least one structure located in the field of view of a radiation imaging device; receive, by one or more of the processors, tracking data describing the spatial position of the at least one structure within the field of view of the radiation imaging device; determine, by one or more of the processors, position data incorporating the geometry data and the tracking data, describing whether a position of the at least one structure lies within a radiation beam trajectory through a target to be irradiated; determine, by one or more of the processors, repositioning data describing a position of the at least one structure away from the radiation beam trajectory through the target; output, from one or more of the processors, the repositioning data allowing for repositioning of the at least one structure.

30. A system for positioning a target of a patient's body part relative to an irradiation source of a radiation imaging device, generating a radiation beam directed towards the target, comprising memory storing instructions; one or more processors executing the instructions stored in the memory to: receive, by one or more of the processors, geometry data describing the geometry of at least one structure located in the field of view of the radiation imaging device; receive, by one or more of the processors, tracking data describing the spatial position of the at least one structure within the field of view of the radiation imaging device; determine, by one or more of the processors, position data incorporating the geometry data and the tracking data, describing whether a position of the at least one structure lies within a radiation beam trajectory through the target; determine, by one or more of the processors, repositioning data describing a position of the at least one structure away from the radiation beam trajectory through the target; output, from one or more of the processors, the repositioning data allowing for repositioning of the at least one structure.

Description

[0062] 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 disclosed in the figures, which show:

[0063] FIG. 1 shows a specific embodiment of the inventive method,

[0064] FIG. 2 shows a specific embodiment of the inventive system.

[0065] As FIG. 1 shows, the inventive method can be performed during intra-operative image acquisition, as well. At first, a patient is placed on a patient table that is movably coupled to the CT-gantry, and the patient's head is immobilised relative to the table. After that, the geometry and the spatial location of the headring is determined which may interfere with the CT's radiation beam. In this case, the spatial location of the headring is determined via tracking markers which are detectable by a surgical tracking system, wherein the headring's geometry is stored in a database of the image guided surgery/navigation system.

[0066] The data obtained so far is sufficient to calculate whether the headring is likely to interfere with the irradiation beam in such a way that artefacts may obscure a region of the image that is of interest. To avoid such interference, an optimal position of the patient relative to the CT-gantry and/or the headring relative to the patient is calculated.

[0067] After the initial CT-imaging procedure, surgery is performed with critical objects such as the headring equipped with tracking markers which allow the system to determine the spatial position of the respective object. Via CT-images registered to the navigation system's coordinate system, the spatial position of the patient is also known.

[0068] During surgery, it is possible to verify proper placement of a biopsy needle inserted into the patient's brain, wherein an optimal position of any objects within the field of view of the CT-imaging device can be calculated for any subsequent CT-scan.

[0069] FIG. 2 schematically shows a mobile intra operative CT-imaging device with a circular gantry, such as AIRO®, having a coordinate system 4. The imaging device further comprises an internal or external calculating unit 5 that is configured to calculate an optimal position of a patient and/or critical structure with respect to the CT-imaging device. A patient table which is movably coupled to the CT-gantry and which is also fitted with tracking markers has an own coordinate system 3 and supports the patient. The patient's head is fixed via a headring having a coordinate system 1 to the table and a stereotactic arc having a coordinate system 2 is fixed to the table. Both, the headring and the stereotactic arc are fitted with tracking markers.

[0070] With both, the geometry and the spatial position of each of the above objects known within the CT-gantry, it is possible to calculate an optimal position for which the irradiation beam generated by the CT-imaging device irradiates a target area within the patient's head, without hitting any critical structures. If necessary, the position of the patient and/or the position of any critical object within the CT-gantry can be altered so as to avoid image artefacts or radiation damage to sensitive anatomical structures.