RADIOTHERAPY SYSTEM AND METHOD USING THE SAME

Abstract

According to an exemplary embodiment of the present disclosure, a determination of a (floating) isocenter of a radiotherapy system can be provided. For example, the radiotherapy system can comprises a patient support structure, a gantry configured to be rotatable around a gantry axis and having a radiation source, and at least one radiation imaging device. The system can include a calibration system comprising at least one first optical detector mounted at the gantry, at least one second optical detector fixed in a surrounding area of the patient support structure and/or the gantry, first fiducial markers selectively attachable at the patient support structure at defined positions and detectable by the first optical detector, and a phantom selectively attachable at the patient support structure at a defined position. The phantom can include second fiducial markers detectable by the second optical detector, and third fiducial markers configured to be detectable by the radiation imaging device. The system can comprises a controller configured to selectively activate the radiation source and rotate the gantry, and, for one or more rotational positions of the gantry, to determine a point of intersection of a beam axis of the radiation source and the gantry axis by linking detection data of the first optical detector, the second optical detector and/or the radiation imaging device.

Claims

1. A radiotherapy system, comprising a patient support structure; a gantry which is (i) rotatable around a gantry axis, and (ii) including a radiation source; at least one radiation imaging device; a calibration system comprising: at least one first optical detector provided on the gantry, at least one second optical detector provided in a surrounding area of at least one of the patient support structure or the gantry, first fiducial markers (i) selectively attachable at the patient support structure at first predetermined positions, and (ii) configured to be detectable by the first optical detector, and a phantom selectively attachable at the patient support structure at a second predetermined position, wherein the phantom comprises (i) second fiducial markers detectable by the second optical detector, and (ii) third fiducial markers detectable by the radiation imaging device; and a controller which is configured to: selectively activate the radiation source, rotate the gantry, and for one or more rotational positions of the gantry, determine a point of intersection of a beam axis of the radiation source and the gantry axis by linking detection data of at least one of the first optical detector, the second optical detector or the radiation imaging device.

2. The radiotherapy system of claim 1, wherein the controller is further configured to control at least one of a position or an orientation of the patient support structure to align the patient support structure at the determined point of intersection.

3. The radiotherapy system of claim 1, wherein the controller is further configured to, based on at least one image of the phantom obtained by the at least one radiation imaging device, calibrate a beam shaper of the radiation source at each rotational position of the gantry.

4. The radiotherapy system of claim 1, wherein the controller is further configured to, based on an image of the phantom obtained by the at least one radiation imaging device, calibrate the radiation imaging device at each rotational position of the gantry.

5. The radiotherapy system of claim 1, wherein the controller is further configured to, based on an image of the phantom obtained by the at least one radiation imaging device, determine an offset of the gantry at each rotational position of the gantry.

6. The radiotherapy system of claim 1, wherein the third fiducial markers are embedded in a material of the phantom to be visible by a usage of the at least one radiation imaging device.

7. The radiotherapy system of claim 1, wherein the phantom is linked to the at least one first optical detector.

8. The radiotherapy system of claim 1, wherein the phantom is associated with at last one absolute position in a free three-dimensional space via the second optical detector.

9. The radiotherapy system of claim 1, wherein the phantom further comprises a further set of the first fiducial markers which are configured to be detected by the at least one first optical detector.

10. The radiotherapy system of claim 1, wherein the first optical detector comprises a further optical detector which is mounted at the at least one radiation imaging device to be arranged opposite to the first optical detector mounted at the gantry.

11. The radiotherapy system of claim 1, wherein the first fiducial markers includes a further set of markers which are selectively attachable at a bottom side of the patient support structure.

12. The radiotherapy system of claim 1, wherein the first fiducial markers are supported by at least one frame structure which is mountable along a top side of the patient support structure at different attachment positions.

13. The radiotherapy system of claim 1, wherein the first optical detector is an infra-red (IR) camera.

14. The radiotherapy system of claim 1, wherein the second optical detector is a laser device.

15. The radiotherapy system of claim 1, wherein the first fiducial markers includes a further set of markers which is provided via a support structure that is attachable to a patient, and wherein the further set of markers are linked to the first fiducial markers which are attached to the patient support structure.

16. The radiotherapy system of claim 1, wherein the controller is further configured to: for the one or more rotational positions of the gantry, to determine at least one of a current position or a predicted position of the patient support structure, and via the first optical detector and the first fiducial markers, to determine at least one of a current position or a predicted position of the gantry relative to the determined current position or the determined predicted position of the patient support structure.

17. The radiotherapy system of claim 1, wherein the controller is further configured to, based on a determination of a mechanical center of the gantry via the first optical detector, determine at least one of (i) a current angular velocity or a predicted angular velocity or (ii) an acceleration of the gantry.

18. A method for operating a radiotherapy system, comprising: providing first fiducial markers at a patient support structure of the radiotherapy system at first predetermined positions; providing a phantom at the patient support structure at a second predetermined position, wherein the phantom comprises second fiducial markers and third fiducial markers; detecting the first fiducial markers by a first optical detector provided on a gantry which is rotatable around a gantry axis and having a radiation source; detecting the second fiducial markers by a second optical detector fixed in a surrounding area of at least one of the patient support structure or the gantry; detecting the third fiducial markers by a radiation imaging device of the radiotherapy system; controlling the radiation source to be selectively activated; controlling the gantry to be rotated; and for one or more rotational positions of the gantry, determining a point of intersection of a beam axis of the radiation source and the gantry axis by linking detection data of at least one of at least the first optical detector, the second optical detector or the radiation imaging device.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Further objects, features and advantages of the present disclosure will become apparent from the following detailed description taken in conjunction with the accompanying Figures showing illustrative embodiments of the present disclosure, in which:

[0043] FIG. 1 is a perspective view of a radiotherapy system according to an exemplary embodiment of the present disclosure;

[0044] FIG. 2 is a side view of an exemplary phantom according to an exemplary embodiment of the present disclosure;

[0045] FIG. 3 is a perspective view of the exemplary radiotherapy system of FIG. 1, in which a phantom has been removed and replaced by a patient to be diagnosed and/or treated;

[0046] FIG. 4 is a schematic front view of the exemplary radiotherapy system shown in FIG. 1; and

[0047] FIG. 5 is a flow diagram of a method of operating the radiotherapy system shown in FIG. 1, according to an exemplary embodiment of the present disclosure.

[0048] Throughout the drawings, the same reference numerals and characters, unless otherwise stated, are used to denote like features, elements, components or portions of the illustrated embodiments. Moreover, while the present disclosure will now be described in detail with reference to the figures, it is done so in connection with the illustrative embodiments and is not limited by the particular embodiments illustrated in the figures and the appended claims.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

[0049] In the following, a detailed description of exemplary embodiments of the present disclosure will be described in further detail.

[0050] FIG. 1 illustrates schematically a radiotherapy system 100, which, in some exemplary embodiments, may be configured as a linear accelerator (LINAC) radiotherapy system. The exemplary system 100 can comprise a patient support structure which can be or include, e.g., a couch 200 configured to support a recumbent patient on a patient support structure/couch top (see FIG. 3). The couch is electronically controllable and movable with six degrees of freedom. The exemplary system 100 can further comprise a gantry 300 having a gantry arm 311 and a gantry head 312. The gantry 300 can be rotatable around a gantry axis 310 and has a radiation source 320. The radiation source 320 may comprises at least one beam shaper, such as a multi leaf collimator (MLC), and may provide or produce X-rays and/or high energy electrons or photons in form of a radiation beam for medicinal purposes in radiation therapy. The system 100 can further comprise at least one radiation imaging device 330, 340, wherein, in some exemplary embodiments, a first radiation imaging device 330 may be configured as a kV imager and a second radiation imaging device 340 may be configured as a MV imager. In the exemplary embodiment shown in FIG. 1, the first radiation imaging device 330 comprises an imager radiation source and an imager receiver panel. Likewise, but offset from the first radiation imaging device 330, the second radiation imaging device 340 comprises an imager radiation source and an imager receiver panel.

[0051] As illustrated in FIG. 1, the system 100 can further comprise a determination or calibration system 400 configured to at least determine an isocenter, which may be regarded as a point of intersection of a radiation beam axis of the radiation source 320 and the gantry axis 310. The determined (floating) isocenter may be the location in which the target volume to be irradiated is to be arranged. At the gantry 300, at least one first optical detector 410 is mounted, wherein, in this embodiment, two exemplary first optical detector 410 in form of infrared/IR cameras are provided. The first optical detector 410 are fixedly mounted near the radiation beam outlet of the radiation source 320 so that they may participate any movement, e.g., the rotation of the gantry 300, but also any deformation of the gantry 300, e.g., of the gantry arm 311 and/or gantry head 312, due to its weight, gravity, centrifugal force, etc. In some exemplary embodiments, at least one further first optical detector 410 may be arranged at a side of the system 100 opposing the first optical detector 410 mounted at the gantry 300. As illustrated in FIG. 1, the further first optical detector 410 are mounted at the receiver panel of the second radiation imaging device 340.

[0052] In a surrounding area of the couch 200 and/or the gantry 300, at least one second optical detector 420 of the system 100, in particular the system 400 is fixed in place. The surrounding area may be a wall, as shown in the exemplary embodiment of FIG. 1, a ceiling etc., of a room accommodating the system 100. By way of example, only two second optical detector 420 are shown, however, one, three, four, five, six or more can be provided and aligned to the system 100, in particular the couch 200 or the couch top. The second optical detector may be a laser tracker.

[0053] Further, the system 100, and, e.g., the system 400 can comprise a set of first fiducial markers 412 which are selectively attachable and detachable at the couch 200 at defined positions and configured to be detectable by the first optical detector 410. In certain exemplary embodiments, the patient support structure (e.g., the couch 200) can comprise several attachment positions 201, e.g., engaging holes, so that the first fiducial markers 412 may be mounted along a top side of the couch 200 at different positions. In some exemplary embodiments, the first fiducial markers 412 are attached to e.g., a reference frame structure 411 which is mountable at an edge region of the couch 200 and extends away from the couch top. In further exemplary embodiments, on a bottom side of the couch 200, a further set of first fiducial markers 412 may be attached to a further reference frame structure 411.

[0054] The system 100, e.g., the system 400 can further comprise a phantom 430 which is selectively attachable to and detachable from the couch 200 at a defined position. The couch top may comprise reference points, lines etc. to facilitate alignment of the phantom, as indicated in FIG. 1 by a dashed line. As shown in FIG. 1, the phantom 430 can be or include a tube and comprises a set of second fiducial markers 421 configured to be detectable by the second optical detector 420, e.g., the laser tracker. In some exemplary embodiments, the phantom 430 may be linked to at last one absolute position in free three-dimensional space via the second optical detector 420 is linked. The phantom 430 can further comprise a set of third fiducial markers 331, 341 configured to be detectable by the radiation imaging device 330 and/or 340. In some exemplary embodiments, the third fiducial markers 331, 341 may be embedded in a material of the phantom 430 to be visible by use of the at least one of the radiation imaging devices 330, 340. In some exemplary embodiments, the phantom 430 may further comprise a further set of the first fiducial markers 412 so that the phantom 430 may be linked to the at least one first optical detector 410.

[0055] The system 100 further comprises a controller 500 which may be an electronic device comprising a processor, a physical memory etc. In particular for calibrating the system 100 and/or determining a (floating) isocenter of the system 100, the controller 500 can be configured to selectively activate the radiation source 320 and rotate the gantry 300 about the gantry axis 310, around any angle section or e.g., 360. This rotation may be also be referred to as a movement in a circular orbit about a target volume to be irradiated. Further, the controller 500 is configured to, for one or more rotational positions of the gantry 300 relative to the starting point of rotation, determine a point of intersection, e.g., the (floating) isocenter, of the beam axis of the radiation source 320 and the gantry axis 310 by linking detection data of at least the first optical detector 410, the second optical detector 420 and/or the radiation imaging device 330, 340.

[0056] In some exemplary embodiments, the controller 500 may be further configured to control a position and/or orientation of the couch 200 to align it at the determined point of intersection, e.g., the (floating) isocenter. The controller 500 may further configured to, based on an image of the phantom 430 captured by the at least one radiation imaging device 330, 340, calibrate the beam shaper of the radiation source 320 at each rotational position of the gantry 300. In addition or alternatively, the controller 500 may be further configured to, based on an image of the phantom 430 captured by the at least one radiation imaging device 330, 340, determine a radiation dose to be delivered by the radiation source 320 at each rotational position of the gantry 300. Further, in some exemplary embodiments, the controller 500 may further be configured to, based on an image of the phantom 430 captured by the at least one radiation imaging device 330, 340, determine an offset of the gantry 300 at each rotational position of the gantry 300. In some exemplary embodiments, the controller 500 may further be configured, for the one or more rotational positions of the gantry 300, to determine a current or predicted position of the couch 200. If the position of the couch 200 is known, via the first optical detector 410 and the first fiducial markers 412, the controller 500 may determine a current or predicted position of the gantry 300 relative to the determined current or predicted position of the couch 200. Further, in some exemplary embodiments, the controller 500 may be further configured to, based on determining a mechanical center of the gantry 300 via the first optical detector 410, determine a current or predicted angular velocity and/or acceleration.

[0057] FIG. 2 shows the exemplary phantom 430 as a single part which is exemplarily formed as the tube and comprises the set of second fiducial markers 421 configured to be detectable by the second optical detector 420, e.g., the laser tracker, the set of third fiducial markers 331, 341 embedded in a material of the phantom 430 to be visible by use of the at least one of the radiation imaging devices 330, 340 and configured to be detectable by the radiation imaging device 330 and/or 340. In this exemplary embodiment, the phantom 430 can further comprise the further set of the first fiducial markers 412 so that the phantom 430 may be linked to the at least one first optical detector 410.

[0058] As illustrated in FIG. 3, the exemplary phantom 430 has been removed from the top side of the couch 200. Instead, as schematically indicated, a patient has been placed on the top side of the couch 200. In some exemplary embodiments, the patient may wear a support structure 413, e.g., a textile part or the like, where a further set of the first fiducial markers 412 is attached. This further set of the first fiducial markers 412 is linked to the other first fiducial markers 412 attached to the couch 200. In some exemplary embodiments, the controller 500 may be configured to detect motion of the patient via the first optical detecting means 410 by detecting e.g., deviations in positional deviations between the patient-sided first fiducial markers 412 and the couch-sided first fiducial markers 412.

[0059] FIG. 4 shows a schematic front view of the system 100, in which the couch 200 is hidden for better illustration. As discussed herein, the controller 500 may be configured to control the angular velocity and/or acceleration of the gantry 300. For that, the first optical detector 410 mounted at the gantry 300 may be used to determine the angular velocity and/or acceleration of the rotating gantry 300. After calibration of the system 100, the gantry 300 mechanical center is already known by use of the first optical detector 410, for each gantry and/or couch position. Since the weight or mass of the gantry 300, e.g., its gantry head and arm, is known, e.g., from a 3D CAD model, trigonometry, or the like, it may be determined what level of energy is needed to drive or stop the gantry 300 to a target angle with a desired speed and acceleration. In the example according to FIG. 4, the gantry 300 is to be moved from its starting point at about 40 to its end point at about +160.

[0060] With reference to the flow chart shown in FIG. 5, an operation and/or a calibration of the radiotherapy system 100 may be as described below.

[0061] For example, in step S1, the set of first fiducial markers 412 can be provided, e.g., mounted, at the couch 200 at the defined positions. These positions may vary in dependency from the patient, the target volume, the location of the target volume etc. In step S2, the phantom 430 is provided, e.g., mounted and/or aligned with a reference mark or the like, at the couch 200 at a defined position, whereas the phantom 430 comprises the set of second fiducial markers 421 and the set of third fiducial markers 331, 341. In step S3, the first fiducial markers 412 can be detected by the first optical detector 410 mounted on the gantry 300 which can be configured to be rotatable around the gantry axis 310 and carrying the radiation source 320. In step S4, the second fiducial markers 421 can be detected by the second optical detector 420 fixed in a surrounding area of the couch 200 and/or the gantry 300. In step S5, the third fiducial markers 331, 431 can be detected by a radiation imaging device 330, 340 of the radiotherapy system 100. In step S6, the radiation source 320 can be controlled to be selectively activated and the gantry 320 is controlled to be rotated. In step S7, for one or more rotational positions of the gantry 300, the point of intersection of the beam axis of the radiation source 320 and the gantry axis 310, e.g., the (floating) isocenter, can be determined by linking detection data of at least the first optical detector 410, the second optical detector 420 and/or the radiation imaging device 330, 340.

[0062] The foregoing merely illustrates the principles of the disclosure. Various modifications and alterations to the described embodiments will be apparent to those skilled in the art in view of the teachings herein. It will thus be appreciated that those skilled in the art will be able to devise numerous systems, arrangements, and procedures which, although not explicitly shown or described herein, embody the principles of the disclosure and can be thus within the spirit and scope of the disclosure. Various different exemplary embodiments can be used together with one another, as well as interchangeably therewith, as should be understood by those having ordinary skill in the art. In addition, certain terms used in the present disclosure, including the specification, drawings and claims thereof, can be used synonymously in certain instances, including, but not limited to, for example, data and information. It should be understood that, while these words, and/or other words that can be synonymous to one another, can be used synonymously herein, that there can be instances when such words can be intended to not be used synonymously. Further, to the extent that the prior art knowledge has not been explicitly incorporated by reference herein above, it is explicitly incorporated herein in its entirety. All publications referenced are incorporated herein by reference in their entireties.