METHOD AND SYSTEM FOR SUPPORTING PATIENT POSITIONING

Description

[0001] The invention relates to a method and a system for supporting the positioning of a patient for irradiation with a radiation device in a treatment room. Such radiation devices are used in radiation therapy, for example, to irradiate tumors. Linear accelerators (LINACs) are among the devices used. A crucial aspect of radiation therapy is precise patient positioning so that the radiation dose generated by the radiation device targets the tissue being treated as accurately as possible.

[0002] Patient positioning using lasers and markings on the patient's skin is a known technique. Such a system is disclosed, for example, in DE 195 24 951 A1. Laser systems for projecting laser planes for patient positioning, particularly coronal, transverse, and sagittal planes, exist, for example, in examination rooms equipped with imaging devices, such as CT scanners for CT simulation, as well as at radiation therapy machines. For instance, during CT simulation and subsequent radiation therapy planning, the isocenter of the tumor to be treated is determined in the patient's body using imaging. This tumor isocenter is then typically aligned as precisely as possible with the isocenter of the radiation therapy machine in a separate treatment room at a later time.To visualize the tumor's isocenter on the patient's body, at least three orthogonal laser planes are aligned within the examination room using the imaging system so that their common intersection point lies at the tumor's isocenter. This alignment can be achieved by moving the laser planes within the room using movable laser rails and / or by moving the patient on a treatment table. The projected laser planes appear as lines on the patient's body surface, with each pair of laser lines forming an intersection point. In this way, for example, three intersection points formed by two of the three orthogonal laser planes can be displayed on the patient's body surface, such as on two opposite sides and on the top of the patient's body.The intersection points of the laser lines can be marked using pens or markers applied to the skin. During subsequent irradiation in the treatment room, the isocenter of the treatment device can be indicated on the patient's body surface by the intersection of three orthogonally aligned laser planes. To align this isocenter of the treatment device with the isocenter of the tumor, the patient can be moved or rotated in the room, for example, using a movable treatment table, so that the intersection points formed on the patient's body surface by each pair of the orthogonal laser planes coincide with the previously applied markers. Once all intersection points on the body surface have been aligned with the previously applied markers, the patient positioning is complete and the irradiation can begin.A similar system is described in US 2011 / 135190.

[0003] This method of patient positioning is easy and intuitive for the user, as it is immediately apparent which patient movement is necessary to align the laser lines and the markings on the patient's surface, thus positioning the patient correctly. A disadvantage of this method is that the patient must wear the markings on their body for at least the duration of the radiation treatment, usually several weeks. There is a risk that the markings will wash off or otherwise become illegible, making precise patient positioning impossible. Furthermore, changes in the patient's body during radiation treatment, such as weight loss or changes in body rigidity or shape, cannot always be detected and taken into account with sufficient accuracy.Furthermore, only three selected points are used for positioning the patient, which should be as accurate as possible even outside the plane of the intersection points.

[0004] 3D surface acquisition systems are known from the prior art that allow patient positioning for radiotherapy without markings on the body. Surface acquisition systems are described, for example, in US 7,348,974 B2, US 7,889,906 B2, US 9,028,422 B2, US 2015 / 265852 A1, and US 2016 / 129283 A1. These systems compare a live-measured three-dimensional surface of the patient's body with a three-dimensional reference surface of the patient's body, created, for example, during treatment planning using a CT simulation. Deviations are displayed in three-dimensional visualizations of the target and actual surfaces. Furthermore, values ​​for required patient displacements and rotations can be calculated and applied to the patient's position to ensure that the target and actual surfaces align.The accuracy of patient positioning is often greater with such three-dimensional surface sensing systems because alignment is possible not only along projected lines or intersection points, but also based on entire surfaces or parts thereof. However, interpreting the values ​​displayed by the system regarding patient positioning is less intuitive and requires a longer familiarization and learning period for the user. This can also lead to operator errors.

[0005] Based on the prior art described above, the invention therefore aims to provide a method and a system of the type mentioned at the outset, which support the positioning of a patient for irradiation at an irradiation device in a simple and intuitive way for the user while maintaining the greatest possible accuracy.

[0006] The invention solves the problem through independent claims 1 and 13. Advantageous embodiments can be found in the dependent claims, the description and the figures.

[0007] For a method of the type mentioned above, the invention solves the problem by the following steps: Using a 3D surface acquisition system, a current surface of the patient's body, preferably in the treatment room, is captured. At least one intersection point of at least two lines with the captured surface of the patient's body, indicating the isocenter of the radiation device, is calculated. Based on a reference surface of the patient's body, which specifies the target position of the patient's body relative to the isocenter of the radiation device, a necessary transformation is calculated to align the captured surface of the patient's body and the reference surface. Based on the calculated transformation, a target position of the at least one intersection point indicating the isocenter of the radiation device with the captured surface of the patient's body is determined.In a visualization system, at least one intersection point indicating the isocenter of the radiation device with the captured surface of the patient's body and its target position are displayed.

[0008] The invention also solves the problem through a system of the type mentioned at the outset, comprising a 3D surface acquisition system configured to acquire a current surface of the patient's body, preferably in the treatment room, comprising an evaluation unit configured to calculate at least one intersection point of at least two lines with the acquired surface of the patient's body indicating the isocenter of the irradiation device, wherein the evaluation unit is further configured to calculate a required transformation, based on a reference surface of the patient's body which specifies the target position of the patient's body relative to the isocenter of the irradiation device, in order to align the acquired surface of the patient's body and the reference surface, wherein the evaluation unit is further configured to determine, based on the calculated transformation, a target position of the at least one intersection point indicating the isocenter of the irradiation device with the acquired surface of the patient's body.and comprising a visualization system designed to display, based on the calculated transformation, at least one intersection point indicating the isocenter of the irradiation device with the captured surface of the patient's body and its target position.

[0009] The radiation therapy device is used to irradiate a patient, for example, for tumor treatment. It may be a linear accelerator (LINAC). According to the invention, the position of the patient, preferably located in the treatment room, for example on a movable patient table, is detected using a three-dimensional surface detection system. The three-dimensional surface of the patient's body is detected, in particular, multiple times in succession, for example at fixed time intervals or continuously. The three-dimensional surface detection system can be designed in a manner known per se. It can, for example, include cameras, in particular a stereoscopic camera system, as is known per se.

[0010] The radiation dose generated by the irradiation device is often highest at its isocenter. The isocenter of the irradiation device should coincide as closely as possible with the isocenter of the tissue being irradiated, particularly a tumor. According to the invention, this is achieved by calculating the intersection point of at least two lines or planes on the patient's body surface. This intersection point indicates the isocenter of the irradiation device. It is calculated from the intersection lines of orthogonal planes with the body surface that intersect at the isocenter of the irradiation device. The isocenter, as the intersection point of, for example, three orthogonal planes, is typically located within the patient's body as it is positioned on the treatment table.The three orthogonal planes, for example, are thus represented as three lines on the patient's body, intersecting each other in pairs on the body surface, for example, on two opposite sides and the top of the body. The intersection points of any two of the three lines with the body surface indicate the isocenter. According to the invention, these lines and their intersection points can be calculated and visualized. Accordingly, three intersection points of each pair of lines with the captured surface of the patient's body can be calculated, namely the intersection points of the three orthogonal planes intersecting at the isocenter of the irradiation device at three positions on the surface of the patient's body. Of course, more than three intersection points on the body surface could also be calculated and visualized, for example, four intersection points, if, for instance, an intersection point on the underside of the patient's body is also calculated.Where lines and their points of intersection are mentioned, this also includes the (orthogonal) planes that appear as lines on the surface of the body.

[0011] The invention further incorporates a three-dimensional reference surface of the patient's body, which specifies the target position of the patient's body relative to the isocenter of the radiation device. This reference surface defines the target position of the patient's body for irradiation. The reference surface can be created, for example, as part of the treatment planning process prior to irradiation. For this purpose, the tissue to be irradiated, particularly the tumor, can be identified using an imaging technique such as CT or MRI. With a 3D surface acquisition system, for example, in an examination room, the surface of the patient's body can be captured, and the system can then calculate how this surface must be oriented relative to the isocenter of the radiation device for the subsequent irradiation.The 3D surface acquisition system in the examination room can, in principle, be designed in the same way as the 3D surface acquisition system in the treatment room.

[0012] Based on the reference surface created in this way or otherwise, for example from imaging data, a transformation is calculated of the current surface of the patient's body, as captured by the 3D surface acquisition system, particularly in the treatment room, to align it with the reference surface, specifically so that the isocenter of the radiation device coincides with the center of the tissue being irradiated. The transformation may, for example, involve a necessary displacement in all three spatial directions and / or a rotation of the patient's body and / or the reference surface about one or more axes. The transformation can be calculated, for example, using known iterative methods, such as the iterative closest point method.

[0013] According to the invention, a target position of the at least one intersection point indicating the isocenter of the irradiation device with the surface of the patient's body is determined based on the calculated transformation. In a visualization system, the at least one intersection point indicating the isocenter of the irradiation device with the captured surface of the patient's body and its target position determined based on the transformation are displayed. Based on the transformation or an inverse transformation performed on this basis, a target position in the patient's coordinate system is determined for the previously calculated intersection point, as it would appear on the patient's body if the patient's body were oriented to the isocenter of the irradiation device as specified. The target position corresponds to at least one point on the reference surface of the patient's body in the patient's coordinate system.Based on the transformation or inverse transformation calculated according to the invention, a target position can, in principle, be determined for any point on the surface of the patient's body, including, among others, the intersection of lines or orthogonal planes indicating the isocenter. Based on the display of the intersection point and the target position in the visualization system, a user can easily position the patient so that the intersection point coincides with their target position and the patient is aligned with the isocenter of the irradiation device as specified. The visualization system is software-based. It can, for example, be run on a PC, laptop, notebook, tablet, or similar device. The visualization is displayed on a corresponding device's screen.

[0014] When the surface or reference surface of the patient's body is mentioned herein, this generally includes the surface or reference surface of the entire patient's body or only a section of the patient's body, for example, a section of the patient's body of interest for irradiation. It should also be noted that the method according to the invention is preferably carried out in the treatment room with the irradiation device, or that the system according to the invention is preferably located in the treatment room. However, this is not mandatory. The method could additionally or alternatively also be carried out in another room, or the system could be located in another room, for example, in an examination room. For instance, the method according to the invention could be carried out in an examination room before the patient is positioned in a treatment room.

[0015] The invention is based on the concept of calculating and displaying virtual markings and positioning lasers on the captured surface of the patient's body, using a currently captured three-dimensional surface and a transformation of the patient's body calculated from a three-dimensional reference surface. Patient positioning is particularly intuitive and easy to perform based on these virtual markings and positioning lasers. At the same time, the advantages of high-precision surface capture and the resulting transformation are utilized. Thus, with simple and intuitive operation, similar to classic body surface markings and corresponding positioning lasers, the accuracy of 3D surface capture systems is achieved. The advantages of both systems are combined without inheriting their respective disadvantages.By preferably continuously calculating and displaying the at least one intersection point and its target position on the body surface, the user is easily shown in which degrees of freedom and directions the patient must be moved so that the at least one intersection point coincides with its target position.

[0016] The method according to the invention, in particular its steps, can be carried out multiple times in succession, for example at fixed time intervals or preferably continuously. In this way, continuous live monitoring of the patient's position and any necessary repositioning of the patient for irradiation can be displayed in the visualization system and controlled by the user. The user can thus easily and successively move to and / or monitor the correct patient position.

[0017] To facilitate positioning, the at least one intersection point and its target position can be displayed in the visualization system as crosses of lines.

[0018] In one configuration, a patient table supporting the patient's body, and / or the patient on the table, can be moved within the treatment room such that at least one intersection point indicating the isocenter of the radiation device with the captured surface of the patient's body coincides with its target position. Positioning can be controlled automatically or manually. For this purpose, the patient's body can be positioned on a movable table, which, for example, can be moved along three mutually perpendicular directions and also rotated about one or more axes, such as a vertical axis and an axis along a longitudinal and / or transverse direction of the table. This allows the user to position the table or the patient so that the markings indicating the isocenter of the radiation device in the visualization system align with the target position of the markings.

[0019] In a further embodiment, it can be provided that at least three intersection points of at least three lines with the captured surface of the patient's body, indicating the isocenter of the radiation device, are calculated and displayed in the visualization system, and that at least three target positions of the at least three intersection points indicating the isocenter of the radiation device with the captured surface of the patient's body, determined on the basis of the calculated transformation, are displayed in the visualization system. As already explained, the isocenter of the radiation device can be defined by the intersection of three orthogonal planes, particularly in the treatment room.Since this isocenter is generally located within the patient's body, any two of the orthogonal planes, represented as lines on the body surface, form an intersection point on the patient's surface. Three orthogonal planes together form three intersection points, for example, on opposite sides of the patient's body and on the top of the patient's body. These intersection points can be calculated according to the aforementioned configuration and displayed in the visualization system. Similarly, based on the transformation calculated according to the invention, the target positions of these intersection points are also calculated in the manner described above and displayed in the visualization system.This design further improves the positioning of the patient's body by requiring that all points of intersection with their target positions be aligned through a corresponding movement of the patient bed and / or movement of the patient's body on the patient bed.

[0020] According to another particularly practical implementation, the captured surface of the patient's body can also be displayed in the visualization system, whereby the at least one intersection point indicating the isocenter with the captured surface of the patient's body and its target position are shown on the surface of the patient's body displayed in the visualization system. The same applies, of course, to any further intersection points. Displaying the patient's body together with the intersection points and the corresponding target positions on its surface further simplifies the visualization and thus the positioning of the patient for the user.

[0021] With a further refinement, the at least two lines defining the intersection point indicating the isocenter of the radiation device can also be displayed in the visualization system. The target position of the intersection point indicating the isocenter of the radiation device can also be displayed in the visualization system by the intersection of at least two lines. In particular, the lines can be displayed on the currently captured patient surface, which is also shown in the visualization system. Displaying and thus aligning the lines during patient positioning further improves positioning accuracy by ensuring that longer lines, which can extend across the entire length and / or width of the patient's body, are aligned.This essentially involves a complete virtual simulation of the patient positioning described above in the prior art, using projected orthogonal laser planes and their intersections with the patient surface, represented as lines.

[0022] The patient's body reference surface can be created after further refinement as part of the radiation treatment planning process prior to patient positioning. Creating the reference surface can be done, in particular, in an examination room separate from the treatment room. This examination room can include an imaging system, such as a CT or MRI system, in a manner known per se. The patient's body is scanned together with the tissue to be irradiated, for example, a tumor. Based on this scan, the reference surface can be created in a manner known per se.

[0023] In a further embodiment, in addition to the intersection points indicating the isocenter of the radiation device, further intersection points with the captured surface of the patient's body can be calculated. These additional intersection points, along with their target positions determined based on the calculated transformation, can then be displayed in the visualization system. By virtually marking and aligning the patient using these additional intersection points, such as prominent points on the body surface like the hip bones, skull, nose, feet, knee joints, etc., the patient's positioning in space can be further improved. Similar to a mannequin, points on the surface can be marked to visualize movement or deformation of the patient's body, for example, in the abdominal area.In particular, changes in body shape, for example, changes in the rigidity of the patient's body, become apparent. This would not always be reliably detected if only the isocenter were marked. The other intersection points can also be the intersection of two lines or orthogonal planes. Furthermore, the lines defining these other intersection points can also be displayed on the body surface in the visualization system. Since, according to the invention, the surface of the patient's body is captured and a transformation is calculated for this surface, any point on the body surface can, in principle, be marked and displayed.In practice, a suitable compromise is chosen between the number of points to be displayed and thus brought into overlap by means of the patient bed and / or movement of the patient's body on the patient bed, on the one hand, and the required positioning accuracy on the other.

[0024] To further improve patient positioning, additional intersection points could, for example, be points where the markers intersect the patient's surface, such as at opposite ends of the body. By aligning widely separated markers with their respective target positions, particularly precise positioning is possible.

[0025] With further refinement, the visualization system can display at least one intersection point and its target position from various perspectives. This further simplifies positioning. For example, the system can display views from opposite sides of the patient's body and from the top of the patient's body. This also applies to the three-dimensional surface of the patient's body, provided it is also displayed in the visualization system.

[0026] According to a further embodiment, the target position of the at least one intersection point indicating the isocenter of the irradiation device with the captured surface of the patient's body can be verified using line or cross lasers arranged in the treatment room and / or an examination room. In this embodiment, physical lasers arranged in the treatment room or examination room, which project orthogonal laser planes in space, are used to define the position of the virtual laser markings. For this purpose, the current position of the physical lasers located in the treatment room or examination room can be detected and transferred to the virtual surface data of the system according to the invention.

[0027] With further refinement, at least one additional target position of at least one further intersection point with the surface of the patient's body can be determined, and the visualization system can display this at least one further intersection point with the captured surface of the patient's body and its further target position. In this way, further virtual intersection points with the captured surface of the patient's body can be determined and adopted as target positions.

[0028] In a further embodiment, line or cross lasers arranged in the treatment room and / or an examination room can indicate the position of an intersection point on the scanned surface of the patient's body, and the indicated position can be determined as a target position or as a further target position and displayed in the visualization system. Thus, further intersection points with the scanned surface of the patient's body can be indicated by physical line or cross lasers and read out by the system according to the invention. These further intersection points can then be adopted as (further) target positions.

[0029] An embodiment of the invention is explained in more detail below with reference to the figures. They schematically show: Figure 1 shows a system according to the invention in a perspective view, Figure 2 shows a representation in a visualization system of the system according to the invention in a first operating state, Figure 3 shows the representation from Figure 2 in a second operating state, and Figure 4 the representation from Figure 2 in a third operating state.

[0030] Unless otherwise stated, the same reference symbols in the figures denote the same objects.

[0031] In Figure 1The system according to the invention is shown in a treatment room with a radiation therapy device 10, which can be, for example, a linear accelerator (LINAC) for tumor treatment. A patient body 12 is located on a patient table 14 that is movable within the treatment room and can be moved, for example, along the three spatial directions and rotated about a vertical axis. Rotation of the patient table 14 about its longitudinal and / or transverse axis is also possible. The radiation therapy device 10 can be rotated around the patient body 12 during irradiation in a manner known per se.

[0032] The system further comprises a 3D surface acquisition system with, in the illustrated example, two stereoscopic cameras 16. The cameras 16 capture the current three-dimensional surface of the patient's body 12 in the treatment room. This can be done repeatedly, in particular continuously. The captured surface of the patient's body 12 is displayed in a visualization system 18 of the system according to the invention, as explained in more detail below.

[0033] The treatment room is further equipped with three line or cross lasers 20, which project at least three mutually orthogonal laser planes 22 into the room, intersecting at the isocenter 24 of the irradiation device 10. This isocenter 24 is typically located inside the patient's body 12. The laser planes 22 projected by the line or cross lasers 20 are thus depicted as lines on the surface of the patient's body 12, with each pair of laser lines projected onto the body surface forming an intersection point on the surface of the patient's body 12. For example, three intersection points can be formed on the surface of the patient's body, namely on opposite sides, in Figure 1 the left and right sides of the patient's body 12 as well as on the top of the patient's body 12.

[0034] The system according to the invention further comprises an evaluation unit 26 which, independently of the line or cross lasers 20 physically present in the treatment room, calculates the intersection points of at least two lines indicating the isocenter 24 of the irradiation device 10, corresponding to the planes projected by the physical line or cross lasers 20, with the surface of the patient body 12 captured by the 3D surface acquisition system, in particular the cameras 16. For example, as part of irradiation planning prior to irradiation using an imaging system, such as a CT or MRI system, a three-dimensional reference surface of the patient body is also created, which indicates the target position of the patient body 12 with respect to the isocenter 24 of the irradiation device 10.Using this reference surface, the evaluation unit 26 calculates a necessary transformation to align the surface of the patient body 12, as captured by the 3D surface acquisition system, with the reference surface. Based on the calculated transformation, the evaluation unit 26 then determines a target position for the intersection points with the surface of the patient body 12, indicating the isocenter 24 of the radiation device 10. Typically, the target position of the patient body 12 is such that the isocenter of the tissue to be treated, particularly the tumor to be irradiated, coincides with the isocenter 24 of the radiation device 10.

[0035] In the visualization system 18, the intersection points indicating the isocenter 24 of the irradiation device 10 with the captured surface of the patient's body 12 and their respective target positions are displayed. This is intended to be done using the Figures 2 to 4will be explained in more detail.

[0036] In Figure 2 A case is shown in which the patient body 12 is not yet correctly aligned. In the example shown, the lines 28, which define the intersection points indicating the isocenter of the irradiation device, are displayed in the visualization system 18 next to the captured patient body 12. Figure 2 The intersection point 30 is defined by lines 28 as an intersection point formed on the upper side of the patient's body 12. Further intersection points are usually formed on opposite sides of the patient's body. As in Figure 2 As can be seen, the target position 32 of the intersection point 30 is still displayed in the visualization system 18, namely also as the intersection point 32 of two lines 34, i.e., target lines 34. In Figure 2It is evident that the patient's body is not yet correctly positioned for radiation therapy. The intersection point 30 and its target position 32, as well as the lines 28 and 34 defining them, are clearly not yet aligned.

[0037] In Figure 3 A first step in patient positioning has been completed. In particular, the patient body 12 and / or the patient bed 14 has been rotated around a vertical axis of rotation, so that the in Figure 2 The remaining discernible misalignment between lines 28 and 34 has been corrected. The longitudinal lines 28 and 34 are already aligned with each other. A gap still exists between the lines 28 and 34, which run transversely to the longitudinal direction of the patient's body 12, and a corresponding gap also exists between the intersection point 30 and its target position 32.

[0038] In Figure 4This gap is also rectified by moving the patient body 12 longitudinally by appropriately adjusting the patient bed 14 and / or moving the patient body on the patient bed 14 so that all lines 28, 34 and thus the intersection point 30 and its target position 32 are now in overlap.

[0039] The further intersection points of the lines defining the isocenter 24 of the irradiation device 10 are aligned accordingly for the complete positioning of the patient body 12. The patient positioning is complete and the irradiation can take place.

[0040] It is also possible to calculate and display 12 additional intersection points of corresponding lines on the surface of the patient's body. This further improves positioning accuracy. In the visualization system 18, the patient's body 12, with intersection points 30 and 32 and lines 28 and 34, can be displayed from different angles to simplify the alignment of all intersection points.

[0041] If desired, the alignment of the calculated lines 28, 34, which are displayed in the visualization system 18, can be verified using the physical line or cross lasers 20 arranged in the treatment room. Reference symbol list

[0042] 10 Irradiation device 12 Patient body 14 Patient table 16 Cameras 18 Visualization system 20 Line or cross laser 22 Laser planes 24 Isocenter of the irradiation device 26 Evaluation unit 28, 34 Lines 30 Intersection point 32 Target position of the intersection point

Claims

1. A method for supporting the positioning of a patient for irradiation with an irradiation device (10) in a treatment room, comprising the following steps: • a current surface of the patient's body (12) is detected using a 3D surface detection system (16), • at least one point of intersection (30) of at least two lines (28) with the detected surface of the patient's body (12) that is indicative of the isocenter (24) of the irradiation device (10) is calculated, • a required transformation is calculated based on a reference surface of the patient's body (12) that is indicative of the intended position of the patient's body (12) with respect to the isocenter (24) of the irradiation device (10) in order to bring the detected surface of the patient's body (12) and the reference surface into alignment, • a target position (32) of the at least one point of intersection (30) with the detected surface of the patient's body (12) that is indicative of the isocenter (24) of the irradiation device (10) is determined on the basis of the calculated transformation, • the at least one point of intersection (30) with the detected surface of the patient's body (12) that is indicative of the isocenter (24) of the irradiation device (10), and the target position (32) of the point of intersection are displayed in a visualization system (18).

2. The method according to claim 1, characterized in that an examination table (14) supporting the patient's body (12) and / or the patient on the examination table (14) is moved in the treatment room in such a way that the at least one point of intersection (30) with the detected surface of the patient's body (12) that is indicative of the isocenter (24) of the irradiation device (10) matches the target position (32) of the point of intersection.

3. The method according to one of the preceding claims, characterized in that at least three points of intersection (30) of at least three lines (28) with the detected surface of the patient's body (12) that are indicative of the isocenter (24) of the irradiation device (10) are calculated and displayed in the visualization system (18), and in that at least three target positions (32) determined on the basis of the calculated transformation for the at least three points of intersection (30) with the detected surface of the patient's body (12) that are indicative of the isocenter (24) of the irradiation device (10) are displayed in the visualization system (18) and / or in that the detected surface of the patient's body (12) is also represented in the visualization system (18), wherein the at least one point of intersection (30) with the detected surface of the patient's body (12) that is indicative of the isocenter (24) of the irradiation device (10), and the target position (32) of the point of intersection are displayed on the surface of the patient's body (12) represented in the visualization system (18) and / or in that the at least two lines (28) defining the at least one point of intersection (30) that is indicative of the isocenter (24) of the irradiation device (10) are displayed in the visualization system (18), and in that the target position (32) of the at least one point of intersection (30) that is indicative of the isocenter (24) of the irradiation device (10) is also displayed by means of at least two lines (34) in the visualization system (18).

4. The method according to one of the preceding claims, characterized in that the reference surface of the patient's body (12) is created within the scope of irradiation planning prior to positioning of the patient (12) in the treatment room.

5. The method according to one of the preceding claims, characterized in that further points of intersection (30) with the detected surface of the patient's body (12) are calculated, and in that the further points of intersection (30) as well as target positions (32) of the further points of intersection (30) determined on the basis of the calculated transformation are displayed in the visualization system (18), preferably wherein the further points of intersection (30) are points of intersection with edge regions of the surface of the patient.

6. The method according to one of the preceding claims, characterized in that the at least one point of intersection (30) and the target position (32) thereof are displayed in the visualization system (18) from various viewing angles.

7. The method according to one of the preceding claims, characterized in that the target position (32) of the at least one point of intersection (30) with the detected surface of the patient's body (12) that is indicative of the isocenter (24) of the irradiation device (10) is checked using line or cross lasers (20) arranged in the treatment room and / or in an examination room.

8. The method according to one of the preceding claims, characterized in that at least one further target position of at least one further point of intersection with the surface of the patient's body (12) is determined, and in that the at least one further point of intersection with the detected surface of the patient's body (12) and the further target position thereof are displayed in the visualization system (18) and / or in that a position of a point of intersection on the detected surface of the patient's body (12) is displayed using line or cross lasers (20) arranged in the treatment room and / or in an examination room, and in that the displayed position is determined as a target position or as a further target position and is displayed in the visualization system (18).

9. A system for supporting the positioning of a patient for irradiation with an irradiation device (10) in a treatment room, • comprising a 3D surface detection system which is designed to detect a current surface of the patient's body (12), • comprising an evaluation apparatus (26) which is designed to calculate at least one point of intersection (30) of at least two lines (28) with the detected surface of the patient's body (12) that is indicative of the isocenter (24) of the irradiation device (10), • wherein the evaluation apparatus (26) is further designed to calculate a required transformation based on a reference surface of the patient's body (12) that is indicative of the intended position of the patient's body (12) with respect to the isocenter of the irradiation device (10) in order to bring the detected surface of the patient's body (12) and the reference surface into alignment, • wherein the evaluation apparatus (26) is further designed to determine a target position (32) of the at least one point of intersection (30) with the detected surface of the patient's body (12) that is indicative of the isocenter (24) of the irradiation device (10) on the basis of the calculated transformation, • and comprising a visualization system (18) which is designed to display the at least one point of intersection (30) with the detected surface of the patient's body (12) that is indicative of the isocenter (24) of the irradiation device (10), and the target position (32) of the point of intersection on the basis of the calculated transformation.

10. The system according to claim 9, characterized in that it further comprises an examination table (14) that supports the patient's body (12) and that can be moved in the treatment room in such a way that the at least one point of intersection (30) with the detected surface of the patient's body (12) that is indicative of the isocenter (24) of the irradiation device (10) can be brought into alignment with the target position (32) of the point of intersection.

11. The system according to one of claims 9 or 10, characterized in that the evaluation apparatus (26) and the visualization system (18) are designed to calculate at least three points of intersection (30) of at least three lines (28) with the detected surface of the patient's body (12) that are indicative of the isocenter (24) of the irradiation device (10) and to display them in the visualization system (18), and in that the visualization system (18) is further designed to display at least three target positions (32) determined on the basis of the calculated transformation for the at least three points of intersection (30) with the detected surface of the patient's body (12) that are indicative of the isocenter (24) of the irradiation device (10) and / or in that the visualization system (18) is further designed to represent the detected surface of the patient's body (12), and to display the at least one point of intersection (30) with the detected surface of the patient's body (12) that is indicative of the isocenter (24) of the irradiation device (10), and the target position (32) of the point of intersection on the surface of the patient's body (12) represented in the visualization system (18) and / or in that the visualization system (18) is further designed to display the at least two lines (28) defining the at least one point of intersection (30) that is indicative of the isocenter (24) of the irradiation device (10), and to also display the target position (32) of the at least one point of intersection (30, 32) that is indicative of the isocenter (24) of the irradiation device (10) by means of at least two lines (34).

12. The system according to one of claims 9 to 11, characterized in that it further comprises an irradiation planning system that is designed to create the reference surface of the patient's body (12) within the scope of irradiation planning prior to positioning of the patient (12) in the treatment room.

13. The system according to one of claims 9 to 12, characterized in that the evaluation apparatus (26) is further designed to calculate further points of intersection (30) with the detected surface of the patient's body (12), and in that the visualization system (18) is further designed to display the further points of intersection (30) and target positions (32) of the further points of intersection (30) determined on the basis of the calculated transformation, preferably wherein the further points of intersection (30) are points of intersection with edge regions of the surface of the patient.

14. The system according to one of claims 9 to 13, characterized in that it further comprises line or cross lasers (20) arranged in the treatment room, and in that the evaluation apparatus (26) is further designed to check the target position of the at least one point of intersection (30) with the detected surface of the patient's body (12) that is indicative of the isocenter (24) of the irradiation device (10) using the line or cross lasers (20) arranged in the treatment room and / or in an examination room.

15. The system according to one of claims 9 to 14, characterized in that the visualization system (18) is designed to display the at least one point of intersection (30) and the target position (32) thereof from various viewing angles and / or in that the evaluation apparatus (26) is further designed to determine at least one further target position of at least one further point of intersection with the surface of the patient's body (12), and in that the visualization system (18) is further designed to display the at least one further point of intersection with the detected surface of the patient's body (12) and the further target position thereof and / or in that it further comprises line or cross lasers (20) arranged in the treatment room that are designed to display a position of a point of intersection on the detected surface of the patient's body (12), and in that the evaluation apparatus (26) is further designed to determine the displayed position as a target position or as a further target position, and in that the visualization system (18) is further designed to display the target position or the further target position.