NAVIGABLE PRESENTATION OF A VARIETY OF SOLUTIONS FOR THERAPY PLANS

Abstract

The present invention includes a method for representing a plurality of pre-calculated solutions in radiation therapy that are stored in a database and displayed in a manner controllable by a user. Arrays of DVH curves provide the user with essential information on the ‘quality of a plan’. A DVH diagram is displayed as a main diagram, wherein only one of the solutions is visually represented at a time. By selecting a first starting point on a selected DVH curve as the main diagram, a first straight axis extending through the first starting point is placed. A first region, located around the first starting point and on the first straight axis, is highlighted as a first control region for controllable visualization of the plurality of currently non-displayed solutions stored in the database, the DVH curves of which correspond to the selected DVH curve and intersect the first straight axis.

Claims

1. A method for computer implemented representing a plurality of pre-calculated solutions stored in a database and displayed on a display device in a manner to be controlled by a user comprising: displaying a DVH (dose volume histogram) diagram having a plurality of DVH curves; responsive to receiving a selection of a first starting point on a first DVH curve of the plurality of DVH curves in the DVH diagram, positioning a first straight axis extending through the first starting point; highlighting a first region located around the first starting point and on the first straight axis as a first control region; identifying a first fixed point from the plurality of pre-calculated solutions stored in the database, the first fixed point corresponding to a first position in which the first DVH curve intersects with the first control region; identifying a second fixed point from the plurality of pre-calculated solutions stored in the database, the second fixed point corresponding to a first position in which a second DVH curve intersects with the first control region; calculating an intermediate point interpolated from the plurality of pre-calculated solutions stored in the database; and positioning the first fixed point, the second fixed point, and the intermediate point within the first control region.

2. The method according to claim 1, wherein: the first control region comprises an upper final value corresponding to a greatest value of the plurality of DVH curves that intersect the first straight axis; and the first control region comprises a lower final value corresponding to a smallest value of the plurality of DVH curves that intersect the first straight axis.

3. The method according to claim 1 further comprising: responsive to receiving a selection of a second starting point on a second DVH curve of the plurality of DVH curves in the DVH diagram, positioning a second straight axis extending through the second starting point.

4. The method according to claim 3 further comprising: highlighting a second region located around the second starting point and on the second straight axis as a second control region.

5. The method according to claim 1, wherein the first straight axis is vertical or horizontal.

6. The method according to claim 1, wherein the first straight axis is rotatable by ±89° about the first starting point starting point.

7. The method according to claim 1 further comprising: displaying within the display device a selector that is movable to select a point within the first control region to identify a corresponding DVH curve of the plurality of DVH curves in the DVH diagram.

8. The method according to claim 7 further comprising: displaying within the display device a restrictor for restricting upper and lower limit values of the first control region to a reduced control region.

9. A method for computer implemented representing a plurality of pre-calculated solutions stored in a database and displayed on a display device in a manner to be controlled by a user comprising: displaying a DVH (dose volume histogram) diagram having a plurality of DVH curves; responsive to receiving a selection of a first starting point on a first DVH curve of the plurality of DVH curves in the DVH diagram, positioning a first straight axis extending through the first starting point; highlighting a first region located around the first starting point and on the first straight axis as a first control region, the first control region comprising: an upper final value corresponding to a greatest value of the plurality of DVH curves that intersect the first straight axis; and a lower final value corresponding to a smallest value of the plurality of DVH curves that intersect the first straight axis; calculating an extension of the first control region on the first straight axis, the extension being calculated from the plurality of pre-calculated solutions stored in the database; and positioning the extension at a position proximate at least one of the upper final value or the lower final value to create an extended control region.

10. The method according to claim 9, wherein the first straight axis is rotatable by ±89° about the first starting point starting point.

11. The method according to claim 9 further comprising: displaying within the display device a selector that is movable to select a point within the first control region to identify a corresponding DVH curve of the plurality of DVH curves in the DVH diagram.

12. The method according to claim 11 further comprising: displaying within the display device a restrictor for restricting upper and lower limit values of the first control region to a reduced control region.

13. The method according to claim 9 further comprising: identifying a first fixed point from the plurality of pre-calculated solutions stored in the database, the first fixed point corresponding to a first position in which the first DVH curve intersects with first the control region; identifying a second fixed point from the plurality of pre-calculated solutions stored in the database, the second fixed point corresponding to a first position in which a second DVH curve intersects with the first control region; calculating an intermediate point interpolated from the plurality of pre-calculated solutions stored in the database; and positioning the first fixed point, the second fixed point, and the intermediate point within the first control region.

14. The method according to claim 9 further comprising: displaying three auxiliary diagrams within the display device, the three auxiliary diagrams each providing sectional views in directions perpendicular to each other including indicated isodoses, and wherein volumes corresponding to a number of DVH curves in the plurality of DVH curves are represented in the each of the three auxiliary diagrams.

15. The method according to claim 9 further comprising: responsive to receiving a selection of a second starting point on a second DVH curve of the plurality of DVH curves in the DVH diagram, positioning a second straight axis extending through the second starting point.

16. The method according to claim 15 further comprising: highlighting a second region located around the second starting point and on the second straight axis as a second control region.

17. A system as a planning tool for interactively selecting solutions during an interactive navigation of a user, the system comprising: a display device (20) for displaying graphs of dose/volume histograms (30) for the interactive navigation, wherein each dose/volume histogram has a number of dose/volume histogram curves; a visualization module (11) operating for buffering solutions read out from a database (10) via a data path (15), wherein the solutions are processed such that they are provided to the display device as a screen signal, and the screen signal yields a representation on the display device; wherein the visualization module is configured to: display a first dose/volume histogram as a main diagram, wherein one of a plurality of pre-calculated stored solutions from the database is visually represented at a time for manually selecting a first starting point (41a) on one, thereby selecting a curve (40a) of the number of dose/volume histogram curves and displaying a first straight axis (71,73) extending through the first starting point (41a); optically highlight a first region (72,74), located around the first starting point (41a) and on the first straight axis (71, 73), as a first straight portion having an upper and a lower limit to visualize, by a length extension between the limits, un-displayed solutions as stored and present in the database, but un-displayed by shapes of the curves, wherein the length of the first straight portion is defined by all points of intersections of the dose/volume histogram curves corresponding to the selected dose/volume histogram curve (40a).

18. The system according to claim 17, wherein the first straight portion having the upper and the lower limit and the length extension between the limits and the system allows the user to navigate within the length extension between the limits by moving the first starting point and display another dose/volume histogram curve.

19. The system according to claim 17, wherein a control element (71e) is provided that, by displacement thereof, restricts the first straight portion (76), from the top or bottom, to a reduced longitudinal extension (76a).

20. The system according to claim 17, wherein the visualization module (11) is configured to request a new plan, when a requested plan is not present in the database, and the new plan is generated by a calculation module (12) using pre-calculated plans stored in the database and read out via an access line (14).

21. The system according to claim 17, wherein a further starting point (61a) is manually selected by the user on another one of the number of dose/volume histogram curves; and wherein the visualization module is configured to: receive a selection of a further starting point on the other dose/volume histogram curve and displaying a further straight portion (71,73) extending through the further starting point; optically highlight a region (72,74), located around the further starting point and on the further straight portion, having an upper and a lower limit to visualize, by a length extension between the limits, un-displayed solutions as stored and present in the database, but un-displayed by shapes of the curves.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Embodiments of the claimed invention are explained by reference to the Figures.

[0033] FIG. 1 is a system structure including components of the computer system controlling the display device 20. On the display device 20, a DVH diagram 30 is represented in the lower portion of the screen, the array of curves 39 of which represents the plurality of curves indicated in the DVH diagram 30 and associated with a single solution, wherein a variety of solutions is stored in the database 10.

[0034] FIG. 2 is a cutout of the screen display 20 of FIG. 1 including the DVH diagram 30. The array of curves 39 can be seen here as well as the auxiliary views 35, 36 and 37 as three sections perpendicular to each other.

[0035] FIG. 3 is the DVH diagram 30 of FIG. 2 comprising visualizations of axes of a total of four planning criteria, one on each of two parotid glands and one on each of the two tumor volumes, all of them are to be seen as examples of volumes under consideration.

[0036] FIG. 4 is a simplified illustration for explanation of the system of FIGS. 1 to 3, wherein only three curves of a DVH diagram 30 and the configuration of the viewed volumes R, T and N are shown. Volume R in the center is the risk (an organ to be protected), the tumor is T, which is placed around the risk in the shape of a horseshoe in the simplified example, and the residual region outside of the two described regions R and T is the non-classified region N, which also forms a volume represented in the curves of the array of curves 39. Corresponding to the simplification in shape of the volumes, only three curves can be seen in the DVH diagram 30, which are associated with r (for the risk R), n for the non-classified region N and t for the target volume T.

[0037] FIG. 5 shows the illustration of FIG. 4, wherein isodose lines are also indicated in the volume region of auxiliary view 35 which are part of the technical setting represented by three curves in the DVH diagram 30. The distance between the isodose lines is 10 Gy in each case. Due to the two-dimensionality of the viewed case, the two other auxiliary views 36a, 37a, which are oriented perpendicularly to view 35, are simple lines. They are of no informative value, which is a consequence of the simplification for the sake of explanation of the system.

[0038] FIG. 6 is the illustration of FIG. 5, wherein control of representation is started oriented towards a determination of a point 41a on curve n. Notations r, n and t are abandoned here in favor of selected curve 40a and the other curves 50a and 60a associated with this solution, which curves are each part of a respective array of curves 40, 50, 60 provided by the variety of solutions stored in the database 10.

[0039] FIG. 7 is an illustration of the DVH diagram of FIG. 6, wherein the vertically oriented straight axis 71 is ready to be rotated. This is implemented about a pivot point 71a*.

[0040] FIG. 8 is the state of FIG. 7 after rotation of the straight axis 71 for obtaining a horizontally extending straight axis 73 extending in parallel with the dose axis in the x-direction.

[0041] FIG. 9 is the illustration of FIG. 8 including a corresponding control region 74 located around the point of intersection 41a and formed on the horizontally extending straight axis 73 between 73a and 73b.

[0042] FIG. 10 is the illustration of FIG. 6 with a different mode “add an axis” (=add) being activated.

[0043] FIG. 11 is the added new straight axis oriented in the vertical direction and intersecting the DVH graph 60a at 65 Gy. The point of intersection 61a opens up a new control region 76.

[0044] FIG. 12 illustrates the mode “navigation” (=nav) and reduces the control region 76 of FIG. 11 to a reduced control region 76a, with respect to the DVH graph 60a.

[0045] FIG. 13 illustrates a reduction of the control region 72 of FIG. 12 by means of an upper control element 71e displaced downwards on the straight axis 71 and to be referred to as “restrictor” since it reduces the upper final value of the control region 72 and determines a reduced control region 72a.

[0046] FIG. 14 shows an already added third straight axis which is oriented vertically. This straight axis 77 is associated with the third graph 50a in the DVH diagram 30.

[0047] FIG. 15 illustrates the representation of a new plan (plan ‘b’), which is selected by displacing point 61a to point 61b in the control region 76a and is then displayed.

[0048] FIG. 15a illustrates a system diagram of a portion of a vertically oriented straight axis 70 between values 97.5% and 98% wherein, in addition to the pre-calculated solutions a, a.sub.1, a.sub.2 stored in the database, further solutions d.sub.1, d.sub.2 . . . d.sub.10 are added to the straight axis 70 as additional interpolation values by post-calculation in the sense of a “recombination”.

[0049] FIGS. 15b, 15c, 15d

[0050] Illustrate, in a sequence of a plurality of diagrams, how a few stored and pre-calculated solutions a, b, c are turned into a plurality of solutions serving as intermediate points (interpolation values). This is implemented between the pre-calculated solutions in order to fill the existing gaps and to thus achieve a perceived continuity of navigation.

[0051] FIG. 16 shows a Figure following FIG. 15, wherein the lower limit value (lower restrictor 75f) is changed in an upward direction on the straight axis 75 associated with the tumor. The control interval 76a is again reduced and now has a length 76b only.

[0052] FIG. 17 is an illustration of a starting point for removing an axis (mode ‘remove’). The mode is set to such an axis removal by button 23. The axis to be removed is axis 75.

[0053] FIG. 18 illustrates FIG. 17 with the straight axis 75 removed, wherein the restrictions determined by it due to the narrow control region 76b also cease to apply.

[0054] FIG. 19 shows the beginning of a further possible navigation step, i.e. the “extension”. The control region 72b is to be expanded to a region below the lower end 71f of this control region 72b.

[0055] FIG. 20 illustrates the extension of the control region 72b to a not yet continuous greater length 72c (still open between 41b and 71g).

[0056] FIG. 21 illustrates the added portion 72b′ which can now be used for changing the point of intersection 41b since this point of intersection 41b, as a “selector”, can be changed in a downward direction, thereby displaying other solutions which, however, suggest to a user that they are achieved by displacement.

[0057] FIG. 22 shows a re-calculated third solution including the displayed/represented graphs 40c, 50c and 60c, which is achieved and displayed by a downward change of point 41b to point 41c, instead of the previously displayed solution of FIG. 21 including graphs 40b, 50b and 60b. The new graphs 40c, 50c and 60c represent a new solution achieved by recombination, wherein the point of intersection 41c is located on the straight axis.

DETAILED DESCRIPTION OF THE INVENTION

[0058] FIG. 1 illustrates the system behind the screen display. The system S (on the left in FIG. 1) is the control technology responsible for the display device 20, i.e. a monitor, a tablet or other portable PC, or a screen display projected onto a canvas by a projector.

[0059] The display device 20 is insofar represented by embodiments as a user is to visually experience what pre-calculated solutions are included in the database, each of which comprising a plan of its own including a variety of technical parameters, which plan can be specified to a therapy device having a radiation head where these technical parameters then take effect.

[0060] It is not the subject matter of this description how the therapy itself is implemented, rather the subject matter is the way of handling the technical parameters representative for a respective therapy plan which, as such, are purely technical setting parameters of a technical device operating with technical parameters and comprising corresponding motors, control buttons and actuators exactly tracking the technical parameters once they are set.

[0061] The display device 20, illustrated as a monitor here, comprises a display region, in which four portions can be seen. A lower, larger and square first region 30 is the DVH region visualizing a dose/volume histogram view. Two axes, x and y, are illustrated as a dose axis (in the x-direction) and as a percent-by-volume axis (in the y-direction). A plurality of graphs 39 are symbolically illustrated, which are dose/volume graphs of a diagram, the number of which corresponds to the number of those determined as defined volumes in a target area. Three auxiliary views constituting an example are disposed above the larger dose/volume diagram 30. In the example, these three auxiliary views 35, 36 and 37 are three sections, as is illustrated in FIG. 2, in a horizontal direction, a vertical direction and a direction vertically perpendicular thereto with respect to the target area in which the defined volumes are located. At least one of these volumes is a target represented by a tumor. At least one volume is a risk constituted, for example, by a sensitive organ or a sensitive tissue region. A further volume can be defined (but not necessarily) as a surrounding volume or a non-classified volume.

[0062] The control of the graphic representation operates with the controller S consisting of a visualization module 11 operating in the manner of an interpreter and in most cases also with a cache buffering the solutions read out from the database 10 via data path 15. The solutions are processed such that they are provided to the display device 20 via connecting line 11a as a screen signal. The screen signal yields the representation schematically displayed on the display device 20.

[0063] The visualization module 11 outputs the solutions either from the database 10 or from its own internal cache to the display device 20. When a requested solution is not present, the visualization module 11 requests a new plan via line 11b. The new plan is generated by the calculation module 12. This calculation is performed using already pre-calculated plans stored in the database 10 read out via access line 14. The calculation module determines the new plans which can be “recombined” solutions or completely new solutions which are not “between” but outside already pre-calculated solutions stored in the database.

[0064] These new solutions can either be buffered in a separate buffer of the calculation unit 12, or they can be stored into the database via memory line 13, from where they can be read out via access line 15 and supplied to the display device 20 by the visualization module 11.

[0065] In a separate, not shown embodiment, the calculation module 12 can also calculate intermediate solutions lying between two or between even more existing solutions which are not to be stored separately in the database 10, but to be supplied to the visualization module 11 via the direct path 13a in order to gain display speed.

[0066] The monitor line 11a is bidirectional for evaluating requests input by the monitor in the visualization module 11 and for revoking corresponding plans from the database or for causing calculation of said plans by the calculation module 12.

[0067] A plurality of plans, at least 20, however, in most cases several hundreds of plans, are held in the database, which plans have been pre-calculated as finished solutions in a calculation system not shown here and are capable of representing multi-criteria optimized (MCO) solutions. With respect to acquirement of such plans, it is referred to the US patent referred to at the beginning which also mentions other references as to how these pre-calculated plans are generated, obtained and stored.

[0068] Control of the display device 20 and control of representation of the variety of solutions in the database is to be the subject matter of the further Figures. This control of the variety of possible solutions can also be understood such that a type of navigation is to be enabled which operates interactively. The described system is also a planning tool for interactively selecting suitable solutions in the sense of therapy plans which are each composed of a number of technical control parameters. The graphs displayed on the monitor 20, in particular in the area of the dose/volume histogram 30, and represented in their entirety by 39 are used for navigation.

[0069] A more detailed illustration of this plurality of dose/volume graphs 39 is shown in FIG. 2.

[0070] Portion 30 in the lower screen half is apparent therein. Percent by volume is plotted on the vertical axis and dose is plotted on the horizontal axis. A plurality of graphs are apparent, some of which dropping very steeply at a very early stage and others dropping at a very late stage only. The right-hand graphs dropping at a late stage are those representing the undesired tissue zones, i.e. the target (tumor). The graphs dropping at an early stage represent the endangered risk organs. The organs are illustrated in the three sectional views 35, 36, 37 in three sections perpendicular to each other. They are characterized by outlines (also: contours) therein. Isodoses (lines of equal dose) are also illustrated which are indicated in the three sectional views. By means of selection buttons and selection zones, various layers (slices) available in the three planes can be selected. In the left-hand image 35, as a first auxiliary view, the transversal view can be seen. Therein, slice 58 is shown with a magnification factor of 1.5. In the central, upper auxiliary view 36, a sagittal view can be seen with slice 234 and a magnification of 1.5. In the right-hand auxiliary view 37, a frontal view can be seen, it is slice 289 with a magnification of 1.5.

[0071] At the bottom of the Figure, mode selectors are shown for switching the mode of navigation present in region 30. Navigation can be activated by selector 22, addition of an axis can be defined by means of selector 21 and removal of an axis can be set by selector 23.

[0072] The mode of operation of this mode selection is described in the following.

[0073] A first overview is provided by FIG. 3 which is explained in greater detail in the following and is also simplified for the sake of illustration of the explanation. However, the plurality of dose/volume graphs 39 can analogously be applied to the other images, wherein only three graphs are assumed to be present in the further explanation, and wherein the left-hand upper auxiliary view shows a simplified shape of the volumes to be viewed.

[0074] FIG. 3 shows the same views as FIG. 2, the only difference being that additional vertical straight axes 70 are indicated, each of which intersecting at least one dose/volume graph forming a respective point of intersection. Below and above a point of intersection, i.e. “around a respective point of intersection”, a region is defined or indicated by upper and lower limit values, which represents a control region by means of which navigation is performed, as explained in greater detail in the following.

[0075] It should be noted that the three shown upper auxiliary views 35, 36 and 37 may also involve other ways of representation, for example, a three-dimensional view in only one image which can be rotated, pivoted or tilted in various axes for conveying or visually representing the solution set in the dose/volume histogram 30 to the user in a different way. Navigation, which is explained in the following, is apparent from the control regions indicated as a longitudinal portion on the vertical axis 70 around a respective point of intersection with a dose graph.

[0076] The control portions 70a are effectively optically highlighted relative to the rest of the straight axis 70 and visualize the variety of solutions not shown but present. They are present in the database 10 and can be displayed directly on the monitor 20 in the dose/volume histogram 30 via the visualization module 11, when the point of intersection, which is also called selector, is “displaced” within the control portion 70a defining the upper and lower limits of a displacement. The upper and lower limits can also be displaced (also called: restrictor), a further type of navigation. Thereby, the control region 70a is reduced in size. A further type of navigation is changing the smaller control region 70a into a new control portion, i.e. above the upper final value and/or below the lower final value, which portions have not been available for changing the position of the selector so far, but which will then be a point of intersection between the newly calculated dose graph and the vertical straight axis 70. This enlargement is called extension.

[0077] “Recombined” solutions, which are also present, but are re-calculated between solutions stored in the database 10, can be added to the visualized variety of solutions. They can fill the control portions 70a with further values, as is explained in the following.

[0078] The outlined navigation in one or more control regions 70a, which are therefore also referred to as navigation portions or navigation windows, is apparent from the simplified illustration of the following Figures.

[0079] The simplification is explained by means of FIG. 4. For this purpose, the volume is assumed to be planar, i.e. two-dimensional, as shown in the left top partial image (also called auxiliary view). Three volumes are shown in portion 35, the risk R in the center, the target T located around it in the shape of a horseshoe, and the non-classified portion N therebetween and outside of target T, see FIG. 6, portion 35. The other two sectional views perpendicular thereto each yield a line (or several points on a line) of no informative value. Associated with the defined volume regions of the flat disk shown in auxiliary view 35 are the three dose graphs in the DVH diagram 30: The left bottom graph r dropping at an early stage represents the risk. The central graph n substantially extending 45° from the left top towards the right bottom represents the non-classified region N located outside the risk and outside the target, as shown in auxiliary view 35. The graph dropping at a late stage only, extending at 100% far to the right up to 60 Gy is t and represents the dose for the target T. These three graphs are associated with the viewed volumes R, T and N. They represent a solution completely shown in FIG. 4 in the area of the DVH diagram. Other solutions are not shown, they are located in the database 10 of the controller S for screen display.

[0080] In FIG. 4, the representation is prepared for addition of an axis (mode: add) which is added as a straight axis 71 corresponding to axes 70 of FIGS. 2/3 in such a manner that it forms a straight line extending parallel to the y-axis of percent by volume.

[0081] This is to be explained with reference to FIG. 6. Before that, it is apparent from FIG. 5 that the two lines 36a and 37a are sections perpendicular to image 35. Here, the indicated volumes are provided with isodose lines corresponding to the graphs r, n and tin the DVH diagram 30 displayed or visualized on the display device 20. Also in this case, the system is prepared for inserting a straight axis corresponding to axis 70, which is then exemplarily implemented by means of FIG. 6.

[0082] It is to be noted once again that the three graphs of the DVH diagram view 30 constitute a simplified representation only which can and, in the practical case, will definitely take the form and shape of FIGS. 2 and 3, however, the three dose/volume graphs and the associated viewed volumes are entirely sufficient for explaining the functionality of the DVH navigation.

[0083] The solution shown in FIG. 6 including the three curves 40a (non-classified), 50a (risk) and 60a (tumor) is also illustrated in FIG. 7. In FIG. 7, the vertical axis 71 is modified. This can be achieved by some kind of activation performed outside the illustrated modes 21, 22, 23 (bottom of Figure), for example, by means of a right click on the point of intersection 41a or on the axis 71 itself. As a result, a symbol 71a* is illustrated indicating the option to pivot or rotate the axis 71. For example, it can be rotated in the manner illustrated in FIGS. 8 and 9 with respect to axis 73. The straight axis 71 then, as the straight axis 73, has a horizontal orientation.

[0084] Other orientations of the axis 71 are possible as well, intermediate positions between 90° and 0°, for example 40°, 50° or 60°. This angular range can be set in a plus or minus direction so that the vertical axis 71 can be pivoted by ±89° (with each intermediate value). The same point of intersection 41a (or 71a) as in FIG. 6 is achieved thereby, only with a different orientation of the straight axis.

[0085] Correspondingly, a different control region 74 lying on axis 73 and representing the variety of solutions stored in the database is indicated in FIG. 9. Analogous to region 72 of FIG. 6, region 74 in FIG. 9 is configured as a control region or “navigation portion”. The selected solution, which is solely illustrated in the DVH diagram, is the one shown in FIG. 6. The upper greatest value 71b and the lower smallest value 71c of the array of curves 40 (all curves 40a, 40b, 40c and more with respect to the stored pre-calculated solutions) here correspond to the left and right value 73a, 73b. With respect to the dose axis, they correspond to the smallest and greatest value, respectively. With respect to the surface area of the DVH diagram 30, they correspond to the left value 73a and the right value 73b. In FIG. 6, the upper and lower value thus correspond to the greatest and smallest value with respect to the volume axis.

[0086] The illustration of FIG. 9 is ready for navigation set via the control in the mode selector 22.

[0087] In FIG. 10, the representation of the DVH diagram returns to the representation of FIG. 6. Control activates the mode selector 21 permitting addition of a new axis.

[0088] An explanation of the three illustrated mode selectors is to be given here. The left selector 22 (as a radio button) enables navigation within a region, for example, the control region 74 in FIG. 9. Clicking on or activating the mode selector 21 enables addition of a further axis. This axis is defined at a point of intersection lying on one of the illustrated three DVH curves. The axes can be placed on different curves, however, a plurality of axes having the form of axis 71 of FIG. 10 can also be placed on the same DVH curve 40a as the selected curve. Then, they are spaced in the x-direction and have an associated control region each which is shown in a manner placed around the point of intersection and highlighted. The highlighting represents the variety of solutions stored in the database 10.

[0089] The third mode selector is the one for removing an axis. When it is selected, one of the axes placed in the DVH diagram can be removed. This will be explained later on when a plurality of straight axes will be present.

[0090] In the example of FIG. 10, the axis 71 can be removed so that the illustration of FIG. 5 is obtained. In an example, removal of the axis is performed such that the third mode selector is activated and the axis to be removed is identified to the system, for example by clicking on some point on the axis. In the example, the mode selectors are configured as “buttons”, however, they may also take a different form, such as a “drop-down menu”, or these mode selectors are not explicitly shown and arise from an invokable context menu which opens, for example, when the user clicks on a neutral surface area in the DVH diagram 30 with the right mouse button in order to open the context menu, and selects one of the three described modes, i.e. navigation (nav), addition of an axis (add) or removal of an axis (remove). In a not shown embodiment, the respective then selected (active) mode can be illustrated as active by means of words in a clearly visible location of the screen. One type of illustration is: “now active”, followed by the mode now being activated (nav, add or remove).

[0091] According to FIG. 10, the mode for adding an axis (by means of mode selector 21) is activated. This mode results in FIG. 11. This Figure illustrates the added further vertical axis 75 which is inserted by clicking on a starting point 61a. A point of intersection 61a of the DVH curve 60a with the added axis 75 arises in the solution shown in FIG. 10.

[0092] By determining the second starting point 61a, please be reminded that the first starting point was used 41a for determination of the first vertical axis 71, the navigation window (control region), which is region 76, is opened as well. It is located on axis 75 and has a maximum value and a minimum value with respect to the percent-by-volume axis. This control region 76 or second navigation portion (navigation window) is greater than the control region 72 of FIG. 10. It is located in the upper region of the percent-by-volume axis since it relates to the tumor characteristic. The point of intersection 61a indicates that more than approx. 92% is irradiated with a radiation dose of 65 Gy with respect to the tumor T in the left top auxiliary view.

[0093] The value range of the solutions stored in the database generated by the second control region 76 ranges from 44% to 100% of the percent-by-volume axis. The selector is at 92% and no restrictors are activated, which will be explained later on.

[0094] In FIG. 11, the mode selector 22 is activated so that navigation is possible in the now formed two control regions 72, 76, which is explained in the following Figures. Both control regions 72, 76 represent the variety, or variety of stored solutions, only one of which is represented in the diagram 30 by three curves 50a, 40a and 60a.

[0095] Navigation is performed by changing the size of the control regions 72 and 76 or by displacing the points of intersection 61a or 41a within the respective navigation portion. Both actions, i.e. the specification of the limits of the navigation portions and the “displacement” of the point of intersection within the (specified) limits of the control region, are navigation actions and serve the purpose of identifying a solution from the variety of stored solutions.

[0096] Two types of navigation are shown in FIGS. 12 and 13. They involve displacement of the lower or upper final values of the navigation portions 76 and 72.

[0097] In FIG. 12, the lower final value or the minimum value has been changed from value 75c of FIG. 11 to value 75d in FIG. 12. This lower limit 75d can arise either from the lower limit value, the minimum value 75c, or from the lower end of the straight axis 75, as symbolically illustrated in FIG. 11 in form of a vertically oriented wedge at the lower end of this axis. It is grabbed by the mouse pointer and displaced upwards on the axis until it reaches position 75d at 85% of the percent-by-volume axis. This newly formed navigation portion only has the size 76a as compared to size 76 of FIG. 11. It remains on the same curve 60a and at the same point of intersection 61a which has not changed.

[0098] Accordingly, the upper final value 71b on the first placed axis 71 can also be displaced, namely downwards in the example, which results in the new value 71e of FIG. 13. The region 72a thus reduced in size is formed and has an upper limit of 34 percent by volume.

[0099] By changing the two limits, both at the top and bottom, on two curves according to FIGS. 12 and 13, the representation on the respective other straight axis (the respective other “criterion”) remains unchanged in the shown example.

[0100] However, changes to the upper and lower limits of the “nav-prt” (navigation portions) can also be made such that a change to the one portion also results in a change to at least one or both other limit value(s) on the other straight axes.

[0101] These changes in limit value on the other axes are caused by the fact that the points of intersection of solutions located on these axes, the points of intersection of which are located outside of the changed “nav-prt” on the starting axis, are removed from the navigation regions, as nav-prt, on the other axes. When one of these points of intersection forms a limit value for a navigation region (nav-prt) on another axis, removal thereof from the nav-prt results in the said change in limit value. This removal of points of intersection from the nav-prt on other axes has the effect that the change in starting values exclusively results in solutions, the points of intersection of which are located within the respective nav-prt on all axes.

[0102] FIG. 14 shows the addition of a further axis, wherein the mode selector 21 (add axis) has been previously activated. The newly inserted axis 77 is defined as a vertical axis and is determined by clicking on the point of intersection 51a on curve 50a. Since this curve represents the radiation exposure of risk R, it is located far in the left region of the array of DVH curves 39. The control region 78 thus generated between the upper and the lower limit, i.e. the greatest and the smallest value of all stored solutions for risk R. The greatest value is 77d (at 100%), the smallest value is 77c (at 3%), and the specified range 78 is a little less than 100%.

[0103] In the right portion of FIG. 14, the state apparent from the right side of FIG. 12 has been re-set. This state has a raised lower final value 75d on the target curve 60a and includes no restriction to the first control region 72 determined by the point of intersection 41a.

[0104] It is apparent from FIG. 14 that three vertically oriented straight axes 77, 71 and 75 are present, each associated with a different curve in the DVH diagram 30. This representation can also be modified, when two or more vertical axes are placed on a curve, for example the curve 40b lying between the two other curves. Then, different dose values are positions, which each cause a point of intersection formed between the curve 40a and each one of the vertical axes.

[0105] The vertical axes 71, 77, 75 mentioned in the description are graphically indicated on the monitor 20 and can be handled by the user via a mouse pointer or via a tablet, wherein actions are transferred to the system S of FIG. 1 underlying the screen display by means of direct contact.

[0106] These vertical axes can also be horizontal or can be pivoted, in accordance with the previous representation, about their point of intersection with the respective curve of the DVH diagram.

[0107] The axes may also be referred to as criteria. A criterion is, in a way, a planning aspect, according to which a user or planner can evaluate the quality of the plan (of technical control parameters) underlying the representation. The representation in the control region around the selected point on the selected curve is particularly helpful in this connection. This control range (the navigation interval) tells the user what options and scope are available to him for changing the currently displayed plan, thus providing him with a view on his options and making the planning options transparent to him. Or else, this control range, for example 72 in FIG. 14 or 76 in FIG. 11, shows him the options he may use when he is involved in changing the plan currently displayed.

[0108] Navigation portion 76 or portion 72 is respectively located on a vertical axis or line 71 or 75 and is thus the criterion or part of the criterion enabling improvement of a currently displayed plan, or by means of which the user wishes to improve the displayed plan.

[0109] The display of a further new plan, which is also stored in the database 10 in a pre-calculated state, is explained with reference to FIG. 15. Based on FIGS. 15a to 15d, the calculation of new solutions is described.

[0110] The starting point 61a of FIG. 14 is displaced upwards. It becomes the displaced starting point 61b (also shown as 61a′) in FIG. 15. By use thereof, the curve is seemingly displaced, however, in reality another solution is displayed which consists of curves 60b, 40b and 50b and has been stored in the database.

[0111] Displacement can be implemented by grabbing with a mouse pointer or by direct displacement on a screen of a tablet.

[0112] By displacing the point of intersection 61b, which is actually not an upward displacement of the starting point within the navigation portion 76a, another plan having three dose/volume graphs is selected in reality. Point 61a can be displaced within this region 76a, between the upper final value 75b and the lower, upwards displaced threshold value 75d, to value 75f. One of these displacements is shown in FIG. 15 and represents a further solution including the exemplary three DVH graphs which is now displayed instead of the previous solution including the three graphs 40a, 40b, 40c, in case auxiliary views 35, 36 and 37 are also present, they are updated as well. In the example, mainly auxiliary view 35 is involved.

[0113] Due to the “displacement” of the starting value 61a to the new displaced starting value 61b, the first starting value 41a in control region 72, cf. FIG. 12, is also displaced (changed) to the new displaced starting value 41b in FIG. 15. Accordingly, the starting value 51a of curve 50a is also “displaced upwards”, when a new curve 50b with its “displaced” starting value 51b (also symbolized by the first starting value 51a displaced to 51a′) is displayed.

[0114] Of the stored solutions, different further pre-stored solutions can be represented by “displacing each starting value” on each of the straight axes, which solutions are obtained in this way by representation of corresponding curve triples, for example 40c, 50c and 60c.

[0115] Reasonably, the displacement of the dose of the target in FIG. 15 is implemented such that an upward displacement also causes a higher exposure of the other viewed volumes R and N. Accordingly, all points of intersection of FIG. 14 are displaced upwards and are at a higher value in FIG. 15.

[0116] In numbers, the value 61a has been raised from 92% to 98%. The other three DVH curves are thus represented by the system S of FIG. 1 in an updated state. The risk criterion has been raised from 58% to 71%, the residual body tissue on curve 40b has been raised from 28% of curve 40a of FIGS. 14 to 32% in curve 40b of FIG. 15. It is to be emphasized that this raise is not a linear displacement, but is obtained by representation of a different, pre-calculated plan in the database. This new represented plan has the values 98%, 71% and 32% on the dose graphs 60b, 50b and 40b.

[0117] The illustration of FIG. 15a symbolically shows a small portion of a straight, vertically oriented axis 70.

[0118] On the left side of the Figure, an original region is shown which is assumed to be located in a control region 76a according to FIG. 15, but is illustrated in a state cut off at the top and bottom. This region, which is located within a control region, is illustrated greatly magnified in the vertical direction in the right field of FIG. 15a. “Fixed interpolation points” from the pre-calculated stored solutions are provided, which are called a, a.sub.1 and a.sub.2. These fixed interpolation points are points of intersection of equivalent dose/volume graphs, corresponding to graph 60b of FIG. 15, but from three non-equal solutions. When a user navigates his point of intersection (the selector) 61b upwards or downwards within the control region 76a, he is able to reach point of intersection a, point of intersection a.sub.1 and point of intersection a.sub.2. At these points, there is a solution or a corresponding dose/volume graph having its point of intersection with the straight axis 70 here (as a criterion).

[0119] Effectively, the user displaces his selector (or the point of intersection which is here assumed to be located in “a”) downwards towards a.sub.1 or a.sub.2. Within the system S of FIG. 1, actually new solutions are displayed, only one of these in each case.

[0120] When greater continuity is to be suggested to the user, i.e. when his movement starting from point a in a downward direction is to permit also smaller moves, intermediate solutions are calculated. Each one of the intermediate solutions has a point of intersection with the straight axis 70, which are illustrated by d.sub.1, d.sub.2 . . . d.sub.10. These intermediate values are between two or even more already existing solutions and are generated by the calculation module 12 having access to the solutions stored in the database 10. These intermediate solutions are supplied via line 13a to the visualization module 11 which is capable of displaying the same via line 11a depending on the position, in which the user places the ‘selector’ on the straight portion 70 of FIG. 15a.

[0121] Only one solution is displayed in the DVH diagram 30 at a time in each case. When the user “displaces” his selector downwards, a next solution is displayed taking the place of the previous displayed solution on the dose/volume histogram 30.

[0122] It is apparent that the distances between the pre-calculated solutions decrease considerably and an extent of continuity is achieved which gives the user the feeling that he is displacing a graph in the dose/volume histogram. However, the perceived displacement itself is only an optical effect conveyed to the user, he rather selects a new graph in each case which in parallel causes a change to the other displayed dose/volume graphs so that all in all a new plan is displayed.

[0123] From a limited number of pre-calculated solutions, a great number of solutions arise due to the mentioned recombination in the calculation unit 12 so that the points of intersection thereof on the axis, which can be selected, form a virtually continuous control region, as shown in FIG. 15a including ten interpolation points and three pre-calculated values within a portion of 0.5 percent by volume.

[0124] The following FIGS. 15b, 15c and 15d show the generation of these interpolation points by means of calculative recombination.

[0125] In FIG. 15b, only one solution is shown, which includes three graphs in the DVH diagram 30 in the—simplified—example, wherein the central graph intersects the vertical straight axis 70 and defines the point of intersection b′. Navigation is to be performed starting from this point of intersection, and there is a control region (as a navigation window) around this point of intersection which is determined by three pre-calculated plans in FIG. 15c. This navigation or control region 70a has three points of intersection, the upper limit, the lower limit and the point of intersection b′ corresponding to plan b. Admittedly, the other two graphs also have points of intersection in FIG. 15b, however, they are not considered here.

[0126] Graphs corresponding to each other and present in the database 10 as pre-calculated solutions are combined in the control region 70a.

[0127] If no intermediate calculation was employed, i.e. no recombination, only three selectable points would be available to the user in the control region 70a. Normally, a much greater number of plans are available in a pre-calculated state so that a quasi-continuum is already present, however, this quasi-continuum can be further refined by the fact that a plurality of interpolation points is calculated by module 12 in accordance with the illustration of FIG. 15a, as symbolized by FIG. 15d.

[0128] When carefully examining the quasi-continuous region, it can be seen from FIG. 15d that it is composed of a plurality of individual points. When the user or planner navigates with his selector, i.e. when he “displaces” this selector on the straight axis 70, he gets the feeling that the transition from one displayed solution to the next displayed one is continuous. He will no longer feel the hops from one plan to the next, since the plans are so close to each other.

[0129] The intermediate plans calculated from stored plans a, b and c fill, for example, the singled-out region 70a′ below plan b, which is a partial portion of the control region 70a described above in FIG. 15c. The module 12 of FIG. 1 introduces a plurality of intermediate plans into this region 70a′, which intermediate plans are located below plan b and create a perceived continuum which is instinctively felt by the user during navigation.

[0130] Such a recombination can be calculated according to the following pattern.

[0131] In certain cases of conformity of the setting parameters, e.g. angular positions and energy values in the technical parameters of a plan, existing pre-calculated plans can be “recombined” permitting a transition from the originally discrete variety of such plans to a “continuous variety”. When vectors x.sub.1, x.sub.2 . . . x.sub.N denote the entirety of non-negative irradiation times for the re-combinable plans indicated by 1 to N, then said plans can be recombined via the weighted sum . . . .

X.sub.comb=W.sub.1.Math.X.sub.1+W.sub.2.Math.X.sub.2+ . . . +W.sub.N.Math.X.sub.N

[0132] using the coefficients w.sub.1, w.sub.2 . . . w.sub.N to form an entirety X.sub.comb and assuming non-negative irradiation times of a new plan.

[0133] If the variety of plans disintegrates into a plurality of subsets of plans which can each be recombined with each other, recombination is implemented within these subsets in each case.

[0134] FIG. 16 stabilizes the high dose achieved according to FIG. 15 on the graph 60b for the tumor. When a value of 98% is achieved, this dose is not supposed to again deteriorate considerably during further navigation. Therefore, the lower restrictor, so far 75d in FIGS. 13/14, is raised and placed in a new position of approx. 97% just below the displaced starting point 61b. This placement causes an update of all control regions 72b, 78a. On graph 60b for the tumor (target), the new reduced control region 76b is present, which is determined by the upwards displaced lower restrictor 75f. Thus, the point of intersection 61b in the control region 76b cannot deteriorate further downwards.

[0135] Due to the narrow specification of the control region 76b on the risk graph 60b, a respective new control region 72b and 78a remains for the other two straight axes 71, 75, the lower limit values of which are 71f and 77e, respectively. For the risk, the lower value is raised to 31% instead of the original 3% of FIG. 14, and for the residual tissue on graph 40b, the lower value is raised to 31% instead of the previous 26% of FIG. 14. Arrows P1, P2 indicate the direction of change.

[0136] FIG. 17 illustrates the starting point for removing a previously determined vertical axis. It is the tumor 75 axis which is to be removed. The mode selector 23 is activated and the axis 75 is removed by clicking thereon, as shown in FIG. 18.

[0137] Removal of the straight axis 75 also has an effect on the further navigation in that the restriction in the narrow control region 76b is eliminated, i.e. more solutions are enabled for the other control regions 72b and 78a. Thus, new control regions on the still present axes 71 and 77 arise as a result, which again have the original sizes 72 on the straight axis 71 and 78 on the straight axis 77.

[0138] After removing the vertical straight axis 75 (as a “criterion” for the target), FIG. 18 is obtained. The second solution including graphs 40b, 50b and 60b is still indicated therein. By selecting the mode (button 21 to “navigation”), navigation can be continued in FIG. 18 in accordance with the described types of restriction of the control regions or placement of vertical straight axes as a determination of criteria or “displacement” of the points of intersection.

[0139] FIG. 19 shows the beginning of an extension. Extension is a change of a control region into a portion on the straight axis not yet occupied with pre-calculated solutions.

[0140] Extension is to be explained with reference to FIGS. 19, 20, 21 and 22.

[0141] The starting point is FIG. 19, which basically corresponds to FIG. 16 not including the third straight axis 77 inserted therein. The second and the first inserted straight axes 75 and 71 are shown and the point of intersection 41b on the straight axis 71 is located such that it is placed close to the lower end of the control region 72b. This point of intersection (selector) is to be displaced downwards (“selection” of new solutions). This is the starting point in FIG. 19, therefore the mode “navigation” (=nav) is activated by means of button 22.

[0142] A downward movement of the point of intersection 41b is hardly possible any longer on the DVH graph 40b in diagram 30, at best the lower final value 71f of the control region 72b can be selected and a corresponding solution can be displayed instead of the displayed solution 40b, 50b, 60b. This is all the range the user or planner is given.

[0143] Extension provides help here and enables a downward displacement of the lower limit 71f. The lower limit 71f is supposed to expand the control region downwards, where no pre-calculated plans have existed so far in the database 10 which can be displayed via the visualization module 11 on the display device 20 in the area of the DVH diagram 30.

[0144] From a scientific point of view, the result is as follows. The lower restriction in the tumor criterion (axis 77, restrictor 75f in FIG. 16) had the effect that the value range in the criterion of the residual body tissue (DVH graph 40b) ends just below the current selector position, i.e. a selection for improvement in this criterion would not be possible. When changing over to the next image, the lower extender is thus displaced downwards from 31% (of the percent-by-volume axis) in order to increase the value range in this direction.

[0145] In practical application, the user/planner is provided with an expanded navigation region, his control region 72c is increased in FIG. 20, namely by the line portion between 41b and 71g.

[0146] Initially, this displacement of the lower limit 71g from 71f of FIG. 19 is a request and a signalization in the sense of a control (from a tablet screen or by means of a mouse pointer) transferred via the bidirectional connection 11a is to the visualization module 11, which causes a recalculation via the calculation module 12 for generating new plans and storing them in the database 10.

[0147] However, the line portion between 41b and 71g is initially empty and cannot be activated by a change or displacement of the point of intersection 41b on axis 71.

[0148] After completion of the calculations by the calculation module 12, intermediate plans are present, the control parameters of which for the technical device are configured such that they fill the gap between 41b and 71g (as a plurality of possible points of intersection) and form a complete graph of the DVH diagram 30 also in the residual region.

[0149] The addition of the new intermediate plans to the existing pre-calculated stock plans causes an update of the available value ranges (the control regions). A corresponding re-positioning of the ‘extenders’ in all criteria (the straight-line axes, i.e. axes 71 and 75 in the example of FIG. 20) is implemented, if necessary.

[0150] One example of how the numerical calculation can be implemented in the calculation module 12 can be found in Philipp Süss, A primal-dual barrier algorithm for the IMRT planning problem—An application to optimization-driven adaptive discretization, thesis, Department of Mathematics, TU Kaiserlautern, mensch and buch verlag, Berlin, Germany (2008).

[0151] The optimization process described therein is implemented such that the resulting criteria values for the viewed criterion are located between the previous end of the available value range and the desired criteria value, and are located within the axis portions limited by the respective restrictors for all other criteria.

[0152] In FIG. 20, the lower end of the control region 72c is changed and now amounts to 25% of the percent-by-volume axis only. The illustration of FIG. 21 arises as a result having a control region 72c occupied with points of intersection, wherein also the lower portion 72b′ above the lower new end 71g is available including selectable values for a downward change of the point of intersection 41b.

[0153] The density of the post-calculated solutions, which are also placed in the database 10, can be made conditional on the size or length of the portion 72b′ to be filled relative to the starting portion 72b.

[0154] This has happened in the following illustration of FIG. 22, preparations for which were made in FIGS. 19 to 21. The calculation module 12 has filled the region 72b′ with values and the selector (or point of intersection 41b) on the straight axis 71 (the criterion) has been displaced downwards, as symbolized by the small downward arrow in FIG. 22, wherein a new point of intersection 41c selects one of the re-calculated graphs. This graph 40c is associated with a re-calculated third solution being represented, wherein the remaining associated graphs, here graphs 60c and 50c in the DVH diagram 30, are also updated with this graph. By updating the other graphs, auxiliary view 35 showing the isodoses is updated as well.

[0155] It is also ensured that the re-calculated graph 60c for the tumor volume T is within the specified control portion 76b, but extends considerably steeper in the descending branch. Point of intersection 61c with axis 75 of the control region 76b (with lower restriction 75f) can be displaced, however, remains within the specified control region 76b.

[0156] Evaluated as to quality, the central graph has been “displaced” downwards at higher dose values, in fact other plans have been displayed due to the downward displacement of point 41b to point 41c, which plans have lower percentages by volume at higher dose values, however, graph 50c for the risk is increased in dose value and its descending branch does not end at approx. 28 Gy, but at approx. 37 Gy.