U.S. patent application number 13/989448 was filed with the patent office on 2013-11-14 for customization of a dose distribution setting for a technical appliance for tumour therapy.
This patent application is currently assigned to Fraunhofer-Gesellschaft Zur Foerderung Der Angewandten Forschung E.V.. The applicant listed for this patent is Michael Bortz, Karl-Heinz Kuefer, Michael Monz, Alexander Scherrer, Philipp Suess. Invention is credited to Michael Bortz, Karl-Heinz Kuefer, Michael Monz, Alexander Scherrer, Philipp Suess.
Application Number | 20130304503 13/989448 |
Document ID | / |
Family ID | 45390128 |
Filed Date | 2013-11-14 |
United States Patent
Application |
20130304503 |
Kind Code |
A1 |
Kuefer; Karl-Heinz ; et
al. |
November 14, 2013 |
Customization of a Dose Distribution Setting for a Technical
Appliance for Tumour Therapy
Abstract
The aim of the invention is to provide a planner with the
opportunity to effect local improvement of an IMRT treatment plan
which is available to him. To this end, a method for customizing a
dose distribution setting for a technical appliance in tumor
therapy is proposed. A first plan (10) is read from a data memory
(100). The first plan (10) for dose distribution in a plan volume
(Z) is presented on a presentation device (110), the reason for
this being the possibility of setting the technical appliance for
tumor therapy to dispense the set dose distribution to a patient.
The presentation is made for the purpose of changing the first plan
(10) in at least one degree of fineness (10a) specific in terms of
volume and for producing or ascertaining a causal follow-up plan
for the setting on the technical appliance for tumor therapy. It is
possible to prescribe a new dose value for a local/small group of
voxels (z) in the or as the degree of fineness (10a) specified in
terms of volume at a particular point in the plan view (Z) which
does not have this new dose value. The particular point is
stipulated by selecting an initial voxel (z1) which is situated in
a layer (y.sub.i) of the plan volume. The first plan (10) is
converted into a first navigation plan (11). This conversion takes
account of the first plan (10) and the change of dose in the
small/local voxel group. The first plan (10) or the first
navigation plan (11) is presented on the same presentation device
(110), depending on a setting on a first operating aid (40) with
two end positions (41, 42), wherein the first end position
corresponds to the first plan and the second end position (42)
corresponds to the first navigation plan.
Inventors: |
Kuefer; Karl-Heinz;
(Weilerbach, DE) ; Scherrer; Alexander;
(Kaiserslautern, DE) ; Monz; Michael; (Mainz,
DE) ; Suess; Philipp; (Kaiserslautern, DE) ;
Bortz; Michael; (Kaiserslautern, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Kuefer; Karl-Heinz
Scherrer; Alexander
Monz; Michael
Suess; Philipp
Bortz; Michael |
Weilerbach
Kaiserslautern
Mainz
Kaiserslautern
Kaiserslautern |
|
DE
DE
DE
DE
DE |
|
|
Assignee: |
Fraunhofer-Gesellschaft Zur
Foerderung Der Angewandten Forschung E.V.
Munich
DE
|
Family ID: |
45390128 |
Appl. No.: |
13/989448 |
Filed: |
November 23, 2011 |
PCT Filed: |
November 23, 2011 |
PCT NO: |
PCT/IB11/55249 |
371 Date: |
July 31, 2013 |
Current U.S.
Class: |
705/2 |
Current CPC
Class: |
A61N 5/103 20130101;
A61N 5/1031 20130101; A61N 5/1045 20130101 |
Class at
Publication: |
705/2 |
International
Class: |
A61N 5/10 20060101
A61N005/10 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 26, 2010 |
DE |
10 2010 060 847.5 |
Nov 27, 2010 |
DE |
10 2010 062 079.3 |
Claims
1. A method for adjusting a dose distribution setting for a
technical device for tumor therapy, the method comprising: reading
out a first plan (10) from a data memory (100); illustrating the
first plan (10) of a dose distribution in a plan volume (Z) on a
display device (110) suitable for a setting of the technical device
for tumor therapy to deliver the previously set dose distribution
to a patient; in purpose of changing the first plan (10) in at
least one local area of fineness (10a) specified in terms of
volume, and generating or determining a causal follow-up plan;
specifying a new dose value for a local group of voxels (z) in or
as the local area of fineness (10a) specified in terms of volume at
a specific point of the plan volume (Z) not having said new dose
value; wherein the specific point is determined by selecting an
initial voxel (z1) located in a layer (yi) of the plan volume;
converting the first plan (10) into a first navigation plan (11),
the conversion taking into account the first plan (10) and the
change in dose in the local voxel group; and illustrating the first
plan (10) or the first navigation plan (11) on the same display
device (110) depending on a setting of a first operating aid (40)
having two end positions (41, 42), wherein the first end position
of the operating aid corresponds to the first plan and the second
end position (42) corresponds to the first navigation plan.
2. (canceled)
3. The method according to claim 1, wherein a plurality of
intermediate positions exist between the two end positions of the
first operating aid (40), each of which intermediate positions
corresponds to an intermediate plan, wherein each of said
intermediate plans corresponds to an interpolation from the first
plan (10) towards the first (11) and third navigation plans (13),
respectively.
4. The method according to claim 3, wherein a setting of the first
operating aid (40) closer to the first end position illustrates an
intermediate plan on the display device (110) which, being
interpolated from the first plan (10), is close to this first
plan.
5. The method according to claim 3, wherein a setting of the first
operating aid (40) closer to the second end position (42)
illustrates another intermediate plan on the display device (110)
which, being interpolated from the first navigation plan (11), is
close to this first navigation plan.
6. The method according to claim 3, wherein a central position of
the first operating aid (40) illustrates an intermediate plan on
the display device (110) being interpolated between the first plan
(10) and the first navigation plan (11) or the third navigation
plan (13).
7. The method according to claim 3, wherein each of the
intermediate plans of a dose distribution in a plan volume (Z)
corresponds to a respective setting of the technical device.
8. The method according to claim 3, wherein the interpolated
intermediate plans are not stored in the database (100).
9. The method according to claim 1, wherein the local group of
voxels (z) comprises less than 500 voxels and the plan volume
comprises more than 2000 voxels.
10. The method according to claim 1, wherein the local group of
voxels takes up less than 5% of the plan volume (Z).
11. The method according to claim 1, wherein the first plan (10) is
converted into a second navigation plan (12) according to the first
conversion and by specifying mathematical weights in the conversion
so that the first and second navigation plans (11, 12) differ from
each other, wherein the mathematical weights increase with
increasing distance from the initial voxel (z1) and the second
navigation plan (12) comprises locally defined changes as compared
to the first navigation plan (11).
12. The method according to claim 11, wherein a second operating
aid (30) assigns the first or second navigation plan (11, 12) to
the second end position (42) of the first operating aid (40).
13. The method according to claim 12, wherein the second operating
device (30) has a plurality of intermediate positions, each of
which corresponds to an intermediate plan, wherein each of the
intermediate plans corresponds to an interpolation between the
first navigation plan (11) and the second navigation plan (12), and
wherein a selected intermediate position (33) determines the third
navigation plan (13) which is assigned to the second end position
(42) of the first operating aid.
14. The method according to claim 11, wherein the mathematical
weights are configured such that they are set or specified over
various directions starting from the initial voxel (z1) depending
on the respective tissue in this direction.
15. An arrangement for adjusting a dose distribution setting for a
technical device for tumor therapy, comprising: reading out a first
plan (10) of a dose distribution from a database (100) and
illustrating the first plan (10) in a plan volume (Z) on a display
device (110) for a setting of the technical device (TG) for tumor
therapy and for delivering the set dose distribution to a patient;
specifying a new dose value for a local group of voxels (z) as an
area of fineness (10a) specified in terms of volume at a specific
point of the plan volume (Z) not having said new dose value,
wherein the specific point is determined by specifying an initial
voxel (z1) located in a layer (yi) of the plan volume (Z);
providing a navigation plan (11, 12, 13) generated by conversion
from the first plan (10) and taking into account the new dose value
in the local voxel group (z); illustrating an intermediate plan on
the same display device (110) depending on a changeable setting of
a first operating aid (40) having two end positions (41, 42) and a
plurality of intermediate positions (43), wherein the first end
position corresponds to the first plan (10) and each of the
intermediate positions corresponds to another intermediate plan,
which corresponds to a respective interpolation from the first plan
(10) towards the navigation plan (11, 12, 13); and for the purpose
of changing the first plan (10) in the at least one area of
fineness (10a) specified in terms of volume, and generating or
determining a causal follow-up plan (20, 21) as one of the
interpolated intermediate plans to be set (later) on the technical
device.
16. A method for adjusting a dose distribution setting for a
technical device for tumor therapy, comprising: reading out a first
plan (10) from a data memory (100); illustrating the first plan
(10) of a dose distribution in a plan volume (Z) on a display
device (110) for a possible setting of the technical device for
tumor therapy for delivering the set dose distribution to a
patient; for the purpose of changing the first plan (10) in at
least one area of fineness (10a) specified in terms of volume, and
generating or determining a causal follow-up plan for setting the
technical device for tumor therapy; specifying a new dose value for
a local group of voxels (z) in or as the area of fineness (10a)
specified in terms of volume at a specific point of the plan volume
(Z) not having said new dose value; wherein the specific point is
determined by selecting an initial voxel (z1) located in a layer
(yi) of the plan volume; providing a third navigation plan (13)
generated by conversion from the first plan (10), taking into
account the change in dose in the local voxel group (z) and another
influence; and illustrating the first plan (10) or the third
navigation plan (13) on the same display device (110) depending on
a setting of a first operating aid (40) having two end positions
(41, 42), wherein the first end position corresponds to the first
plan (10) and the second end position (42) corresponds to the third
navigation plan (13).
17. The method according to claim 16, wherein a plurality of
intermediate positions exist between the two end positions of the
first operating aid (40), each of which intermediate positions
corresponds to an intermediate plan, wherein each of said
intermediate plans corresponds to an interpolation from the first
plan (10) towards the first (11) and third navigation plans (13),
respectively.
18. The method according to claim 17, wherein a setting of the
first operating aid (40) closer to the first end position
illustrates an intermediate plan on the display device (110) which,
being interpolated from the first plan (10), is close to this first
plan.
19. The method according to claim 17, wherein a setting of the
first operating aid (40) closer to the second end position (42)
illustrates another intermediate plan on the display device (110)
which, being interpolated from the first navigation plan (11), is
close to this first navigation plan.
20. The method according to claim 17, wherein a central position of
the first operating aid (40) illustrates an intermediate plan on
the display device (110) being interpolated between the first plan
(10) and the first navigation plan (11) or the third navigation
plan (13).
21. The method according to claim 17, wherein each of the
intermediate plans of a dose distribution in a plan volume (Z)
corresponds to a respective setting of the technical device.
22. The method according to claim 17, wherein the interpolated
intermediate plans are not stored in the database (100).
23. The method according to claim 16, wherein the local group takes
up less than 5% of the plan volume (Z).
24. The method according to claim 16, wherein a second operating
aid (30) assigns the first or second navigation plan (11, 12) to
the second end position (42) of the first operating aid (40).
25. The method according to claim 24, wherein the second operating
device (30) has a plurality of intermediate positions, each of
which corresponds to an intermediate plan, wherein each of the
intermediate plans corresponds to an interpolation between the
first navigation plan (11) and the second navigation plan (12), and
wherein a selected intermediate position (33) determines the third
navigation plan (13) which is assigned to the second end position
(42) of the first operating aid.
26. The method according to claim 16, wherein the first plan (10)
is converted into a second navigation plan (12) according to the
first conversion and by specifying mathematical weights in the
conversion so that the first and second navigation plans (11, 12)
differ from each other, wherein the mathematical weights increase
with increasing distance from the initial voxel (z1) and the second
navigation plan (12) comprises locally defined changes as compared
to the first navigation plan (11).
27. The method according to claim 26, wherein the mathematical
weights are configured such that they are set or specified over
various directions starting from the initial voxel (z1) depending
on the respective tissue in this direction.
Description
[0001] The invention relates to a method for optimizing a set state
of a device for tumor treatment. In particular, this involves a
substantial improvement of an already patented system, cf. U.S.
Pat. No. 7,391,026 B2. The plan finding control disclosed therein
for determining an optimum plan for the treatment of a patient
suffering from a tumor disease was a quantum jump. It was a
reversal of the approaches suggested so far and has become
generally known as IMRT in the field. The approach called "inverse
therapy planning" has been suggested by Bortfeld, cf. US '026 (as
above), col. 1, line 43 et seq. In the course of application and
practical testing thereof, possibilities of improvement have opened
up over time which are the subject matter of this invention.
[0002] When starting from the cited prior art, the planner finds a
suitable plan by means of a design tool. The suitable plan is
extensive and comprises setting parameters for the setting of (or:
on) the therapeutic device which performs the tumor therapy on the
patient at a later stage. It is correspondingly clear that the
setting of this device and the generation or determination of the
setting of the device is not yet a therapeutic treatment or a
medical treatment as such, but a preliminary stage implemented long
before. Setting parameters of technical nature are determined on
the basis of which a therapy can be performed at a later stage and
in a completely different location. The said IMRT calls these
parameters a plan. The plan is simultaneously "a solution" selected
from a variety of pre-calculated plans or solutions which are all
suitable; however, only one of these is the optimum one for the
planner. Selecting this optimum one from a variety of already
available plans is enabled by virtue of the design tool according
to U.S. Pat. No. 7,391,026.
[0003] Nevertheless, there is still need for improvement on the
part of the planner. This need for improvement may relate to
critical spots in the plan which can be changed in the plan itself
only to the effect that another plan is selected. This other plan
is changed with a view to an improvement in an "area of interest",
however, is again one of the pre-calculated plans. Also this plan
had already been calculated and provided in the database.
[0004] The invention starts from the object to enable a planner to
locally improve an IMRT treatment plan available to him. A local
improvement includes a plurality of definitions, for example, a
local overdosing in a risk area or a local under-dosing in a target
area. In a specific embodiment, the target area may refer
specifically to the tumor to be provided with a dose as high as
possible, and in another specific embodiment, the risk area may
refer to a specific risk organ (in terms of space). However, also
areas in tissue may be affected which are not defined in terms of
an organ, but are defined in terms of area only. If one wishes to
improve local deficiencies, one may also start, within the scope of
the defining language, from the removal of "critical spots" or
critical spot remover as an object enabled by the invention
described and defined in the following. More abstract, the object
is to remove critical spots (in both directions, towards
under-dosing or overdosing) and to change the already present plan
(the already selected solution) as little as possible. Precisely,
none of the pre-calculated other solutions is to be used, but the
initial solution is to be changed in a locally defined manner.
[0005] The object is achieved by claim 1 or 2 or 15 which are
incorporated herein as a method or arrangement for adjusting a dose
distribution setting.
[0006] By the solution, the initial plan is locally changed, but
not the entire plan. In this connection, a person skilled in the
art would say that a local point, which may be referred to as
small, is changed while practically maintaining the initial plan.
If he used a new plan, he would change the localized critical areas
(the critical spots), but also dislocate them and, as a rule, not
really remove them. Thus, a too global change of the plan is
avoided. In other words, the change in the "first plan" is to be
kept as little as possible outside of the "critical spot".
[0007] This definition of the solution is oriented towards the term
`local change` or `spot change`, respectively, which spot is small
in relation to the total volume.
[0008] Since the dose distribution plan involves computations with
voxels, a local/small volume can include less than 500 voxels. This
regional volume may be called spot or box. A voxel typically has an
edge length of 3 mm. A preferred dimension of this local spot (box
or spot) is less than 7.times.7.times.7 voxels in the three
directions in space, i.e. less than approximately 350 voxels, or
below an upper limit of 500 voxels (claim 9). In other words, less
than 5% of the volume affected by dose distribution as a plan
volume is involved (claim 10).
[0009] The setting which makes adjustments on the technical device
or adjusts the technical device for tumor therapy to such a therapy
can be set with a plurality of technical parameters of various
nature. In the IMRT method, multi-leaf heads using a plurality of
strip-shaped setting sliders may provide a first setting, cf. FIG.
3 and associated description of US '026, as mentioned at the
beginning. Furthermore, radiation doses, angles of rotation for a
rotating head, dwell times of the rotating head in specific
locations and, of course, also combinations of the multi-leaf head
setting with the mentioned other parameters may be specified. In a
rough overview, the period of time (radiation time), the profile of
a respective irradiation by the multi-leaf head and various
positions of angles of incidence can be specified which fall under
the term `setting of the technical device for tumor therapy`.
Photons, electrons, heavy ions or protons can be used as radiation,
depending on the therapist, patient and available technical
equipment as well as the kind and nature of the tumor area to be
treated (to be irradiated), cf. again US '026, paragraph [068]
therein.
[0010] A plan, detailed explanations of which were provided in
advance, is available for this treatment. This first plan is read
out from a data memory, for example an ordered database, and
illustrated on a monitor. There is a variety of possibilities of
illustration depending on the nature of the user or his preferred
selection criteria. In the examples described in the following, a
DVH diagram and three sectional representations (transverse,
sagittal and frontal) are explained which give a good overview on
the radiation doses in the spatial distribution and convey some
kind of mean value to the user enabling an overall assessment of a
respective plan, the DVH diagram in the example. In general, the
entire plan volume affected by the dose distribution is
illustrated, wherein both, the target volume (the tumor area, one
or a plurality thereof) and a number of risks or risk organs, which
may also be present in form of areas independent of a physically
defined risk organ, are located within this plan volume. In order
to achieve the set object, a point having a dose value of an
undesired level or an undesired weakness is specified in the
illustrated plan. This "initial voxel" is a voxel located in the
spatial area of, for example, the three sectional representations
located perpendicularly to each other. It may be selected in the
sagittal representation, in the transverse representation or in the
frontal representation, however, relates to a spatial area defined
as a box around this initial voxel. This serves the purpose of
changing the illustrated plan in at least one area of fineness
specified in terms of volume which is small as compared to the size
of the plan volume. At this specified point and by means of the
small/local group of voxels defined by the initial voxel, a change
is to take place either in the upward direction towards higher
radiation doses or in the downward direction towards lower
radiation doses in the specified small area.
[0011] A causal follow-up plan as close to the illustrated plan as
possible is supposed to result therefrom, i.e. which changes the
DVH diagram to a small extent only, but which is to change the
specified small point as an area of fineness specified in terms of
volume.
[0012] According to the invention, this takes place precisely by
not retrieving a new plan having a dose corresponding to a desired
value in this area of fineness specified in terms of volume from
the previously stored plans/solutions, since this plan will, with
almost absolute certainty, involve very great differences in many
other points which would cause a markedly different DVH which is
precisely what is to be avoided according to the invention. By the
selection of the specific point by means of the initial voxel,
which can be identified by a cursor and is located in a layer of
the plan volume, the group of voxels surrounding this initial voxel
is determined.
[0013] According to the invention, the group is very small (claims
10, 9) and its size can be defined as desired by the user. The
selection of the initial voxel in a layer, as discussed above,
relates to the sagital layers, the transverse layers or the frontal
layers. However, after determination of the initial voxel, the
group of voxels will extend into three-dimensional space, i.e. into
all layers; however, it needs to be identified in one layer
only.
[0014] In this connection, the user has the choice to determine the
position of the initial voxel in one of the illustrated layers.
[0015] After determination of the initial voxel and the local group
of voxels as the specified area of fineness in the considerably
larger plan volume, a conversion is initiated. The conversion
starts from the first plan illustrated. It is converted into a
first navigation plan, wherein the first plan is the starting point
(initial plan) and the change in dose in the specified area of
fineness is taken into account. Such a conversion of a plan can be
performed, for example, in the same way as the pre-calculated plans
in the database are calculated for a variety of possible solutions.
The associated method is publicly accessible and may be found in
Philipp Suess, A primal-dual barrier algorithm for the IMRT
planning problem--An application for optimization-driven adaptive
discretization, Mensch and Buch Verlag (mbv), Berlin, 2008.
[0016] The thus generated first navigation plan is not a "new" plan
in the sense of the plans/solutions of the pre-calculated potential
in the data memory, but a converted first plan. Only the first plan
comes out as a plan from the data memory acting as a database and
is illustrated to select the initial voxel therefrom, at the
position or around the position of which a local change in dose is
to be effected. Thus, when the first plan is largely maintained,
claims 1 and 2 speak of a conversion of this plan only.
[0017] A conversion of such a plan can take place in at least two
different ways. A first conversion being the one not specifying any
weights using the method of Philipp Suess. A second conversion
variant by which a second navigation plan can be generated, being
the one using mathematical weights (claim 11). In a conversion of a
starting plan (the first plan according to claims 1, 2), a
mathematical weight has the effect that these mathematical weights
increase with increasing distance from the initial voxel and the
locally defined change is limited to a greater extent in the
presence of mathematical weights. The said second navigation plan
thus comprises locally defined changes as compared to the first
navigation plan. In the first navigation plan calculated without
mathematical weights, the changes are spread more widely.
[0018] The mathematical weights can be configured such that they
are set or specified not uniformly over various directions starting
from the initial voxel, but depending on the respective tissue.
This is a non-uniform weighting dependent on tissue (claim 14).
[0019] According to claim 1 and claim 2, there are two variants of
the invention. Both variants use an operating aid, which is called
first operating aid and can be, for example, a sliding setting
device or a rotary setting device (in brief: slide control or
rotary control), wherein inherently not a control but a change is
effected. The first operating aid has two end positions, wherein
the first end position corresponds to the first plan. This
correspondence is such that the position of the setting button of
the operating aid determines which plan is illustrated on the
display device. When the setting button of the first operating aid
is in the first end position, the first plan is illustrated, which
is the starting point anyway.
[0020] The two variants of the invention now are such that
assignment of the second end position of the first operating aid
can be effected in various ways.
[0021] The second end position can correspond to the converted
first plan called "first navigation plan" above (end of claim 1).
Depending on the position of the setting button (of the operating
aid), interpolation is performed or the parameters of an
interpolation to be performed are specified by the setting of the
operating aid.
[0022] A plurality of intermediate positions can be provided in
addition to these two said end positions (claim 3). Each
intermediate position corresponds to an intermediate plan, wherein
this intermediate plan results from an interpolation. The
interpolation starts with the first plan and proceeds towards the
first navigation plan (with reference to claim 1). The further the
operating aid is adjusted towards the first navigation plan, i.e.
the second end position, the more the illustration resembles the
first navigation plan. In this connection, an interpolation is a
temporarily calculated intermediate solution (as an intermediate
plan) which is located farther or less far from the first plan and
closer or less close to the first navigation plan in terms of
content, respectively, corresponding to the position of the
button.
[0023] Interpolated intermediate plans are not computationally
intensive and can be calculated relatively fast and stored in a
buffer which makes them again available for an adjusting movement
of the operating aid.
[0024] In a second variant of the invention, the end value of the
first operating aid is a different value (claim 2, last and
penultimate features). In this variant, this end position is called
third navigation plan generated by a conversion of the first plan,
taking into account the change in dose in the small/local voxel
group and another influence.
[0025] This other influence may be zero so that the end position of
the first operating aid corresponds to the first navigation plan.
However, this influence can also be exerted differently so that the
change corresponds to the second navigation plan. There is a
plurality of intermediate plans between these two possibilities,
wherein the third navigation plan is generated by way of
interpolation from the first and second navigation plans.
[0026] All the conversions relate to or take into account the
change in dose in the small/local voxel group and are, on
principle, based on the first plan. None of these intermediate
plans is one of the pre-calculated solutions previously stored in
the database, but originate from the first plan and the two
navigation plans calculated according to the regulations of Philipp
Suess. The conversion into the navigation plans is based on a
mathematical description of their targets, i.e. the local
improvement in a small voxel group, while making only slight
changes elsewhere. The method described by Suess enables a
conversion with such a (target) description.
[0027] By means of this at least one converted navigation plan and
the at least one operating aid, intermediate plans can be generated
which enable the user to perform control virtually continuously and
to examine, illustrate and evaluate a plurality of intermediate
plans as to whether they will adequately achieve the desired
target, namely a change in dose in a small group of voxels to be
performed as a locally defined change, while substantially (not
quite, but very close) maintaining the plan and with substantially
the same DVH distribution.
[0028] In a third variant (claim 15, claim 3), the focus is on the
intermediate positions of the at least one operating aid changeable
in its setting. An intermediate plan is illustrated on the same
display device depending on the changeable setting of the first
operating aid. It has two end positions and a plurality of
intermediate positions. The first end position still corresponds to
the first plan (the initial plan) and each of the intermediate
positions corresponds to another intermediate plan. They are
obtained from a respective interpolation between the first plan and
the navigation plan. One of the interpolated intermediate plans is
the causal follow-up plan to be set (later) on the technical device
and by which the change in the first plan has been effected in the
area of fineness specified in terms of volume.
[0029] In the second variant of the invention, the third navigation
plan is generated from the said influences and is provided to the
first operating aid as an end value or placed there for the user
(claim 2). Depending on the setting of the first operating aid,
either the first plan or the third navigation is then illustrated
on the same display device depending on the setting of the first
operating aid with its at least two end positions. The first end
position, usually on the left, corresponds to the first plan. The
second end position, usually on the right, corresponds to the
mentioned third navigation plan.
[0030] Further intermediate positions of the first operating aid
may exist between these two end positions, wherein each
intermediate position corresponds to an intermediate plan
corresponding to an interpolation between the first plan and the
third navigation plan (claim 3). When the operating aid is located
closer to the second end position, the illustration corresponds to
the third navigation plan. When it is located closer to the first
end position, the illustration is closer to the first plan.
[0031] The intermediate positions themselves are not required to be
incremental but may arise virtually continuously, wherein the
length of the operating aid or the angle of rotation of the
operating aid plays a part and determines discretization as to how
may intermediate plans are to be accommodated on the setting length
or setting angle so that the user is given some kind of continuous
feeling even though individual interpolated intermediate plans are
displayed to him during rotation or sliding.
[0032] Within the scope of the second variant of the invention, an
additional operating aid can be provided (claim 12).
[0033] By means of the additional operating aid, it may be
specified what end value of the first operating aid is set. When
the second operating aid is merely a switch, it can be switched
between the first navigation plan and the second navigation plan.
When the second operating aid is also an actuator, for example, a
slide control or a rotary control, a plurality of different plans
can be defined as an end value of the first operating aid which
plans are, in turn, converted by way of interpolation between the
first navigation plan and the second navigation plan. Thus, the
third navigation plan is generated as the end value of the first
operating aid specified or preset by the position of the second
operating aid (claim 13).
[0034] Two sliders (linear setting devices) are illustrated in the
embodiments. Rotary controls or even planar actuators, wherein a
surface area is defined by the two linear operating aids, for
example, in the shape of a triangle, are possible as well. Changes
can be made virtually continuously within the surface area of the
triangle.
[0035] This planar configuration of an operating aid is at least
included in claim 1, wherein two corners of the triangle represent
the two end positions of the first operating aid. When the second
operating aid, for example in form of a linear length, is arranged
perpendicularly to the first operating aid, it forms a triangle
therewith by the end points, and a position taken, for example, by
a cursor deviating from the straight line of the first operating
device (between the first two corners of the triangle) towards the
third corner is a measure of how the second operating device
changes the end value of the first operating device.
[0036] Alternatively, the triangle also works in the specific case
that precisely three plans are interpolated. These three plans are
associated with the corners and the positioning of the operating
aid within the area of the triangle generated by these corners
corresponds to an interpolation between these three plans.
[0037] This kind of operation has a certain similarity to claim 1
in that the three plans are predetermined (specified) irrespective
of their origin and interpolation is performed between them.
[0038] An improvement in fineness of change aiming only at a
locally defined change arises for the user also when using only one
operating aid. The user may move within a continuum of plans by
positioning the first operating aid or by additionally positioning
the second operating aid, if necessary, which plans are all based
on the first plan and are interpolated during the movement of the
operating elements. Such an interpolation involves that a setting
of the first operating aid closer to the first end position
corresponds to an intermediate plan which is closer to the first
plan (claim 4). The same applies to the proximity of a setting
button of the first operating aid with respect to the second end
position, however, in this case, the displayed intermediate plan is
closer to the first navigation plan (first variant of the
invention) or a mixture of two further navigation plans converted,
for example, with and without mathematical weight, or the second
end position corresponds to the second navigation plan when this is
specified by a second operating device and the second operating
device can effect changes between the first and the second
navigation plan or a mixture thereof. This mixture corresponds to
the said other influence on the third navigation plan which is
conceptually addressed in the second variant by the end of the
first operating device and is illustrated on the display means.
[0039] For example, a computation can be used as an interpolation
calculating an intermediate plan from the first plan depending on
the position of the setting button of the first operating aid,
which intermediate plan is located between the first plan and the
first navigation plan. This interpolation can equally be performed
also between the first and second navigation plans, wherein the
first navigation plan is converted without mathematical weights and
the second navigation plan is calculated with mathematical weights
from the first plan using the calculation regulation of Suess and
changing this interpolation further towards the first navigation
plan or further towards the second navigation depending on the
position of the second operating aid in order to define the third
navigation plan which will become the end value of the first
operating aid.
[0040] The interpolation can be configured as follows.
[0041] Interpolation is the generation of a usually transient
intermediate plan from existing navigation plans. According to its
name, this interpolated intermediate plan is located between the
plans used for generation thereof.
[0042] The most widely used method is the so-called convex
combination. Here, a number of initial plans with associated
weights are mixed in accordance with the weights. The weights sum
up to 100% in the process. The mixing is applied to fluences of the
plans (physical plan parameters). Since the radiation dose (in very
good approximation) is linearly dependent on the fluences, the dose
distributions of the plans can be added in a weighted manner
analogous to the fluences.
[0043] However, as the fluences are not the settings of the
irradiation device, but since the leaf settings of the multi-leaf
collimator with associated times are primary quantities, the
fluences (which are theoretically mentioned for this reason) are
converted into such leaf settings in a process called "sequencing".
The conversion of the device settings is thus not performed by
convex combination.
[0044] Apart from convex combination, somewhat more complicated
interpolation mechanisms would also be possible. For example, the
plans could also be scaled.
[0045] The interpolation parameters (e.g. what plans, what weights)
can be read directly from the position of the operating aid or can
be indirectly derived from the position. A quality value (not a
parameter value!) is set by the position of the operating aid and,
in a very small optimization problem, the interpolation parameters
are determined such that the values of the other axes are changed
as little as possible. This problem is so small that it can be
solved in real time so that the user will not be aware of the
interpolation.
[0046] It is understood that the central position of the operating
aid causes the display of, in brief: displays, such an intermediate
plan on the display means being interpolated between the first plan
and the first navigation plan (first variant of the invention) or
the third navigation plan (second variant of the invention),
wherein the third navigation plan can be the first one, the second
once or a mixture thereof (claim 6).
[0047] It is again pointed out that the plans are not pure
information, but technical data and thus correspond to dose
distributions set in the technical device for tumor therapy.sup.1
(claim 7). .sup.1Translator's remark: "or corresponding thereto"
was deleted in the translation as it makes no sense in the sentence
referring to claim 7.
[0048] It is virtually impossible to describe these technical
device settings in a patent claim in a manner intelligible for the
user without reference to a representation comprehensible to the
viewer. A column of irradiation intensities, irradiation times and
associated angle information is not a perceptible or assessable
device setting to a user. It is a purely technical setting
calculated or computed by a higher authority, which higher
authority is conceivably associated with the therapy plan to the
viewer. Such as the sections including the isodose lines which
constitute examples or a DVH diagram providing useful, but not
sufficient representation of the entire plan in an image as a
standard of evaluation.
[0049] The interpolated intermediate plans generated during
movement of the operating aid (the first or second operating aid)
are not stored in the database. They are temporary intermediate
plans which are not pre-calculated plans. They are too similar to
these pre-calculated plans. However, they are stored in a buffer to
be exported when needed, i.e. when favored by the user who approves
of this interpolated plan for his purposes, and to be provided for
the device settings. This exported plan is the causal follow-up
plan to be generated or determined, for which purpose the above
defined steps of the invention are performed. In this sense, a data
base is also memory but not the memory for which the interpolated
(volatile) plans are provided (claim 8).
[0050] Operating aids, cursors and rotary controls or slide
controls have been spoken of before. They are not necessarily to be
understood as tangible rotary adjusters in a physical sense, such
as for example a potentiometer or slider. In application, these
representations are, in most cases, displayed optically on a
monitor and can be displayed on a separate display device, while
the other display device displays the plans, for example, in form
of a DVH diagram and three sectional diagrams with isodose lines
(transverse, sagittal and frontal).
[0051] Further display quantities representing additional
similarities or other values of change can additionally be provided
which can be accommodated either on the first or second display
device.
[0052] If desired, the first or/and second operating aid can also
be implemented physically and provided in form of tangible
potentiometers to the user who will then change the plan on the
monitor by physical rotation or sliding (without using a pointing
device with cursor). The implementation via an AD converter or
incremental potentiometer having discrete positions are only two of
a variety of possibilities of making operational guidance of the
system as easy and practically convenient as possible for the
user.
[0053] A setting button can effectively be represented graphically
directly on a display device and operated by a pointer of a
controller (a mouse device) or can be implemented physically and
provided in tangible form to be touched by the user.
[0054] Embodiments of the invention are explained in greater detail
on the basis of Figures. An overview is given for this purpose.
[0055] FIG. 1 is a block diagram of a control arrangement with two
display devices 110, 111.
[0056] FIG. 2 symbolically shows the plan volume Z illustrated in
following FIG. 4.
[0057] FIG. 3 is a DVH diagram 70.
[0058] FIG. 4a, FIG. 4b and FIG. 4c each illustrate a sectional
plane (slice) in three spatial directions.
[0059] FIG. 5 is a summary of the individual illustrations of FIGS.
3, 4a, 4b, 4c and their partial images 70, 72, 74, 76 with added
operating aids 30, 40.
[0060] FIG. 6 shows the selection of an initial voxel z1.
[0061] FIG. 7 shows the dose value at the selected point z1 of FIG.
6 in a displayed window 77.
[0062] FIG. 8 shows a further window 78 displayed after
confirmation of the window of FIG. 7.
[0063] FIG. 9 shows activated operating aids 30, 40 which are
activated subsequent to the presence of a first navigation plan
and/or a second navigation plan.
[0064] FIG. 10 shows a representation corresponding to FIG. 9.
[0065] FIG. 11 illustrates another setting of operating aids 30,
40.
[0066] FIG. 12 illustrates the generation of the causal follow-up
plan 20.
[0067] FIG. 13 illustrates the generation of a further causal
follow-up plan 21.
[0068] FIG. 14 illustrates a DVH diagram 70''.
[0069] FIG. 1 is a block diagram of a control arrangement with two
display devices 110, 111. 100 is a database and 150 a central
control and calculation core having a buffer 120 used for storage
and buffering of interpolated plans.
[0070] FIG. 2 symbolically shows the plan volume Z illustrated in
following FIG. 4. A plane is illustrated here of which a plurality
of planes exists which are denoted by y.sub.1 to y.sub.n, wherein
the initial voxel z1 comes to lie in plane y.sub.i, as selected
later and explained later. Z represents the plan volume Z divided
into a plurality of layers in three spatial directions for
calculation and illustration, within which plan volume the locally
defined volume z is located illustrating the area of fineness
specified in terms of volume with its boundary 10a.
[0071] FIG. 3 is a DVH diagram 70 showing the volume percentage on
the vertical axis and a dose scale between 0 gy and 100 gy. Plotted
as characteristics are both, the target volume (first and second
tumor, at the far right, reference numerals 80 and 81) and
characteristics (curves) of risks explained in greater detail in
the following.
[0072] FIG. 4a, FIG. 4b and FIG. 4c each illustrate a sectional
plane (slice) in three spatial directions, wherein FIG. 4a shows
sectional plane 289 of the frontal sections, FIG. 4b shows
sectional plane 234 of the sagittal representation, and FIG. 4c
shows sectional plane 57 of the transverse sectional planes.sup.2.
The sectional planes are often also called "slice", wherein the
plane volume is divided in three spatial directions into a specific
number of slices per spatial direction, and wherein isodose lines
are defined within a respective slice similar to the contour lines
of a mountain range, said isodose lines characterizing lines of
equal dose. For example, a gradation of doses of 25 gy, 33 gy, 40
gy, 50 gy, 60 gy and 65 gy, i.e. six grades of doses, is
illustrated in FIG. 4c. In an illustrative example, the outer line
is the isodose line of 25 gy and two organs 60, 61 are spatially
represented which constitute the left and right parotid glands on
the left and on the right in the shape of kidneys. Isodose lines
50, 51, 52 denote three external isodose lines in the examples.
.sup.2Translator's remark: In the drawing of FIGS. 4 a, b and c the
sectional planes as slices are different as 289, 158 and 47 however
in FIG. 5 the slices are 289, 234 and 57 corresponding to the text
here.
[0073] FIG. 5 is a summary of the individual illustrations of FIGS.
3, 4a, 4b, 4c and their partial images 70, 72, 74, 76 with added
operating aids 30, 40. The four illustrations consisting of a DVH
diagram and three sectional planes of isodose lines represent "a
plan".
[0074] A plurality of characteristics of organs, tissue areas and
target volumes are shown in partial image 70 of FIG. 5. The two
right-hand characteristics are two target volumes (tumor volumes).
The central curve with the long slope represents the brain stem.
The two steeper characteristics extending substantially in parallel
represent the left and right parotid glands. The more level curve
extending roughly parallel to the characteristic of the brain stem
in the central portion is the body. The curve approximated to a 1/x
function is the dose characteristic for the entire brain and the
residual steeply sloping curves are risk organs (optics, left and
right eye).
[0075] The operating aids 30, 40 in setting section S can be seen
on the same display device, for example 110 of FIG. 1, together
with the plan representation. The lower section S comprising the
setting aids could also be placed on the display device 111 so that
only section P remains on the display device 110 for representation
of the set plan. Setting section S could also be realized in
hardware, e.g. by two external setting controls which can be
operated manually, such as 130, 140 of FIG. 1. FIG. 5 represents
the first plan 10 which is also a representative of a variety of
technical setting parameters of the non-illustrated device TG for
tumor therapy, cf. e.g. U.S. Pat. No. 6,038,283 A (Carol et al,
Nomos), FIG. 1 therein.
[0076] FIG. 6 shows the selection of an initial voxel z1. This
voxel is located in level 57 of the transverse sections (top right
diagram). The other representations are unchanged as compared to
FIG. 5, since only one selecting action has taken place using a
mouse pointer.
[0077] FIG. 7 shows the dose value at the selected point z1 of FIG.
6 in a displayed window 77 including information on the initial
voxel and setting options regarding the size of the area of
fineness specified in terms of volume and the desired dose.
[0078] FIG. 8 shows a further window 78 displayed after
confirmation of the window of FIG. 7. Here, the parameters of
conversion are set, by which the first and second navigation plans
are generated or converted from the first plan illustrated in FIG.
5.
[0079] FIG. 9 shows activated operating aids 30, 40 which are
activated subsequent to the presence of a first navigation plan
and/or a second navigation plan. The setting buttons X40 and X30 of
the two operating aids represented as sliders 40, 30 are
displaceable between the left and the right and also include
intermediate positions. Each one of the "sliders" has a left and a
right stop called end stop or end position. The end stops 41, 42 of
operating aid 40 and end stops 31, 32 of operating aid 30 are
represented in FIG. 9. The second navigation plan 12 is represented
in the upper plan section P of the display device, which could also
be completely identical with 110 of FIG. 1, while the setting
section S could also be placed on the second display device 111,
however, in the image of FIG. 9 both sections are provided on one
display device.
[0080] FIG. 10 shows a representation corresponding to FIG. 9,
however, in this case, the first navigation plan 11 is illustrated
in plan section P. This is due to the setting of slide buttons X30,
X40 of the two operating aids 30, 40, as explained in greater
detail in the following.
[0081] FIG. 11 illustrates another setting of the operating aids
30, 40. Here, the first operating aid 40 shown on the left is
located at its right stop 42 and illustrates the plan in plan
section P as specified by the right operating aid 30. The setting
button X30 thereof is located in an intermediate area at position
33 and represents an intermediate plan between positions 31 and 32
representing an interpolation between the first navigation plan 11
selected at position 31 and the second navigation plan 12 selected
at position 32. A third navigation plan 13 results at position 33
specifying the end value of the first operating aid 40, and when
the setting button X40 thereof is placed at the second end
position, as shown in FIG. 11, the third navigation plan 13 is
illustrated in plan section P.
[0082] FIG. 12 illustrates the generation of causal follow-up plan
20 as accomplished by intermediate positions 33, 43 of the first
and second operating aids 40, 30 which are interpolated in each
case, as explained in greater detail further below.
[0083] FIG. 13 illustrates the generation of a further causal
follow-up plan 21 as accomplished by different intermediate
positions of the first and second operating aids 40, 30 which are
interpolated in each case, as explained in greater detail further
below.
[0084] FIG. 14 illustrates a DVH diagram 70'' representing both
plans, the first plan 10 and the causal follow-up plan 21 of FIG.
13 in one image illustrated in two views. Only a few curves are
chosen as characteristics, but are always illustrated in pairs,
e.g. the tumor area represented by characteristics 80 and 80'.
[0085] In the above extended overview of the Figures, one plan is
illustrated in plan section P in each case. In the example, this
plan consists of four representations 70 to 76 explained in
connection with FIGS. 3, 4a, 4b and 4c. They comprise one DVH
diagram 70 and three sectional diagrams wherein, for each image
(segment), the sectional plane or slice number is indicated, which
number has been kept consistently identical for the sake of
explanation.
[0086] The transverse section is slice 57, the sagittal section is
slice 158 and the frontal section is slice 258. This applies to all
Figures in order to enable a comparison between all images of the
isodose lines in the representations of cutout images 72, 74 and 76
and the isodose representation of image 70.
[0087] In the representations of the plan section or plan sections
of FIGS. 9 to 13, the image 70 of the DVH representation of FIG. 3
is used twice in order to illustrate the original plan 10 (located
at the starting position 41 of the first operating aid 40) and the
new, changed plan accomplished by changing the position of setting
button X40 and/or X30.
[0088] A further curve representing the change has been
additionally provided for each curve of FIG. 3 in DVH image 70',
however, it is also apparent that this change is so slight that the
original plan 10 (the starting plan) of FIG. 5 is virtually still
present, however, includes a new stipulation made on the basis of
FIG. 6 and the setting of FIGS. 7, 8.
[0089] An overview on the circuit structure and the components of
the system for finding a causal follow-up plan, by which a setting
of the technical device or on the technical device for tumor
therapy is performed, is shown in FIG. 1.
[0090] FIG. 1 is to be read in conjunction with FIG. 5, since the
display device 110 of FIG. 1 visually illustrates at least plan
section P of FIG. 5 to the user. The individual segments 70, 72,
74, 76 are apparent from FIGS. 3, 4a, 4b and 4c and are explained
in greater detail therein. They represent a plan which, in the
image of FIG. 5, is the first plan 10 originating from a previously
stored amount of pre-calculated plans in the database 100.
[0091] The setting portion S of FIG. 5, which, in contrast to plan
section P, is illustrated below this plan section in FIG. 5, may
also be placed separately on a further display device 111 which can
also be a monitor. However, a mechanical actuator can also be used
and the operating aids 30, 40 of FIG. 5 are represented as
mechanical actuators, in form of a potentiometer 130 or slide
control 140, in FIG. 1. They constitute an alternative to the
optically displayed actuators, e.g. sliders 30, 40, as an
English-language synonym to slide controls.
[0092] The operating aids 30, 40 or 130, 140 are used by a
non-illustrated user to change the representation on the screen as
an example of a display device 110. He intends to change a fine
area specified in terms of volume, the volume boundary of which is
represented by 10a in FIG. 2. The plan volume Z is also
schematically shown in FIG. 2 which emerges more realistically from
FIG. 5.
[0093] For this purpose, the setting aids 30, 40 are moved between
their end positions 31 and 32 as well as 41 and 42. This can be
correspondingly performed by the haptic touch adjusters which are
shifted by manual touch. A touch screen is a further variant.
[0094] The central control core 150 couples the said components in
terms of function and data. It accesses the database 100, operates
the display device 110, and possibly 111, via a video interface,
receives signals from the operating aids 30, 40 or 130, 140 and
comprises a buffer 120 in which the interpolated intermediate plans
can be stored and retrieved therefrom.
[0095] The normal case of the coupling 100a between the database
100 and the central control core 150 is that 150 retrieves a first
plan 10 from the database and illustrates it on the display device
110. Usually, it is not intended to restore this plan or further
plans in the database 100 and the plans converted by the central
calculation core 150--also having a control function--are stored in
the temporary memory 120.
[0096] When a causal follow-up plan 20 has been generated from the
initial plan (the first plan 10) on the basis of the mode of
operation of the system and the user guidance, this follow-up plan
can be transmitted at the touch of a button, e.g. by using the
button 47 of FIG. 12, to the data manager 160 and can be buffered
therein. This buffering is converted into setting parameters
supplied to the technical device TG by a technical interface 161
not illustrated in greater detail. Possible technical setting
parameters include time periods, intensities, specifications for
multi-leaf collimators, or angle settings for a radiation head
which can be rotationally moved about the patient. The setting
types of TG are known, the devices TG are known as well so that
only the interface 161 is to be adapted to the known setting
options. However, what settings are made is a matter of the
examples of this description.
[0097] In order to place the object and result of this operating
principle of FIG. 1 or the system of FIG. 1 operable in the
described manner up front, it is referred to FIG. 12.
[0098] The arrangement of the individual images 70', 72, 74, 76 and
of the setting devices 30, 40 of FIG. 12 is comparable, however, a
different plan 20 is illustrated which is accomplished on the basis
of different settings of the sliders 30, 40. After actuating button
47, this plan 20 is transmitted to the data manager 160 and
supplied to the technical device TG via interface 161.
[0099] FIG. 2 illustrates the plan volume Z and the external
envelope 10a of the small local area of fineness z determined by
selection of the initial voxel z1. In the schematic image, slice y
is the one having number 57 so that, in slices y.sub.1 to y.sub.n,
slice y.sub.57 contains the initial voxel. This selection is shown
in FIG. 6, wherein the mouse pointer points to the initial voxel z1
in the right top partial image 72 in the region of the right
parotid gland 60. FIG. 2 schematically represents nothing else,
only in side view and not in top view.
[0100] The user has selected this position z1 on the basis of his
experience, desires or targets and wishes to locally reduce the
dose at this point showing a relatively high dose while
substantially maintaining the residual plan represented by the DVH
diagram in the left top partial image 70.
[0101] The user could also have identified the initial voxel z1 in
the same way in any one of the other sectional views of FIG. 6. In
terms of result, a follow-up image of FIG. 7 is displayed when
selecting the initial voxel z1 in one of the three isodose
representations 72, 74, 76 as partial images of FIG. 6. This is
done by means of the display device 110 or a parallel display
device 111.
[0102] The pop-up window 77 provides more detailed information on
the "clicked on" initial voxel z1 (identified by pointing/clicking
with a cursor). The available setting "options" in window 77 are
specified in setting fields. The dose of the voxel is indicated,
the location of this voxel (right parotid gland) is indicated and
two values can be specified which can be input in setting fields
77a, 77b by the user.sup.3. The user can define the size of a voxel
group corresponding to the volume z. In the example, this has been
done by inputting half an edge length of a cube containing the
clicked on voxel. This is entered in field 77b. The user can input
a desired dose in field 77a which is to be applicable to the entire
voxel group z. In the example, a value of 34 has been input. Thus,
the aim is to reduce the dose from 40 gy to 34 gy.
.sup.3Translator's remark: Evidently reference signs 70a, 70b are
typos, corrected to read 77a, 77b, see lines 20/21 of this page and
FIG. 7.
[0103] In the example, release of this specification is effected by
actuating the button 77c. After release, which corresponds to a
desired change in dose and defines a volume within which this
change is to take place, the follow-up window 78 appears.
[0104] The further window 78 appears in FIG. 8 wherein a plurality
of other parameters can be set. These parameters determine the
conversion which is to take place starting from the first plan 10.
Conversion is performed using the process regulation of Philipp
Suess, as cited at the beginning. Mathematical weights are set
which are initially suggested by a presetting. The presettings are
apparent from the image and relate to spherical shells and weights.
The weights increase with increasing distance from the initial
voxel and enhance the degree of localization in conversion.
[0105] The field 78 may appear once, twice or a number of
times.
[0106] When it appears a second time, different mathematical
weights can be used for calculation, for example no such
weights.
[0107] It is also possible to perform two conversions using two
considerably different weights which result from a first plan 10 in
a first navigation plan 11 or in a second navigation plan 12.
Usually, the user obtains greatest difference of these two
navigation plans 11, 12 when the first navigation plan is
calculated without using mathematical weights and the second
navigation plan is calculated by using the set mathematical
weights.
[0108] Confirmation on the confirmation field 78c starts the
conversion.
[0109] The object of the conversion is the change in dose in the
locally defined volume z with the envelope 10a. The initial volume
is located within this small volume. In the example, a reduction
from 40 gy to 23 gy is to be realized.
[0110] In a variant of the calculation, the small voxel group z can
be examined by the system as to whether it comprises voxels from
the risk area when removing a critical spot from the target area or
voxels from the target area when removing a critical spot from the
risk area. The number of voxels in the voxel group is 500 at the
maximum, preferably less than 350, or, when measured by percentage,
not exceeding 5% of the set voxels of the plan volume. The system
can reduce the number of voxels to be converted by the voxels
associated with the respective other area so that the number of
voxels in the voxel group decreases. As an explanation, it can be
said that the voxels of the respective other area are not relevant
for the removal of a critical spot from an area, i.e. a risk area
or target area.
[0111] As a result of the conversion according to FIGS. 7 and 8, at
least one slider 40 is functionally available as an example of an
operating aid in FIG. 9. It constitutes the "first operating aid".
A setting button X40 can be moved between the left edge 41 and the
right edge 42 of the slider. In the example of FIG. 9, X40 is
located at the right edge. Setting button X40 then selects an
intermediate plan assigned to this (intermediate) position of the
slider 40.
[0112] In one embodiment, this may be the second navigation plan
12. However, it may also be the first navigation plan 11. This
example is illustrated in FIG. 10.
[0113] In both Figures, an additional variant is incorporated which
is enabled by use of a second operating aid 30. This operating aid
30 places the first navigation plan 11 and the second navigation
12, respectively, on its two end positions. The position of the
second setting button X30 selects what intermediate plan is
assigned to the right end position 42 of the first setting aid
40.
[0114] By FIG. 8, actually by applying the conversion according to
FIG. 8 twice using different mathematical weights, two navigation
plans have been calculated which are designated by 11 and 12.
[0115] Assuming that the first navigation plan has been calculated
without using weights, it is located at the right end position 31
of the second operating aid 30 implemented as a slider in the
example. The second navigation plan 12 which has been calculated
using mathematical weights is located at the left end position 32.
Based on the position of button X30 at the left edge of the second
slider 30, the second navigation plan using the mathematical
weights is selected and assigned to the right end position 42 of
the first slider 40. When the setting button X40 is located here,
the second navigation plan 12 represented by the previously
addressed four partial images in the example is illustrated in plan
section P.
[0116] It is apparent that the partial images differ from the
initial images of FIGS. 4a, 4b and 4c in intensity by different
gray levels. Due to the use of the mathematical weights in the
second navigation plan, the changes in plan are more local. This is
apparent from a comparison with FIG. 10.
[0117] In FIG. 10, a setting has been selected by the two operating
aids, wherein the first navigation plan is assigned to the right
end position of the operating aid 40, since the setting button X30
of the first operating aid 30 is located at its right stop 31 which
is representative of the first navigation plan 11 which has been
calculated without using mathematical weights. Consequently, the
first navigation plan 11 is illustrated in plan section P.
[0118] A word to the DVH diagrams 70' of FIGS. 9 and 10. A pair of
curve progressions for an object or area in the plan volume is
illustrated in each case, i.e. the first and second tumor, the left
and right thyroid glands and several other organs for which there
are DVH characteristics calculated by the system of FIG. 1.
[0119] A respective pair of curves shows the difference between the
original starting plan 10 of FIG. 5 and the causal follow-up plan
newly found via the sliders 30, 40 which can only correspond to the
first navigation plan 11 or the second navigation plan 12--without
mixtures thereof.
[0120] From an assessment of the partial image 70' of the two FIGS.
10 and 11 a user may detect that the dose in the target area, i.e.
the tumor, (the right curves 80, 81 in the DVH diagram 70 of FIGS.
3 and 70' of FIGS. 10/11) has decreased, when using the
mathematical weights, i.e. the second navigation plan.
[0121] Without these mathematical weights and thus with the first
navigation plan 11, a considerable increase in dose arises for the
target volume as the tumor. This opens up a further setting option
for the user, namely navigation with the second slider 30 between
the first and second navigation plans 11/12 by way of
interpolation.
[0122] This is illustrated in FIG. 11. FIG. 11 shows a position of
the setting button X30 between the two end positions 31, 32. This
intermediate position is denoted by 33. Here, a third navigation
plan 13 arises, which is assigned to the right end position 42 of
the first operating aid 40 according to the explanations made to
FIGS. 9 and 10. Setting button X40 is also located here so that its
setting makes the third navigation plan, according to the setting
position 33, appear on plan section P. The third navigation plan 13
has been generated by interpolation between navigation plans 11 and
12 in accordance with the position of the setting button X40 and
its spacing from the left and right end positions.
[0123] The DVH diagram 70' in the left top partial image shows a
clear improvement. The user is provided with a causal follow-up
plan which he may generate by shifting the setting button of each
of the two operating aids 30, 40 or 130, 140 in an almost
continuous manner. For this purpose, not only the two end positions
of each of the operating aids, but also one or a plurality of
intermediate positions are provided in each operating aid, wherein
one intermediate position 33 thereof has been explained with
respect to FIG. 11. Further such intermediate positions define
further interpolations between the respective end values of one of
the operating aids, i.e. both 30 and 40.
[0124] The first plan 10 is located at the left end of the left
operating aid 40. FIG. 12 shows that also in this case an
interpolation between this first plan 10 and the (navigation) plan
located at the end stop 42 is possible. This plan is specified by
the right operating aid 30 by setting an intermediate value.
[0125] The right slider enables interpolation between the first and
second navigation plans, provides an interpolated plan at position
33 (by the location of setting button X30 as the third navigation
plan 13) and the left slider 40 interpolates the mentioned mixed
plan, corresponding to slider position 33 here, between the first
plan 10 and the "third navigation plan".
[0126] Both sliders cause one interpolation only, which is
performed by the calculation core 150, during actuation of the
setting buttons of the sliders along their plurality of
intermediate positions. These intermediate plans generated on the
basis of the movement of the two sliders 30, 40, are stored in the
buffer 120 and can be retrieved when the slider is in the
corresponding position.
[0127] When a user has found a plan beneficial to him, which he
identifies as "good" based on the DVH diagram and which he
considers useful also by virtue of the residual isodose partial
images, he may export this beneficial plan to the data manager 160
by actuating button 47. This plan, which is the causal follow-up
plan 20 in the example of FIG. 12, is the desired result.
[0128] This result is obtained from a number
of--slider-induced--interpolations and the previously performed
conversion of the first plan in two navigation plans 11, 12 using
different mathematical weights but taking the one initial plan 10
as a basis.
[0129] Additional setting aids or indicators can be used which are
designated by 45 and 46. Indicator 46 provides a measure of the
size of the area changed as compared to the old plan.
[0130] One example is the arithmetic mean of the distance of all
voxels to the initial voxel z1, the changes of which amount to more
than 0.1 gy. In the example of FIG. 13, a deviation value of 41 is
displayed by the indicator 46 as a measure of the area size. In the
two images of FIGS. 10 and 11, this deviation value would be 60.
The smaller this measure or indication of size, the slighter the
deviation from the first plan 10 (initial plan), however, taking
into account the specification of change in the small/local group
of voxels z set in FIG. 7.
[0131] The generated follow-up plan of FIG. 13 is thus more
favorable in terms of proximity to the first plan 10. When the user
approves of this follow-up plan, it is transmitted as the causal
follow-up plan 21 to the data manager 160 via button 47 and
implemented therein in interface 161 for transfer to the device TG
to be set.
[0132] The proximity of the DVH characteristics shown in pairs,
e.g. the characteristics 80, 80' for the target volume of the first
tumor, is particularly clear in FIG. 13.
[0133] This is shown further enlarged in FIG. 14.
[0134] Hardly any difference between the two characteristics 80,
80' can be seen in FIG. 14 and also the second tumor with the two
characteristics 81, 81' hardly reveals any difference in the
progress of the DVH family of characteristics. Slight differences
can be seen in the curves (also: characteristics) of two other
organs representing the spinal cord by DVH characteristics 82 and
82' and the right parotid gland by DVH characteristics 83, 83'.
[0135] The initial voxel z1 was located close to or in the right
parotid gland. The change in its DVH characteristic 83 according to
FIG. 5 as compared to the setting according to FIG. 13 can be seen
more clearly and is denoted by 83'.
[0136] If one wishes to provide a measure of how the
characteristics of the DVH distribution behave with respect to
their proximity to the original plan 10, one could say in a first
approximation that they, the curves (characteristics) of the DVH
partial image 70, should not deviate by more than 5%. This is shown
particularly well in partial image 70'', is optically
comprehensible and apparent from FIG. 14 as a cutout enlargement.
Of course, this pertains only to the causal follow-up plan
generated by the stages or steps explained within the scope of the
embodiments. Other plans, including the first or second navigation
plan, may deviate more clearly, since they are not required to
represent the causal follow-up plan 20 or 21 but only open up an
aid for virtually continuous navigation, wherein three plans are
available as "basic plans", i.e. the first plan 10 and two
navigation plans 11, 12 converted therefrom.
* * * * *