DE102010021119A1 - Method for operating radiation device for irradiating target volume area of target body, involves modifying irradiated target volume area of target body by control input of radiation device - Google Patents

Abstract

The method involves modifying the irradiated target volume area of a target body by a control input of a radiation device. A delay interval between a control input and a reaction of the radiation device is taken into consideration with the generation of the control input. An independent claim is also included for a radiation device with an irradiation adapting device.

Description

The invention relates to a method for operating an irradiation device for irradiating at least one target volume range of a target body, wherein the target volume range of the target body to be irradiated can be changed by a control input of the irradiation device. Furthermore, the invention relates to an irradiation device for irradiating at least one target volume range of a target body, which has at least one irradiation matching device.

In the meantime, an irradiation of objects is carried out in various fields of technology. Depending on the specific application requirement, different irradiation methods and different types of radiation are used. Thus, in some areas of technology it is necessary to irradiate objects spatially or spatially and as evenly as possible. This is the case, for example, when materials are to be cured or otherwise modified with respect to their material properties. Also, it has become common in the meantime, for example, in the field of food technology to make foods using certain types of radiation preserved.

In other fields of technology, on the other hand, it is necessary to irradiate certain portions of the object to be irradiated with a certain, typically very high dose, while the remaining parts of the object should not be irradiated as little as possible. An example of this is the structuring of microprocessors or other microstructures or nanostructures using electromagnetic radiation (in part down into the X-ray region) and imaging masks.

The structuring of the dose distribution is not necessarily only two-dimensional, but rather can be done in all three spatial directions. As a result, it is possible to directly and immediately irradiate a volume area which lies in the interior of a body to be irradiated, without having to damage or open the body (in particular its outer shell). In this case, the body to be irradiated (in particular a volume region to be irradiated lying in the interior of the body to be irradiated) may not only be static / non-moving. Rather, it can also happen that the target body or parts of the target body (in particular the volume area to be irradiated) move. A movement can not only be translational relative to an external coordinate system, but also in the form of a shift of different areas of the body to be irradiated relative to each other (including twists and deformations).

In order to be able to irradiate such moving bodies, so-called four-dimensional irradiation methods are used. These are ultimately three-dimensional irradiation procedures that exhibit temporal variation (with time as the fourth dimension). Examples of such material processing methods exist in the field of materials science in the production of highly integrated components (in particular microprocessors and memory chips) and in the production of microstructured and nanostructured mechanisms.

Another field of technology in which such three-dimensional or four-dimensional irradiation methods are used is in the field of medical technology. As a rule, it is also necessary here to apply a dose as high as possible to certain volume areas within a body, such as tumors, for example, whereas the surrounding tissue should be as little as possible, or preferably substantially not at all, loaded with a single dose. This is especially true when the surrounding tissue is a so-called critical tissue, such as a sensitive organ (referred to in technical terms as an OAR for "organ at risk"). These may be, for example, the spinal cord, blood vessels or nerve nodes.

Especially in the irradiation of moving target volumes occur diverse, sometimes not or not satisfactorily solved problems. Basically, there are a large number of possible solutions. Specifically for use with scanning methods, three specific approaches are discussed in particular. These are so-called rescanning methods, gating methods and tracking methods.

In rescanning methods, the body to be irradiated is exposed to a large number of consecutive irradiation processes. In the case of a cyclically recurring movement pattern of the moving body (or of the target area to be irradiated), this results in a statistically sufficient irradiation of the target volume. The problem, however, is that it comes almost inevitably to a relatively high radiation exposure of not to be irradiated parts of the target body. In addition, rescanning methods are principally suitable primarily for relatively fast-running, cyclically recurring movements.

In gating procedures, the target body is only actively irradiated if the volume area to be irradiated is located in a relatively narrow, defined area. At other times, however, there is no irradiation (usually by switching off the particle beam). Basically, gating procedures provide good irradiation results. However, a disadvantage is the longer irradiation time, which leads among other things to higher costs.

A particularly promising approach is the tracking method. In this case, the area in which the radiation acts is tracked corresponding to the movement of the volume area of the target body to be irradiated. Tracking methods combine the advantages of a precise, targeted treatment with relatively short irradiation times.

Although tracking techniques work in principle, there is still a need to improve them. In particular, the accuracy of the irradiation (including the irradiation action, the dose input, etc.) is still in need of improvement compared with the values that can be achieved today.

It is the object of the present invention to provide an improved method and apparatus for irradiating a target volume.

The object is achieved with the features of the independent claims. Advantageous developments of the method and the device will become apparent from the independent claims.

A method is proposed for operating an irradiation device for irradiating at least one target volume range of a target body, in which the target volume range of the target body to be irradiated can be changed by a control input of the irradiation device, wherein at least one between a control input and a response of the irradiation device during generation of the control input lying delay period at least temporarily and / or at least partially considered. The inventors have found that in the control of the irradiation device has so far been surprisingly neglected that between the "applying" a control input to the irradiation device and the effective response of the irradiation device to the control input (ie the release of the radiation in the driven area inside) in part can be amazingly long time intervals. These are of an order of magnitude which essentially corresponds to the magnitude of the irradiation time per grid point and / or the magnitude of the movement speed of the target volume range. If, for example, during the irradiation of a moving target volume range, a detection device has localized the target volume range and the thus-detected target volume range is controlled by a corresponding control input, then it may easily occur that at the time at which the irradiation device makes the radiation available in the target volume range , the target volume range has already moved further. As a result, it may happen that the target volume range is no longer (sufficiently) charged with the radiation. In a not inconsiderable number of cases, the effect also arises that the target volume range as a result of its movement is already outside of the finally irradiated volume range. A change in the irradiation intensity, for example during a treatment or from treatment day to treatment day (which may be caused, for example, by a change in the radiation intensity of the radiation source of the irradiation device) can lead to particularly fluctuating time delays from the activation to the "start-up" of a halftone dot. In other words, the point in time at which a halftone dot still to be irradiated is irradiated by the irradiation device with a specific dose may vary greatly depending on the irradiation intensity passing through the irradiation device between the current point in time and the point in time of application of the halftone dot. Therefore, taking into account this delay time span (or several delay periods) when creating the control input (the control input may consist of one or more values), the accuracy of the irradiation can be increased in part significantly. The effect is particularly pronounced in the case of relatively small target volume areas which are to be irradiated precisely, in the case of relatively rapidly moving target volume ranges and / or in the case of relatively strongly fluctuating irradiation intensities (for example particle flow in the case of particle accelerators).

It is advantageous if in the method, a plurality of delay periods is taken into account, in particular a plurality of delay periods with at least temporarily and / or at least partially different and / or varying length. In particular, it is advantageous if as far as possible all delay periods are taken into account, which in relation to the size of the target volume range, the size of the respective active irradiation area, the speed of movement of the target volume range and / or the current irradiation intensity, a relatively long period of time or a relatively large fluctuation of the time duration such that If necessary, the consideration of the corresponding delay time span (or delay periods) makes significantly noticeable. If (substantially) all relevant time delays are considered, this can result in a particularly advantageous and accurate irradiation of the target volume range or of the target body. In particular, the inventors have recognized that delay periods of a different length may occur, and preferably should be taken into account particularly with respect to their different lengths. Thus, it is possible that the change of a first parameter of the irradiation brings about a different delay period than is the case with the change of a second parameter of the irradiation. In addition, it should be pointed out that the delay periods can be both (partly) consecutive ("sequential") and should be added accordingly, but also (in part) "parallel" to each other, and accordingly should be considered independently. Such a "parallel" position of the delay periods can be present in particular when time delays occur in the adjustment of mutually independent parameters of the irradiation.

In particular, it has proved to be advantageous if the method takes into account at least one delay time period which occurs during irradiation adaptation in at least one direction laterally to the irradiation direction and / or at least a delay time period which occurs in a direction longitudinal to the irradiation direction. Thus, the inventors have found that lateral deflection (for example, by applying a corresponding current to suitably arranged magnetic field coils) results in relatively small delay periods. An adaptation of an irradiation in a direction that runs longitudinally to the direction of irradiation, however, is usually much more time consuming. The durations can be separated by a factor of 10 or more. If, during the preparation of the control input, these two different (possibly additionally or alternatively also further) characteristics are discussed, a particularly high-quality and accurate irradiation of the target volume range or of the target body can take place.

It may be particularly useful in this context in particular if at least one delay time span is at least temporarily and / or at least partially in a range below 250 ms, in particular in a range below 100 ms, preferably in one range during an irradiation adaptation in at least one direction laterally to the irradiation direction less than 20 ms, particularly preferably in a range of less than 1 ms and / or if at least one delay period of irradiation adaptation in a direction lying longitudinally to the irradiation direction at least temporarily and / or at least partially in a range below 150 ms, in particular in a range below 80 ms , preferably in a range below 40 ms, more preferably in a range between 20 and 30 ms. The values mentioned have proved to be particularly advantageous for particle beams with hadrons and / or in connection with scanning methods (including raster scanning methods and intensity-controlled raster scanning methods). In particular, the values mentioned are advantageous if a directional adjustment takes place in the lateral direction through one (or more) pair of magnetic field coils standing perpendicular to one another and / or an irradiation adaptation takes place in a direction lying longitudinally to the irradiation direction by passive, moving energy modulator elements. In particular, it may be at the passive; moved Energiemodulatorelementen act around a wedge-shaped body of an energy absorbing material, which is moved by means of a motor, in particular a stepping motor, such that the length of the distance, which must cover the radiation (for example, a particle beam) through the body, by the displacement of the energy absorbing body can be changed. Often, a pair of two wedge-shaped bodies are used, which are arranged point-symmetrical to each other and "moved against each other". In part, a larger number of such bodies is proposed in the meantime. Another variation of the underlying idea is that instead of moving the body, the particle beam itself is moved relative to the bodies, which can produce a similar effect.

Furthermore, it is proposed that the method is carried out in such a way that at least one delay time span takes into account signal conditioning effects and / or signal propagation effects. Such signal conditioning effects and / or signal routing effects may include, for example, signal computation in computers, time delays through signal routing in computer networks (eg, Ethernet or other packet-oriented power systems), and the like. These time delays are often relatively constant, but may also change if, for example, a computer program with an adaptive algorithm is used and a larger number of iterations are performed. A need for this may, for example, arise if a higher accuracy is to be achieved and / or with constant accuracy, a larger target volume to be irradiated. In particular, the signals may be one or more control inputs.

It is particularly advantageous if, in the method, the control input of the irradiation device is used at least temporarily and / or at least partially to compensate for the movement of a target body moving at least intermittently and / or at least in regions. The movement is not necessarily limited to the target body as a whole. Rather, it is also conceivable that the target body at least partially "in itself" moves. In extreme cases, it is also conceivable that the outer shell of the target body (essentially) does not change, but parts move within the target body against each other. Incidentally, in the case of a "displacement", consideration should be given not only to degrees of freedom of translation, but also to changes in density, rotational degrees of freedom and the like.

It can also be particularly advantageous if a temporal prediction algorithm is used in the method at least temporarily and / or at least partially. In particular, it is possible that based on the current or the past movement of a target body and / or a target volume range of a target body, a prediction about the further movement of the target body / the target volume range, in particular for the near future, made. As a result, in particular the delay periods described above (possibly also other time delays) can be taken into account. Furthermore, the temporal prediction may be in a time range that substantially coincides with the delay periods. Incidentally, the prediction can also relate to the prediction of the (probable) length of a varying time interval (for example, to a varying delay time span). In this way, the irradiation result can once again be significantly improved if necessary. The prediction algorithm can be carried out, for example, by linear extrapolation, cubic extrapolation, spline extrapolation, neural networks, Markov chains or other algorithms (if appropriate also of an analytical nature). In order to further increase the accuracy of the temporal prediction algorithm, it is also conceivable that the values on which the extrapolation is based are at least averaged to a certain extent in order to be able to reduce or even largely avoid "statistical outliers" or noise effects ,

It is particularly preferred if the method is carried out such that the control input takes place at least temporarily and / or at least in regions such that, taking into account at least one delay time period, a target volume range of a target body to be irradiated is selected. It is particularly advantageous if a plurality, preferably (substantially) all relevant delay periods are taken into account. This applies in particular to delay periods which are (at least partially) "sequential" and / or (at least partially) "parallel" to one another. The control input can thus take place in such a way that the volume range (in particular corresponding raster point in the volume range) is controlled by which, taking into account at least one delay time span (possibly also further inputs), it is to be expected that it will be there at the time of the actual irradiation, where the radiation of the irradiation device actually acts. If the control input has been selected appropriately, the movement of the target body or of the target volume range, the target body or the target volume range at the time at which the radiation is ultimately released by the irradiation device in the region of the target body or the target volume range, in the corresponding, irradiated area moves. This irradiates the "intended" target volume range. In other words, at the time of the control input, an actually "wrong" target volume range is targeted. However, this is done so that the "correct" target volume range is taken at the time of the actual irradiation. The proposed development of the method can be particularly advantageous if it is combined, at least temporarily and / or at least in regions, with a temporal prediction algorithm.

A particularly advantageous further development of the method can result if at least temporarily and / or at least partially a temporally variable and / or time-varying radiation intensity of the irradiation device is taken into account in the control input. For example, with particle accelerators, the effect often occurs that the released dose rate (particle flux) is not constant even during an extraction phase. Such temporally variable and / or time-varying irradiation intensity may have effects on the beam tracking to be performed, and thus on the control parameters to be applied, in particular during the irradiation of moving target volume ranges. Because if, for example, a high radiation intensity is present, then the number of particles to be deposited per grid point is deposited after a correspondingly short period of time. At low irradiation intensity, the irradiation time per grid point is correspondingly longer. Accordingly, for example, the five-next dot to be irradiated is to be irradiated after 10 ms or only after 30 ms, depending on the irradiation intensity. Conversely, when applying positional corrections to the ( main) irradiation action must take into account, for example, taking into account a time delay of, for example, 20 ms, the location correction, for example, already on the third or next to the 20-nearest grid point. The presently mentioned numerical values (time / halftone dot number) are of course only given by way of example and, in the specific case, can also assume other values. The problem here is often that the extraction profile can be subject to strong daily fluctuations or fluctuations from the day of irradiation to the day of irradiation, and accordingly can not or can not be considered with sufficient accuracy in the treatment planning. However, it has been shown that the irradiation profile (extraction profile) is usually relatively similar to one another in successive extraction cycles. A significant change in the extraction profile usually occurs on a time scale of several hours or longer. Accordingly, a measurement that takes into account the extraction profile (or other temporally variable and / or temporally varying radiation intensity of the irradiation device) can be used to improve the irradiation process, with measurements typically at intervals of several hours and / or once or more times a day and / or immediately before treatment. If such a time-varying or variable and / or time-varying radiation intensity of the irradiation device is taken into account, the radiation dose to be deposited into individual subvolumes of the target volume range (for example the radiation dose to be deposited in a single raster point of the target volume range) can be particularly accurate, which is advantageous. Especially great advantages can usually be achieved in combination with the different types of scanning methods.

It is also advantageous if in the method an already irradiated irradiation of a volume region of the target body has an influence on the control input of an irradiation of a volume region of the target body still to be effected. In the medical field in particular, it is often necessary in any case for a treatment to take place in the form of a plurality of fractions which are spaced apart from one another in time (hours and / or days are typically present between individual fractions). This may be necessary for the differential repair capability of tumor and normal tissue to allow for increased integral tumor dose. If the current irradiation is also logged in each case, then the dose already taken in the irradiation planning for the next fraction (or the next fractions) can be taken into account accordingly. In this way, the accuracy of the irradiation can be increased again. Additionally or alternatively, however, it is also possible that such an adjustment also takes place within a single fraction. Thus, a single fraction is often applied today in the form of several individual passages. As a rule, different individual passages from different irradiation directions are applied. In this case, for example, a single passage (or can several individual passages) have an influence on the following to be applied individual passages. Again, the quality of the irradiation can be increased again.

It can also be advantageous if the irradiation is carried out at least partially and / or at least partially as a scanning method, in particular as a raster scanning method, preferably as an intensity-controlled raster scanning method. Such scanning / raster scanning methods are generally particularly advantageous for the method described above and / or for its further developments. For example, when using scanning / raster scanning techniques, a single thin beam (eg, a particle beam, particularly a so-called "pencil beam") may also be used to apply a relatively large target volume range, with the target volume range through the pencil beam is scanned or scanned. This is advantageous because the beam does not have to be expanded, which would typically result in inaccuracies in the irradiation.

It may be particularly advantageous for the method to generate the control input at least temporarily and / or at least partially using irradiation planning, in particular at least temporarily and / or at least partially using a pre-established and / or generated during the irradiation and / or. or adapted treatment planning. It has been found that treatment planning, which is typically numerically relatively complex and often created as an iterative process using a large number of iteration steps, may take several minutes and even hours of computation time, even if very fast computers are used. By (partially) decoupling the calculation of the irradiation planning and the actual irradiation, the accuracy of the irradiation can thus be further increased. By (partially) preparing and / or adapting the irradiation planning in the course of the irradiation, it is possible, in particular, to take into account effects which, for example, only occur or become known during the course of the treatment.

A typical example of this is, for example, the extraction process in a Particle accelerator to call and / or other machine parameters and / or certain patient parameters (for example, the exact location of a tumor area and / or movement of the patient).

It is particularly advantageous if the irradiation device is at least partially a particle beam device or particle beam device, in particular a heavy ion accelerator device, a proton accelerator device, a hadron accelerator device, a pion accelerator device, a helical ion accelerator device, is a linear accelerator device, a synchotron accelerator device, a lepton accelerator device, and / or an electron accelerator device. Especially particle beams or particle beams are particularly effective in the destruction of tumor tissue, or in the application of certain materials. In addition, especially with the use of particles or particles or ions, the effect of the energy release in the target volume in the form of the so-called Bragg peak can be used. When particles pass through a material, they do not lose their energy in even "portions," especially not continuously. Rather, the energy output is concentrated on an area just before the point at which the particles are completely deposited in the material, in other words: "get stuck" - the majority of the energy output takes place in the so-called Bragg peak. In this way, a variation of the dose entry in the direction of the particle beam (in the z-direction) is possible by changing the position of the Bragg peak in the target volume, in particular selectively changing it. As a result, irradiation can also take place within a target body, even without the regions lying around the target volume region of the target body (to a greater extent) being exposed to the radiation. In this case, the position of the Bragg peak is controlled such that it lies only in the target volume range.

Furthermore, an irradiation device for irradiation of at least one target volume range of a target body is proposed, which has at least one irradiation adapter, wherein the irradiation device has at least one particular electronic control device, which is designed and arranged to perform a method with the features described above. The irradiation device also has the properties and advantages described above in connection with the method in an analogous manner. The electronic control device may be, for example, an electronic computer (computer) or an electronic hardware module. This can retrieve the control signals from a storage device and / or process or also, calculate online.

In the following the invention will be explained in more detail by means of advantageous embodiments and with reference to the accompanying drawings. Show it:

1 : an irradiation device for irradiating an internal volume region of a body to be irradiated in a schematic principle representation;

2 : an illustration of a 4-D radiation planning;

3 : a schematic illustration of a target point vector correction;

4 : a respiratory trace as an example of a cyclical, recurring movement pattern;

5 a schematic flow chart for a delay time corrected irradiation method;

6 : A schematic flow chart for a method for determining corrected target coordinates.

In 1 is a schematic diagram of an irradiation device 1 for irradiating one in a target body 2 lying target volume range 3 shown. The irradiation device 1 is in the present embodiment illustrated as a synchotron particle accelerator 4 formed with a known per se structure. The Synchotron Particle Accelerator 4 has an ion source 5 on, in which individual atoms are generated and ionized, thus present as ions. Helium ions, protons, neon ions and, in particular, carbon ions have proven particularly advantageous and effective for medical purposes. A major advantage of the particle types mentioned is, in particular, that they - especially carbon - are biocompatible, and therefore do not produce any tissue incompatibility when implanted in a living organic tissue. In addition, an advantage of said particles (as well as other heavy ions) is that their energy deposition in the tissue has a relatively sharply pronounced Bragg peak. By means of the particle energy of the corresponding particle, the penetration depth of the particle beam into matter, in particular in the tissue, can thus be controlled (and thus, in particular, the region of greatest energy release controllable, for example to treat a tumor in the interior of a body). Of course, the use of others Particles or particles conceivable, such as protons, electrons and pions, and / or in general leptons and hadrons (wherein the irradiation device 1 if necessary, to be modified).

The from the ion source 5 released particles are initially in a linear accelerator 6 pre-accelerated before entering the actual accelerator ring 7 of the synchotron particle accelerator 4 be shot. The in the accelerator ring 7 particles are then accelerated to the desired energy. Once this energy is reached, the accelerator ring acts 7 as a storage ring and the high-energy particles are passed through an extraction septum 8th slowly out of the accelerator ring 7 taken, typically extracted (typical extraction times are in the range of a few seconds to Dekasekunden). The extracted particle beam 9 is using a deflector 10 , which in the present case is in the form of two mutually perpendicularly arranged pairs of magnetic coils, in a lateral direction to the particle beam direction 9 distracted direction. In this way, in the area of the target body 2 an arbitrary point in an xy plane (is essentially perpendicular to the particle beam 9 ) (the maximum size of the xy plane being due to the precise construction of the irradiation device 1 is determined). In this way, the target volume range can be 3 in the target body 2 be successively "approached" with a scan process. In particular, individual volume units or volume ranges in the target volume range 3 , generally referred to as screen dots, are targeted and successively approached.

When the particle energy of the particle beam 9 remains constant while being in the target volume range 3 Reaches points that lie in a so-called iso-energy level. The iso-energy plane is substantially perpendicular to the direction of the particle beam 9 , The depth of the iso-energy plane essentially corresponds to the position of the Bragg peaks. To the target volume 3 in the target body 2 also in the z-direction (parallel to the direction of the particle beam 9 Therefore, it is necessary to scan the energy of the particles in the particle beam 9 to vary. Today's Synchrotron Particle Accelerator 4 however, the particle energy may at best vary between two consecutive extraction cycles. For the treatment of a patient, this would result in unreasonably long treatment times.

In order to be able to carry out a rapid variation of the particle energy, in the present example a passive energy modulator is used 11 used. The passive energy modulator 11 consists of two substantially identical to each other, but symmetrically arranged wedges 12 from an energy absorbing material. The wedges 12 are for example using servo motors 13 (For example, linear motors) in a direction substantially perpendicular to the direction of the particle beam 9 slidable (each indicated by a double arrow). The movements of the two wedges 12 are synchronized with each other. Depending on the position of the two wedges 12 must the particle beam 9 a different length by the energy absorbing material of the two wedges 12 run through it. Accordingly, the energy of the particles of the particle beam 9 correspondingly greatly reduced. In this way, the energy of the particles that are at the actual target body 2 arrive, variable, so that the Bragg peak shifts and thus the target volume 3 can also be scanned in z-direction.

As a scanning method, a so-called raster scanning method is often used nowadays, in which the target volume to be irradiated or the target volume range 3 (usually also part of the target volume 3 surrounding tissue of the target body 2 ) is divided into a larger number of small volume units, so-called halftone dots. The particle beam 9 moves in succession each individual grid point. Taking into account the extracted intensity is determined by appropriate detectors and the residence time of the particle beam 9 At the individual halftone dots, it is ensured that the dose optimized in the radiation planning is deposited in the halftone dot. The implications of such variations in intensity are explained in more detail below.

The intensity fluctuations are due to the so-called "extraction spectrum". Even if it is attempted, the accelerator devices (such as the irradiation device 1 ) in such a way that during the extraction phase as constant as possible, homogeneous particle flow from the accelerator ring 7 is taken, so at least certain fluctuations of the particle flow are usually unavoidable. However, it has been found that the extraction spectrum - although not constant per se - during operation of the irradiation device 1 only changes relatively slowly. Typically, there is a significant change over a time scale of several hours. Therefore, it is possible that the extraction spectrum is measured, for example, at the beginning of a treatment day, or at the beginning of a single treatment, and the extraction spectrum thus measured is used as the basis for the further calculations. It is also possible that a planned treatment (see following description) in advance in an empty cavity or in a phantom or a Dummy is introduced. This makes it possible, in particular, to determine the later, temporal course of the treatment at least approximately beforehand.

In today's treatment method, a so-called treatment planning is typically created in advance. This is - roughly speaking - on the basis of imaging data, basic physical data, (biological) models and prescribed by a doctor (biologically effective) dose distribution a control record for the irradiation device 1 optimized.

In practice, the radiation planning is carried out by calculating which biological effect a particle beam 9 from one or more directions with a specific (three-dimensional) movement pattern (scanning method) in the target volume range 3 of the target body 2 is brought in caused. The calculated biological effects are compared with the biologically effective dose distribution prescribed by the physician. Optimization techniques attempt to minimize the difference between the prescribed dose distribution and the calculated biological effects. It has proven itself, the particle beam 9 from two different (in particular opposite) directions in time to the target volume range 3 of the target body 2 to judge.

Within the framework of an irradiation planning, a large number of different effects must be considered. For example, dose contributions that the particle beam introduces into other grid points are also taken into account. As a rule, the dose entries behind the "current" grid point are very small (so that they can often be neglected), whereas in the direction of the beam, they can cause relevant dose entries before the "current" grid point. Furthermore, especially in the case of heavy ion particle radiation, it should be borne in mind that so-called relative biological effectiveness (RBE) depends in a complex and non-linear manner on physical parameters. For example, the relationship between the deposited physical dose (corresponding to the energy loss of the particle beam) and the tissue damage (ie the biologically effective dose) may vary depending on the particle energy. Also, it can - again, especially in the case of heavy ion particle radiation - come to so-called secondary radiation by fractionation, particles induced by the heavy ion beam. This also brings with it nonlinear biological effects. Furthermore, the dose introduced (both the physical and the biologically effective dose) varies with the type of tissue. Thus, among other things, bones, muscle tissue, blood vessels, cavities and the like are to be weighted differently in the treatment planning. With a large number of halftone dots (in practice, 20,000-50,000 halftone dots can easily be taken into account), scheduling an irradiation plan can take a considerable amount of time (several hours), even if very fast computers are used. Supplementary information on the preparation of treatment planning can be found in particular in the two articles "Treatment planning for heavy ion radiotherapy: clinical implementation and application" by M. Krämer, O. Jäckel, T. Haberer, G. Kraft, D. Schardt and U. Weber in Phys. Med. Biol., Vol. 45, Jahrg. 2000, pages 3299-3317 , such as "Treatment planning for heavy ion radiotherapy: calculation and optimization of biologically effective dose" by M. Krämer and M. Scholz in Phys. Med. Biol., Vol. 45, Jahrg. 2000, pages 3319-3330 ,

An additional problem arises when the target body 2 and / or in the target body 2 located target volume range 3 emotional. This is in 1 indicated by arrows A. The shape of the arrows A is intended to indicate that the movement of the target volume range 3 not necessarily limited to a linear motion. Rather, the movement can take place along an irregularly shaped curve. It can not only come to movements in the form of translational degrees of freedom, but also it can still be rotational movements, as well as density changes in the tissues involved (especially the latter can lead to a stronger and / or weaker absorption of the particle beam 9 lead, so that the position of the Bragg peak - and thus the iso-energy level - shifts). Such a movement of the target volume range 3 may arise, for example, when a tumor is to be treated, which is located in or near the lungs (respiratory movement), located in or near the heart (heartbeat) or located in the intestine (intestinal peristalsis).

In order for such moving target volume ranges 3 to be able to perform a targeted irradiation using an irradiation planning, the movement of the target volume range becomes advance 3 , in particular the course of its movement studied. By way of example, imaging methods such as a so-called 4-D CT method (CT for computed tomography) can be used for this purpose. For the monitoring of the actual therapy, CT procedures are rather undesirable, because they bring with them an additional (unwanted) radiation exposure and, moreover, are relatively slow. Therefore, when measuring the target volume range movement 3 typically a substitute signal recorded simultaneously. in this connection it may, for example, be a video recording of the corresponding body region, the movement of implanted sensors or strain gauges or the like. Was the correlation between replacement signal and the actual movement of the target volume range 3 determines the location of the target volume range 3 be determined with quite good accuracy alone on the basis of the substitute motion signal.

Irradiation planning now takes place in that instead of a single planning data record 14 (please refer 2 ), a variety of different planning records 14a . 14b . 14c ... is used. Each planning record 14a . 14b . 14c ... stands for a certain movement phase of the target volume range 3 , A typical number of scheduling records 14a . 14b . 14c ... is ten planning records 14a . 14b . 14c ... during the actual irradiation of the target body 2 is then based on the replacement motion signal (or other signal representing the location of the target volume range 3 describes) the appropriate, appropriate planning record 14a . 14b . 14c ... used. Has the target volume range 3 moved sufficiently far, so on the next, suitable planning data set 14a . 14b . 14c ... changed.

The inventors have now recognized that this method can be problematic, especially when the target volume range 3 moved relatively quickly, the adjustment of individual device parameters of the irradiation device 1 takes place relatively slowly and / or the particle flux fluctuates greatly during the extraction phase. In order to achieve a sufficiently high accuracy of treatment for medical purposes, the application of a correction vector is required.

The correction vector, which is the "output" of the treatment planning 14a . 14b . 14c ... on the control input of the irradiation device 1 transformed depends on several parameters.

A first parameter is the speed of movement of the target volume range 3 or a material section 16 opposite the outer space coordinates. This is in 3 (especially in 3a and 3b ). 3 shows a material section 16 , where in 3a and 3b different temporal snapshots are shown. The target volume range 3 (and thus its material section 16a ) is located in an in 3a indicated by arrows B movement. After a certain period of time is therefore the material section 16b (please refer 3b ) compared to the original location 16a postponed. In reality, of course, it is a three-dimensional arrangement of halftone dots. In 3 For reasons of illustration, a merely two-dimensional target area is shown.

For example, if at time t ₀ (corresponds 3a ) a grid point V _{i, j are} irradiated, then the corresponding "sheet" 14a . 14b . 14c ... of the overall treatment plan 15 selected. This sheet represents a kind of precalculated "look up" table containing the control parameters with which the irradiation device 1 (or parts thereof) is controlled.

In this case, in particular, the deflection device 10 , as well as the energy modulator 11 to call.

Until the individual components of the irradiation device 1 However, the target volume range has been realized according to the control signals 3 moved on. So if at a later time t ₁ (see 3b ) the grid point V _{i, j is} actually to be irradiated, the "actually to be irradiated grid point" has already moved on. Falsely, the halftone dot V _{i-1, j-3} would now be irradiated. If at time t ₁ ( 3b ) the "correct grid point" are irradiated, the particle beam must now irradiate the grid point V _{i + 1, j + 3} . This in turn means that already at time t _0, V _{i + 1, j + 3} must be selected as the target raster point (although this is the "wrong" raster point at time t ₀ ), thus at time t ₁ (at which the control input is implemented ) the "correct" halftone dot is irradiated.

A second parameter represents the time delay between the control input and the implementation of the control input by the accelerator 1 lies. The time delay may well be different in different directions. Thus, the movement B of the material section 16 in 3 into a component of motion longitudinal to the particle beam 9 , as well as a component of motion lateral to the particle beam 9 be split. The component of motion lateral to the particle beam 9 can by a suitable suitable control of the deflection 10 be compensated or compensated. In this case, a control input can be implemented relatively quickly. The delay caused by the deflector 10 is typically in the range of 1 ms.

The motion component longitudinal to the particle beam 9 must, however, by the energy modulator 11 be compensated. Since here relatively large masses (the wedges 12 ), the time delay between application and implementation of a control input takes a longer time. Typical values are in the range of 25 ms. In addition, it comes in addition to those already described Time delays at certain time delays by the calculation of the respectively to be used machine parameters (or the control signals). These are particularly due to the hardware (computer, network topology, etc.) of the irradiation device 1 certainly. Typical values are in the range of 5 ms. It should be noted, moreover, that although these time delays usually remain relatively constant during the course of irradiation, they can certainly change between two different irradiations (for example because of a larger target volume range) 3 must be irradiated, so that a larger number of grid points is used, which can lead to a correspondingly more complex calculation.

In addition, a third parameter for the direction and size of the correction rectifier is also the actual particle flux (irradiation intensity) emitted by the irradiation device 1 provided. By way of illustration, it should be assumed that the in 3a and 3b shown, previously described correction at a certain particle flux Φ ₁ takes place. In this particle flux Φ ₁ , the scan progress takes place at a certain speed, which results in 3c is illustrated (in 3c For reasons of illustration, there is no movement of the material section 16 ).

If, for example, at the time point t ₀ at the grid point V _{i, j is} started, the grid point V _{i, j + 3 is} irradiated at the time t ₁ . However, as already mentioned, the particle flux is not constant, but varies over the course of an extraction cycle. If the particle flux is, for example, greater than Φ ₁ , the number of particles to be introduced into the respective grid point is reached faster and the scan progress correspondingly faster. This has the consequence that the irradiation of the halftone dot V _{i, j + 3} already takes place at a time t ₁ ', which lies before the time t ₁ . With a low particle flow, the scan progress is correspondingly slower. This effect also requires a correction in the form of a correspondingly adapted correction vector.

As in particular from 3a and 3b can be seen, already at time t _0, the future position of the material section 16b for the future time t ₁ , so that a suitable correction vector can be determined, and the appropriate control signals can be generated. It is therefore necessary that a period of time Δt = t ₁ -t _{0 must be} "seen in the future", wherein the time interval Δt may be different in different directions (as already explained) and possibly also on the (changing) particle flux can depend.

In order to be able to "look into the future" in this way, it is necessary to extrapolate the current state of motion at time t ₀ (see 4 ), so the location of the target volume range 3 at time t ₁ (at least approximately) is known. For extrapolation a wide variety of algorithms can be used. Perhaps the simplest option is linear extrapolation. Significantly better results can, however, be achieved if, for example, a cyclic pattern of movement determines a complete, typical cycle of motion and is used for extrapolation. This is particularly easy because the movement pattern of the target volume range 3 anyway for the creation of the total irradiation planning 15 (please refer 2 ) must be determined in advance.

In 4 is exemplarily a respiratory movement curve 17 shown. In reality, there will usually be slight deviations between the typical "average" respiratory movement curve and the actual respiratory movement curve. Nevertheless, the nutritional value determined thereby is typically sufficiently accurate for practical purposes. In the event that the actual respiratory movement curve deviates very much from the typical value (for example, because the patient is coughing), it is otherwise possible, a (short-term) rapid shutdown of the particle beam 9 to make (too strong) mistreatment of the target body 2 to avoid.

The determination of the target point to be controlled, around the target volume range 3 in the target body 2 To irradiate, then carried out by a convolution of the expected to the actual time of irradiation treatment planning 14a . 14b . 14c ... and the correction vector described above. Since the calculation of the correction vector is usually too complex to be carried out online, it is proposed according to a preferred embodiment, for all realistically possible parameter combinations of the irradiation device 1 in each case to calculate a correction value to be applied and to store it in a correction matrix of suitable size and dimension. During the irradiation, the correction vector can then be read out of the matrix.

In 5 is the irradiation procedure 18 again shown in the form of a schematic flow diagram. At the beginning 19 of the irradiation process 18 becomes the irradiation device 1 initialized and the overall treatment planning 15 into the control computer (in 1 not shown) of the irradiation device 1 read. This can in particular be the determination of the current extraction profile of the accelerator device 1 include. In a first step 20 of irradiation method 18 becomes the next point to be irradiated (or at the beginning of the process the first point to be irradiated) using the respective planning data set 14a . 14b . 14c ... the overall treatment planning 15 and the applicable correction vector. (The investigation 20 of the new spot to be irradiated is in 6 shown in more detail.) Based on the thus determined, to be irradiated point, a control signal is generated 21 , which values suitable for controlling the irradiation device 1 having. For example, these are the target currents for the deflection device 10 and the target positions for the energy modulator 11 , With the thus determined 21 Control signals are accordingly driven the individual machine components 22 , With the appropriately equipped irradiation device 1 thus the irradiation takes place 23 the corresponding grid point. If the desired dose is deposited in the corresponding grid point (after expiry of the corresponding period of time), then in step 24 checks whether the treatment planning has already been fully implemented (branch 25 ), or if there are other points to be irradiated (Zweig 26 ). Will in the verification step 26 determined that the irradiation has already been completed 25 so will the irradiation procedure 18 in the process step 27 completed. In contrast, it is found that the irradiation process 18 not yet completely finished (branch 26 ), then jump back to the beginning of the process and in the step 20 a new point to be irradiated is determined.

In 6 is done in more detail, as in the step 20 a new point to be irradiated is determined. It is initially from the treatment planning 15 determines the point to be irradiated at the current time (step 28 ).

In the subsequent step 29 is (if necessary also in advance or parallel to the step 28 ) the current movement phase of the target volume range 3 recorded and determined. Based on this, a prediction is made about the expected movement of the target volume range 3 made. This makes it possible to determine the expected position at a later time, in particular at a time which is to determine the expected time delay between application of a control signal and implementation of the control signal in the future.

At the same time, in step 29 the current particle flux (the current irradiation intensity) is determined. Based on the current and past values of the particle flow, the position in the extraction spectrum is deduced, so that the (near) future particle fluxes can at least be estimated. Based on this, the speed of the scan progress is determined.

Taking into account both influences, the correction values to be applied (correction vectors) are determined (step 30 ) and on the from the radiation planning 15 applied target values.

This gives you in the step 31 the actually applied, corrected irradiation coordinates. These coordinates will now be used for the irradiation procedure 18 ( 5 ) used.

It is to be understood that the features described in the methods may be applied to the device, and vice versa, not all features of the method being described in the immediate context of the device.

LIST OF REFERENCE NUMBERS

1

irradiator

2

target body

3

Target volume range

4

Synchrotron particle accelerator

5

ion source

6

linear accelerator

7

accelerator ring

8th

extraction septum

9

particle

10

deflector

11

energy modulator

12

wedge

13

servomotor

14

Planning record

15

Total treatment planning

16

material cut

17

Respiratory motion curve

18

irradiation method

19

Beginning

20

Determination of irradiation point

21

Determination of control signal

 22

Control of machine components

23

Irradiation halftone dot

24

Verification step

25

Irradiation finished

26

Irradiation not yet finished

27

The End

28

Determination target point

29

Determination movement phase

30

Determination and application correction vector

31

Corrected irradiation coordinate

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited non-patent literature

• "Treatment planning for heavy ion radiotherapy: clinical implementation and application" by M. Krämer, O. Jäckel, T. Haberer, G. Kraft, D. Schardt and U. Weber in Phys. Med. Biol., Vol. 45, Jahrg. 2000, pages 3299-3317 [0044]
• "Treatment planning for heavy ion radiotherapy: calculation and optimization of biologically effective dose" by M. Krämer and M. Scholz in Phys. Med. Biol., Vol. 45, Jahrg. 2000, pages 3319-3330 [0044]

Claims (14)

Procedure ( 18 . 20 ) for operating an irradiation device ( 1 ) for irradiating at least one target volume range ( 3 ) of a target body ( 2 ), wherein the target volume range to be irradiated ( 3 ) of the target body ( 2 ) by a control input ( 21 ) of the irradiation device ( 1 ), characterized in that during production ( 20 . 21 ) the control input ( 21 ) at least one between a control input and a response of the irradiation device ( 1 ) lying delay period (At) at least temporarily and / or at least partially considered ( 30 ). Procedure ( 18 . 20 ) according to claim 1, characterized in that a plurality of delay periods (.DELTA.t), in particular of delay periods (.DELTA.t) with at least temporarily and / or at least partially different and / or varying length is taken into account. Procedure ( 18 . 20 ) according to claim 1 or 2, in particular according to claim 2, characterized in that at least one delay time span (Δt) in an irradiation adaptation in at least one laterally to the irradiation direction (z) lying direction (xy) and / or at least one delay time period (.DELTA.t) in one is taken into account in the direction (z) lying longitudinally to the direction of irradiation (z). Procedure ( 18 . 20 ) according to one of the preceding claims, in particular according to claim 3, characterized in that at least one delay time span (Δt) at an irradiation adjustment in at least one laterally to the irradiation direction (z) lying direction (xy) at least temporarily and / or at least partially in a range between 0 and 5 ms, in particular in a range between 0.2 and 4 ms, preferably in a range between 0.5 and 3 ms, particularly preferably in a range between 0.7 and 2 ms, and / or that at least one delay period (Δt) at an irradiation adjustment in a direction (z) lying longitudinally to the irradiation direction (z) at least temporarily and / or at least partially in a range between 10 and 40 ms, in particular in a range between 15 and 35 ms, preferably in a range between 20 and 30 ms, more preferably in a range between 22 and 27 ms. Procedure ( 18 . 20 ) according to one of the preceding claims, in particular according to claim 3 or 4, characterized in that at least one delay time period (Δt) takes into account signal conditioning effects and / or signal propagation effects. Procedure ( 18 . 20 ) according to one of the preceding claims, characterized in that the control input ( 21 ) of the irradiation device ( 1 ) is used at least temporarily and / or at least partially for the movement (A) of a target body moving at least intermittently and / or at least in some areas ( 2 . 3 ) to compensate. Procedure ( 18 . 20 ) according to one of the preceding claims, in particular according to claim 6, characterized in that at least temporarily and / or at least partially a temporal prediction algorithm ( 17 ) is used. Procedure ( 18 . 20 ) according to one of the preceding claims, in particular according to claim 7, characterized in that at least temporarily and / or at least partially the control input ( 21 ) such that, taking into account at least one delay period (Δt) ( 3 ) a target volume range of a target body to be irradiated ( 2 ) is selected. Procedure ( 18 . 20 ) according to one of the preceding claims, characterized in that at the control input ( 21 ) at least temporarily and / or at least partially a temporally variable and / or time-varying radiation intensity of the irradiation device ( 1 ) is taken into account. Procedure ( 18 . 20 ) according to one of the preceding claims, characterized in that an already irradiated irradiation of a volume region of the target body has an influence on the control input ( 21 ) has yet to be irradiated a volume range of the target body. Procedure ( 18 . 20 ) according to any one of the preceding claims, characterized in that the irradiation at least partially and / or at least partially as a scanning method, in particular as a raster scanning method ( 18 ), preferably as an intensity-controlled raster scanning method ( 18 ) is carried out. Procedure ( 18 . 20 ) according to one of the preceding claims, characterized in that the generation of the control input ( 21 ) at least temporarily and / or at least partially using irradiation planning ( 14 . 15 ), in particular at least temporarily and / or at least partially using a previously prepared and / or created during the irradiation and / or adapted irradiation planning ( 14 . 15 ) he follows. Procedure ( 18 . 20 ) according to one of the preceding claims, characterized in that it is in the irradiation device ( 1 ) at least partially around a particle beam device ( 4 ), in particular a heavy ion accelerator device ( 4 ), Proton accelerator device, hadron accelerator device ( 4 ), Pion accelerator device, helium ion accelerator device ( 4 ), linear accelerator device ( 6 ), Synchrotron accelerator device ( 4 ), Lepton accelerator device and / or electron accelerator device. Irradiation device ( 1 ) for irradiating at least one target volume range ( 3 ) of a target body ( 2 ), comprising at least one irradiation adjusting device ( 10 . 11 ), characterized by at least one in particular electronic control device, which is designed and arranged such that it has a method ( 18 . 20 ) according to one of claims 1 to 13 performs.

Images