Device for irradiating a tumor tissue

The invention relates to a device for irradiating a tumor tissue of a patient by means of ion beam according to the independent claim.

Recently developed ion beam scanning devices and methods, such as those based on European Patent Application EP-0986 070-A, allow for increased precision of irradiation of deep-seated tumors.

With these devices and methods, the target volume, such as a tumor of a patient, divided into layers of equal range, which are then scanned grid-shaped with an ion beam. This ion beam is delivered with respect to a stationary coordinate system in a treatment room, wherein the solid angle of an ion beam axis is fixed in the irradiation room or can be delivered by means of a gantry from different solid angles.

In order to position the tumor of a patient in this fixed coordinate system of the irradiation room, it is necessary to bring the patient in the beginning in the correct desired position with respect to this coordinate system, so that the actually irradiated or sampled volume of the ion beam matches the intended target volume of the tumor in the patient. Moreover, in these known systems, it is necessary to maintain the target position of the patient during the irradiation. In order to maintain the desired position, elaborate devices such as custom-made thermoplastic mask systems are used to fix the patient in order to adjust the patient to the nearest millimeter before the irradiation and to immobilize it during the irradiation through the mask. Accordingly, only spatially fixed target volumes can be irradiated with the known devices and methods, eg Tumors in the head and neck area and tumors near the spine, where either the head is fixed by a suitable mask alone or a whole body mask immobilizes the spine.

Irradiation of moving target volumes, eg in the thorax region, is not possible with such methods. For example, the target volume in a thorax region is shifted by a few centimeters by a respiratory movement, and thus the targeted millimeter precision is made impossible. Thus, it is impossible to achieve a fixation with an accuracy of millimeters, if at the same time internal movements move the target volume in the centimeter range. In addition, a movement of the target volume with simultaneous beam scanning causes strong dose inhomogeneities.

While the relatively fast, areal and grid-like scanning with constant energy of the ions in the ion beam could follow the lateral movements of the target volume in the centimeter range, the energy variation by the accelerator is not sufficiently fast to the organ movements, for example by respiration or heartbeat in the thorax region of a tumor patient to follow in the depths.

The object of the invention is to provide a device for irradiating a tumor tissue of a patient by means of ion beam, in which the ion beam is adaptable to spatial and temporal change, in particular spatial and temporal periodic changes of the target volume both perpendicular to the beam direction and in depth.

This object is achieved by the subject matter of the independent claim. Features of preferred embodiments are defined in the dependent claims.

According to the invention, the device for irradiating a tumor tissue of a patient by means of an ion beam has a deflection device of the ion beam for slice-wise surface scanning of the tumor tissue and an accelerator with an ion beam energy control device for stepwise depth scanning of the ion beam. In addition, the apparatus comprises an ion decelerator, which is used as a depth-scan adapter to adjust the range of the ion beam and has a faster depth match than the energy controller of the accelerator. Furthermore, the device has a movement detection device for detecting a temporal and spatial change of the position of the tumor tissue in a treatment room and a control device, which the deflection and the depth-scan adjustment device for tracking the ion beam direction or Ion beam range when scanning the tumor tissue with temporal and local change in position of the tumor tissue in the treatment room controls.

The device according to the invention has the advantage that moving target volumes of a moving patient can be irradiated with the same precision as unmoved target volumes in a fixed patient. For this purpose, the movement detection device detects the movements of the patient during the irradiation and the irradiation points are corrected accordingly with the aid of the control device. In principle, this device also eliminates the need for an initial, millimeter-accurate adjustment of the patient in the spatially fixed coordinates since, with the aid of the movement detection device, the actual initial position of a patient is also adapted to the irradiation program or the irradiation program can be corrected accordingly.

In a preferred embodiment of the invention, the device has two electromagnets, with which the deflection device enables a flat scanning. These electromagnets deflect the ion beam orthogonally to the ion beam axis in an X and a Y direction, which in turn are perpendicular to each other to provide disk-wise rapid scanning of the tumor tissue relative to depth scanning by ion beam energy control means. For this, the electromagnets are controlled by responsive power supplies and gauges. These devices can thus also be used to achieve a correction and adaptation when scanning a tumor tissue with temporal and spatial change in location of the tumor tissue in the treatment room orthogonal to the ion beam axis.

In a preferred embodiment of the invention, the device has at least one accelerator with which the energy of the ion beam can be adjusted, so that the tumor tissue can be irradiated slice by slice in depth.

This has the advantage that one after the other, the entire tumor tissue is scanned disc by disk, from disk to disk, the range of the ion beam is adjustable by changing the energy of the ion beam. The accelerator consists for this purpose essentially of a synchrotron or a synchro cyclotron in which ions of equal mass and the same energy can be accelerated in stages to higher energies. The energy adaptation of the ion beam to predetermined ranges within the irradiation space or Within the tumor volume is due to the complexity of the control functions for the accelerator not so short-term and with the required precision adaptable that the movements of the tumor tissue or the patient can be followed automatically.

In a preferred embodiment of the invention, therefore, the depth-scan matching device has two cross-section wedge-shaped ion-brake plates covering the entire irradiation field of the ion beam and enabling rapid depth-scan adjustment on moving tumor tissue.

For this purpose, the ion-braking plates are arranged on electromagnetically actuated carriage in a preferred embodiment of the invention. With the aid of these electromagnetically actuated slides, the position of the wedge-shaped ion-braking plates can be changed within milliseconds and thus the length of the Abbremsweges of the ions in an overlap region of the wedge-shaped braking plates can be varied by the ion-braking plates. For this purpose, the ion-braking plates overlap in the entire irradiation field of the ion beam and can thus adapt the ions within their range to local and temporal changes of a moving target volume, regardless of location.

In a preferred embodiment of the invention, the ion-braking plates are mounted on linear motors. Such linear motors have the advantage that a continuous fine adjustment of the ion deceleration is possible for adjusting the depth scanning of the target volume. In addition, the adjustment of the position of the wedge-shaped ion-brake plates by means of linear motors not only locally extremely precise, but also very responsive to temporal shift of the target volume in depth adaptable.

In another embodiment, instead of the wedges, a water-filled cylinder whose thickness varies is used. The covers of the cylinder consist of transparent plates, eg made of two plexi or quartz glass discs, of which the upper disc is moved by 2 or 4 powerful linear motors. The side cover of the cylinder is realized by a bellows made of steel or rubber. The variation in the thickness of the water layer is aided by a hydraulic system that pumps water into the cylinder as the cylinder is pulled apart and sucks water as it is compressed to relieve the drive and prevent the formation of vacuoles.

This embodiment has the advantage that a smaller minimum thickness than in the wedges is possible. For the wedges, the minimum thickness is calculated from wedge pitch x field size (typically 5 cm). In the cylinder design, the minimum thickness is given by the thickness of the two covers (typically 1 cm). This small minimum thickness reduces the scattering of the beam and thus improves the beam quality. Furthermore, the cylinder construction in the transverse direction is more compact than the wedge construction.

In a further preferred embodiment of the invention, the movement detection device has at least two measuring sensors which detect the temporal and spatial position of markings on a body region of a patient contained in a tumor tissue from two solid angles with respect to an ion beam axis. Such markings can be applied with skin-compatible luminous colors in the form of dots, lines or other geometric shapes or as lighting elements in order to be clearly perceived and measured by the measuring sensors.

In a further preferred embodiment of the invention, the transducers are precision video cameras which interact with an image evaluation unit. This advantageously achieves that the movements of a body region in the vicinity of a tumor tissue can be measured accurately and can be correlated with the temporal and spatial displacements of the tumor tissue.

As an alternative to the motion detection system using markings on the body surface and a precision video system, another embodiment of the invention includes an x-ray system that detects movements of the tumor tissue directly in the body. In this motion detection system, two x-ray tubes are mounted with beam direction orthogonal to the ion beam. The two x-ray tubes are also oriented perpendicular to each other. For this purpose, two opposing, on the other side of the patient sensitive X-ray image intensifier are attached. The X-ray tubes emit short low power X-ray flashes to keep dose exposure low, at a frequency of, for example, 20 Hz. The associated X-ray images are recorded and digitized by the image intensifiers. As a result, a sequence of images for two directions is obtained from which, with a suitable method and corresponding software, the displacement of the target points P_i is determined in near real time at about 50 ms delay.

This embodiment has the advantage that much more information about the movements in the interior of the body is obtained from the x-ray images than from external markings on the body surface. This allows a more precise determination of temporal and local organ shifts.

In principle, the irradiation of the tumor volume is composed of pixels which are arranged in a grid-like manner in a disk shape, the ion beam being deflected from sample point to sample point orthogonal to its beam axis in an X and Y direction. Although the energy of the ions in an ion beam can be kept constant by the corresponding accelerator, the number of ions per volume point over time is not constant. In order nevertheless to irradiate an equally large dose of ion beam in each volume point of the tumor tissue, in a preferred embodiment of the invention an ionization chamber with rapid readout for monitoring the intensity of the ion beam current is arranged as a transmission counter in the beam path of the ion beam. Such a transmission counter determines the residence time of the ion beam at a volume point of the tumor volume to be irradiated, and a control unit connected thereto deflects the ion beam to the next volume point as soon as a predetermined radiation dose is reached. Thus, advantageously, a volume slice of a tumor volume can be scanned in a grid-like manner in a planar manner.

Preferably, the ionization chamber is located between the deflector and the depth-scan adapter, especially as the depth-scan adapter with its wedge-shaped ion-brake plates or water layer between transparent plates controls only the ions within its range, but does not affect the ion dose.

A method for irradiating a tumor tissue of a patient by means of ion beam for use of the device according to the invention comprises the following method steps:<ul id="ul0001" list-style="dash" compact="compact"><li>Positioning the patient on a patient contour adapted device for placing the patient in an irradiation room,</li><li>Applying markings on a body region of the patient near the tumor tissue,</li><li>Detecting the temporal and spatial change of the markers via a movement detection device or detecting X-ray images of the tumor tissue from two mutually perpendicular directions of X-rays orthogonal to the ion beam,</li><li>Tracking the ion beam upon scanning the tumor tissue with an ion beam deflector and an ion beam energy controller by means of an additional depth scan adapter which adjusts the range of the ion beam to the temporal and spatial changes in the markings detected by the motion detector in cooperation with the ion beam deflector.</li></ul>

With this method, it is advantageously possible to achieve the same precision as in the fixed patient even in the moving patient in the millimeter range in the irradiation of moving tumor volumes, even if the tumor tissue is moved up to several centimeters periodically, for example by heartbeat or breathing air , The ion beam irradiation constantly follows the temporal and spatial shift of the tumor tissue and it does not have to wait with the irradiation until a repetitive local situation is reached. Even slow movements of the patient, which are non-periodic, are permissible and can be adjusted by means of the depth adjustment device and the deflector temporally and spatially in their ion irradiation. Only in the case of sudden changes of position such as coughing fits, the irradiation process must be stopped.

Compared to methods which allow only irradiation when reaching identical layers of tumor tissue, the method has the advantage that the irradiation time of a patient can be significantly shortened, since the irradiation process, for example, is not dependent on the periodicity of the heartbeat or the respiration of a patient.

Further advantages and features of the present invention will now be explained in more detail by means of embodiments with reference to the accompanying drawings.

Fig. 1 shows a schematic diagram of an embodiment of the invention under irradiation of a tumor tissue in the thorax region of a patient.

Fig. 2 shows a schematic diagram of an embodiment of a movement detection device.

Fig. 3 shows a comparison between adjacent Volumenabtastpunkten with locally and temporally fixed and thus static target volume and spatially and temporally moved and thus dynamic target volume.

4 shows a schematic diagram of an embodiment of the invention under the irradiation of a tumor tissue in the head region of a patient.

5 shows a schematic diagram of an ion-braking device by means of variable water volume.

6 shows a schematic diagram of a further embodiment of the invention with irradiation of the tumor tissue in the head region of a patient.

FIG. 1 shows a schematic diagram of an embodiment of the invention under irradiation of a tumor tissue 3 in the thorax region 23 of a patient 10th For this purpose, the device has an ion beam 2 which is deflected from its ion beam axis 15 by an ion beam deflector 1 orthogonal to the ion beam axis 15, in an X direction when passing through a gap 24 of an electromagnet 13 and in the Y direction when passing through a Gap 25 of an electromagnet 14, wherein the gaps are perpendicular to each other.

The ion beam also passes through an electromagnetically driven in the direction of arrow R ion-stopping device 11 before hitting the tumor tissue 3 of a patient, 12 which is used as a depth-scan adjustment device 5 for adjusting the range of the ion beam 2 and has a faster depth adjustment than a power control device (not shown), with the energy of the ion beam before entering the column 24, 25 the electromagnets 13 and 14 is controlled.

The ion beam energy controller, not shown, effects a staggered depth scan of the tumor tissue 3, whereby by stepwise increasing the energy, the ion beam penetrates deeper into the tumor tissue after each slice scan, ultimately destroying the entire tumor tissue by slice-wise depth scanning of the ion beam.

Upon movement of the patient 10 sketched here into a position which is drawn with a dashed line, the position of the tumor tissue 3 also shifts, so that healthy tissue would be irradiated and destroyed during a static irradiation which can not follow the patient's movement.

To avoid this, the device in FIG. 1 a movement detection device 7 for detecting a temporal and spatial change in the position of the tumor tissue 3 in a treatment room 8. This movement detection device 7, which in this embodiment of the invention consists of two precision video cameras 21 and 22, tracks the movement of markings on a body region of the patient 10 and communicates with an image evaluation device which detects the detected change values ​​of the markers with the temporal and spatial variation of the markers Location of tumor tissue 3 correlated.

One in Fig. 1 Not shown control device controls both the deflector 1 with the two electromagnets 13 and 14 and the Tiefenabtast-adjusting device with the ion-Abbremseinrichtung 11, 12 for tracking on the one hand the ion beam direction and on the other hand, the ion beam range in scanning the tumor tissue with temporal and spatial change in position of the tumor tissue 3 in Treatment room 8. With the in Fig. 1 The device shown achieves a higher precision of the beam application and thus an improved clinical success in the more than one hundred year history of the development of radiotherapy.

The continued increase in precision has led to the use of this scanning system of two mutually perpendicular electromagnets through whose magnetic column, an ion beam is guided and deflected. In the application of the device of FIG. 1 the target volume, namely the tumor tissue 3, is scanned with a fine beam of ions of variable intensity. The diameter of this ion beam is in the millimeter range and the precision with which the target volume can be exposed to an ion dose is also in the range of a few millimeters.

When the target volume 26 is displaced during the irradiation, there is a deviation between the current radiation center of gravity and the current target point and thus an incorrect irradiation within the target volume 26. This is associated with a local underdosage or overdose. Therefore, scanning methods without the inventive apparatus of FIG. 1 can not currently be applied to moving target volumes 26.

Other irradiation devices work with greatly expanded beam and with a likewise very widespread maximum dose depth. Such expanded beams can detect the entire target volume slice-by-slice and, due to the large field of radiation, can not produce dose inhomogeneities within the target volume, as would be the case with the use of slice-type scanners when the target volume was moved. The movement of organs affects only peripherally in devices with expanded beam and can therefore be compensated by increasing the irradiation volume, so that moving parts of the target no longer leave the irradiation volume. Conversely, this means that a large area of ​​healthy normal tissue must be irradiated along the edge of the target volume, so that with a widened beam with simultaneous movement of the irradiated body reduced precision and simultaneously increased negative side effects for the patient the result.

With a device as shown in FIG. 1 is shown, but without a depth-scan adjustment device 5, organ movements can only be taken into account if the cross-section of the ion beam 2 is significantly increased. However, such a solution also means a reduction in the precision in the lateral region, and in the longitudinal dose profile no correction takes place, since with a beam expansion, the movement in the beam direction can not be corrected. Thus, in the case of a beam widening to cover the organ movements, an inhomogeneous dose distribution of the inner target volume in the beam direction still results.

Another possibility, the device of FIG. 1 Without the use of a depth-scan adjustment device 5 and nevertheless taking into account organ movements, it may be that with the aid of the movement detection device 7 periodic movements of, for example, the thorax region of a patient are detected and irradiation only takes place when the thorax assumes identical positions. Such a device, in which no depth adjustment device is provided, but the periodic movement of a thorax of a patient is detected, the irradiation or To extend the treatment time of a patient by a multiple, since for each volume point in the disk-by-sample scanning of the tumor volume, the identical position of the tumor is first to wait. Only a beam widening can here reduce the treatment time to realistic sizes, which in turn, as mentioned above, is associated with a loss of precision.

Thus, the device according to the invention proves to be the concept with which the penetration depth of the ion beam can be optimally adapted to the organ movements of a patient, so that a tumor tissue can be irradiated with millimeter precision with temporal and spatial changes of position with high precision.

FIG. 2 shows a schematic diagram of an embodiment of a movement detection device. 7 This embodiment detects the movement of a body region of a patient 10 by means of second precision video cameras 21 and 22, which detect markings 4 on the thorax of a patient 10 from two different solid angles α and β and supply them to an image evaluation unit (not shown). The markers 4 are chosen so that they are arranged on the one hand in the vicinity of the tumor tissue to be irradiated and on the other hand detect the thorax movements so accurately that can be closed on the temporal and spatial changes of the markers 4 on the temporal and spatial shifts of the tumor tissue.

The solid angles α and β in the Cartesian coordinate system of the irradiation space 8 with the coordinate directions X, Y and Z have solid angle components α_x, α_y and α_z for the solid angle α and β_x, β_y and β_z for the solid angle β. With these components, the solid angles α and β are uniquely correlated in the irradiation space 8 with the coordinate system X, Y and Z.

The position of a first precision video camera 21 in this case has the projection points A_α, B_α and C_α on, wherein the projection point A_α the plane spanned by the coordinates X and Z, the projection point B_α the plane spanned by the coordinates Y and X and the projection point C_α pierces the plane spanned by the coordinates Z and Y level. The position of the second camera 22 has the projection point A_β, B_β and C_β on, wherein the projection point A_β the plane spanned by the coordinates X and Z, the projection point B_β the plane spanned by the coordinates Y and X and the projection point C_β the plane that is spanned by the coordinates Z and Y pierces. The position of the precision cameras 21 and 22 in the irradiation space 8 is also uniquely defined via these projection points, the coordinates of the solid angle α of the first precision video camera 21 x_α, y_α and Z_α and the coordinates of the solid angle β at the position of the second precision video camera 1 x_β, y_β and Z_β are.

The largest organ movements and thus the greatest temporal and spatial changes of the mark 4 result in a patient in the lung area during breathing. In the middle thoracic region 23, displacements with amplitudes of up to 1 cm and at the edge of the lung of up to 3 cm are detected. These shifts through breathing are periodic. The displacement of the internal structures is correlated with the movements of the body surface. Therefore, optical monitoring and detection of the body surface by means of the precision video cameras 21 and 22 respectively provide actual location coordinates of the internal structures. For this purpose, 4 color strokes, color dots or lighting elements such as light-emitting diodes can be attached to the body surface as markings. Thus, advantageously without invasive surgery, the geometry can be detected in the patient's interior at any time and thus a temporal course of the shifts of the internal structures and the tumor tissue and the speed of the respective movements are detected.

Fig. 3 shows a comparison between adjacent volume sampling points P_i and P_{i + 1} or P '_{i + 1} with spatially and temporally fixed and thus static target volume V_s or spatially and temporally moved and thus dynamic target volume V_d, The detection of the movement of the internal structures in correlation to the surface must be known before the irradiation. This can come from model calculations or from measurements.

If a momentary image is assumed at the time t = 0, the target volume in layers with a depth coordinate z_i same particle range and each layer with a lateral network in the X and Y directions with reference pixels, the Volumenabtastpunkten P_i (x_i, y_i, z_i) cover. During irradiation, these pixels are moved to a position P 'due to movement._i (x_i + Δx_i (t) y_i + Δy_i (t) z_i + Δ z_i (t)) shifted. The deviations or shifts Δx, Δy and Δz result from the three-dimensional velocity distribution of the organ movement in the time Δt, which is necessary for the dose application of a volume point P of the tumor tissue 3. For a maximum stroke of the thorax region 23 of 3 cm and a respiration frequency of about 0.5 Hz, that is to say a duration of 2 s, the organ movements, for example, have a speed of about v_organ = 3 cm / s.

The pixels P_i, which now become Volumenabtastpunkten lie in a lateral and longitudinal scanning 1 to 3 mm apart, that is, after an irradiation dose at point P._i the next adjacent point is in 1 to 3 mm distance P_{i + 1} approached and introduced again in this Volumenabtastpunkt a radiation dose. The time to dose the dose in a volume sampling point P_i or P_{i + 1} is less than 10 ms. Consequently, the target point in these 10 ms moves by a maximum of 0.3 mm, which is much less than the distance between two Volumenabtastpunkten P._i and P_{i + 1}, Since the currently irradiated Volumenabtastpunkt P_i while irradiation moves by less than the blurring of the irradiation, it is not necessary to change the point P_i to move during the respective irradiation. After irradiation of P._i the beam must be at a point P '_{i + 1} wandering from the originally planned point P_{i + 1} is removed according to the coordinate movement of the organ. This organ movement is denoted by r in FIG. 3 and results from the velocity r = v_organ · At. The actual position of the (i + 1) -th point is:<maths id="math0001" num=""><math display="block"><mrow><msub><mrow><mtext>P '</mtext></mrow><mrow><mtext>i + 1</mtext></mrow></msub><msub><mrow><mtext> = (x</mtext></mrow><mrow><mtext>i + 1</mtext></mrow></msub><msub><mrow><mtext> + Δx</mtext></mrow><mrow><mtext>i + 1</mtext></mrow></msub><msub><mrow><mtext> (t), y</mtext></mrow><mrow><mtext>i + 1</mtext></mrow></msub><msub><mrow><mtext> + Δy</mtext></mrow><mrow><mtext>i + 1</mtext></mrow></msub><msub><mrow><mtext> (t), z</mtext></mrow><mrow><mtext>i + 1</mtext></mrow></msub><msub><mrow><mtext> + Δz</mtext></mrow><mrow><mtext>i + 1</mtext></mrow></msub><mtext> (T)).</mtext></mrow></math><img file="EP1294445B1_D0001.tif" /></maths>

The deviation or displacement of the moving points P'i from the original static network of the volume sampling points P_i results from the shift during the irradiation time. In the usual cyclic and periodic movements such as breathing, heart rate, etc. These points also undergo a cyclic curve that can be correlated with the movement of the body surface. Therefore, a parameterization of the way with time is possible. Nichtzy cyclic processes can be controlled with the device and the method according to the invention for irradiating a tumor tissue of a patient by means of ion beam only if the movement does not occur spontaneously, but at a speed which is much slower than the scanning speed of the ion beam. In sudden hasty movements, such as occur in a coughing fit, the device must be switched off at short notice to protect healthy tissue from incorrect dosage.

FIG. 4 shows a schematic diagram of an embodiment of the invention under irradiation of a tumor tissue 3 in the head region 6 of a patient 10th The device of FIG. 4 corresponds substantially to the device of FIG. 1 and also has two electromagnets 13 and 14 for deflecting the ion beam 2 from its axial direction 15, the ion beam being controlled in its range by wedge-shaped ion-braking plates 16 and 17 in profile. The overlapping areas 28 and 29 cover at least the entire irradiation area, whereby the braking distance of the ion beam 2 by the braking plates 16 and 17 is increased by moving the wedge-shaped profiles of the braking plates 16 and 17 together and thus the range of the ion beam is reduced. By moving apart of the wedge-shaped braking plates of the Abbremsweg is reduced and thus increases the range of the ion beam.

The direction of movement of the wedge-shaped braking plates 16 and 17 is indicated by the arrows R in FIG. 4 indicated. The slidable brake plates with wedge-shaped profile are driven in this embodiment with a powerful linear motor, so that a beam-intensive controlled depth adjustment can be completed. For the linear drive, the depth-scan adjustment device 5 has an electronic control system which interacts with the movement-detection device 7 and the deflection device 1. To ensure a quick response, the runners of the linear motor, which carries the brake plates 16 and 17 on a carriage, are air-bearing, and the motor currents of the linear motor are controlled by a stepper motor controller.

Fig. 5 shows a schematic diagram of an ion-Abbremseinrichtung 43 by means of variable volume of water. Components with the same functions as in the preceding figures are identified by the same reference numerals and are not explained separately.

Reference numeral 44 denotes a water layer sandwiched between two transparent plates 31 and 32. Of the transparent plates 31, 32, the plate 31 is movable by means of linear motors 34 and 35. The number of linear motors can be arbitrarily increased to increase the speed of displacement of the plate 31. The water layer 44 is secured laterally at the outlet by a bellows 37. To catch the water volume or Add water depending on the direction of movement in the direction of arrows G and F, a surge tank 36 is provided which hydraulically supports the linear motors 34 and 35 in that water is pumped in enlarging the water layer 44 and 44 water is sucked off when reducing the thickness of the water layer. The reference numeral 33 indicates the space filled with water. The ion beam 2 is sent through the water layer 44 for deceleration and must also penetrate the transparent plates 31 and 32, which may be made of glass or Plexiglas. The slightest deceleration is achieved when the two plates 31 and 32 are on top of each other. Then they also have an extremely small thickness, which minimizes the scattering of the ion beam.

6 shows a schematic diagram of a further embodiment of the invention under irradiation of a tumor tissue 3 in the head region of a patient. Components having the same functions as in the previous figures are identified by the same reference numerals and will not be discussed separately.

This further embodiment differs from the embodiment according to FIG. 4 in that not the wedge system is used as the ion-braking device 43, but the in Fig. 5 shown Abbremseinrichtung 43. Furthermore, the further embodiment differs in FIG. 6 from the embodiments in FIG. 1 and FIG. 4 in that a system comprising at least two x-ray tubes is used as the movement detection system. The transducers 19 and 20 are x-ray tubes that direct x-rays 38 and 39 at a right angle to each other on the tumor tissue 3 of the patient 10. These X-rays are directed by X-ray flashes with low power at a frequency of, for example, 20 Hz on the tumor tissue and received by respective image intensifier plates or sensor plates 40 and 41, which pass their signals to the evaluation unit 42. This movement detection system with X-rays can track the movements of the tumor volume directly inside the body and thus control the deceleration device 43 very precisely.

1. Implementation example of the method for using the device according to the invention

In a first implementation example of the method, before the irradiation, the surface of the patient is provided with significant markings, such as Color markings on the skin or light emitting diodes, etc .. For example, the patient is placed on a foam bed as shown in FIG. 1 and FIG. 4 with the reference numeral 30 stored, which is adapted to his body. This allows a storage accuracy of approx. 1 cm can be achieved. In irradiation position, as the figures Fig. 1 and FIG. 4 10, the patient 10 is monitored with a precision video system of at least two precision video cameras 21 and 22 from different spatial directions at solid angles α and β which determine the position of the markers 4 (see FIG. 2) as a function of time and a time-dependent correction function of the pixels or Volume scan points P_i'(t) create.

In order to achieve a fast displacement of the ion beam 2 in three dimensions, the lateral intensity-controlled raster scanner of two electromagnets 13 and 14 is combined with a depth-scan matching device 5, since a rapid energy variation by an ion beam energy control device during the irradiation of a volume point P of no ion accelerator ago is possible. The lateral scanning part, which as mentioned above consists of two electromagnets whose deflection direction is perpendicular to each other and the beam axis 15, is controlled by fast power supplies, so that a fast lateral scanning adjustment in the X and Y direction is ensured.

In addition to the scanning device 1 in the X and Y directions, an electromechanically operated depth-scanning matching device is arranged directly in front of the patient, essentially consisting of two wedges, which are mounted in opposite directions on a linear motor and cover the entire irradiation field. This depth-scan adjustment device merely serves to correct the depth-positional change of the pixels by movement of the patient or the patient's organs. This depth-scan adjustment device does not have to illuminate the entire depth of the target volume.

For coarse depth variation, the energy variation of a synchrotron or other accelerator is used. In this case, the beam current is monitored with an ionization chamber installed in the beam path in front of the patient and read from a volume sampling point P_i to the next sampling point P_{i + 1} switched on when the required particle dose per Volumenabtastpunkt P is reached. At the same time, the surface motion is measured according to the precision video camera monitoring of the patient and from this the movement of the internal structures in the target volume is calculated.

Due to the migration of the target points in three dimensions, the magnet values ​​of the deflection magnets and the depth adjustment values ​​of the wedge-shaped braking plates are corrected. Since the beam is not interrupted in this type of process and the device during the irradiation, there are no unexposed spots in the tumor tissue. The precision inside and also the sharp edge drop of a static radiation is thus also achieved for moving organs under dynamic irradiation.

In addition, the device and method is also invariable to the compression of bulk doses. For a volume compression, eg in the lungs, the pixels come closer together. This increases the local particle fluence. At the same time, the compression also increases the mass density. Since the dose is defined as the energy deposition per density, it remains as a first approximation during compression. This means that the particle movement of the individual beam positions during irradiation does not have to be corrected in the apparatus and method according to the invention.

Second Implementation example of the method for using the device according to the invention

In a second embodiment of the method, instead of the mark on the body of the patient, the temporal and local changes of the tumor tissue are detected directly by X-rays. For this purpose, after the patient has been aligned, two X-rays are directed onto the tumor tissue, which are arranged perpendicular to the ion beam 2 and which deliver short X-ray flashes at low power, in order to minimize the dose load on the patient. These flashes may be directed at the tumor tissue at a frequency of about 20 Hz. The X-ray directions are mutually offset by 90 ° and together they are arranged orthogonal to the ion beam 2. With the help of the X-ray flashes image intensifier plates are exposed, which give their signals to an evaluation unit 42, wherein the evaluation unit 42 control the Abbremseinrichtung 43. The braking device 43 is in this second embodiment of the invention, a water layer 33, the thickness of which is varied and which is arranged between two transparent plates 31 and 32. The rapid variation of the water layer thickness is effected by changing the gap 33 between the two transparent plates 31 and 32. This shift is made by linear motors 34 and 35, at the same time a surge tank 36 ensures the pressure equalization and the volume compensation of the water. All other irradiation steps for the treatment of the tumor volume correspond to the procedural steps already mentioned in the first implementation example.

LIST OF REFERENCE NUMBERS

<dl id="dl0001" compact="compact"><dt>1</dt><dd>Ion beam deflecting means</dd><dt>2</dt><dd>ion beam</dd><dt>3</dt><dd>tumor tissue</dd><dt>4</dt><dd>mark</dd><dt>5</dt><dd>Depth-wise adaptation device</dd><dt>6</dt><dd>head area</dd><dt>7</dt><dd>Movement detection device</dd><dt>8th</dt><dd>treatment room</dd><dt>9</dt><dd>Ion beam energy control device</dd><dt>10</dt><dd>patient</dd><dt>11, 12</dt><dd>Ion-braking device</dd><dt>13</dt><dd>Electromagnet for X-deflection</dd><dt>14</dt><dd>Electromagnet for Y-deflection</dd><dt>15</dt><dd>Ion beam axis</dd><dt>16, 17</dt><dd>Ion-braking plates</dd><dt>19, 20</dt><dd>two transducers</dd><dt>21, 22</dt><dd>two precision video cameras</dd><dt>23</dt><dd>thorax</dd><dt>24</dt><dd>Gap of the electromagnet 13</dd><dt>25</dt><dd>Gap of the electromagnet 14</dd><dt>26</dt><dd>target volume</dd><dt>27</dt><dd>Edge of the lung</dd><dt>28, 29</dt><dd>Overlapping areas</dd><dt>30</dt><dd>foam bed</dd><dt>31, 32</dt><dd>transparent plates</dd><dt>33</dt><dd>gap</dd><dt>34, 35</dt><dd>linear motors</dd><dt>36</dt><dd>surge tank</dd><dt>37</dt><dd>bellow</dd><dt>38, 39</dt><dd>X-rays</dd><dt>40, 41</dt><dd>sensor plates</dd><dt>42</dt><dd>evaluation</dd><dt>43</dt><dd>Ion-braking device</dd><dt>44</dt><dd>water layer</dd></dl><dl id="dl0002" compact="compact"><dt>V_s</dt><dd>static target volume</dd><dt>V_d</dt><dd>dynamic target volume</dd><dt>P, Pi</dt><dd>Volumenabtastpunkt</dd><dt>P_{i + 1}</dt><dd>to P._i adjacent volume sampling point</dd><dt>α, β</dt><dd>solid angle</dd><dt>α_x, α_y, α_z</dt><dd>Components of the solid angle α</dd><dt>β_x, β_y, β_z</dt><dd>Components of the solid angle β</dd><dt>x_α, y_α, z_α</dt><dd>Coordinates of the solid angle α at the first camera position</dd><dt>x_β, y_β, z_β</dt><dd>Coordinates of the solid angle β at the second camera position</dd><dt>A_α, B_α, C_α</dt><dd>Projection points on the levels XZ (A_α); YX (B_α); ZY (C_α) of the first camera position</dd><dt>A_β, B_β, C_β</dt><dd>Projection points on the levels XZ (A_β); YX (B_β) and ZY (C_β) of the second camera position</dd></dl>