EP1948313A1

EP1948313A1 - Particle therapy installation, therapy plan, and irradiation method for such a particle therapy installation

Info

Publication number: EP1948313A1
Application number: EP06807775A
Authority: EP
Inventors: Sven Oliver GRÖZINGER; Klaus Herrmann; Eike Rietzel; Andres Sommer; Torsten Zeuner
Original assignee: Siemens AG
Current assignee: Siemens AG
Priority date: 2005-11-10
Filing date: 2006-11-08
Publication date: 2008-07-30
Also published as: US7834334B2; WO2007054511A1; US20080237495A1; DE102005053719B3

Abstract

The invention relates to a particle therapy installation for irradiating a volume of a patient to be irradiated with high-energy particles, comprising a radiation outlet of a radiation delivery and acceleration system from which a particle beam exits in order to interact with the patient positioned in an irradiation position, said irradiation position being defined in a therapy plan relative to an irradiation isocentre of the particle therapy installation; an imaging device for verifying the position of the volume to be irradiated in relation to the particle beam; and a patient-positioning device with which the patient can be brought into the irradiation position for irradiation, wherein the imaging device is designed for checking the position of the volume to be irradiated in an imaging position of the patient that is spatially remote from the irradiation position, and wherein the patient-positioning device is designed for automatic changing of position between imaging position and irradiation position.

Description

description

Particle therapy system, treatment ^plan and irradiation ^¬ method for such a particle therapy system

The invention relates to a particle therapy system for irradiating a volume of a patient with high-energy particles to be irradiated, which has a beam exit of a beam delivery and acceleration system from which exits a particle beam to interact with the positioned in an irradiation position patient, the irradiation position is given with respect to an irradiation isocenter of the particle therapy facility; the particle therapy system further comprises an imaging device for verifying the position of the target volume with respect to the particle beam and a patient positioning device, with which the patient can be brought to the irradiation position for irradiation, wherein the imaging device is designed to verify the position of the volume to be irradiated in an imaging position of the patient that is from the

Radiation position is arranged spatially distant, and wherein the patient positioning device for automatic position change between imaging and irradiation position is formed. Furthermore, the

Invention, the planning and implementation of an irradiation with such a system.

Various irradiation systems and techniques are described by H. Blattmann in "Beam delivery Systems for charged particles",

Radiat. Environ. Biophys. (1992) 31: 219-231. A particle therapy system is known, for example, from EP 0 986 070.

An irradiation therapy facility according to the preamble of

Claim 1 can be found for example in JP 11009708 A, wherein a patient positioning is arranged between a magnetic resonance device and the gantry of a treatment system.

A particle therapy system usually has an accelerator unit and a high-energy beam guidance system. The acceleration of the particles, e.g. Protons, pions, helium, carbon or oxygen ions, for example, using a synchrotron or cyclotron.

The high energy beam transport system directs the particles from the accelerator unit to one or more treatment rooms. A distinction is made between "fixed beam" treatment rooms, where the particles hit the treatment site from a fixed direction, and so-called gantry-based treatment rooms, where the latter allows the particle beam to be directed at the patient from different directions.

A control and safety system of the particle therapy systems ensures that a particle beam characterized by the required parameters is guided into the corresponding treatment room. The parameters are defined in the so-called treatment or treatment plan. This indicates how many particles from which direction and with which energy should hit the patient.

Usually, the treatment plan is generated by means of imaging techniques. For this purpose, for example, a 3D data set is generated with a computed tomography device. The tumor is localized within this image data set and the required radiation doses, directions of incidence, etc. are determined.

During irradiation, it is necessary for the patient to assume the treatment position underlying the treatment plan. This is done, for example, with fixing masks. In addition, before the irradiation, the position of the Patients checked with imaging agents. In this case, the actual irradiation position is compared with the image data set on which the therapy planning is based.

In the case of this so-called position verification, images from different directions are compared with, for example, projections from the CT planning data record before irradiation. These are u.a. Also obtained radiographic images in the beam direction and orthogonal to the beam direction. These shots are taken in the irradiation position near the

Beam exit performed; that is, there is limited space for imaging.

Further, there are imaging methods for obtaining 3D image data sets that rely on transillumination from different directions. Similar to a CT image, 3D image data sets can be obtained from the image data. One option for such an imaging device is an imaging robot that can be freely aligned around a patient to be screened. For fluoroscopy of the patient from different directions, adequate space must be available. Another way of obtaining 3D images is e.g. a C-arm X-ray machine.

Such imaging units for obtaining SD image data sets require sufficient space to be able to illuminate the patient from different directions. That is, imaging unit elements must be capable of being moved around the patient at a sufficient distance for imaging.

In general, it is advantageous in particle therapy to position the patient as close to the beam exit as possible in order to minimize the spread of the beam due to scattering. A usual distance between the isocenter of an irradiation site and the beam exit is about 60 cm. The above-mentioned preferred distance of the irradiation isocenter from the beam exit restricts the imaging of the position verification to correspondingly less space consuming imaging devices.

An object of the invention is to enable the planning and execution of a patient's irradiation using a 3D imaging technique. Furthermore, it is an object of the invention to provide a method and a particle therapy system that allow to use also space-consuming imaging techniques in the position verification.

The object related to the above-mentioned particle therapy system is achieved by a particle therapy system according to claim 1. Furthermore, the object related to the planning or irradiation is achieved by a treatment plan according to claim 11 or an irradiation method according to claim 15.

In one embodiment of the particle therapy system, the imaging device is designed to verify the position of the volume to be irradiated in an imaging position of the patient. This imaging position is located spatially distant from the irradiation position and thus has at least the minimum distance of the imaging device from the beam exit necessary for 3D imaging. The imaging position is arranged between the patient positioning device and the irradiation position, whereby the travel paths from the imaging position to the irradiation position and back are particularly short. The patient positioning device is controlled, for example, by a control system that implements a corresponding therapy plan and if necessary causes the position change between imaging and irradiation position. An advantage of the invention is that an optimal distance to the beam exit can be set for each type of particle and for each irradiation procedure, without having to forego 3D imaging by a correspondingly space-consuming imaging device. This makes it possible on the one hand to perform a very precise irradiation with a particle beam, which due to the proximity to the beam exit diverges less and thus has a small beam diameter, and on the other hand, the position verification with 3D or at least 3D-like data sets can be performed.

In an advantageous embodiment of the particle therapy system of the imaging position is associated with an imaging center, preferably with the

Irradiation isocenter is arranged on a beam center axis. In this case, the beam center axis is to be understood, for example, as the beam path given by the zero position of a raster scanning device.

In a further advantageous embodiment, the distance between the irradiation isocenter and the imaging center is not more than 2 m, preferably less than 1 m and, if possible, less than 0.5 m, so that during irradiation, the position verification, if possible without multiple loss of time by long travel paths, also multiple times can be made. This is particularly possible when the patient's travel is minimized, i.e. when e.g. the imaging center has or nearly the minimum distance to the irradiation iso center.

In an advantageous embodiment, the patient positioning device comprises a robotic patient table. Preferably, the

Patient positioning device controlled by a therapy control unit of the particle therapy system. This has the advantage that, for example, the Parameters for performing a change of position in the treatment plan can be stored, which is the therapy control unit for controlling the radiation is based.

A therapy plan is a data set created, for example, with a computer unit, in which, among other things, patient-related data are stored. These may include, among other things, a medical image of the tumor to be treated, and / or selected areas to be irradiated in the body of a patient and / or organs at risk whose radiation exposure should be kept as low as possible. Furthermore, this includes, for example, parameters which characterize the particle beam and which indicate how many particles from which direction and with which energy should strike the patient or specific regions to be irradiated. The energy of the particles determines the depth of penetration of the particles into the patient, i. the location of the volume element at which the maximum interaction with the tissue occurs in the particle therapy; in other

Words, the place where the maximum dose is deposited. On the basis of the therapy plan, the therapy control unit can determine the control instructions necessary for the control of the irradiation.

Such a therapy plan preferably comprises a reference point for positioning the patient in an imaging or irradiation position and information about the relative position of the imaging and irradiation positions relative to one another. The latter can be present, for example, in the form of a displacement vector, which defines a displacement movement of the patient positioning device of the therapy system, with which the patient is displaceable from the imaging position to the irradiation position. Preferably, the displacement vector is parallel to the beam axis of the particle beam. Such a treatment plan has the advantage that even during treatment planning there is freedom over the spatial choice of the irradiation isocenter, ie its distance to the beam exit. Because the position verification can be performed independently of the irradiation position.

Further advantageous embodiments of the invention are characterized by the features of the subclaims.

The following is the explanation of several embodiments of the invention with reference to FIGS 1 to 4. It is shown:

1 shows schematically an embodiment of a

Particle therapy system to illustrate the invention,

2 shows an exemplary flowchart for

Clarification of an irradiation method according to the invention in interaction with a treatment plan and

3 and 4 are schematic representations of a

Radiation station where the patient is in the imaging position and in the irradiation position.

1 schematically shows a particle therapy system 1 for irradiating a volume of a patient to be irradiated with high-energy particles. A

Particle accelerator system 3 imitates a particle beam 7 from a jet outlet 5. If the particle therapy system comprises, for example, a raster scanning device 9, then a scan region of, for example, 40 cm × 40 cm can be scanned. One

Isocenter 11 is preferably located centrally to the scan area. The particle beam diverges due to scattering processes in the beam or with irradiated matter, so that the Isocenter as close to the beam exit 5 is arranged to irradiate with the smallest possible beam diameter. When irradiated with protons, a distance of 60 cm is preferably selected. At this distance, the beam diverges to the desired beam size assumed in the therapy plan; For example, the irradiation is carried out with a raster scan method with a beam diameter of about 3 to 5 mm.

Furthermore, the particle therapy system 1 has a

Imaging device 13, which is preferably also designed to generate a 3D data set of the patient in the region of the volume to be irradiated. By means of the imaging device 13, the position verification of the volume to be irradiated with respect to the particle beam is to be undertaken. The imaging device 13 has an imaging center 15. The distance of the

Imaging center 15 from the beam exit 5 is due to the formation, i. the dimensions and structure, the imaging device 13 is greater than the distance of the

Irradiation isocenter 11 from the beam exit 5. Preferably, the imaging center 15 is also arranged on the beam center axis. The distance between the irradiation isocenter 11 and the imaging center 15 is kept as small as possible, for example, the distance of the irradiation center 15 from the beam exit 5 is 100 cm. A displacement in or against the beam direction of 40 cm can be carried out quickly and without stressing the patient during an irradiation session.

FIG 2 illustrates an irradiation session 21, which is carried out on the basis of a treatment plan 23. The treatment plan 23 has, in addition to the required beam parameters, the particle energy and particle intensity for, for example, different volume elements of the volume to be irradiated. In addition, it contains information about the position (X, Y, Z) of the irradiation isocenter and / or the position (X ₁ , Y ₁ , Z ₁ ) of the imaging center and / or a displacement vector 25. The irradiation session 21 preferably begins with a position verification 27 in which the patient is positioned in the imaging position according to the therapy planning in the irradiation center (X, Y, Z). Subsequently, a displacement 29 is performed according to the displacement vector 25. Now the patient is in the irradiation position. In this position, a first irradiation process 31 is performed.

If, for example, a suspicion arises during the irradiation that the position of the patient has changed, a second displacement 33 can now take place back into the imaging position in order to carry out a further position verification 35.

Such positional verifications can occur repeatedly, be it on the basis of suspected changes in position, for safety reasons, or to carry out further irradiation, for example, from another direction of incidence.

The preparation of the treatment plan 23 on which the radiation session 21 is based takes place, for example. in several steps. In one step, an imaging operation is planned in which an isocenter of the volume to be irradiated is located in the irradiation center of the imaging device. In this position (the imaging position), the imaging for verifying the position of the patient is to be performed according to the irradiation planning. No beam is planned and applied in this imaging position.

In another step, an irradiation process is planned. For this purpose, an irradiation isocenter is defined and one or more irradiation fields are planned. The

Planning of the irradiation process includes, for example, that at the beginning of the irradiation procedure, the patient is positioned by means of the patient positioning device such that the irradiation isocenter is located in an isocenter of the irradiation site. The irradiation isocenter is planned so that the patient moves as close as possible to the beam exit without danger, ie, the isocenter of the volume to be irradiated is moved from the imaging center to the irradiation isocenter. In this position (the irradiation position) then the actual irradiation takes place.

Further imaging procedures and irradiation processes, even under changed directions of incidence, can be planned as needed.

3 shows an example of a treatment room with a jet outlet 41, a patient positioning device 43 and an imaging device 45 with a

Imaging volume 47. The patient positioning device 43 has a patient couch 49 on which a patient 51 lies. The volume of the patient 51 to be irradiated lies, for example, within a skull 53 of the patient 51. The imaging volume 47 has an imaging center 55. The imaging center 55 is preferably located on the beam center axis 57 of the particle beam, e.g. at a distance of 100 cm to the beam exit 41. For positional verification, a photograph, preferably a 3D image of the volume to be irradiated, is then taken with the aid of the imaging device 45. The selected distance allows the imaging device to be positioned in all positions required for 3D imaging, i.e., e.g. to rotate around the imaging center. The 3D image is compared with images on which the therapy planning was based and, if necessary, the patient 51 is readjusted with the aid of the patient positioning device 43 to the position underlying the therapy planning. He is then in the imaging position defined in the therapy plan.

From the imaging position, the patient 51 is moved to the irradiation position shown in FIG. postponed. The volume previously to be irradiated around the imaging center 55 is now around the

Irradiation isocenter 61 and can be irradiated volume-specific, for example, using a raster scan device.

Claims

claims

1. Particle therapy system for irradiating a volume of a patient to be irradiated with high-energy particles having

a beam exit of a beam delivery and acceleration system, from which a particle beam emerges to interact with the patient positioned in an irradiation position, the irradiation position being given in a treatment plan relative to an irradiation isocenter of the particle therapy system,

an imaging device for verifying the position of the volume to be irradiated with respect to the particle beam,

a patient positioning device, with which the patient can be brought into the irradiation position for irradiation, wherein the imaging device is designed to verify the position of the volume to be irradiated in an imaging position of the patient, which is located remote from the irradiation position, and wherein the patient positioning device for automatic Position change between imaging and irradiation position is formed, characterized in that the irradiation iso center is adjustable in its distance from the beam exit.

2. Particle therapy system according to claim 1, characterized in that the irradiation isocenter is dependent on the particle type, e.g. Protons, carbon or oxygen ions, is adjustable.

3. Particle therapy system according to claim 1 or 2, characterized in that the imaging position between the

Patient positioning and the irradiation position is arranged.

4. The particle therapy system according to claim 1, wherein the position change of the patient from the imaging position to the irradiation position is based on a translational movement in the beam direction.

5. Particle therapy system according to claim 4, characterized in that an imaging center can be assigned to the imaging position, which in particular, like the irradiation isocenter, is arranged on a beam center axis.

6. The particle therapy system according to claim 1, wherein the

Distance between the irradiation position and the treatment position in the range ≤ 1 m, in particular ≤ 0.5 m.

7. Particle therapy system according to claim 1, wherein the imaging device is designed for 3D imaging.

8. The particle therapy system according to claim 1, wherein the

Imaging device has dimensions that define a minimum distance to the beam exit, and that the imaging device is arranged at least at this minimum distance from the beam exit, wherein the minimum distance is greater than the distance between the beam exit and Irradiation iso center.

9. The particle therapy system as claimed in claim 1, wherein the imaging device is a C-arm X-ray device or a C-arm X-ray device

Imaging robot, which are designed for 3D imaging rotatable about the imaging position, in particular around the imaging center, and that a Minimum distance to the beam exit is determined by the rotatability and the imaging device is arranged at least at this minimum distance from the beam exit.

10. The particle therapy system according to claim 1, wherein the patient positioning device comprises a robotic patient table that can be activated for patient displacement from the imaging position to the irradiation position, in particular by a therapy control unit of the particle therapy system.

11. Therapy plan for irradiating a patient with particles of a particle therapy system according to one of the preceding claims.

12. Therapy plan according to claim 11, comprising

a reference point for positioning the patient in an imaging or irradiation position, and information about the relative position of the imaging and irradiation positions relative to one another.

13. Therapy plan according to claim 12, wherein the information is given in the form of a displacement vector which defines a displacement movement of a patient support device of the therapy system with which the patient is displaceable from the imaging position to the irradiation position.

14. Therapy plan according to claim 13, wherein the displacement vector is parallel to a beam axis of the particle beam.

15. An irradiation method for irradiating a volume to be irradiated of a patient with high-energy particles of a therapy system according to one of claims 1 to 10 with the following method features:

- at least one imaging operation to verify the situation the volume to be irradiated, wherein an imaging of the volume to be irradiated is performed by means of an imaging device while the patient is in an imaging position,

at least one irradiation procedure in which the patient positioned in an irradiation position is irradiated, wherein the irradiation position of the patient with respect to an irradiation isocenter of the particle therapy system is given by the therapy plan and is arranged spatially remote from the imaging position,

- At least one position change operation in which a change in position of the patient from the imaging position to the irradiation position or from the irradiation position to the imaging position by means of actuation of a patient positioning unit.

16. Irradiation method according to claim 15, wherein for the change of position of the position change process, a displacement of the patient in or against the direction of irradiation takes place.