DE102014221562B4 - Method for positioning a patient in an irradiation device and therapy system - Google Patents

Abstract

The invention relates to a method for positioning a patient in an irradiation device (20), comprising at least the steps: storing and fixing the patient by means of fixing means (13) on a couch (12) of a CT device (10) in a first reclining position, performing a 3D CT scan of the patient fixed on the couch (12) and the 3D position marker (1), fixing an irradiation isocenter (I) in the 3D CT scan, transferring the positions and the position of the fixation means (13) relative to the couch (12) of the CT apparatus (10) and the position of the irradiation isocenter (I) relative to the couch (12) of the CT apparatus (10) on the irradiation apparatus (20), relocating and fixing the patient on a couch ( 22) of the irradiation device (20) by means of fixing means (23) in a second lying position identical to the first lying position on the basis of the transmitted relative positions, and automatic alignment of the couch (22), so that the irradiation isocenter (I) in the irradiation center (M) of the irradiation device (20) is arranged. Furthermore, the invention relates to a therapy system for carrying out the method according to the invention.

Description

The invention relates to a method for positioning a patient in an irradiation device and a therapy system for carrying out the method.

As part of the preparation and planning of a radiotherapy treatment, a recording of the patient with a CT device is created, which serves as a basis for calculating the dose to be applied to the patient and on the basis of which the so-called irradiation isocenter, for example, as the focus of a to be irradiated tumor of the patient. It is important for the radiation therapy treatment that the patient is stored during the CT scan just as during the subsequent irradiation. For this it is necessary that the patient with the help of fixations, for example, head masks, armrests, etc., is positioned on the couch. Here it must be ensured that the identical construction and position fixings are used both for performing the CT scan and during the irradiation, and also the settings of the fixations, for example an angle between the arm support and the couch surface, are identical. Furthermore, during irradiation, the patient's radiation isocenter must be aligned in a specific position. Although the position of the irradiation isocentre can be determined with the aid of the CT scan alone, it is not possible to draw any conclusions about the position and positioning of the patient in the room. The patient should be stored and aligned in the irradiation device in such a way that the irradiation isocenter lies in the center of rotation of the irradiation device, ie its center of irradiation.

Up to now, after the CT scan has been carried out, it is manually noted which fixations were used on the couch in the CT unit and in which settings, ie position on the couch, angle, length etc., these were. This is achieved, for example, by reading degrees at the corresponding joints of the fixation. In addition, photos are taken of the individual positions of the fixation. These settings on the fixations will later be reproduced on the couch of the irradiation device based on the notes and photos and the fixations are set there as well. However, manual writing and the lack of external verification make this process error-prone and inaccurate.

The publication DE 698 33 881 T2 (D1) describes a method for positioning a patient in an irradiation device.

To align and position the patient at the radiation isocenter, the patient has been identified with tattoos and radio-opaque lead marks, such as small globules. For this purpose, a reference point on the patient is determined with the help of an external laser system and marked with the help of skin tattoos as well as with lead markings, so that this reference point is also visible in the CT scan.

In the data of the CT scan, the position of the irradiation isocenter can then be compared with the position of the reference point. An accurate positioning of the patient ensures that the irradiation isocenter and the reference point are congruent. Initial deviations between these points, for example, initially offset by a manual moving and aligning the patient bed. However, this process is very time consuming, especially since the alignment of the patient based on the reference point has been done manually. Furthermore, this process is costly due to the need for an external laser system on the CT device and the lead markers used for the patient. An automatic calculation of the position of the couch or patient based on existing CT data is not yet possible.

It is therefore the object of the invention to provide a simplified and automated method for positioning the patient on a couch for radiotherapy treatment. Furthermore, it is an object of the invention to provide a therapy system for this purpose.

This object is solved by the subject matters of the independent claims. Advantageous developments of the invention are the subject of the subordinate claims.

The inventors have recognized that by means of cameras on the CT device and on the irradiation device, the position of the patient can be optically detected, compared and aligned, so that the storage of the patient during the CT scan corresponds to the storage during the subsequent radiation therapy treatment in the irradiation device. In addition, the patient fixed on the couch can be aligned in the irradiation apparatus so that the previously defined irradiation isocenter is located in the irradiation center of the irradiation apparatus.

For this purpose, the fixations on the couch of the CT device and on the couch of the irradiation device are marked so that their positions are clearly recognizable both in an optical image and in the CT scan. The exact position of the patient, for example, where a hand or an elbow can be determined hereby. Furthermore, markings are applied to the couches of the CT apparatus and the irradiation apparatus in order to be able to determine the positions of the couches and the fixations relative to the CT apparatus or to the irradiation facility.

Using the camera on the CT scanner, the markers can be used to capture the positions of the fixations and the couch in a fixed coordinate system of the CT unit and to determine their orientation and position in the room. The exact fixation and lying position of the patient in the CT device is thus known. In the CT scan, the patient's radiation isocenter is also defined in the coordinate system of the CT device. The relative position of the irradiation isocenter to the markings or the fixations and the couch can also be determined by CT scan.

At the treatment device, the patient is positioned on the couch with an identical fixation and lying position as in the CT device. For this purpose, the fixations previously used in the CT device, their type, alignment, etc., as well as the determined positions of the fixations and the couch are transferred to the irradiation device. The camera on the irradiation device detects the positions of the fixations and the couch in a fixed coordinate system of the irradiation device.

The determined positions in the CT apparatus and in the irradiation apparatus are compared with one another, in particular the position of the defined irradiation isocentre is compared with the known position of the irradiation center of the irradiation apparatus. If applicable, deviations of the irradiation isocenter from the irradiation center are automatically compensated for at the irradiation device, by automatically adjusting the reclining position of the patient. Thus, automatic alignment of the patient's irradiation isocenter is possible without the use of other aids, such as lasers or lead markers.

• – Lagern und Fixieren des Patienten mittels Fixiermitteln auf einer Liege eines CT-Geräts in einer ersten Liegeposition, wobei die Liege und die Fixiermittel 3D-Positionsmarker aufweisen, deren Positionen sowohl optisch als auch in einem 3D-CT-Scan eindeutig erkannt werden, wobei als 3D-Positionsmarker jeweils drei eine Ebene aufspannende Markierungselemente verwendet werden und für unterschiedliche Fixiermittel 3D-Positionsmarker mit unterschiedlichen Markierungselementen verwendet werden,
• – Durchführen eines 3D-CT-Scans des auf der Liege fixierten Patienten und der 3D-Positionsmarker,
• – Festlegen eines Bestrahlungsisozentrums in dem 3D-CT-Scan,
• – Übertragen der Positionen und der Lage der Fixiermittel relativ zur Liege des CT-Geräts sowie der Position des Bestrahlungsisozentrums relativ zur Liege des CT-Geräts auf das Bestrahlungsgerät,
• – Umlagern und identisches Fixieren des Patienten auf einer Liege des Bestrahlungsgerätes mittels Fixiermitteln mit identischen 3D-Positionsmarkern und Markierungselementen in einer zu der ersten Liegeposition identischen zweiten Liegeposition anhand der übertragenen relativen Positionen, wobei die Liege und die Fixiermittel 3D-Positionsmarker aufweisen, die optisch erkannt werden und die die Position und Lage der Liege und der Fixiermittel eindeutig festlegen, und
• – automatisches Ausrichten der Liege mit dem darauf fixierten Patienten, sodass das zuvor festgelegte Bestrahlungsisozentrum im Bestrahlungsmittelpunkt des Bestrahlungsgerätes angeordnet ist.

Accordingly, the inventors propose a method for positioning a patient in an irradiation device, comprising at least the steps:

• - Storing and fixing the patient by means of fixing means on a couch of a CT device in a first lying position, wherein the couch and the fixing means have 3D position markers whose positions are recognized both visually and in a 3D-CT scan, as 3D position markers are used in each case three marking elements spanning a plane and for different fixing means 3D position markers with different marking elements are used,
• Performing a 3D CT scan of the patient fixed on the couch and the 3D position markers,
• Determining an irradiation isocenter in the 3D CT scan,
• Transferring the positions and the position of the fixing means relative to the couch of the CT device as well as the position of the irradiation isocenter relative to the couch of the CT device on the irradiation device,
• - Relocating and identical fixing of the patient on a couch of the irradiation device by means of fixing with identical 3D position markers and marking elements in an identical to the first lying position second lying position based on the transmitted relative positions, wherein the couch and the fixing means have 3D position markers, the optically detected and which clearly define the position and position of the couch and fixative, and
• - Automatic alignment of the couch with the patient fixed thereon, so that the predetermined irradiation isocenter is located in the irradiation center of the irradiation device.

In a first step, the patient is stored on the couch of the CT device and fixed with the aid of fixing agents. Arms and / or leg supports, pads, etc. are used as fixing agents. The fixative serve to fix the patient for the examination on the couch in a clear lying position. The fixation means and the couch are provided with 3D position markers, referred to below for short as markers or markers, which can be recognized both visually and in a 3D CT scan. By the markers, the positions and the position of the fixing means relative to the bed and the absolute position of the bed are clearly defined.

According to the invention, three markers spanning one plane are used as 3D position markers. As a result, the position of a fixative or the couch can be clearly defined. The markers are preferably so-called optically passive position markers. Preferably, 3D position markers are attached to the same fixing means in the same relative positions. The marking elements are designed, for example, as simple 3D geometric shapes such as spheres, cuboids, pyramids, etc. The marking elements used are advantageously designed uniformly per marker. In addition, identical fixing means are advantageously marked with the same 3D position markers. As a result, in the optical recording or in the 3D CT scan additional information about the fixation of the patient can be detected. For example, the markers on armrests can generally be provided with other marking elements than the markers on the couch. In the transmitted position information is then easy to see which fixing means were used on the couch of the CT device in which position.

Advantageously, as soon as the patient is fixed and stored in an unambiguous position, an optical image of the patient on the couch with the fixing means is next created. In this case, the positions of the fixing means relative to the couch and the position of the couch are detected on the basis of the markings in a fixed coordinate system of the CT apparatus.

Furthermore, a 3D-CT scan of the patient fixed on the couch and the markings attached to the fixation means and to the couch are carried out. In turn, the positions of the couch and of the patient fixed with the fixing means are clearly recognizable in the scan.

In the 3D CT scan, the irradiation iso center is also defined. The irradiation isocenter is located in the body region of the patient, for example a tumor, which is subsequently to be irradiated in the irradiation device. For this purpose, in one embodiment, in this 3D CT scan, a predetermined body region of the patient, for example a tumor, can be determined and defined as an irradiation isocenter. In another embodiment, a predetermined body region is determined in a previously performed, another 3D examination of the patient, whose position and position are transferred to the 3D CT scan and defined there as a radiation isocenter. Advantageously, in this embodiment, it is not necessary to administer the patient again a contrast agent for the 3D-CT scan. For example, other 3D CT scans, SPECT, PECT, NMR, nuclear spin or ultrasound examinations can be used as 3D examinations. In the 3D examination data, the position of the area to be irradiated can be unambiguously determined by means of unchangeable positions in the patient, for example ribs or pelvic bones. The position data can then be transferred to the 3D CT scan, where this area is defined as the irradiation isocenter.

The position of the fixing means and the couch of the CT apparatus determined in the optical recording of the first reclining position of the patient as well as the position of the irradiation isocenter relative to the couch of the CT apparatus determined in the 3D CT scan are transmitted to the irradiation apparatus or to the reclining position of the patient on the couch there. The patient is then rearranged in a next step on the couch of the irradiation device and fixed there identically. Identical fixation in the sense of the invention means that the first reclining position on the recliner of the CT device, whose position and the fixing means used for this are known from the optical recording, is reproduced identically on the couch of the irradiation device, ie the second reclining position of the patient in the Irradiation device corresponds to the first lying position in the CT device. The couch of the irradiation device and the fixing means used here also have markings which are optically recognized and which clearly define the position and position of the couch and the fixing means.

Advantageously, identical, and in particular identical, beds are used for identical storage and fixing. Furthermore, this advantageously identical fixatives are used, which are attached to identical positions of the bed. However, it is also possible in principle to compensate for differences in the fixation with the fixatives and resulting differences in the lying positions mathematically.

The transmitted position of the irradiation isocentre is compared with the previously known position of the irradiation center, and any deviations of these positions are determined. Subsequently, the couch with the patient fixed on it is automatically displaced and aligned so that possible deviations are compensated and the irradiation isocenter is arranged in the irradiation center of the irradiation apparatus.

Overall, the inventive method has the advantage that the positions of the fixative and the couch relative to the CT device or to the irradiation device can be detected and the subsequent verification whether the same fixation was used and whether the same position was set on both devices. This can contribute to error reduction in the workflow and increase the accuracy of the irradiation. Furthermore, labor and time are saved by automatically moving the couch of the irradiation device to align the irradiation isocenter, rather than having to locate it using positioning lasers, markers on the patient, and manual table control.

Furthermore, the inventors propose a therapy system for carrying out the method according to the invention described above, at least comprising a CT device with at least one emitter-detector system, a couch for supporting a patient and a position detection device, an irradiation device with at least one irradiation device, a couch to Storage of the patient and a position detection device, a data transmission connection between the CT device and the irradiation device for transmitting position data, and a control and processing unit having at least one memory, is stored in the program code, which in operation a method for positioning a patient in a Irradiation device performs.

Both devices of the therapy system have couches for storing the patient. In this case, the couch of the CT apparatus is preferably of identical design, advantageously identical, to the couch of the irradiation apparatus. As a result, the identical storage of the patient on the couch of the irradiation device is facilitated. The first reclining position on the couch of the CT device can thus be simplified on the couch of the irradiation device and the patient stored in an identical second lying position. For this purpose, it is further advantageous that the couches have identical, in particular identical, fixing means for fixing the patient in an unambiguous lying position.

Furthermore, the couches and the fixing means each have 3D position markers which clearly characterize their position and position. According to the invention, the markers can be recognized both optically and in the 3D-CT scan performed. Advantageously, the markers each comprise three marking elements spanning a plane, which define a unique position. The marker elements per marker are preferably uniform, for example as a sphere, cuboid, etc., formed. Further advantageously, the markers are identically formed on the same fixing means. Thus, for example, in the CT scan, it can be easily recognized which fixing means have been used at which position, and this information can be easily transferred to the irradiation apparatus.

For carrying out the method according to the invention, the CT apparatus and the irradiation apparatus each have a position detection device for the optical detection of the 3D position markers. By means of the position detection device, an optical 3D image of the 3D position markers on the couch and on the fixed patient with the fixation means is received in the devices. The position detection device can be designed, for example, as at least two 2D cameras or at least one 3D camera. By means of these embodiments of the position detection device, a 3D image is possible in which the individual positions of the markers can be clearly recognized. Of course, however, other 3D capture devices may also be used to determine the positions.

In the following the invention with reference to a preferred embodiment with reference to the figures will be described in more detail, with only the features necessary for understanding the invention features are shown. The following reference symbols are used: 1 : 3D position marker; 2a . 2 B : Marking elements; 3 : Fastener; 10 : CT device; 11 : 3D camera of the CT device; 12 : Couch of the CT device; 13 : Fixative on the couch of the CT-device; 20 : Radiation device; 21 : 3D camera of the irradiation device; 22 : Couch of the irradiation device; 23 : Fixative on the couch of the irradiation device; 24 : Irradiation device; I: radiation isocenter; M: irradiation center; (x, y): coordinates / positions; (Δx, Δy): distance.

They show in detail:

1 : a 3D position marker in a first embodiment,

2 a 3D position marker in a further embodiment,

3 : a schematic CT apparatus with a couch in a fixed coordinate system,

4 : a CT scan of a patient with a defined radiation isocenter,

5 : the CT device according to 3 with fixed radiation isocenter, and

6 : A schematic irradiation device with a couch in a stationary coordinate system.

The 1 and 2 each show a 3D position marker 1 , hereafter called marker for short, in two different embodiments. The marker 1 is designed as an optical-passive marker and is used to uniquely recognize a position of one with the marker 1 characterized object, such as a couch or a fixative, see 3 . 5 and 6 ,

The markers shown 1 each comprise three leveling marking elements 2a respectively 2 B , In the embodiment of the marker 1 according to 1 are the marking elements as a cuboid 2a formed and in the embodiment according to 2 as balls 2 B , The marking elements 2a and 2 B are each formed uniformly. Both markers 1 each have a fastener 3 in the form of a stand, with which they can be secured to a couch or a fixative.

The 3 shows an exemplary CT device 10 in a fixed coordinate system (x, y). The CT device 10 is part of a therapy system for carrying out the method according to the invention for positioning a patient in an irradiation device 20 , The therapy system also includes an irradiation device 20 , please refer 6 , a non-illustrated data transmission connection between the CT device 10 and the irradiation device 20 for the transmission of position data and control and computing unit, which is likewise not further detailed, with at least one memory in which a program code is stored, which carries out the method according to the invention during operation.

The CT device 10 comprises a radiator-detector system arranged in a housing of a gantry, a couch 12 for storage and fixation of the patient and a 3D position detection device. The patient is not shown for clarity. The 3D Posistionserfassungseinrichtung is according to 2 as a 3D camera 11 trained and on the ceiling over the couch 12 arranged.

At the couch 12 are two fixatives 13 arranged with those on the lounger 12 stored patient can be fixed in a clear lying position. Both fixatives 13 are each with a marker 1 Mistake. Furthermore, the chaise longue 12 at the foot of a marker 1 on. The markers 1 each mark the position of the fixing 13 and the couch 12 in the coordinate system. An example is a position (x1, y1) of a fixing agent 13 marked in the header area.

When 4 a photograph of a 3D CT scan is shown showing a section through the abdominal area of a patient. In the image a tumor is identified, which is defined as Irradiation I center. The tumor then places it in the irradiation device 20 to be irradiated area.

The 5 again shows the CT device 10 according to the 3 with the CT scan according to 4 determined Irradiation iso center I. The same components are identified by the same reference numerals. The position (xI, yI) of the irradiation isocenter I can also be uniquely determined in the coordinate system.

The 6 shows an exemplary irradiation device 20 in a fixed coordinate system (x ', y'). The radiation device 20 comprises an irradiation device 24 , a couch 22 for storage and fixation of a patient and a 3D position detection device. The patient is not shown for clarity. The 3D Posistionserfassungseinrichtung is as a 3D camera 21 trained and on the ceiling over the couch 22 arranged.

The couch 22 is identical to the couch 12 formed of the CT system and has identical fixative 23 on which at the same positions and with the same settings as on the couch 12 of the CT system are arranged. Next also points the couch 22 of the irradiation device 20 at the foot of a marker 1 on. The markers 1 at the fixatives 23 and on the couch 22 are also identical. The patient can by means of identical fixative 23 on the couch 22 simply be stored in the same lying position as in the CT device. For this purpose, the positions of the fixative 13 and the couch 12 of the CT device 10 on the fixative 23 and the couch 22 of the irradiation device 20 in the coordinate system (x ', y') of the irradiation device 20 transfer. The position of the irradiation isocenter I is also transferred to the coordinate system (x ', y').

The irradiation device 24 has an irradiation center M whose position (x'M, y'M) in the coordinate system (x ', y') is known. In the embodiment shown here, the transmitted position (xI, yI) of the irradiation isocenter I deviates from the position (x'M, y'M) of the irradiation center M by the amount (Δx, Δy). The couch 22 with the patient fixed on it is then automatically aligned so that the irradiation iso center I is located in the irradiation center M.

Overall, the invention thus proposes a method for positioning a patient in an irradiation device, comprising at least the steps of: storing and fixing the patient by means of fixing means on a couch of a CT device in a first reclining position, performing a 3D CT scan of immobilizing the patient and the 3D position marker, determining an irradiation isocenter in the 3D CT scan, transmitting the positions and location of the fixation means relative to the recliner of the CT device, and the position of the irradiation isocenter relative to the recliner of the CT device Irradiation device, repositioning and identical fixing of the patient on a couch of the irradiation device by means of fixing in an identical to the first lying position second lying position based on the transmitted relative positions, and automatic alignment of the couch, so that the irradiation isocenter angeor in the center of irradiation of the irradiation device dnet is. Furthermore, a therapy system for carrying out the method according to the invention is proposed.

Although the invention has been illustrated and described in detail by the preferred embodiment, the invention is not limited by the disclosed examples, and other variations can be derived therefrom by those skilled in the art.

Claims (8)

Method for positioning a patient in an irradiation device ( 20 ), comprising at least the following steps: 1.1. Storing and fixing the patient by means of fixing means ( 13 ) on a couch ( 12 ) of a CT device ( 10 ) in a first lying position, wherein the couch ( 12 ) and the fixing agents ( 13 ) 3D position markers ( 1 ), the positions of which are clearly recognized both visually and in a 3D-CT scan, being used as a 3D position marker ( 1 ) each have three marking elements spanning a plane ( 2a . 2 B ) and for different fixatives ( 13 ) 3D position markers ( 1 ) with different marking elements ( 2a . 2 B ), 1.2. Perform a 3D CT scan of the patient on the couch ( 12 ) fixed patient and the 3D position marker ( 1 ), 1.3. Determining an irradiation isocenter (I) in the 3D CT scan, 1.4. Transferring the positions and the positions of the fixing means ( 13 ) relative to the couch ( 12 ) of the CT device ( 10 ) and the position of the irradiation isocenter (I) relative to the couch ( 12 ) of the CT device ( 10 ) on the irradiation device ( 20 1.5. Relocation and identical fixation of the patient on a couch ( 22 ) of the irradiation device ( 20 ) by means of fixatives ( 23 ) with identical 3D position markers ( 1 ) and marking elements ( 2a . 2 B ) in an identical to the first lying position second lying position based on the transmitted relative positions, wherein the couch ( 22 ) and the fixing agents ( 23 ) 3D position markers ( 1 ), which are optically recognized and the position and position of the couch ( 22 ) and the fixing agent ( 23 ), and 1.6. automatic alignment of the couch ( 22 ) of the irradiation device ( 20 ) with the patient fixed on it, so that the previously defined irradiation isocenter (I) in the irradiation center (M) of the irradiation device ( 20 ) is arranged. Method according to the preceding claim 1, characterized in that the same fixing means ( 13 . 23 ) with the same 3D position markers ( 1 ). A method according to one of the preceding claims 1 to 2, characterized in that the 3D position of marker ( 1 ) at the same fixative ( 13 . 23 ) are mounted in the same relative positions. Method according to one of the preceding claims 1 to 3, characterized in that in the 3D-CT scan, a predetermined body region of the patient is determined and set as irradiation isocenter (I). Method according to one of the preceding claims 1 to 3, characterized in that in a previously performed 3D examination of the patient, a predetermined body area is determined, the position and position of which is transferred to the 3D-CT scan and set there as irradiation isocenter (I) , Therapy system for carrying out a method according to one of the preceding claims 1 to 5, at least comprising: 6.1. a CT device ( 10 ) with at least one emitter-detector system, a couch ( 12 ) for storing a patient and a position detection device, 6.2. an irradiation device ( 20 ) with at least one irradiation device ( 24 ), a couch ( 22 ) for storage of the patient and a position detection device, 6.3. a communication link between the CT device ( 10 ) and the irradiation device ( 20 ) for the transmission of position data, and 6.4. a control and computation unit having at least one memory, in which program code is stored, which in operation comprises a method for positioning a patient in an irradiation device ( 20 ), 6.5. couches ( 12 . 22 ) identical fixing agents ( 13 . 23 ) for fixing the patient in a clear lying position and the couches ( 12 . 22 ) and the fixing agents ( 13 . 23 ) each 3D position marker ( 1 ), which clearly characterize their position and positions, wherein the 3D position markers ( 1 ) each as three one-level marking elements ( 2a . 2 B ) are formed trained and different fixing means ( 13 ) 3D position markers ( 1 ) with different marking elements ( 2a . 2 B ) exhibit. Therapy system according to the preceding claim 6, characterized in that the couch ( 12 ) of the CT device ( 10 ) identical, in particular identical, to the couch ( 22 ) of the irradiation device ( 20 ) is trained. Therapy system according to one of the preceding claims 6 to 7, characterized in that the position detection devices as at least two 2D cameras or as at least one 3D camera ( 11 . 21 ) are formed.

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