DE19915720A1 - Stereotactic localization method and measurement phantom for medical use - Google Patents

Abstract

The invention relates to a stereotactic coating method for a medical application with a detection of a spatial configuration (1, 5, 5 ', 5' ', 5' '', ..., 6, 6 ', 12, 12', 12 '' ) by imaging and assigning the configuration to pixels (2, 2 ', 2', 2 '', 2 '' ', ...) and layers (3, 3', 3 '', 3 '' ',. ..) a digital spatial representation (4) with a reference coordinate system (x, y, z) for the application. The invention further relates to a measurement phantom (7) for this method. DOLLAR A The invention makes it possible to set up and / or verify high precision by using reference spaces (5, 5 ', 5' ', 5' '', ..., 12, 12 ', 12' ') with known coordinates (x ', y', z '; z¶1¶ ..., z¶n¶') of their mutual assignment, recorded by imaging and evaluated, the arrangement of the reference spaces (5, 5 ', 5' ', 5' '', ..., 12, 12 ', 12' ') is such that the evaluation allows an assignment to the reference coordinate system (x, y, z), and thus also an assignment of further imaging information which is the accuracy of the resolution in pixels (2, 2 ', 2' ', 2' '', ...) and layers (3, 3 ', 3' ', 3' '', ...) of Imaging exceeds.

Description

The invention relates to a stereotactic localization method for a medical Application with acquisition of a spatial configuration through imaging and an assignment of the configuration to pixels and layers of a digital spatial Representation with a reference coordinate system for the application.

The invention further relates to a computer program and a measurement phantom for through conduct of the procedure.

Stereotactic localization methods are used, for example, to conform to tumors Radiotherapy, neurosurgery and other uses, provided these use stereotactic methods.

The goal of tumor-conforming radiation therapy is to provide a sufficient dose in the so-called Deposit target volume without nearby healthy structures ("Risk organs ") beyond their tolerance with dose. This places high demands the precision with which both diagnostics and therapy are planned and must be carried out.

For this purpose, a coordinate system is established, which is fixed to the anatomy of the Patient is linked and serves to provide an exact spatial assignment of (target) To reach points in three-dimensional space. This method is called Stereotaxy. With the help of this stereotactic coordinate system as well suitable target systems can even in different application situations, for example, with high-precision radiation, an exact, reproducible position tion of the patient on diagnostic and / or therapeutic devices. These devices must be set up accordingly and checked regularly.  

The determination of target points is based on imaging methods such as X-ray computer tomography (CT), magnetic resonance imaging (MR), positro NEN emission tomography (PET) acquired series of slices of the patient. To one Relationship between the image data and the stereotactic coordinate system to manufacture, is used on the patient couch and holder arrangement Localization systems with markers, which represent the mapping of reference points in effect the pictures. The stereotactic Coordinates of any pixel can be determined, because due to a suitable Neten fixation of the localization system the position of the markers in the stereotactic Coordinate system is known.

A setup and verification of the exact spatial allocation of the with Anatomy of the patient linked coordinate system with the coordinate systems diagnostic and / or therapeutic methods, for example tomography device and / or the treatment device serve phantoms, which are defined on the Patient lying and holding device are arranged. Such phantoms also have markings, by means of their imaging by means of an imaging Procedure this check is possible.

The known methods and phantoms for setting up and checking allow the Identification of a target point in tomograms only with the accuracy given by whose spatial resolution is specified. For example, stereotak when used tical methods in the extracranial area typically 1 × 1 mm pixel size and 5 mm layer thickness specified by the devices. Therefore, the verification cannot sufficient precision, d. H. the setting and / or verification with the known phantoms is insufficient.

The invention is therefore based on the object of a method of the aforementioned Art, as well as to make a measurement phantom available with which a device and / or Verification of high precision are possible.  

With regard to the method, the object is achieved in that Arranged reference spaces with known coordinates of their mutual assignment, can be detected and evaluated by imaging, the arrangement of the ref Reference spaces is such that, through the evaluation, an assignment to the reference coordinate nate system and thus also an allocation of further imaging information is possible, the accuracy of the resolution in pixels and layers of imaging exceeds.

With regard to the device, the object is achieved in that the Measuring phantom reference spaces with known coordinates that can be determined by imaging contains, which are arranged such that an assignment to a reference group dinate system and thus also an assignment of further ones that can be detected by the imaging Information is possible, the accuracy of pixels and layers of a digital Resolution of the spatial representation of a configuration exceeds.

The invention makes it possible despite a predetermined, relatively coarse resolution localization of the imaging system, which is many times is more precise than the specified resolution. This enables a more precise verification of the devices and the software for localization and a more precise verification of these Accuracy. But a facility is also possible. In the diagnostic field takes place the aforementioned assignment for setting up and / or checking the tomography device instead of ensuring that the anatomy associated with the patient Coordinate system coincides with the coordinate system of the tomography device. For the therapy, these coordinates must then in turn match those of the Treatment device match. The invention serves to verify this Matches and, if necessary, a corresponding attitude, be it that this is done in the area of the hardware, i.e. the devices, or in the area the software by correctly assigning the data to these coordinate systems is carried out by a corresponding coordinate transformation. Through the Invention is no longer the accuracy of such verifications and assignments due to the resolution accuracy of the respective imaging process. On In this way, a reliable diagnosis and / or therapy can be carried out in the nearby healthy structures are protected as much as possible.  

The stereotactic localization method is expediently designed in such a way that that in addition to assigning a spatial configuration to pixels and layers of the Reference coordinate system a fine assignment by detecting the location of the Limits of the pixels and layers occur. This can be done, for example achieved that at least one of the linear position determinations by means of a staggered arrangement of reference rooms. So the coordinates of a or several target points with a resolution exceeding the resolution of the imaging Accuracy can be determined.

An embodiment of the method for checking a tomography device is provided before that a measurement phantom with defined mappable reference spaces in a Patient couch is defined and fixed. Then the Tomogra The procedure involves imaging with the patient bed, the loci arranged on it sensors and the measurement phantom performed. When evaluating the location and Orientation of the markers of the localizers and the reference spaces with respect to the Reference coordinate system of the tomography device checked for correctness.

In addition to the verification, the aforementioned method can also be used for a New implementation of hardware or software the reference coordinate system according to the Coordinates of the reference spaces is set.

A further embodiment provides that for the assignment of at least two coordinates coordinate systems takes place. Allocation means the Assignment of the patient's actual stereotactic coordinates or - there known - the phantom to the coordinates of the diagnostic device and / or the therapeutic device. This assignment can be made more precise by the invention because the assignment accuracy is no longer determined by the Image resolution accuracy of the diagnostic device or - if there is imaging with limited image resolution - the therapy, for example the Irradiation device is limited.  

Another method for checking an irradiation device provides that a Measurement phantom defined with a film inserted over a large area in a patient couch is arranged and fixed. Thereafter, radiation with the patient bed and the measuring phantom arranged on it performed. The evaluation is based on the exposure and exposure of the at least one film the position and intensity of an irradiation geometry with respect to a reference coordinate system checked for correctness. The In this application, the reference coordinate system is expediently the one with stereotactic coordinate system linked to the patient. This procedure leaves perform with any radiation geometry. This requires the Measurement phantom only the film as well as any arranged radiation geometry. The latter can of course also be at least one of the aforementioned reference spaces.

The invention further proposes a computer program for performing the mentioned procedure. Computer program in this sense means software moderate provision of the aforementioned technical process and thus a Device consisting of a computer that is used to carry out the said Process steps is set up. With the computer program in the tomo graphic image data recorded the coordinates of the markers and the reference spaces and then, using the coordinates of the markers, the position and orientation of the Layers of the tomographic image data are checked. Furthermore, the Coordinates of at least one reference space the correct position of the same in relation checked to a reference coordinate system and, if necessary, on the basis both checks pre-set or coordinate transformation taken. This computer program can also include that based on the coordina the markers in the tomographic image data on their mutual relative position the correct location of the locators is checked. This can cause a bend or other damage to a localizer is found and then rectified.

The features mentioned only reflect basic functions, further details Forms of the computer program can implement all of the above Provide procedural steps or the aforementioned measurement phantom and the Orient the following design options of the measurement phantom.  

For the measurement phantom there are a multitude of possibilities through imaging provide detectable reference spaces through which the high resolution can be achieved. An expedient embodiment provides that the measurement phantom is spatially indicated arranged a crosshair with three axes that can be detected by imaging contains. However, additional reference spaces are expediently provided. So it is suggested that several parallel to one of the axes of the cross hairs horizontal reference rooms are arranged. An advantageous embodiment provides that the reference rooms are staggered. These or other reference rooms can surround the crosshair, through their mutual association and the Assignment to the crosshairs the resolution and thus the localization more precisely to be able to make.

In particular, it can be provided that the reference spaces run in the longitudinal direction. In this direction there is a staggered arrangement with a corresponding increase The localization accuracy is particularly necessary because it is in this direction extending layers of a tomography image usually have a thickness of 5 mm. This grid is for a setting, the basis of a treatment is much too coarse and therefore requires the more precise assignment according to the invention. Man can also distribute a staggered arrangement unevenly, which means an additional Evaluation regarding a possible inclination of the phantom for reference coordinate system is possible.

A specific embodiment provides that the crosshairs in one component is arranged in the measuring phantom at at least one defined position is insertable. It can also be provided that the other reference spaces in are arranged in a component that is in exact position in at least one defined position the measurement phantom is insertable. For example, the crosshairs can be in a target body, the exact position in a reference body with the other reference space men is insertable and the reference body in turn in the measuring phantom is insertable. These configurations have the advantage that the measurement phantom with differently designed crosshairs and reference rooms can. In this way, the required accuracy of calculation can be taken into account  can be worn and the measuring phantom can be used in many ways, for example for different types of imaging.

Another expedient embodiment provides that the measuring phantom has several parts contains, the parts can occupy different positions in the measurement phantom and that the reference spaces are arranged in at least one of the parts. A concrete one Design provides, for example, that the parts are at least two, preferably four interchangeable and reversely insertable half cylinders. This Design offers the advantage that both the crosshairs and the reference spaces eight different exact positions can be assigned. The more such exactly defined positions are possible, the more precise is the checking and setting up of the devices.

The above purpose also serves a further training, which provides that the measurement phantom can be brought into several defined position arrangements. For example, in several defined angular positions can be brought. A concrete design too this purpose provides that the measuring phantom is attached to the patient bed on one bar part is arranged. Will both the above half cylinders as If the dividing disc is also provided, the eight possible settings are multiplied through the half cylinders with the number of different settings which the indexing disc permits.

There are a multitude of options for designing the measurement phantom. It can be designed as a compact body, then it can be in the reference rooms to act as cavities. It is also possible that the reference rooms have other materials if this is necessary for imaging with the respective imaging. This Materials can be stored in the cavities or they can in other ways be placed in the measurement phantom.

A further development of the measurement phantom provides that at least one film can be inserted. It can be at least one film that covers a large area in the longitudinal direction can be inserted or can be inserted over a large area in the transverse direction. In one configuration  of the measuring phantom as four half cylinders, the films between the half cylinders be arranged lengthways and crossways.

The measurement phantom can be made of different materials. Expedient however, a material is used which has a similar radiation absorption like water, because then the radiation is similar to that of the human body behaves.

The invention is described below with the aid of sketches and the graphic representation development of an embodiment explained. Show it

Fig. 1 is a schematic diagram for explaining the localization method using a localization in a linear region,

Fig. 2 is a sketch to illustrate the spatial location,

Fig. 3 shows a computed tomography layer of the human pelvis with the array of locators,

Fig. 3a, a localizer,

Fig. 4 shows a detail from the computer tomography layer having a tumor

Fig. 5 shows an embodiment of a Meßphantoms,

Fig. 6, a reference body with reference areas,

Fig. 7 is a target body with a cross-hair,

Fig. 8 the measuring phantom, partially cut and

Fig. 9 is a diagram of a coordinate transformation.

Fig. 1 shows a schematic diagram for explaining the localization method using a localization in a linear region (along the z-axis). A coordinate z 'is plotted on the right-hand side. These are the coordinates for the mutual assignment of reference spaces 5 , 5 ', 5 ", 5 "",... Reference space 5 is a crosshair 5 which indicates the target point 6 'of the measurement phantom 7. In the reference spaces 5 ', 5 ", 5 "",. . . For example, it can be a staggered arrangement of cylindrical reference spaces 12 ". The target point 6 'is located exactly in the middle between two cylindrical reference spaces 12 ", the ends 13 of which have the lengths z ₄ ' and z ₅ ' Four reference spaces 5 , 5 ', 5 ", 5 ''' are arranged below the crosshair 5 and above the crosshair 5 . The ends 13 of these reference spaces are stepped uniformly, a distance of 1 mm being chosen as an example here. The coordinates of a reference coordinate system in the z direction are plotted on the right side. The layers 3 , 3 ', 3 ",... Of computer tomography are assigned to this reference coordinate system. In the example selected, these layers are 5 mm thick, so that, according to the conventional localization method, the position of the crosshairs 5 with the target point 6 ' within the layer 3 'could not be determined. The accuracy of the assignment would thus be ± 2.5 mm. With the method according to the invention it can be determined that there are two reference spaces below the cross hair 5 and three reference spaces above the cross hair 5 in the same layer 3 ' the mutual assignment of the reference spaces 5 , 5 ', 5 ", 5 "',. . . is known, it follows that the target point 6 'must be at least 1.5 mm higher than 22 and at least 2.5 mm lower than z ₃ . This gives the position of the target point 6 'as 22 plus 2 mm with a tolerance of ± 0.5 mm. This position z _{n of} the target point 6 'in the reference coordinate system z therefore corresponds with a tolerance of + 0.5 mm to the position z _n ' of the coordinate system z ', which is the mutual assignment of the reference spaces 5 , 5 ', 5 ", 5 ''' In this way it is made clear that the invention enables a target point 6 'to be classified and thus enables two coordinate systems to be assigned, the tolerance of which is no longer ± 2.5 mm but ± 0.5 mm.

Normally, computed tomography scanners are operated in the stereotactic localization in the trunk area with a field of 500 mm square with 512 × 512 pixels. In this plane, that is, in the xy plane, the assignment is relatively precise, however, with the layer thickness of 5 mm, the localization just mentioned is definitely necessary in order to achieve the required accuracy. However, a more precise assignment can also be carried out for the xy plane, although, as a rule, it does not have to involve as much effort as was described above. Often the evaluation by means of two or three reference spaces 5 , 5 ', 5 ", 5 ''' ... is sufficient.

Fig. 2 shows a sketch to illustrate the spatial localization. 4 A reference coordinate system x, y, z is shown, in which the recording volume in pixels 2 , 2 ',. . . and divided into layers 3 , 3 ', 3 ",... In this way, the entire room is divided into small square columns, each of which can be assigned spatial information. For better clarity, only two of these room units are shown as an example These spatial units fill the entire relevant space and are the smallest resolution units of the above-mentioned computed tomography If the method described for Fig. 1 is used in the spatial area, then a target point 6 , 6 'within such a space can be more precisely than with the specified spatial units , more precisely than through the pixels 2 , 2 'or the layers 3 , 3 ', 3 ". The coordinate system x ', y', z 'of reference spaces 5 , 5 ', 5 ", 5 ''', ... to be assigned is indicated. For a basic setting, such an assignment of the coordinate systems is necessary in such a way that the reference spaces with respect to their actual Location with the coordinates of the computed tomography and these agree with the coordinates of the radiation device. This will be checked from time to time later in order to ensure the agreement when treating a tumor. In addition to a shift, there may also be a different angular arrangement in space Locators 8 with markers 9 can be used to correct such a different angular arrangement. This is described in the following:
Fig. 3 shows a computed layer 18 of the human pelvis with the array of locators. 8 Such a locator 8 is shown in FIG. 3a. The locator contains markers 9 which run at angles with respect to the z plane. In this manner, by imaging the marker 9 in the computer-to mographieschicht determined 18 whether a skew of CT layer 18 is provided to the locators. 8 With such an inclination, the distances between the markers are different. If the distances between the markers are the same at all four localizers 8 , the computed tomography layer 18 is imaged exactly vertically in the reference coordinate system x, y, z. In the event of errors, a corresponding correction can be carried out so that the angular offset shown in FIG. 2 is corrected.

The spatial configuration 1 of a tumor 1 , which is shown enlarged in FIG. 4, is also indicated in the computed tomography layer 18 .

Fig. 4 shows the section from the computed tomography layer 18 to the Tumor 1. This is the representation of a layer 3 . Within this layer 3 , the tumor 1 can be represented by its assignment to the square field of pixels 2 , 2 ', 2 ", 2 "",... The representation of the tumor 1 at the pixels 2 , 2 ', 2 ", 2 ''',. . . tied to the image resolution, but here too, with the method described at the beginning, the target point 6 of the treatment plan can be classified more precisely. Such a target point 6 is set by the doctor in order to be able to irradiate a tumor 1 in an optimal manner and to protect the surrounding tissue as much as possible, especially if it is tissue that needs special protection, such as the spinal cord. The target point 6 is entered with the coordinates x _n and y _n , which can also be determined relatively exactly with the method according to the invention. It can be seen that shifting the target point within a pixel also shifts the overall arrangement of the tumor 1 in the same way and thereby causes errors in the overall image.

Fig. 5 shows an embodiment of a measuring phantom 7 which is used in the manner mentioned at the outset for setting and checking the devices and the software. The measuring phantom 7 shown consists of a base plate 27 on which a base ring 25 is located. In the manner shown, four half cylinders 16 , 16 ', 16 ", 16 ""can be placed and joined on this base ring 25. There is a recess in at least one of the half cylinders 16 , 16 ', 16 ", 16 "" 19 incorporated for a reference body 15 . In order to ensure a defined insertion of the reference body 15 , it has a nose 20 which engages in a nose recess 21 of the recess 19 . The reference body 15 in turn contains a recess 22 for a target body 14 .

The reference body 15 is shown in FIG. 6. Reference spaces 5 , 5 ', 5 ", 5 "',... Are arranged in it, which are designed here as cylindrical reference spaces 12. Four reference spaces 12 'of the same extent and eight reference spaces 12 "are arranged in a staggered arrangement in the reference body 15 molded. These can be bores, but it is also possible to provide other material that can best be represented by the imaging used in each case. The reference spaces 12 "of the staggered arrangement correspond to the principle already explained above in relation to FIG. 1, the rear ones only being indicated by the bore openings. Here, instead of the ordered staggering, an uneven arrangement of the same was chosen in order to be able to correct an inclined position. In the middle There is a recess 22 in the reference body 15 , which serves to insert a target body 14. The recess 22 also has a nose recess 24 in order to ensure a defined insertion of the target body 14 , which has a nose 23 .

Fig. 7 shows the target body 14 with cross hairs. 5 The crosshair 5 has three axes 11 _x , 11 _y , 11 _z , which are at an angle of 90 ° to each other and define a target point 6 'of the measurement phantom 7 .

Fig. 8 shows the measuring phantom 7 partially cut. In addition to the above description, a cover ring 28 is added, which is held by fastening screws 29 on the holding rods 26 and holds the half cylinders 16 , 16 ', 16 ", 16 ""together. The position of the reference body 15 , which contains the target body 14 by the Ausneh mung 19 drawn in. it is the dashed representation. the possible positions 19 'are shown in broken lines. it can be seen that it staltung due to the extended with the four half-cylinders 16, 16', 16 ", 16 ''' there are eight such possible positions 19 ′ for the reference body 15 with the target body 14 . In addition, the base ring 25 is mounted on a base plate 27 , this bearing being ausgebil det as part disk 17 . The graduated disk 17 has a ring of holes 32 , into which a holding pin 33 can optionally be inserted. Each engagement of the holding pin 33 in a hole 32 corresponds to a certain angular position of the measuring phantom 7 relative to the base plate 27 , so that, for example, eight different angular positions are possible with eight holes 32 . With the eight positions already shown, this results in a defined positioning of the reference body 15 with the target body 14 at sixty-six different positions. These different positions make it possible to make an exact localization determination and in this way to set or check devices precisely.

In Fig. 8, a pivot 34 is also shown, which serves to rotate the measuring phantom 7 on the base plate 27 . The base plate 27 is equipped with mounting holes 30 so that it can be brought to the patient bed in a precisely defined position. Furthermore, pins 35 are also drawn in, which serve for the exact positioning of the half-cylinders 16 , 16 ', 16 ", 16 "". Between these half-cylinders of the 16 , 16 ', 16 ", 16 "" there can either be a film horizontally 10 'are inserted, or it is possible to insert such a film 10 also in the vertical into a recess 31 . In this way, the method for checking an irradiation device already mentioned above can be carried out. For this purpose, the measurement phantom can also be used without reference spaces, in particular if an irradiation geometry is available in another way.

These film inserts 10 and 10 'serve to check the position directly in the irradiation device by imaging the reference spaces 5 , 5 ', 5 ", 5 ''', ... , 12 , 12 ', 12 ". The markers 9 of the localizers 8 can also be imaged in this way and the entire system can be checked.

Fig. 9 is a diagram showing a coordinate transformation. This is necessary in order to achieve an exact assignment of the tomography coordinates to the stereotactic coordinates of the treatment. On the basis of the tomographic image data [40] and the geometry of the localization system [41], the markers 9 are searched for [42] and the CT (computed tomography) coordinates of the markers 9 are determined [43]. Based on the known geometry of the localization system [41] and the CT coordinates of the markers [43], an evaluation [44] can be carried out, the result of which is the position and orientation of the CT slices in the stereotactic coordinate system [45]. This is the process already described for FIG. 3, wherein, of course, a conversion or a check can also be carried out instead of an alignment. Knowing this position and orientation of the CT slices, it is possible to assign the CT coordinates of the target point [47] to the stereotactic coordinates of the target point [48] by means of a coordinate transformation [46].

The aforementioned statements served to explain the method and the measuring phantom according to the invention. Of course, this is only an example. Other arrangements of the reference spaces 5 , 5 ', 5 ", 5 "',..., A different configuration of the measurement phantom 7 or further configurations of the method are of course possible.

Reference list

1

spatial configuration (tumor)

2nd

,

2nd

',

2nd

",

2nd

''',. . . pixel

3rd

,

3rd

',

3rd

",

3rd

''',. . . layers

4th

spatial representation

5

,

5

',

5

",

5

''',. . . Reference rooms

5

Crosshair

5

',

5

",

5

'''further reference rooms

6

Target point (treatment plan)

6

'' Target point (measurement phantom)

7

Measurement phantom

8th

Localizers

9

Markers of the localizers

10th

,

10th

' Movie

11 _x

,

11 _y

,

11 _e.g.

Crosshair axis

12th

cylindrical reference spaces

12th

'' Reference spaces of the same extent

12th

"staggered arrangement of reference rooms

13

Ends of reference spaces

14

Target body

15

Reference body

16

,

16

',

16

",

16

'''Half cylinder

17th

Dividing disc

18th

CT slice of the human pelvis

19th

Recess for reference body

19th

'Possible positions of the recess

19th

20th

Nose of the reference body

21

Nasal recess

22

Recess for target body

23

Nose of the target body

24th

Nasal recess

25th

Base ring

26

Handrails

27

Base plate

28

Cover ring

29

Mounting screws

30th

Mounting holes for the base plate

31

Recess for film insert

32

Holes in the indexing disc

33

Holding pin of the indexing disc

34

Pintle pivot

35

Cones

40

Tomographic image data

41

Geometry of the localization system

42

Search the markers

43

CT coordinates of the markers

44

evaluation

45

Position and orientation of the CT slices in the stereotactic coordinate system

46

Coordinate transformation

47

CT coordinates of the target point

48

Stereotactic coordinates of the target point
x ', y', z '; z ₁

',. . . z _n

'' Coordinates of the mutual allocation of reference spaces
x, y, z; x _n

, y _n

, z _n

Reference coordinate tomography (CT) coordinates and / or stereotactic coordinates

Claims (32)

1. Stereotactic localization method for a medical application with a detection of a spatial configuration ( 1 , 5 ', 5 ', 5 ", 5 "", ... , 6 , 6 ', 12 , 12 ', 12 ") by imaging and an assignment of the configuration ( 1 , 5 , 5 ', 5 ", 5 "',..., 6 , 6 ', 12 , 12 ', 12 ") to pixels ( 2 , 2 ', 2 ", 2 ",...) and layers ( 3 , 3 ', 3 ", 3 ''',...) of a digital spatial representation ( 4 ) with a reference coordinate system (x, y, z) for the application, characterized that reference spaces ( 5 , 5 ', 5 ", 5 ''', ... , 12 , 12 ', 12 ") with known coordinates (x', y ', z'; z ₁ ',... z _n ') their mutual assignment arranged, captured by imaging and evaluated, the arrangement of the reference spaces ( 5 , 5 ', 5 ", 5 ''',..., 12 , 12 ', 12 ") is such that through the evaluation an assignment to the reference coordinate system (x, y, z) and thus also an assignment of further information of the imaging is possible ch is the accuracy of the resolution in pixels ( 2 , 2 ', 2 ", 2 ",. . .) and layers ( 3 , 3 ', 3 ", 3 ''',...) of the imaging exceeds. 2. The method according to claim 1, characterized in that in addition to an assignment of a spatial configuration ( 1 , 5 , 5 ', 5 ", 5 ''', ... , 6 , 6 ', 12 , 12 ', 12 ") to pixels ( 2 , 2 ', 2 ", 2 ",...) and layers ( 3 , 3 ', 3 ", 3 ''',...) of the reference coordinate system (x, y, z) through a fine assignment The position of the boundaries of the pixels ( 2 , 2 ', 2 ", 2 ",...) And layers ( 3 , 3 ', 3 ", 3 ''',...) Is recorded. 3. The method according to any one of claims 1 or 2, characterized in that at least one of the linear position determinations (x, y and / or z) by means of a staggered arrangement of reference spaces ( 5 ', 5 ", 5 ''', .... , 12 "). 4. The method according to any one of claims 1 to 3, characterized in that the coordinates (x _n , y _n , z _n ) of at least one target point ( 6 ) are determined with an accuracy exceeding the resolution of the imaging. 5. The method according to any one of claims 1 to 4 for checking a tomography device, characterized by the following method steps:

• a) a measurement phantom ( 7 ) with fixed, reproducible reference spaces ( 5 , 5 ', 5 ", 5 ''',..., 12 , 12 ', 12 ") is arranged and fixed in a patient couch,
• b) a tomography procedure is carried out with the patient couch, the localizers ( 8 ) arranged thereon and the measurement phantom ( 7 ),
• c) the position and orientation of the markers ( 9 ) of the localization ( 8 ) and the reference spaces ( 5 , 5 ', 5 ", 5 "", ... , 12 , 12 ', 12 ") is compared with a reference coordinate system ( x, y, z) checked for correctness.

6. The method according to any one of claims 1 to 5, characterized in that for a new implementation of hardware and software a reference coordinate system (x, y, z) according to the coordinates (x ', y', z '; z ₁ ',. . z _n ') of the reference spaces ( 5 , 5 ', 5 ", 5 ''', ... , 12 , 12 ', 12 ") is set. 7. The method according to any one of claims 1 to 6, characterized, that one coordinate for assigning at least two coordinate systems transformation takes place.   8. The method, in particular according to one of claims 1 to 7, for checking an irradiation device, characterized by the following method steps:

• a) a measuring phantom ( 7 ) with at least one film ( 10 , 10 ') inserted over a large area is arranged and fixed in a patient couch,
• b) radiation is carried out with the patient couch and the measuring phantom ( 7 ) arranged thereon,
• c) on the basis of the exposure of the at least one film ( 10 , 10 '), the position and intensity of an irradiation geometry with respect to a reference coordinate system (x, y, z) is checked for correctness.

9. Computer program for performing a method according to one of claims 1 to 8, characterized in that in the tomographic image data the coordinates of the markers ( 9 ) and the reference spaces ( 5 , 5 ', 5 ", 5 ''', .... , 6 ') that the position and orientation of the layers ( 3 , 2 ', 2 ", 2 "",...) Of the tomographic image data are checked on the basis of the coordinates of the markers ( 9 ) and that the coordinates are checked at least one reference space ( 5 , 5 ', 5 ", 5 ''',..., 12 , 12 ', 12 ") the correct position of the same in relation to a reference coordinate system (x, y, z) is checked and, if necessary a setting or coordinate transformation is made. 10. Computer program according to claim 9, characterized in that the correct position of the localizers ( 8 ) is checked on the basis of the coordinates of the markers ( 9 ) in the tomographic image data via their mutual relative position. 11. Measuring phantom for performing a stereotactic localization method according to one of claims 1 to 8, characterized in that the measuring phantom ( 7 ) by reference imaging detectable reference spaces ( 5 , 5 ', 5 ", 5 "",..., 12 , 12th ', 12 ") with known coordinates (x', y ', z'; z ₁ ',... Z _n ') of their mutual assignment, which are arranged such that an assignment of the imaging to a reference coordinate system (x, y, z) and thus also an assignment of further information which can be detected by imaging is possible, which the accuracy of pixels ( 2 , 2 ', 2 ", 2 ",...) and layers ( 3 , 3 ', 3 ", 3 ''',...) A digital resolution of the spatial representation ( 4 ) of a configuration ( 1 , 5 , 5 ', 5 ", 5 ''', ... , 6 , 6 ', 12 , 12 ', 12 "). 12. Measuring phantom according to claim 11, characterized in that it contains as a spatially arranged target point ( 6 ') a crosshair ( 5 ) with three axes ( 11 _x , 11 _y , 11 _z ) which can be detected by imaging. 13. Measuring phantom according to claim 11 or 12, characterized in that as further reference spaces ( 5 ', 5 ", 5 ''',...) Several parallel to one of the axes ( 11 _x , 11 _y , 11 _z ) of the crosshairs ( 5 ) lying reference spaces ( 12 , 12 ', 12 ") are arranged. 14. Measuring phantom according to one of claims 11 to 13, characterized in that the reference spaces ( 5 , 5 ', 5 ", 5 ''',..., 12 , 12 ', 12 ") are staggered. 15. Measuring phantom according to one of claims 11 to 14, characterized in that the reference spaces ( 5 , 5 ', 5 ", 5 '''..., 12 , 12 ', 12 ") surround the crosshairs ( 5 ). 16. Measuring phantom according to one of claims 11 to 15, characterized in that the reference spaces ( 5 ', 5 ", 5 ''',..., 12 , 12 ', 12 ") run in the longitudinal direction (z'). 17. measurement phantom according to one of claims 11 to 15, characterized, that the staggered arrangement is unevenly distributed. 18. Measuring phantom according to one of claims 11 to 17, characterized in that the crosshair ( 5 ) is arranged in a component ( 14 , 15 ) which can be inserted in at least one defined position in the measuring phantom ( 7 ). 19. Measuring phantom according to one of claims 11 to 18, characterized in that the further reference spaces ( 5 ', 5 ", 5 ''',..., 12 , 12 ', 12 ") are arranged in one component ( 15 ) , which can be inserted into the measuring phantom ( 7 ) at exactly one defined position. 20. Measuring phantom according to claim 18 or 19, characterized in that the crosshair ( 5 ) is in a target body ( 14 ), which is in a precise position in a reference body ( 15 ) with the further reference spaces ( 5 ', 5 ", 5 '''' ,..., 12 , 12 ', 12 ") can be inserted and that the reference body ( 15 ) can be inserted in the measuring phantom ( 7 ) in a precise position. 21. Measuring phantom according to one of claims 11 to 20, characterized in that it contains several parts, wherein the parts can occupy different positions in the measuring phantom ( 7 ) and that at least in one of the parts the reference spaces ( 5 , 5 ', 5 ", 5 ''', ... , 12 , 12 ', 12 ") are arranged. 22. Measuring phantom according to claim 21, characterized in that the parts are at least two interchangeable and reversibly insertable half cylinders ( 16 , 16 ', 16 ", 16 '''). 23. measuring phantom according to one of claims 11 to 22, characterized, that it can be brought into several defined position arrangements. 24. measurement phantom according to claim 23, characterized, that it can be brought into several defined angular positions. 25. Measuring phantom according to claim 24, characterized in that it is arranged on a partial disc ( 17 ) which can be fastened to the patient bed. 26. Measuring phantom according to one of claims 11 to 25, characterized in that the reference spaces ( 5 , 5 ', 5 ", 5 ''',..., 12 , 12 ', 12 ") are cavities in one Body acts. 27. Measuring phantom according to one of claims 11 to 26, characterized in that the reference spaces ( 5 , 5 ', 5 ", 5 ''',..., 12 , 12 ', 12 ") are arranged materials that are depicted in the imaging. 28. Measuring phantom according to one of claims 11 to 27, characterized in that in the measuring phantom ( 7 ) at least one film ( 10 , 10 ') can be inserted. 29. Measuring phantom according to claim 28, characterized in that at least one film ( 10 ) can be inserted over a large area in the longitudinal direction. 30. measuring phantom according to claim 28 or 29, characterized in that at least one film ( 10 ') can be inserted over a large area in the transverse direction. 31. Measuring phantom according to claim 29 or 30, characterized in that at least one of the films ( 10 , 10 ') between the half cylinders ( 16 , 16 ', 16 ", 16 ''') can be inserted. 32. measuring phantom according to one of claims 11 to 31, characterized in that the measuring phantom ( 7 ) consists at least predominantly of a material which has a similar radiation absorption as water.