JPH0450010B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is a patented method for measuring the position of brain structures using spatial coordinates in computer tomography and NMR examination, and transmitting the coordinates to a stereotaxic device. Adapter according to the preamble of claim 1, comprising an ear support, a nasion support for supporting the root of the nose, and a laterality indicator device for reproducibly fixing the adapter to the patient's head. Regarding.

For examinations and surgeries of the patient's head, for example in computer tomography examinations and NMR examinations (NMR stands for nuclear magnetic resonance) of the brain, the patient's head must be fixed in the same position repeatedly and reproducibly. It is important to be able to measure the location of brain structures with a transparent reference device. If this were possible, it would be possible to consider whether brain structures have changed shape or position during repeated examinations, for example due to tumor growth. Coordinates from computerized tomography are also transferred to a stereotaxic device, and surgical procedures (thalamotomy) are performed.
Tumor treatment (electrode implantation, etc.) can preferably be carried out without any use of eg pneumoencephalography or angiography. In addition, computer angiography and
It is desirable to stereotactically illuminate deep brain structures with a conventional linear accelerator using NMR coordinates.

An ideal adapter for the above purpose should satisfy the following criteria:

1. (Not fixed to the skull with screws) No tissue damage.

2. It is easy to fix and loosen and is relatively convenient for the patient.

3. Can be fixed to the head in the same position repeatedly.

4. Be able to accurately determine the coordinates of the head relative to the adapter.

5. Can be used with various types of stereotactic instruments.

6. One and the same adapter can be used for all patients.

[Conventional technology]

Several well-known attempts have been made to solve the aforementioned problems, and these attempts can be categorized into three main types. In the first case, a computer tomography study is performed with the patient fixed in a stereotaxic device. This method only satisfies the fourth criterion listed above.

Another method in computerized tomography examinations is to use bony reference points in the skull and then use the same reference points in stereotaxic operations. Although this method requires no equipment, it is inaccurate because it is rare to find the same fiducial point in a computer radiograph or a stereotactic radiograph.

Yet another method is to reproducibly secure the adapter to the patient's head, one method being based on a plastic mask that is placed over the patient's head and held in place by the patient's dentures. . Although this method satisfies criteria 1, 3, and 4, it is inconvenient for the patient, makes stereotaxic operations cumbersome, and does not satisfy criteria 5 and 6 at all.

There are other known methods and devices for immobilizing a patient's head for x-ray examinations, but these do not take into account the location of brain structures. Examples of such methods and apparatus are U.S. Pat.
No. 2846587, No. 3154683, No. 3514606 and No. 4256112. however,
None of the devices described in the aforementioned patents allow accurate determination of brain coordinates to the adapter and cannot be used with stereotactic instruments.

[Problem that the invention seeks to solve]

The main object of the invention is to provide an adapter of the type described in the preamble, which allows the position of brain structures to be measured using a reference device that can be reproducibly and repeatedly fixed in the same position on the head of a patient. That's true. Another object of the present invention is to measure the position of a brain structure by three-dimensionally defining the position of the brain structure using three-dimensional coordinates with respect to a desired reference structure. Other objects of the present invention are to satisfy criteria 1 to 6 above, reduce the time for computerized tomography and NMR examinations to a minimum, and allow the use of existing stereotactic instruments in the neurosurgical facility. is to provide an adapter. Another object of the invention is to provide an adapter that is inexpensive and easy to manufacture. Yet another object of the invention is to be able to use a conventional linear accelerator for external stereotactic illumination of intracranial targets and also use the same adapter in NMR examinations.

These and other objects of the invention are achieved in that the adapter provides the features defined in the claims.

The invention will now be described in detail with reference to the accompanying drawings.

〔Example〕

The adapter shown in FIG. 1 includes a frame secured to the patient's head by two ear supports and a nasion support. The frame members are preferably made of a suitable somewhat resilient material such as plastic or light metal, preferably a hard resilient aluminum alloy. However, other materials are of course also conceivable. An almond-shaped ear support 10 is attached to an arm 12 rearwardly relative to the patient's face (FIG. 4) in a triangular frame portion, which also includes a forearm 14; rear arm 1
one or more arms 16 connecting the two.
Preferably, the ear support 10 is provided with air holes for relieving ear pressure and for patient interaction. Triangular frame portions 12, 14, 16 are right triangular in the illustrated embodiment, with rear arm 12 and arm 16 forming the short sides, while front arm 14 forming the hypotenuse. The angle α between arms 12 and 14 is an acute angle, with a preferred angle ranging from 10 to 30 degrees, with 20 degrees being more preferred. an arm 16 that connects the rear arm 12 and the front arm 14 on which the ear supports are mounted and is perpendicular to the rear arm 12;
Additionally, one or more lateral arms 18 are provided, which are also perpendicular to the rear arm 12 and connect the arms 12, 14 at a predetermined distance from the ear support. .

A bearing bracket 20 is fixed to the pointed ends of the rear arm 12 and the front arm 14, through which the split ends of two neutral support arms 22, 24 pass. The ends of the arms 22, 24 are in the form of racks that mesh with cogwheels, which are carried in bearing brackets 20 and can be operated from the outside by means of a foil 26. The position of the arms 22, 24, each set by a foil 26, can be locked by a locking screw 28. Also, bearing bracket 2
At the ends of the arms 22, 24, carried at zero, there are scales, for example graduations in millimeters, for reproducible adjustment of the arms. As previously mentioned, the nasion support 30 is constructed from plastic or aluminum alloy and is shaped to rest against the upper portion of the nasion due to its large surface. 2a to 2c, the nasion support 30 is secured to the nasion support arms 22, 24 by joints, such as pins 32, for example. The adjustment screw 34 above the joint 32 allows the arms 22, 2 to
4 are pulled together while the ear support 10 is simultaneously pushed into the ear canal as the adjustment screw 34 is tightened. As the adjusting screw 34 is tightened, the joints 32 and their labyrinth-like ends (second
The arms 22, 24 supported on each other in FIG.
and is pressed downward. The Nasion support arm is constructed from a material that is resilient and permanent in shape. These arrangements are Nasion Support 3
0, which allows detection of the pressure and position of the ear support 10 that is stable and familiar to the patient. At the hinge center of the joint 32, above the nasion support 30, as shown in FIG.
The indicator is in the form of a rod with either a bent end or a straight end engaging the mounting member 36. The function of the rod 38 will be explained in detail below.

In the middle part of the arm 16 in the triangular frame part there is a threaded pin with a rectangular base part, which is aligned with the longitudinal slot 40 of the connecting plate 42. In this way, the triangular frame part has slot 40.
and the set position is locked by a nut 44 in the form of a foil. Since the set position is fixed, the triangular frame part 1
2, 14 are positioned generally perpendicular to the connection plate and/or in contact with the patient's skull. In order to indicate the setting position, the connecting plate 42 is provided with a scale by which the setting of the triangular frame part can be read. As shown in FIG. 1, a slit arm 46 is disposed at the upper edge of the connecting plate 42, and a rod 38 is engaged and fixed in the slit of the arm. The connecting plate 42 also connects the mounting part 4
8, the mounting portion 48 is fixed to an angle bracket 50 by a locking screw 54, which bracket 50 is adjustable by means of a slot, and the foil 56 is fixed to another angle bracket 52.
to enable the adapter to be locked to the rectangular plate of the computer tomography table, as described in more detail below.

To indicate the rear left-right difference, a rear left-right difference indicator device 58 is provided which consists of two symmetrical rectangular devices of metal wire, the ends of which are bent and attached to the rear arm 12. It can be fixed at a predetermined marked point.
At the rear of the indicator device, there are aluminum pins 5 on each side as rear left-right differential indicators.
8a is provided. The left and right indicator devices 58 are connected to the rubber band 6 behind the patient's head.
0, aluminum pin 58
a is pressed against the skull (Fig. 1, 3
Fig. 4). The arms 12 and 18 of the adapter and the left/right difference indicators 38 and 58a are
Consisting of a plastic tube filled with liquid containing ±, the adapter is suitable for defining the position of brain structures for NMR examination.

As seen in FIGS. 3 and 4, the adapter is secured to the plate 62 of the computer tomography table by means of an angle bracket 52. The angle bracket is inserted into a clamp arm 64 with a locking wheel 66. To secure the patient's head to the computer tomography table, the plate 62 is preferably made of plastic or plexiglass and has a square raised section, e.g. made of plastic, with a concave recess in which the back of the patient's head rests comfortably. It has 68. The adapter shown in FIG. 1 is thus secured to the patient's head against the plate 62 of the computerized tomography table by means of a device that allows for stable retention. The aim is to keep the patient's head still during the test, rather than holding it in the same position relative to the table during repeated tests.

The above-mentioned adapter is installed as follows (Figs. 1 to 4).
(see figure) is fixed to the patient's head. The adjustment screw 34 of the nasion support 30 is loosened, the nasion support arms 22 and 24 are placed in the outermost position of the bearing bracket 20, and the connection plate 42 is loosely fixed to the arm 16 of the triangular frame part. , while the almond-shaped ear support 10 is pushed into the ear canal, first from one side of the head and then to the other side. Once the two ear supports 10 are inside, the adjustment screws 34 of the nasion supports 30 are tightened and the ear supports are stabilized within the ear canal. The nasion support 3 is then pressed against the patient's nasal root as the cogwheels 26 on both sides are rotated simultaneously. After the adjusting screw 34 is further tightened or the cogwheel is also tightened,
The cogwheel is secured by a locking screw 28.
The triangular frame portion is then adjusted until the arms 16 are positioned proximate the skull on both sides. In this way, the adapter is located in a reproducible position on the patient's head and adjusts all four scales, i.e. at the two nasion support arms 22, 24 and at the end of the connecting plate 42. The scale adjustment value is recorded. Rear left/right difference indicator 58
are symmetrically clamped to the rear arm 12 at a suitable height. A front indicator or rod 38 is then secured between the mounting member 36 of the nasion support and the slit arm 46. During repeated fixation of the adapter in this manner, the front and rear laterality indicators are always located in the same reproducible position on the head. Furthermore, these indicator devices are used to indicate the midline of the adapter at the patient's head, increasing the stability of the adapter and allowing the Z coordinate to be correlated during computerized tomography examinations and surgeries.

In this state, the patient should place the back of the head on the raised area 68.
By positioning the computer in the recess of the head and turning the head, the computer can create a section parallel to the transverse arm 18 and thus at right angles to the rear arm 12. The adapter is now firmly secured to the table by brackets 50, 52 and 64.

The computer coordinates for the desired target T and
The NMR coordinates are determined as follows with reference to FIG. 5, which schematically shows a section of the patient's head parallel to the transverse arm 18 of FIG. Forward arm 14
and the shadow of the rear arm 12 indirectly indicates the Y coordinate, which Y coordinate is the distance between the shadow of the lateral arm 18
It is most often referred to as the height of If the arm 18 is seen at different heights on the left or right side, the difference should be taken into account for defining the Y coordinates for brain structures located at varying distances from the midline. Several transverse arms make it possible to relate a fault level to an adjacent arm, thus increasing the accuracy of the Y-coordinate definition.

The distance of the target T from the line 71 connecting the front edges of the shadow of the rear arm 12 (the plane of both ears) functions as the X coordinate. The distance of the target T from the intermediate line 72, which occurs when the front left-right difference indicator, that is, the shadow of the rod 38, is connected to the midpoint m of the line connecting the left and right shadows of the rear left-right difference indicator 58a is the Z coordinate. It is shown.

When the computer tomography coordinates are transferred to the stereotaxic device S, shown schematically in FIGS. 6 and 7, the adapter adjusts the four scales so that they have the same reading as during the previous computer tomography examination. fixed to the head. The rear left-right difference indicator 58a should also be fixed at the same height of the rear arm 12 as in the previous computer tomography. It is then fixed to the head of the stereotaxic device by inserting screws. In the frontal (anterior-rear) X-ray photograph (FIG. 6), the shadows of the left-right difference indicators of the front part 38 and the rear part 58a appear, respectively, and the left-right difference of the computer target with respect to the midline 72 of the adapter is drawn out, It can be projected onto the Z-axis shadow of the localization device S. The lateral radiograph (Figure 7) shows the lateral arm 18, anterior arm 14 and posterior arm 12.
appears, and the plane 71b-b of both ears and the reference plane of the Y coordinate (plane t of the transverse arm) can be extracted. At that time, the target T of the computer is extracted according to the X and Y coordinates and projected onto the X-axis shadow s-s of the stereotactic device S.

〔Effect of the invention〕

As is clear from the foregoing description, the adapter according to the invention allows the same reference device to be used to transfer computer coordinates to the stereotactic radiograph by means of a stereotaxic device fixed to the patient's head, so that the brain The desired target can be captured with a high degree of precision, making it possible to obtain a reference device that can be reproducibly fixed in the same position relative to the patient's head at the same time for brain computer tomography and brain NMR examinations. can. As can be seen, this is achieved by the three spatial coordinates X, Y and Z relative to a given reference structure. The adapter also satisfies all the criteria set out in the introduction to this specification as desirable for an adapter. For satisfactory functioning of the adapter for stereotaxic operations, it is important that the adapter requires a minimum of space within the stereotaxic device. Also in this regard, it is clear that the adapter of the invention has been designed with maximum precision.

[Brief explanation of drawings]

FIG. 1 is a perspective view of an adapter according to the invention; FIG.
Fig. 2a is a cross-sectional view of the bearing bracket of the nasion support along the line - of Fig. 2b; Fig. 2a is a front view of the nasion support; Fig. 2c is a cross-sectional view of the bearing bracket of the nasion support along the line - of Fig. 2b;
Figure 3 is a diagram showing how to secure the adapter of Figure 1 to a computer tomography table; Figure 4 is a plan view of the Nasion Support shown in Figures 1 and 2b; A side view of the adapter fixed to the tomography table; FIG. 5 shows how computer tomography coordinates are formed on the computer radiograph; FIG. 6 shows how the computer tomography coordinates are transferred to the stereotactic radiograph. FIG. 7 is a schematic side view corresponding to the front view shown in FIG. 6; 10...Ear support, 12, 14, 16, 18
...Arm, 20...Bearing bracket, 2
2, 24...Nasion support arm, 30...
Nazion Support, 32...Joint, 34...
...Adjustment screw, 38...Indicator, 42...Connection plate, 46...Slit arm, 36,4
8...Mounting part, 50...Angle bracket,
52...Angle bracket, 58...Wire,
58a... Indicator, 60... Rubber band,
62...table.

Claims (1)

[Claims] 1. An adapter for detecting the position of brain structures in a patient's head based on spatial coordinates in computerized tomography and NMR examinations, and transmitting the coordinates to a stereotaxic device, the adapter being connected to the first arm 12; In an adapter comprising an ear support 10 so supported and another support 30 for reproducibly fixing the adapter to the patient's head, the two lateral frames are adapted to fit on either side of the patient's head, the first arm 12
the first arm 1 extending at an angle with respect to the first arm 1;
2 and another third arm 16 forming a triangular lateral frame 12 , 14 , 16 , said lateral frame on either side of the patient's head carrying another support 30 . connection device 22,
24, 42, and a front left-right difference indicator 38 and two rear left-right difference indicators 58 for defining a reference plane passing through the midline of the adapter.
A left-right difference indicator device 3 consisting of a.
8, 58a. 2. In the adapter according to claim 1, the other support 30 is a nasion support, and the nasion support is pivotally connected to the nasion support arms 22, 24, and the arms are connected to the nasion support arms 22, 24. An adapter characterized in that it is adjustably connected to the ends of triangular side frames 12, 14, 16. 3. Adapter according to claim 2, characterized in that the side frames 12, 14, 16 are adjustably connected at their other ends by a connecting plate 42. 4. In the adapter according to claim 2, the nasion support arms 22, 24 are connected to the side frames 12, 14 by means of bearing brackets 20 disposed on the side frames.
16 and the racks of the nasion support arms 22, 24 mesh with the cogwheels 26 of the bearing bracket 20, the nasion support arms 22, 24 being lockable in the bearing bracket 20; Adapter characterized in that their position on the bearing bracket can be read on a scale. 5. In the adapter according to any one of claims 1 to 4, the nasion support arms 22, 24 are connected by a joint 32, and the joint is connected by an adjustment screw 34. , presses the nasion support arms 22, 24 made of a hard, slightly elastic material, thereby pressing the lateral frames 12, 14, 16 against each other and moving the ear support 10 into the patient's ear canal. An adapter characterized by generating a lever action for pushing into. 6. In the adapter according to any one of claims 1 to 5, the left-right difference indicator device is connected to the nasion support 30.
and the mounting portion 46 of the connection plate 42.
and two rear laterality indicators 58a, the rear laterality indicators pressing the rear laterality indicators 58a against the first arm 12 of the side frame and the patient's head. An adapter characterized in that it is pivotally mounted to. 7. In the adapter according to claim 6, the rear left-right difference indicator is supported by an arm 58 provided with a hook, and a device for pressing the rear left-right difference indicator 58a against the patient's head is provided. An adapter characterized in that it consists of an elastic band connecting the indicators to each other. 8. The adapter according to any one of claims 1 to 7, characterized in that it includes attachment devices 48, 50, 52 for fixing to a computer tomography table or the like. 9. In the adapter according to any one of claims 1 to 8, the side frames 12, 14, 16 have a right triangular shape, and the first arm 12 and the first arm 3 arm 1
6 constitutes a short side, and the second arm 14 constitutes an oblique side. 10. The adapter of claim 9, wherein one or more transverse arms 18 are connected to said third
an adapter, characterized in that it is arranged parallel to the arm 16 of the ear support 10 and at a known distance from the ear support 10. 11. Adapter according to claim 9 or 10, characterized in that the acute angles of the triangular side frames 12, 14, 16 are between 10 and 30 degrees. 12. The adapter according to any one of claims 1 to 11, wherein the front left-right difference indicator 38, the rear left-right difference indicator 58a, the first arm 12, and the lateral arm An adapter characterized in that 18 consists of a tube filled with a liquid that emits an NMR signal during an NMR examination.