JP4434514B2 - Reference frame and position measurement system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a reference frame and a position measurement system used for specifying the position of an affected area in navigation performed during surgery.
[0002]
[Prior art]
In recent years, in the field of brain surgery and the like, navigation using medical imaging equipment has been introduced as a technique for supporting surgery. This navigation associates the image of the diseased part acquired in advance with an X-ray CT device or the like during the operation with the actual patient, and displays the image, so that the doctor can easily grasp the position of the diseased part etc. It is something that can be done. For associating this image with an actual patient, a device called a reference frame that is replaced with the position of the patient is used.
[0003]
FIG. 10 is a diagram illustrating an example of a conventional reference frame. The reference frame 100 has LEDs arranged at predetermined intervals, and is fixed to a Mayfield frame 101 for fixing a diseased part of a patient. Associating the tomographic image of the diseased part and the actual patient as navigation is executed by the correspondence between the marker attached to the patient pointed by the pointer and the marker displayed on the tomographic image of the diseased part. However, when the operation progresses, for example, if the surgical target site is the head, the skull or the like with the color marker or the like attached by craniotomy or the like is removed, and thus the color marker or the like may be lost. Therefore, during the operation, the coordinates of the marker measured with the pointer are replaced with the reference frame 100, and the position of the patient (marker) is represented by the position of the reference frame 100 (the position of the LED of the reference frame 100). Therefore, the positional relationship between the reference frame 100 and the patient must be kept unchanged.
[0004]
In general, the larger the size of this reference frame, the higher the measurement accuracy,
The greater the number of frames used, the higher the measurement accuracy. On the other hand, if the size of the reference frame is increased or the number of use is increased, the operation work is disturbed. Therefore, in consideration of both, one reference frame having a predetermined size is usually used in an actual medical field.
[0005]
[Problems to be solved by the invention]
However, the conventional reference frame has the following problems.
[0006]
As described above, since the positional relationship between the reference frame 100 and the patient needs to be prevented from moving, the configuration does not change (that is, has no joint portion). Therefore, since the shape cannot be arranged according to the surgical environment, convenience may be lacking. In addition, due to the restriction due to the shape, the number of frames that can be used within a range that does not affect the surgical operation is at most one.
[0007]
Moreover, blood, water, etc. may scatter in surgery. At this time, the blood or the like adheres to the LED of the reference frame, which may reduce the measurement accuracy. For example, in the reference frame having five LEDs 1 to 5 shown in FIG. 11 (a), when blood or water scatters on the LED 1 and the LED 1 becomes impossible to measure, as shown in FIG. 11 (b). Only 4 LEDs from 2 to 5 can be measured. This effectively corresponds to a decrease in the reference frame, and as a result, the position measurement accuracy decreases. Therefore, the conventional reference frame cannot sufficiently withstand a surgical environment in which blood, water, and the like are scattered.
[0008]
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a reference frame and a position measurement system that have high measurement accuracy and do not interfere with surgical operations.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the present invention takes the following measures.
[0010]
The invention according to claim 1 is a reference frame used as a reference for specifying a spatial position of a disease in a subject specific site, and is arranged in a plurality of rows at predetermined intervals, and the spatial of the disease At least four or more light emitting means used for specifying a position, an installation means for installing the at least four or more light emitting means , and at least one joint part that can be fixed at an arbitrary angle A reference frame comprising: an arm unit that supports the installation unit with respect to a fixing unit that fixes the subject specific site .
The invention according to claim 2 is a fixing means for fixing a specific part of a subject, and at least four or more used for specifying a spatial position of a disease in the specific part arranged in a plurality of rows at a predetermined interval. The at least one first light emitting means , the installation means for installing the at least four or more first light emitting means , and at least one joint part that can be fixed at an arbitrary angle, and the subject specifying part An arm portion for supporting the installation means with respect to the fixing means for fixing the at least two reference frames fixed to the fixing means, and a second light emitting means for optically indicating the disease, an optical pointer having a third light-emitting means used to identify the spatial position of the second light emitting means for said disease, the location of the at least four or more first light emitting means A serial third optical position detecting means for detecting the position of the light-emitting means, and storage means for storing a plurality of tomographic images relating to the specific site of previously acquired the subject, the optical detection means detects Selection means for selecting, from the storage means, a tomographic image including the disease pointed to by the optical pointer based on the positions of the at least four or more first light emission means and the position of the third light emission means And an image display device that displays the selected tomographic image.
[0012]
According to such a configuration, it is possible to provide a reference frame and a position measurement system that have high measurement accuracy and do not interfere with the surgical operation.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, components having substantially the same function and configuration are denoted by the same reference numerals, and redundant description will be given only when necessary.
[0014]
First, the configuration of the position measurement system 10 according to the present embodiment will be described with reference to FIG.
[0015]
FIG. 1 is a schematic configuration diagram of a position measurement system 10. In FIG. 1, the position measurement system 10 includes a Mayfield frame 11, a reference frame 12, a pointer 14, an optical position measurement device 16, and a workstation 18.
[0016]
The Mayfield frame 11 is a mechanism for fixing the patient so as not to move during the operation. In the present position measurement system 10, in addition to the Mayfield frame 11, for example, a Sugita frame or the like can be used.
[0017]
The reference frame 12 is used for grasping the position of the disease during the operation. The configuration of the reference frame 12 will be described in detail later.
[0018]
The pointer 14 is an optical pointer that points to a desired part of the patient. The pointer 14 is provided with at least two LEDs (Light Emitted Diodes). From the viewpoint of improving measurement accuracy, the LEDs are preferably provided at least at both ends of the pointer 14. In place of the pointer 14 or the LED of the reference frame 12 described later, for example, a light reflecting means (for example, a mirror ball, a color marker, etc.) having a size capable of sufficiently receiving the reflected light by the optical position measuring device 16 is provided. It may be a configuration.
[0019]
The optical position measuring device 16 receives light from optical means such as an LED included in the pointer 14 and the reference frame 12 and measures the position of a predetermined part of the patient indicated by the pointer 14. When an optical means is used instead of the LED of the pointer 14 or the reference frame 12, the optical position measuring device 16 emits light to the optical means, and the optical means The position is measured based on the reflected wave reflected by.
[0020]
The workstation 18 displays an X-ray CT image or the like. Further, the workstation 18 selects an image corresponding to the part pointed by the pointer 14 from the previously collected X-ray CT images based on the information from the optical position measuring device 16 and displays the selected image on the display device 20. .
[0021]
(Reference frame)
Next, the configuration of the reference frame 12 will be described in detail with reference to FIGS.
[0022]
FIG. 2A shows the reference frame 12. As shown in the figure, the reference frame 12 includes an LED 120, a housing 122 for housing the LED 120, an arm portion 123 that supports the housing 122 and has an articulating portion 121 for providing an arbitrary angle. And a fixing jig 124 for fixing the arm portion 123 to the Mayfield frame 11 or the like.
[0023]
The LED 120 is used to indicate the position of a disease instead of a marker, and is arranged at a predetermined interval. In particular, the reference frame 12 has at least two rows in which a plurality of LEDs 120 are arranged at a predetermined interval. This is because the length of the reference frame 12 measured by the optical position measuring device 16 is not shortened even when blood, water, or the like is scattered during the operation. Therefore, according to the present reference frame 12, it is possible to always provide the LED 120 arrangement information of the maximum length, and therefore it is possible to always provide highly accurate position measurement.
[0024]
In addition, even if a mirror ball, a color marker, etc. are used instead of LED120, the measurement by the optical position measuring device 16 is possible, and it can play the same role. Moreover, although the shape of the member which installs LED120 becomes a rectangle in Fig.2 (a), there is no limitation in the shape. For example, as shown in FIG.3 (d), it can be set as the shape according to surgical environments, such as L shape.
[0025]
The fixing jig 124 is for fixing the arm portion 123 to the Mayfield frame 11 or the like. FIG. 2A shows a clamp that can be opened and closed as an example. As shown in FIG. 2 (b), the clamp can be opened and closed by turning the screw 12, and is fixed to the frame 11 by sandwiching the frame 11 in the opened state and turning the screw 12 to close. can do.
[0026]
The joint part 121 is a movable part for arbitrarily deforming the shape of the reference frame 12, and has a configuration shown in FIG. That is, in FIG. 3, the joint part 121 has a configuration in which the concave and convex nails of the upper joint part 121a are engaged with the concave and convex nails of the lower joint part 121b and fixed by screws 121c. 3B shows a view of the upper joint part 121a as seen from the screw 121c side, and FIG. 3C shows the lower joint part 121b as seen from the direction of the concavo-convex nail. The figure is shown. When the reference frame 12 is angled at an arbitrary angle, the screw 121c is loosened, the upper joint part 121a or the lower joint part 121b is moved to a desired angle, and the screws 121c are engaged with each other. What is necessary is just to rotate and fix as shown in FIG.3 (b). In FIG. 3C, the nail having a certain height from the center to the circumference indicates the upper joint part 121a and the lower joint part 121b shown at predetermined angles. However, the configuration of the upper joint part 121a and the lower joint part 121b is not limited to this, and even if each joint part is a coronal disk in which nails are formed only on the circumference, the same An effect can be obtained.
[0027]
Therefore, according to the present reference frame 12, since it is possible to take an appropriate shape according to the surgical environment, it is possible to install it so as not to interfere with the surgical operation, and to install a plurality of reference frames. It is also possible to do. As a result, the convenience of the reference frame can be improved and the measurement accuracy can be improved.
[0028]
Further, as will be described later, the positional relationship between the reference frame 12 and the patient must not be changed during the operation. According to the reference frame 12, the joint 121 has a configuration in which the concave and convex teeth of the upper joint part 121a and the concave and convex teeth of the lower joint part 121b are meshed and fixed by screws 121c. Therefore, once fixed, the shape does not change unless a strong impact or the like is given from the outside, and the positional relationship with the patient can be kept constant.
[0029]
2A shows the reference frame 12 having two joint portions 121, the number of the joint portions 121 is not limited. However, if the shape of the reference frame 12 is required to be maintained, it is preferable that the number of joint portions 121 is small.
[0030]
(Position measurement processing)
Next, position measurement processing realized by the position measurement system 10 will be described with reference to the drawings. In order to make the story more concrete, a case where navigation is performed during surgery using an X-ray CT image in brain surgery will be described. However, the present system and reference frame can also be used in operations such as orthopedics.
[0031]
FIG. 4 is a flowchart showing the work procedure of the position measurement process. In FIG. 4, first, the patient's head is shaved and a plurality of markers are attached so as to surround the disease. At this time, a number is attached to the marker. Then, X-ray CT images are collected so as to include markers and diseases (step S1). The acquired CT image is read into the workstation 18.
[0032]
Next, the workstation 18 measures the position, that is, the coordinates (x _i , y _i , z _i ) of each marker in the three-dimensional volume space based on the read CT image (step S2). Note that the subscript i is a number for identifying the marker. For example, in the case of the marker 1, the coordinates are expressed as (x ₁ , y ₁ , z ₁ ).
[0033]
Next, the patient's head is fixed to the Mayfield frame 11, and each position of each LED 140 of the pointer 14 when pointing to each marker attached to the head is measured by the optical position measuring device 16. The position of each marker is calculated from each position of the LED 140 (step S3). Specifically, the following processing is performed in the optical position measuring device 16 and the workstation 18.
[0034]
FIG. 5 is a diagram for explaining the position measurement executed in step S2. In FIG. 5, for example, when the position of the marker 1 is measured, the marker 1 is pointed by the pointer 14, and each position of each LED 140 of the pointer 14 is measured by the optical position measuring device 16. Each position of each LED 140 measured by the optical position measuring device 16 is transmitted to the workstation 18, and the position (coordinates) (X ₁ , Y ₁ , Z ₁ ) of the marker 1 is calculated from each position of each LED 140. To do. The same measurement / calculation is executed for the other markers 2 to 5.
[0035]
Next, the workstation 18 performs registration for associating the coordinates (X _i , Y _i , Z _i ) of each marker measured in step S2 with (x _i , y _i , z _i ) (step S4). ). By this registration, correspondence between an X-ray CT image (or a three-dimensional volume space composed of the image) collected in advance and an actual patient is taken.
[0036]
Next, a plurality (two in this case) of reference frames 12 are attached to the Mayfield frame 11, and the position of each LED 120 of the reference frame 12 is measured by the optical position measuring device 16. The workstation 18 calculates coordinates of the measured positions of the LEDs 120 in the three-dimensional volume space, replaces the positions of the markers 1 to 5 with the positions of the LEDs of the reference frame 100, and positions of the LEDs of the reference frame 100. Thus, the association for indirectly representing the position of the marker (that is, the position of the patient) is performed (step S5). This is because when the operation progresses, if the head is a head, the marker becomes invisible due to craniotomy or the like, and the position of each LED 120 of the reference frame 12 is always measured by the optical position measuring device 16. Therefore, when the LED 120 moves, the coordinates of the LED 120 in the three-dimensional volume space are updated in real time.
[0037]
FIG. 6 is a diagram illustrating a state in which the reference frame 12 is attached to the Mayfield frame 11. As shown in the figure, since the reference frame 12 has a joint part 121, the shape of the reference frame 12 can be determined according to the surgical environment.
[0038]
After step S5, the position of the LED 140 in the three-dimensional volume space when the pointer 14 points to a predetermined position is grasped by the relative position of the reference frame 12 to the LED 120. Therefore, the positional relationship between the patient's head and the reference frame must not be changed during the operation.
[0039]
Thereafter, when displaying a cross-sectional image at a desired position, by pointing the desired position with the pointer 14 (step S6), correspondence with the position in the three-dimensional volume space is taken, and a desired tomographic image ( For example, an MPR image, an original image, etc.) are displayed (step S7).
[0040]
FIG. 7 is a diagram illustrating a state in which a tomographic image relating to the desired position is displayed on the display unit when the desired position is indicated by the pointer 14. The operation of the system 10 in steps S6 and S7 will be described more specifically with reference to FIG.
[0041]
First, the position of each LED 140 and the position of each LED 120 of the reference frame 12 when the desired position is pointed by the pointer 14 are measured by the optical position measuring device 16. The workstation 18 calculates the coordinates of the desired position in the three-dimensional volume space based on the positions of the LEDs 120 and 140 from the measurement result measured by the optical position measuring device 16. That is, since the position of the LED 140 of the pointer 14 when pointing to the desired position represents the desired position, the workstation 18 determines whether each LED 140 in the three-dimensional volume space is related to each LED 120 or not. The position is obtained, and the desired position indicated and the X-ray CT image including the position can be determined according to the association in step S4. The determined X-ray CT image is displayed on the display device 20.
[0042]
In addition, as described above, the desired position is represented by the position of the LED 140 of the pointer 14 when the desired position is pointed out. This is because it becomes invisible during surgery.
[0043]
Thereafter, when it is desired to display a tomographic image including a predetermined position as required, the above-described processing may be executed for the predetermined position.
[0044]
Next, effects obtained by the reference frame 12 will be described.
[0045]
FIG. 8 is a diagram for explaining the effect obtained by the reference frame 12. In the figure, at least two reference frames 12 are arranged so as to surround the patient.
[0046]
In general, the position of the reference frame measured by the optical position measurement device includes a measurement error. However, like this position measurement system, it is possible to cancel measurement errors by installing multiple reference frames so as to surround the patient. As a result, CT images and the like can be displayed with high accuracy during the operation. It becomes possible.
[0047]
Further, when an error is measured in which one end of a reference frame having a length d shown in FIG. 9A is raised by 1 mm and the other end is lowered by 1 mm, and one end of a reference frame having a length of 3d shown in FIG. 9B. Is compared with the case where an error is measured in which the other end is lowered by 1 mm and the other end is lowered by 1 mm, the error is 2 mm in length d in the case of FIG. 9A and the length in the case of FIG. 9B. An error of 2 mm was measured at 3d. Therefore, if the length of the reference frame is tripled, it can be said that the measurement error is 1/3.
[0048]
Since the reference frame 12 includes a plurality of LEDs 120, even if blood, water, or the like may scatter during the operation, the number of effective LEDs 120 can be ensured to the maximum. Therefore, unlike the conventional case, the number of LEDs that can be measured due to scattering of blood, water, or the like is reduced, and the effective length of the reference frame can be prevented from being shortened. As a result, highly accurate position measurement can be realized.
[0049]
Furthermore, since the reference frame 12 can be given an arbitrary angle, the reference frame 12 can have a shape suitable for the surgical environment. Therefore, a plurality of installations are possible within a range that does not interfere with the surgical operation, and high convenience and high position measurement can be realized.
[0050]
Although the present invention has been described based on the embodiments, those skilled in the art can come up with various changes and modifications within the scope of the idea of the present invention. It is understood that it belongs to the scope of the present invention. For example, in the above-described embodiment, the position measurement system that associates with the tomographic image acquired by the X-ray CT apparatus is shown. In addition to this, it may be configured to associate with a tomographic image acquired by another medical imaging device such as a magnetic resonance apparatus or an ultrasonic diagnostic apparatus.
[0051]
The above-described embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent requirements. For example, even if some constituent requirements are deleted from all the constituent requirements shown in the embodiment, the problem described in the column of the problem to be solved by the invention can be solved, and the effect described in the column of the effect of the invention If at least one of the following is obtained, a configuration in which this configuration requirement is deleted can be extracted as an invention.
[0052]
【The invention's effect】
As described above, according to the present invention, it is possible to realize a reference frame and a position measurement system that have high measurement accuracy and do not interfere with surgical operations.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of an embodiment of a position measurement system 10 of the present invention.
FIG. 2A is a perspective view showing a configuration of a reference frame 12 used in the position measurement system 10. FIG. FIG. 2B is a view showing a fixing jig for fixing the reference frame 12 to the frame.
FIG. 3 is a side plan view for explaining a specific structure of a joint part included in the reference frame 12;
FIG. 4 is a flowchart showing a work procedure of position measurement processing in the position measurement system 10;
FIG. 5 is a conceptual diagram for explaining a state of position measurement executed in step S2 of FIG.
FIG. 6 is a diagram illustrating a state of a reference frame 12 fixed to a Mayfield frame 11 in the position measurement system 10;
FIG. 7 is a diagram illustrating a state in which a tomographic image relating to a desired position is displayed on a display unit when a desired position is indicated by a pointer in the position measurement system.
FIG. 8 is a diagram for explaining an effect obtained by the reference frame 12 in the position measurement system 10;
FIG. 9 is a diagram for explaining an effect obtained by the reference frame 12 in the position measurement system 10;
FIG. 10 is a diagram for explaining a configuration of a conventional reference frame.
FIG. 11 is a diagram for explaining a configuration of a conventional reference frame;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Position measuring system 11 ... Mayfield frame 12 ... Reference frame 14 ... Pointer 16 ... Optical position measuring device 18 ... Workstation 20 ... Display apparatus 100 ... Reference frame 101 ... Mayfield frame 102 ... Optical pointer 120, 140 ... LED
121 ... Joint part 121a ... Joint part 121b ... Joint part 121c ... Screw

Claims (2)

A reference frame used as a reference for specifying a spatial position of a disease in a subject specific site ,
At least four or more light-emitting means arranged in a plurality of rows at a predetermined interval and used for specifying the spatial position of the disease ;
Installation means for installing the at least four or more light emitting means ;
An arm portion that has at least one joint part that can be fixed at an arbitrary angle, and that supports the setting unit with respect to a fixing unit that fixes the subject specific part ;
A reference frame comprising: Fixing means for fixing a specific part of the subject;
At least four or more first light emitting means arranged in a plurality of rows at predetermined intervals and used for specifying the spatial position of the disease at the specific site, and the at least four or more first light emitting means are installed. And at least one joint part that can be fixed at an arbitrary angle , and an arm part that supports the setting means with respect to the fixing means that fixes the subject specific part. At least two reference frames fixed to the fixing means;
An optical pointer comprising: a second light-emitting means for optically indicating the disease; and a third light-emitting means used for specifying a spatial position of the second light-emitting means for the disease ;
An optical position detecting means for detecting the position of the at least four first light emitting means and the position of the third light emitting means ;
Storage means for storing a plurality of tomographic images relating to the specific part of the subject acquired in advance;
Based on the positions of the at least four first light emitting means and the positions of the third light emitting means detected by the optical detection means, a tomographic image including the disease indicated by the optical pointer is Selecting means for selecting from the storage means;
An image display device for displaying the selected tomographic image;
A position measurement system comprising:

Images