JPH03284253A - Apparatus for displaying in vivo three-dimensional position - Google Patents

Abstract

PURPOSE:To display the leading end position of an arm in the state superposed on a CT image regardless of the shift of a patient by mounting a position correcting operation part accessing the three-dimensional positions of a standard point before and after the movement of the patient at the leading end of the arm and calculating the conversion matrix related to the positions of the head before and after movement. CONSTITUTION:Six arms 2a, 2b, 2c, 2d, 2e, 2f are respectively connected to the arm base stand 2 arranged to the stand 1 of an operation table in a freely bendable manner through joints 4a, 4b, 4c, 4d, 4e, 4f and a probe 3 is mounted to the leading end of the foremost arm 2f. Potentiometers each detecting an angle of rotation are mounted on the respective joints 4a-4f and the outputs thereof are inputted to an A/D converter 7. The output of the A/D converter 7 is corrected by a movement correcting coordinates converting operator 11 and a leading end position signal is outputted. Then, the conversion matrix with the coordinates at the time of CT photographing sent from a CT image data base 9 is calculated and the leading end position of the probe 3 is converted to the position on a CT image by conversion operation to be outputted to an image display apparatus 10.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an in-body three-dimensional position display device, and in particular, in order to quickly reach the target lesion site during closed head surgery, etc. The present invention relates to a surgical position detection device that accurately displays the tip position of a probe superimposed on a CT cross-sectional image displayed on a CRT regardless of patient movement.

[Prior Art] In recent years, with the progress of image diagnostic techniques such as X-ray CT and MRT, it has become possible to determine the intracranial lesion site with high accuracy. However, at the stage of performing surgical operations on the determined lesion site, doctors rely on their anatomical knowledge.
While considering the rough correspondence between the seven images and the actual surgical location, the decision on the head closure position and the removal of the lesion were performed through trial and error. In order to establish an accurate correspondence between the actual surgical operation position and the lesion position on the C7 image, it is effective to use a device that displays the three-dimensional tip position of the multi-jointed arm in a superimposed manner on the C7 image. Are known(
Japanese Patent Publication No. 62-327).

[Problems to be Solved by the Invention] However, with the above-mentioned conventional device, the position of the patient's head, once fixed, often shifts during surgery, and the arm coordinates that describe the three-dimensional position of the probe Because the correspondence between the system and the CT gantry coordinate system that describes the C7 image was in the machine groove, it was impossible to calculate the
There was a problem in that it was not possible to accurately grasp the three-dimensional positional relationship between the dimensional position and the lesion, and that it could not be fully utilized for head closure surgery and the like.

SUMMARY OF THE INVENTION The present invention aims to provide an apparatus that can display the position of the tip of the Arno and the C7 image in a superimposed manner regardless of the presence or absence of patient displacement.

Means for Solving Problem F] This invention considers arbitrary three points on the head that are not in the same straight line as reference points for calibration, and calculates three of these reference points before and after moving the patient.
Equipped with a position correction calculation unit that calculates a transformation matrix regarding the head position before and after movement by accessing the dimensional position at the arm tip, and displays the arm tip position superimposed on the C7 image, etc., regardless of the presence or absence of patient displacement. [Function] The arm tip position can be displayed correctly superimposed on the lesion area displayed in the C7 image, etc., regardless of whether the patient is displaced or not.
Precise head-closed surgery is made possible by allowing free changes in the patient's position to avoid inadvertent positional displacement during surgery.

[Example] An example of an embodiment of the present invention will be described based on the drawings.

FIG. 1 shows the configuration of the sensor arm and the entire device, in which five arms 2a, 21], 2c, 2d, 2e, and 2f are attached to a joint 4a, respectively, on an arm base 2 installed on a pedestal 1 of a surgical table. , 41], 4(, 4d, 4e, and 4f).

A probe 3 is attached to the tip of the arm 2f. A potentiometer that detects the rotation angle is attached to each joint 4a to 4f, and the output of each potentiometer is
The signal is input to a converter 7. The output of the A/D converter 7 is sent to the coordinate converter 8 via the arithmetic unit 11, which will be described later. Here, a conversion matrix is obtained between the coordinates at the time of CT imaging sent from the CT image database 9, and the probe is Convert the tip position in step 3 to the position on the CT image, and display it on an image display device (CRT).
)10. Then, the position of the tip of the probe 3 is displayed as a mark on the CRT image of the display device 10.

Here, the concept of positional deviation correction according to the present invention will be explained with reference to FIG. In the same figure, assume that the three points on the surface of the cranium SK before head closure are A, B, and C, and the same three points after the patient's head is moved are A', B', and C', respectively. . Furthermore, the f vertical vector of each point seen from the arm coordinate system is UA, UR,
Uc, and UA', UR', and Uc'. Here, the vector (UR-UA) heading from point A to B and the vector from 8 to C.
\If the foreign currency of the vector (U, -UA) towards is ~', the end point of that vector is D, and the position vector of the dot is UU, then the following formula (%) (1) Similarly, for each position vector after position shift. can be defined as the following formula.

V' = (UR' - UA') X (IJC'
-UA').

U ll -U A ten \t' ---------
~------------(1') Let the position vector of the probe tip P accessing the head after the position shift be U,
+, the position vector of the same point in the brain observed before the position shift is U, then the position vector of the virtual origin of the head UD, U
, ° and rotation], the following equation holds, and the observation point after the position shift is at the position U1 before the position shift.
It is converted to ゜.

U, = [Sko(U,'-u.')---111-(2)
IrisiS] = [Ul, U2. U3 j [U
l', 02 °, U, ■ (3) U, = -V, U,' = -V U2 = UR - UD, U2' = UR' - UllU, = Uc
−U1.1, U,'=Uc'U1゜〈4) In other words, the position vector U of the three points on the skull before the position shift
, , U n , U c , according to equation (1), V ,
U u is obtained, and VU o ゛ is similarly obtained from equation (1') from the three points after the positional shift. After substituting these into equation (4) and further substituting equation (4) into (3), calculate the inverse matrix and [
8] is obtained. As a result, equation (3) and equation (1) (1°) are converted into (
By substituting 2), the position vector Up of each point on the head after the position shift can be returned to the position vector U before the position shift.

The movement correction coordinate transformation calculator 11 in FIG. 1 performs the calculation described in "1" and outputs a corrected tip position signal. Third
The figure shows a flow chart of the operation, in which program (2) is executed only once before a deviation occurs, and (2) is executed every time a deviation occurs. Normally, correction is performed by program ■→■.

[Effects of the Invention] As is clear from the above description, the in-body three-dimensional position display device of the present invention considers arbitrary three points on the head that are not on the same straight line as reference points for calibration, and calculates the position before and after the movement of the patient. is equipped with a position correction calculation unit that calculates a transformation matrix regarding the head position before and after movement by accessing the three-dimensional positions of these reference points at the tip of the arm. Since it is configured so that it is always displayed correctly and superimposed on both CT images, there is no need to worry about inadvertent misalignment during surgery.
It is now possible to freely change the patient's position, which is effective in planning and implementing accurate head closure surgery. Furthermore, C
If it is difficult to access the calibration points set for conversion calibration between T and arm coordinates on the operating table, calibrate between the CTrlE and arm coordinates using old calibration points in the examination room before surgery. After that, three calibration points for misalignment correction (movement correction) according to the present invention are newly installed in a location that is easily accessible during surgery, and after movement correction during surgery, normal position detection operation is started to adjust the position of the operating table. It is also possible to increase the optionality of patient fixation.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the entire apparatus, FIG. 2 is an explanatory diagram showing the concept of deviation correction of the present invention, and FIG. 3 is a flowchart showing the deviation correction operation of the apparatus. 10. trestle, 210. Arm base, 2a, 2 +), 2
c, 2d, 2e, 2f, , arm, 31. probe,
4a, 4b, 4c, 4d, 4e, 4f. Joints, 7. , , A/D converter, 819. Coordinate converter, 9
, ,C7 image database, 10. , image display device, 11. ,,Coordinate transformation performance WS for movement correction.

Claims (1)

[Claims] A three-dimensional position detection probe, a tip position detector of the probe, a coordinate conversion calculator for converting to the same coordinate system as the internal tomographic image, and a coordinate conversion for movement correction based on the coordinates of calibration points before and after patient movement. It is composed of an image display unit that displays a tomographic image and a probe position marker in a superimposed manner, and an image display unit that displays a probe tip position marker in a superimposed manner, and is characterized by displaying the probe tip position on the internal tomogram. A three-dimensional position display device in the body.