JP5558864B2 - Slit mechanism device and X-ray computed tomography apparatus - Google Patents

Description

  The present invention relates to a medical imaging apparatus, and more particularly to a slit mechanism apparatus of an X-ray computed tomography apparatus (CT apparatus).

  The CT apparatus is a medical diagnostic apparatus that diagnoses a patient with X-rays. As shown in FIG. 1, the CT apparatus detects an X-ray by an X-ray tube 10 that emits X-rays, a slit mechanism (optical adjustment means) 11a that adjusts the width of the X-rays, a bed 12 on which a patient is placed, and X-rays. A detection unit 13 that performs signal processing is included.

  Generally, before making a diagnosis with a CT apparatus, it is necessary to preheat the X-ray tube 10 that emits X-rays. In order to avoid irradiating unnecessary X-rays during the remaining heat period, it is necessary to block X-rays with a shutter plate (X-ray blocking mechanism).

  The shutter plate is provided in the optical system unit 11. The shutter mechanism is equipped with a shutter plate having an X-ray blocking function, for example, a lead plate, in the X-ray passage in order to realize X-ray blocking.

  Further, when the X-ray tube 10 normally emits X-rays, X-ray blocking is not performed. At this time, the shutter plate that blocks X-rays is separated from the X-ray passage.

  As shown in FIG. 2, the conventional optical system unit of a CT apparatus includes a wedge mechanism 11a that filters X-rays, a slit mechanism 11b that adjusts the width of the X-rays, and a shutter mechanism 11c. The wedge mechanism can have multiple types, and different types of wedges are applied to different types of diagnostics. The wedge and the shutter plate share the same drive mechanism, and the wedge and the shutter plate are moved by driving the drive mechanism to realize switching between the different types of wedges and the shutter plate.

  The conventional shutter mechanism is integrated with the wedge mechanism, and the drive mechanism drives the shutter plate so as to move along the straight rail to the X-ray path, and its structure is complicated. In particular, as shown in FIG. 3, when only one wedge is required and the movement of the wedge does not need to be controlled, a drive like a wedge mechanism is also used to realize switching between X-ray blocking and normal radiation. The system needs to be driven and moved, increasing the number of unnecessary structures and increasing the cost.

  An object of the present invention is to simplify the control and structure of the shutter mechanism and the slit mechanism.

  One aspect of the present invention is that two slit plates L3 and L4 for adjusting the width of the X-ray and two slit link bars pivotally supported at both ends of the two slit plates in order to interlock the two slit plates. S2 and S4, two shafts R1 and R2 for attaching two slit link bars to rotate the two slit link bars, respectively, two shutter plates L1 and L2 for blocking / passing X-rays, Provided a slit mechanism device having two shutter link bars S1 and S3 that are pivotally supported at both ends of two shutter plates to be linked with two shutter plates and are attached to two shafts together with two slit link bars. To do.

  According to the present invention, the control and structure of the shutter mechanism and the slit mechanism can be simplified.

FIG. 1 is a schematic view showing the structure of a CT apparatus. FIG. 2 is a schematic view showing the structure of a wedge mechanism and a slit mechanism in a conventional CT apparatus. FIG. 3 is a schematic view showing a structure having a conventional wedge plate. FIG. 4 is an external view of the slit mechanism of the CT apparatus according to the present embodiment. FIG. 5 is a perspective view of the slit mechanism according to the present embodiment. FIG. 6 is a front view of the slit mechanism according to the present embodiment. FIG. 7 is a schematic view of the length relationship between the shutter plate and the shutter link bar according to the present embodiment. FIG. 8 is a conceptual diagram of an operation process of the slit mechanism according to the present embodiment. FIG. 9 is a conceptual diagram of the angular relationship between the shutter link bar and the slit link bar according to the present embodiment. FIG. 10 is a conceptual diagram of a change in the angle-length relationship between the shutter link bar and the slit link bar.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 4 is an external view of the slit mechanism of the CT apparatus according to the present embodiment. In the present embodiment, the slit mechanism and the shutter mechanism share the opening / closing mechanism and the driving mechanism.

  FIG. 5 is a perspective view of the slit mechanism according to the present embodiment, and FIG. 6 is a front view of the slit mechanism according to the present embodiment. The slit mechanism according to the present embodiment has a shutter function for blocking X-rays as well as a slit function for adjusting the width of the X-rays. The slit mechanism of this embodiment includes a shutter mechanism. The slit mechanism includes two slit plates (X-ray width adjusting plates) L3 and L4 having the same length and the same width. The slit plates L3 and L4 are connected to each other by two link bars S2 and S4 having the same length. The link bars S2, S4 are attached to the two shafts R1, R2 that rotate together. The rotation of the two shafts R1 and R2 causes the slit plates L3 and L4 to approach / separate while maintaining a state parallel to each other. This changes the width of the gap (slit) between the slit plates L3 and L4. The X-ray width is changed according to the change in the slit width.

  The two shutter plates L1 and L2 are connected to each other by two link bars S1 and S3 having the same length. The link bars S1 and S3 are attached together with the link bars S2 and S4 to the two shafts (common shafts) R1 and R2 to which the link bars S2 and S4 of the slit plates L3 and L4 are attached. The link bars S1, S3 are attached to the shafts R1, R2 at a predetermined distance from the link bars S2, S4 so that the slit plates L3, L4 and the shutter plates L1, L2 do not interfere with each other. The rotation of the two shafts R1 and R2 opens and closes the gap between the shutter plates L1 and L2 while maintaining a parallel state to each other. Thereby, X-rays are blocked / passed.

  The shutter link bars S1 and S3 intersect the slit link bars S2 and S4 at any angle in the range of 50 ° to 140 °, for example, 90 °. Thereby, two crossbars (switching means) are configured. As a result, when the slit plates L3 and L4 are separated from each other by the forward rotation of the two shafts R1 and R2, the shutter plates L1 and L2 approach each other and are finally completely closed. When the shutter plates L1 and L2 are separated from each other by the reverse rotation of the two shafts R1 and R2, the slit plates L3 and L4 approach each other.

  The shutter link bar S1 and the slit link bar S2 may not be provided separately. The shutter link bar S1 and the slit link bar S2 may be provided in an integrated structure. Similarly, the shutter link bar S3 and the slit link bar S4 may be provided in an integrated structure.

  Both ends of the two shutter link bars S1 and S3 are respectively pivotally connected to both ends of the two shutter plates L1 and L2 with screws, for example, to form a parallelogram, and both ends of the two slit link bars S2 and S4 are Each of them is pivotally connected to both ends of the two slit plates L3 and L4 with screws, for example, to form another parallelogram.

  The shutter link bar S1 and the slit link bar S2 are installed so as to cross each other at a predetermined angle to form one “cross bar”, and the shutter link bar S3 and the slit link bar S4 are at a predetermined angle. They were installed crossing each other to form one “cross bar”. When the intersection is fixed by the shafts R1 and R2, the shutter link bar S1 and the slit link bar S2, and the shutter link bar S3 and the slit link bar S4 can rotate around the common shafts R1 and R2 at the intersection. it can. When the shutter link bar S1 and the slit link bar S2, and the shutter link bar S3 and the slit link bar S4 rotate about the shafts R1 and R2 at the intersections, the long sides of the two sets of parallelograms are in opposite directions. Moving.

  By previously determining the length relationship between the shutter link bar S1 and the slit link bar S2, the length relationship between the shutter link bar S3 and the slit link bar S4, and the crossing angle relationship between the cross bars, the slit mechanism and the shutter mechanism Can realize that their functions are linked to each other and do not interfere with each other. Here, the length of the shutter link bar S1 is the same as that of the shutter link bar S3, and the length of the slit link bar S2 is the same as that of the slit link bar S4.

  Hereinafter, the length relationship between the shutter link bar S1 and the slit link bar S2 and the length relationship between the shutter link bar S3 and the slit link bar S4 will be described with specific examples. The present invention is not limited to the above embodiment.

  In the present embodiment, for example, the length of the shutter link bars S1, S3 is set to 39 mm, the slit link bars S2, S4 are set to 35 mm, and the crossing angle of the cross bars is set to 90 °. FIG. 7 further shows that the distance from the side of the shutter plate L1 to the center of the pivot contact between the shutter plate L1 and the shutter link bar S1 is 8.3 mm, and from the side of the slit plate L3 to the slit plate L3 and the slit link bar S2. This indicates that the distance to the center of the pivot contact is 9.5 mm.

  FIG. 8 is a conceptual diagram of an operation process of the slit mechanism according to the present embodiment. FIGS. 8A to 8B show a change process from when the slit width of the slit mechanism is increased to when the X-ray is not blocked by the shutter mechanism. In this process, the slit width through which the shutter mechanism passes X-rays is always larger than the slit width through which the slit mechanism passes X-rays. With such an installation, the shutter mechanism does not interfere with the adjustment of the X-ray width by the slit mechanism. In order to realize this requirement, it is necessary that the length of the shutter link bars S1 and S3 is not less than the length of the slit link bars S2 and S4. Moreover, in the apparatus type of this embodiment, the adjustment range of the slit width by a slit mechanism is 1 mm-6.7 mm.

  FIG. 8C is a conceptual diagram when X-rays are blocked by the shutter mechanism. When blocking X-rays, the two shutter plates of the shutter mechanism partially overlap to completely block the X-ray path.

  FIG. 9 is a conceptual diagram of the angular relationship between the shutter link bar S1 and the slit link bar S2, and between the shutter link bar S3 and the slit link bar S4. FIG. 9B shows the angular relationship after the angle of FIG. 9A is rotated clockwise.

  As shown in FIG. 9, A, B, A ′ and B ′ are the four end points of the shutter link bars S1 and S3, and C, D, C ′ and D ′ are the four end points of the slit link bars S2 and S4. It is. The left and right have exactly the same structure, and A, B, C, D, A ′, B ′, C ′, and D ′ have eight degrees of freedom of plane rotation.

  L (AB) and L (CD) intersect at the point O and are fixed to each other. The fixed L (AB) and L (CD) constitute a “crossbar”. L (AB) and L (CD) intersect at an angle β. L (A′B ′) and L (C′D ′) intersect at the point O ′ and are fixed to each other. L (A′B ′) and L (C′D ′) constitute a “crossbar”. L (A′B ′) and L (C′D ′) intersect at an angle β.

  The parallelogram ABB'A 'can rotate around O and O'. AA 'and BB' are the two long sides of the parallelogram ABB'A '. The parallelogram CDD'C 'can rotate around O and O'. CC 'and DD' are the two long sides of the parallelogram CDD'C '.

  When the two “crossbars” rotate clockwise around O and O ′, the distance between AA ′ and BB ′ decreases as shown in FIG. L (AB) = L (AB) * (SINα−SINα ′), and the distance between CC ′ and DD ′ increases, and the amount of change is ΔL (CD) = L (CD) * {SIN (Α ′ + β) −SIN (α + β)}.

  As a result, the change amount ΔL (AB) between the distances AA ′ and BB ′ and the change amount ΔL (CD) between the distances CC ′ and DD ′ are reversed in direction. The change relationship is shown in FIG.

  The actual situation can be summarized as follows (but not limited to this range):

    1) L (AB)> L (CD), that is, the short side of the parallelogram of the shutter mechanism is larger than the short side of the parallelogram of the slit mechanism.

  Among them, the range of the short side L (AB) of the parallelogram of the shutter mechanism is 20 mm to 150 mm.

  The range of the short side L (CD) of the parallelogram of the slit mechanism is 20 mm to 140 mm.

    2) The short side of the parallelogram of the shutter mechanism and the short side of the parallelogram of the slit mechanism are fixed to the “crossbar” mold. The range of the distance from the fixed part to the center of each short side is 0 mm to 50 mm.

    3) The angle β formed by the short side of the parallelogram of the shutter mechanism and the short side of the parallelogram of the slit mechanism is an arbitrary fixed value of 50 ° to 140 °.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

  The present invention can be used in the field where a shutter mechanism and a slit mechanism are provided.

  L1 ... Shutter plate, L2 ... Shutter plate, L3 ... Slit plate, L4 ... Slit plate, S1 ... Shutter link bar, S2 ... Slit link bar, S3 ... Shutter link bar, S4 ... Slit link bar, R1 ... Common shaft, R2 ... Common shaft.

Claims (12)

A first slit plate and a second slit plate for adjusting the width of the X-ray;
A first slit link bar pivotally supported at one end of each of the first slit plate and the second slit plate for interlocking the first slit plate and the second slit plate; A second slit link bar pivotally supported at the other end of each of the slit plates;
A first shutter plate and a second shutter plate for blocking or passing the X-ray;
A first shutter link bar pivotally supported at one end of each of the first shutter plate and the second shutter plate to interlock the first shutter plate and the second shutter plate; A second shutter link bar pivotally supported on the other end of each of the shutter plate and the second shutter plate;
In the first slit link bar and the first shutter link bar, the moving direction of the first slit plate is opposite to the moving direction of the first shutter plate, and the second slit plate A first shaft attached at an intersecting angle in which the moving direction of the second shutter plate and the moving direction of the second shutter plate are opposite directions;
In the second slit link bar and the second shutter link bar, the moving direction of the first slit plate is opposite to the moving direction of the first shutter plate, and the second slit plate A second shaft attached at an intersecting angle in which the moving direction of the second shutter plate and the moving direction of the second shutter plate are opposite to each other;
A slit mechanism device comprising:   2. The slit mechanism device according to claim 1, wherein the first and second shutter link bars have a longer length than the first and second slit link bars.   2. The slit mechanism device according to claim 1, wherein the first and second shutter link bars are fixed to the first and second slit link bars at a constant crossing angle.   2. The slit according to claim 1, wherein the first and second shutter link bars intersect with the first and second slit link bars at an angle of 50 ° to 140 °. Mechanical device.   2. The slit mechanism device according to claim 1, wherein the first and second shutter link bars intersect with the first and second slit link bars at an angle of approximately 90 °.   The first and second shutter link bars are predetermined with respect to the first and second slit link bars so that the first and second slit plates do not interfere with the first and second shutter plates. The slit mechanism device according to claim 1, wherein the slit mechanism device is attached to the shaft at a distance. An X-ray tube for generating X-rays, an X-ray detector for detecting X-rays transmitted through the subject, a rotation mechanism for rotating the X-ray tube around the subject, and adjusting the width of the X-ray In order to do this, an X-ray computed tomography apparatus comprising a slit mechanism device provided between the X-ray tube and the subject,
The slit mechanism device is
A first slit plate and a second slit plate for adjusting the width of the X-ray;
A first slit link bar pivotally supported at one end of each of the first slit plate and the second slit plate for interlocking the first slit plate and the second slit plate; A second slit link bar pivotally supported at the other end of each of the slit plates;
A first shutter plate and a second shutter plate for blocking or passing the X-ray;
A first shutter link bar pivotally supported at one end of each of the first shutter plate and the second shutter plate to interlock the first shutter plate and the second shutter plate; A second shutter link bar pivotally supported on the other end of each of the shutter plate and the second shutter plate;
In the first slit link bar and the first shutter link bar, the moving direction of the first slit plate is opposite to the moving direction of the first shutter plate, and the second slit plate A first shaft attached at an intersecting angle in which the moving direction of the second shutter plate and the moving direction of the second shutter plate are opposite directions;
In the second slit link bar and the second shutter link bar, the moving direction of the first slit plate is opposite to the moving direction of the first shutter plate, and the second slit plate An X-ray computed tomography apparatus comprising: a second shaft attached at an intersection angle in which the moving direction of the second shutter plate and the moving direction of the second shutter plate are opposite to each other.   8. The X-ray computed tomography apparatus according to claim 7, wherein the first and second shutter link bars have a length longer than that of the first and second slit link bars.   8. The X-ray computed tomography apparatus according to claim 7, wherein the first and second shutter link bars are fixed at a constant crossing angle with respect to the first and second slit link bars. .   8. The X according to claim 7, wherein the first and second shutter link bars intersect with the first and second slit link bars at an angle of 50 ° to 140 °. Line computed tomography equipment.   The X-ray computed tomography apparatus according to claim 7, wherein the first and second shutter link bars intersect with the first and second slit link bars at an angle of approximately 90 °. .   The first and second shutter link bars are predetermined with respect to the first and second slit link bars so that the first and second slit plates do not interfere with the first and second shutter plates. The X-ray computed tomography apparatus according to claim 7, wherein the X-ray computed tomography apparatus is attached to the shaft at a distance.

Images