JPS58137780A - Scanner for emission ct device - Google Patents

Abstract

PURPOSE:To wobble a detector ring and facilitate the production and the assembling, by rotating a supporting material to move the detector ring on a circle. CONSTITUTION:A scanner for emission CT device is provided with a detector ring 10 where radiation detectors 14 are arranged radially with respect to a center O of a virtual circle and at equal intervals, the first supporting material 11 to which the detector ring 10 is fixed, the second supporting material 12 which supports the first supporting material 11 so that the detector ring 10 can be rotated around the center O, the third supporting material 13 which holds the second supporting material 12 so that the second supporting material 12 can be rotated around the second center O' off the center O, and a means which guides the first supporting material 11 so that the first supporting material 11 is moved only linearly in two directions orthogonal to each other. The detector ring 10 is moved on a virtual circle, which has the second center O' as the center and has the length between centers as the radius, by rotation of the second supporting material 12.

Description

[Detailed Description of the Invention] This invention is an emission CT! ! This invention relates to a stationary running device.

In an emission CT scanning device, a detector ring is supported so as to be movable on a circumference with the center of the detector array as a radius of 4, which is the distance between the detectors, and measurements are taken at four locations on the circumference. A so-called wobbling scan is known. This scanning is generally provided by a jaw crank mechanism.

ixh shows an example of such a scanning device. Detector jja is rotatably supported on roller b.

Sprocket wheel C is eccentric to the roller and is defeated.

A chain d is wrapped around a sprocket wheel c1, an idle sprocket wheel e, and a sprocket wheel g of a motor f. When the motor rotates the chain, the detector ring can be moved on a circular chest whose radius is the eccentricity of the roller and sprocket wheel.

In such a detector ring wob ring using multiple crank mechanisms, each crank mechanism is manufactured with the eccentricity precisely matched, and the phase of each crank mechanism must be precisely matched during assembly. This is necessary, and the manufacturing cost is enormous.

The present invention is a scanning device that wobbles a detector ring.
The present invention aims to provide a more practical scanning device that can be manufactured and assembled easily.

An embodiment of the scanning device for an emission CT apparatus according to the present invention will be explained below with reference to FIGS. 2 to 6.

In the drawing, 10 is a detector ring, 11 is a support body, 1
2 represents a second support, and 13 represents a third support. Detector 11 includes a number of radiation detectors 14. Each radiation detector consists of a figurative scintillation crystal and a photomultiplier tube.
They are arranged on a circle at equal intervals and in a radial direction with respect to the central axis O of the virtual circle. The first support has rings 1 on both ends of the body.
6 and 17 are integrally provided, and the bearing 1 is mounted on the second support.
It is attached via 8. The detector ring is fixed to the ring 16 so that the center of the detector array reaches the rotation center axis O of the first support. The second support body itself has a hollow cylindrical shape, but the central axis of the outer circumferential surface 19 is
It is eccentric with respect to the central axis O' of the peripheral surface. 1
The amount of eccentricity or the distance between the center axes of the inner and outer circumferential surfaces is set to a ring with a spacing ΔX between the radiation detectors.

The first support body is attached to such a second support body so that its rotation center axis O coincides with the center axis of the outer circumferential surface. The third support has a cylindrical body. The second support body is engaged with this third support body K, and is rotated about the central axis 0' on the third support body by a bearing 21 arranged between the inner and outer peripheral surfaces of each support body. can. Although not shown, the third support is fixed to the floor or the like by appropriate means.

On the other hand, the guide plates are mounted 9 on the first support 11 so that they can move in a plane perpendicular to the central axes o and o'. For this purpose, the guide plate is approximately ring-shaped and is located between the rings 16 and 17 on the first support and is tightly fitted to the body. The inner hole 23A of the guide plate, which is fitted into the body part, is an eccentric hole or a concentric hole that is sufficiently larger than the diameter of the body part, as clearly shown in Fig. 86. Furthermore, there are two sets of straight lines #I24.24 on the guide plate.
and 6.25 are provided near the periphery. -Gumi no Mizome, 2
4 is arranged on the guide plate so as to be orthogonal to the other set of #125.25. In addition, - group's roller invitation, 2
6 is provided on the back side of the ring 16 forming the first support 11, and another set of rollers 4, 27 is provided at the end of the arm 28 extending from the third support. Laura I.

A is the guide plate tk24, 24, roller nail, 27 is the groove δ.

They are fitted together so that they can each slide in the direction of δ.

The roller 1.27 is on the third support and therefore fixed in its position. For this reason, the guide plate hello n, z'tt
- The first support can move only on the line connecting the rollers on such a guide plate, that is, in the Y direction, and the first support can only move on the line connecting the rollers on such a guide plate, that is, in the X direction, and It can only move linearly in the direction, and rotation is completely restricted.

When the second support 12 is rotated on the third support 13, the first support 11 rotates around the center @0' together with the second support 9.
Try to rotate eccentrically. However, since the first support is restrained from rotating 5 times, it is moved IIJJ in the X and Y directions. That is, when the second rotating body rotates, the roller guide 26 moves the guide plate 23 in the Y direction, moves in the groove in the X direction, and translates the central axis O of the first support. For example, when the second rotary body is rotated through an angle of 9 [J0, the first support body moves along the guide plate to the roller n.

n and moves itself to the left, the center @0 of the first support body is centered on the central axis O'
A point B moves on a circle E whose radius is the distance between and O'.
Ki is advanced. When the second support is rotated a further 90 degrees, the first support moves itself to the right while lowering the guide plate further, translating its center axis 0 to point C on circle E. When the second support is rotated to an angle of 270°, the first support moves to the left while raising the guide plate, and translates on the circle E so that the central axis O points toward the dot. When the second support completes one rotation, the first support moves to the right while further raising the guide plate, and its central axis is translated to point A on circle E. As described above, the center axis of the detector ring 10 is aligned with the center 111 of the first support, so the center of the detector ring 10 is translated into the circle E by the rotation of the second support. In other words, it can wobble. Some points on the welfare circle E of the gamma line, for example, point A.

The rotation of the second rotating body on B, C, and D is performed by an electric motor via a chain and a sprocket wheel, as shown in FIG. Returning to FIGS. 1 and 2, the sprocket wheel 31
is provided at the end of the second support body 12 so that it can rotate around the rotation center @θ' of the second support body 12. The electric motor has a sprocket wheel fixed to its rotating shaft. Chain U
is wrapped around these sprocket wheels, and the electric N
The second support body is rotated on the third support body by the rotation of the machine b.

In the embodiments described above, the rollers that restrict the rotation of the detector ring and the first and third supports are fixed in position on the first and third supports, respectively, and these rollers are connected to guide plates. The detector ring and the first support are attached to the second support by allowing the detector ring and the first support to move on each support so that they completely emerge from the grooves of the second support. It may be possible to rotate freely on the top. By performing such rotation by the radiation detector spacing A at each position A, B, C, and D of the circle E, the positional resolution can be further improved.

As shown in the embodiments described above, the emission CT scan station of the present invention includes a first support body to which a detector ring is fixed, and a second support body to which a third support body is rotatably held. Two supports and m eccentric from the central axis of the detector ring.
a third support for rotatably holding the second support; and means for guiding the third support so that the first support can be moved linearly in only two orthogonal directions within one plane. In this known glazed scanner, the first support body is moved on a circumference having a radius equal to the distance between the two axes by the rotation of the second support body, so as to give a wobbling to the detector ring. In comparison, it does not require much effort and expense for processing and assembly, and is highly practical.

[Brief explanation of the drawing]

FIG. 1 is a clear diagram illustrating the configuration of a known emission CT scanning device. Figures 2 through 6 show an embodiment of the scanning device for an emission CT apparatus according to the present invention. Figure 2 is a front view, Figure 8 is a side view, Figure 4 is a rear view, and Figure 5 is a rear view. 4 is a cross-sectional view taken along the line ■-■, and FIG. 6 is a cross-sectional view taken along the line ■-■i in FIG. 10...Detector ring, 11...First support body, 12...
・Second support, 13...Third support, 14...Radiation detector, Rugo...Guiding means, 0...First central axis, 0'...Second central axis . Applicant Hitachi Medeico Co., Ltd. Agent Patent Attorney Tadashi Akimoto Figure 4 Figure 5 W

Claims (1)

[Claims] L A detector ring in which radiation detection windings are arranged on a virtual circle in the radial direction and at equal intervals with respect to its central axis, a first support body on which the detector ring is fixed, and a detector ring in front of the detector ring around the central axis. a second support supporting the first support so that the second support can be rotated once, and a second support supporting the first support so that the second support can be rotated about a second central axis eccentric from the central axis; a third support for holding the support, and a means for guiding the first support so that the first support can only be moved linearly in two mutually orthogonal directions, and the detector ring is connected to the second support. A scanning device for an emission CT device, which is configured to move on a virtual circle centered on a second central axis and having a radius equal to the distance between the central axes by one rotation of the body.