JPS58169076A - Scintillation camera - Google Patents

Abstract

PURPOSE:To achieve a higher sensitivity by a method wherein a parallel flat- plate-shaped collimator is arranged rotatably in front of a scintillator to introduce light emitted therefrom to a photoelectric converter and a number of incident radiation distribution data to reconstruct an image. CONSTITUTION:A parallel flat-plate-shaped collimator 7 made up of flat-plate- shaped shield plates arranged in plurality is arranged rotatably in front of a flat-plate-shaped scintillator 1 with a bearing 71. The collimator 7 is provided with a rack 72 in the perimeter thereof and turned with a motor 74 through a pinion 73. The angle of the collimator 7 is detected with a rotary encoder 76 through a pinion 75 meshed with the rack 72. Thus, the collimator 7 is rotated to obtain a number of distribution data from various angles for one turn, thereby enabling the reconstruction of an RI distribution image as original.

Description

[Detailed Description of the Invention] This invention is based on the RI (radioactive isotope) present in the subject.
This invention relates to a scintillation camera that captures distribution images of .

In a conventional scintillation camera, a grid collimator 2 is arranged in front of a flat scintillator 1 as shown in FIG. Only light incident in a direction perpendicular to the scintillator 1 is allowed to enter the flat scintillator 1, and the emitted light is transferred to a large number of photoelectric converters 3.3. ..., these photoelectric converters 3, 3 .・・・
・Sends the output of
．． ... Since the magnitude of each output corresponds to the distance to the light emitting position, the magnitude relationship of these outputs is determined.) The light emitting position is determined and the X direction position signal and Y direction position signal are obtained. There is.

Therefore, conventional scintillation cameras do not use
There is a problem in that sensitivity is low because most of the radiation emitted from Kl going in other directions is not detected.

In view of the above, an object of the present invention is to provide a nine-scintillation sun camera with increased sensitivity.

Hereinafter, one embodiment of the present invention will be explained with reference to the drawings. As shown in FIGS. 2 and 3, a parallel flat collimator 7 is formed by arranging a large number of flat shield plates in parallel.
is rotatably arranged on the front surface of the flat scintillator 1 by a bearing 71. A rack 72 is provided around the collimator 7, and the collimator 7 is rotated by a motor 74 via a pinion 73 that meshes with the rack 72, and a rotary encoder 76 is rotated by a rack 721) via a pinion 75 that meshes with the rack 72. The rotation angle of the sicolimator 7 is detected.

Here, if we assume that the direction perpendicular to the shield plate of the collimator is the direction of the person, the incident radiation is regulated in the direction of the person, but not within the plane perpendicular to A. Radiation from this direction will be incident on the scintillator l. Therefore, sensitivity increases dramatically. The position of the light emitted according to the incident radiation is detected as X and Y position signals by a position calculation circuit similar to the conventional one, but this position signal is coordinate-transformed and arranged only in the A direction (the component perpendicular to the A direction is (doesn't matter) and distribution data P#1 of the number of incident radiations in the direction of incidence are obtained as shown in FIG. When the collimator 7 is rotated so that the A direction is at the angle θ, distribution data Pk is similarly obtained. By rotating the collimator 7 and obtaining a large number of distribution data Pak from various angles for one rotation, as can be seen from Figure 4, the RI distribution, which is the original image, can be reconstructed through mathematical processing. can do.

Therefore, in this embodiment, the memory 81 is connected to a CPU (central processing unit) via an interface 82t in FIG.
Under the control of 83, the distribution data Pak corresponding to the angle # is collected.

When the distribution data is changed, the distribution data is read out, converted into convolutions (convolution integral) by a congelstork 84, then back-projected by a pack projector 85, and written into an image memory 86. Then, the image memory 86 contains 9, for example 256.
The original image of the X256 bit image is reconstructed. If this image memory 86 is read out and displayed on a display device such as a CRT device 87, it will be reconstructed and a 1 in 9 distribution can be seen.

Note that the rounding data processing method for image reconstruction is not limited to the above-mentioned cond IJ z-shine method, but other filter correction back projection methods and the like can be used.

A parallel plate collimator is not necessarily a flat plate scintillator.
It does not necessarily have to be oriented perpendicularly to the surface, but may be inclined at a predetermined angle (for example, 600 degrees) as shown in FIG. By shifting the center position of each of the distribution data P# obtained using such an inclined parallel plate collimator 9 and performing rounding data processing for image reconstruction, the scintillator 1 can be placed on a plane at a predetermined distance from the scintillator 1. Only the information about this plane converges, and the information before and after this plane is dispersed and blurred.
R distributed on this plane, IO image, that is, scintillator l
It is possible to obtain the tomographic image of the object in the plane of the plane or at a given depth.

As described above with respect to the embodiments, according to the present invention, it is possible to obtain a scintillating camera whose sensitivity is dramatically improved by 10 to 30 times compared to the conventional camera.

[Brief explanation of drawings]

Fig. 1 is a block diagram of a conventional example, Fig. 2 is a perspective view of an embodiment of the present invention, Fig. 3 is a sectional view of the same embodiment, and Fig. 4 is a diagram showing the relationship between the collimator angle and distribution data. Schematic diagram, 5th
The figure is a block diagram of the data processing system, and FIG. 6 is a sectional view of another embodiment. l... Flat scintillator 2... Grid collimator 3... Photoelectric converter 4... Position calculation circuit 5
... Subject 6 ... Lesion 7.9 ... Parallel flat collimator 71 ... Bearing 72 ... Rack 73.7
5...Binion 74...Motor 76...Rotary encoder 81...Memory 82...Interface 83...CPU 84...Controller
85...Pack! Ronoecta 86... Image memory 87... CRT device 56''

Claims (1)

[Claims] (1) A parallel plate-shaped collimator consisting of a large number of plate-shaped shield plates arranged in parallel is rotatably arranged in front of a scintillator, and the output of the photoelectric converter is guided to a photoelectric converter that emits light in the scintillator. Obtaining incident radiation distribution data in a direction perpendicular to the shield plate of the collimator,
The premeter is rotated to collect a large number of incident radiation distribution data in various directions, and a radioisotope distribution image is reconstructed by performing image reconstruction processing on these large numbers of incident radiation distribution data. camera.