JPS5940284A - Collimator for radiation image forming apparatus - Google Patents

Abstract

PURPOSE:To obtain a collimator for a radiation image forming apparatus capable of simply and easily forming anisotropic collimator having arbitrary aperture effect, by forming the collimator by flat plates each high in radiation absorbability and corrugated spacers each low in absorbability. CONSTITUTION:Flat plates 1 each high in radiation absorbability are arranged through corrugated spacers 2 each low in radiation absorbability at long intervals to form a collimator and aperture effect and collimation anisotropic function are added by the spacers 2. By this constitution, the collimator for a radiation image forming apparatus capable of simply and easily forming the anisotropic collimator with arbitrary aperture effect is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a collimator used in a synnarration camera, an ECT device (emission-type combinator tomography device), etc. to regulate the direction of radiation incidence and to obtain a diaphragm effect.

Conventional collimators of this type have an aperture effect in the X direction and a
Most collimators are isotropic, with almost the same directional constriction effect. However, scintillation cameras and ECT
In the device, it is necessary to use an anisotropic collimator whose constriction effect is different in the X and Y directions, and in extreme cases, it has a constriction effect only in the X direction and no constriction υ effect at all in the Y direction. It often happens.

In view of the above, an object of the present invention is to provide a collimator for a radiation imaging device that can easily form an anisotropic collimator having an arbitrary aperture effect.

An embodiment of the present invention will be described below with reference to the drawings. In Figures 1 and 2, there are many flat plates 1
They are arranged at equal intervals in the direction, and corrugated plates 2 are arranged as spacers within each of these intervals, and these are integrated with adhesive or the like. The flat plate 1 is made of a material with high radiation absorption, such as lead, and the member 2 is made of a thin plate of iron or copper, which has a lower radiation absorption than the flat plate 1, or a transparent material that hardly absorbs radiation. Made of good quality polyester sheet.

In addition, in FIGS. 1 and 2, the corrugated plate-like part 2 is connected to the flat plate 1 and Z
Although the shape is such that a triangular hole is formed through the hole in the direction, the shape may be such that a square hole is formed as shown in FIG.

Next, the aperture effect of the above-mentioned collimator will be explained. As shown in Fig. 4, a lead plate 3 having a pinhole 31 is placed on one side of the collimator shown in Figs. 1 and 2 (Fig. 3), and a small A radiation detector 4 is placed. Then, a radiation source 5 is placed above and moved in the X and Y directions, and the radiation count value per unit time is measured. Then, when we plot the distribution of the count value against the moving distance, we obtain a Buekaap as shown in Fig. 5. Curve a shows the count value distribution in the Y direction when member 2 is a polyester film, curve b shows the count value distribution in the Y direction when member 2 is an iron plate, and curve C shows the count value distribution in the Y direction when member 2 is a steel plate.
The distribution of count values in the direction is shown (the same curve C is obtained whether the member 2 is a polyester film or a steel plate). Therefore, in the case of polyester film, there is almost no drawing effect in the Y direction and only a drawing effect is obtained in the X direction, and in the case of iron plates, the drawing effect in the Y direction is due to the drawing effect in the It can be seen that this is intermediate between the case of film and the case of film. In this way, any anisotropic collimator can be obtained by making the material of the corrugated plate-like member 2 used as a spacer a material having appropriate radiation absorbing properties.

Note that the above collimators are arranged in two layers (upper and lower), and the diaphragm effect of the two collimators is synergized (for example, when the collimators in Fig. 1 are arranged in two layers, the X direction of one side is Alternatively, it is also possible to obtain arbitrary aperture characteristics in both the X and Y directions.

As described above, according to the present invention, the corrugated member is
This is because it serves both as a spacer that maintains the distance between the flat plates and as a member that determines the unidirectional squeezing effect.

The structure is simple and easy to manufacture, and the corrugated plate member itself can be manufactured easily and with high precision. 1. Radiation incident in the Z direction is not absorbed by the corrugated plate, so it is not attenuated.

[Brief explanation of drawings]

Fig. 1 is a perspective view of one embodiment of the present invention, Fig. 2 is a plan view of the same embodiment, Fig. 3 is a plan view of another embodiment, and Fig. 4 explains a method for measuring the aperture effect. FIG. 5 is a partially cutaway schematic perspective view showing a count value distribution graph showing the constriction effect. 1...Flat plate 2...Corrugated plate member 3...Lead plate 4...Radiation detector 5...Radiation source applicant Shimadzu Corporation

Claims (1)

[Claims] (1) A plurality of flat plates with high radiation absorption are arranged at equal intervals, and within each interval, a member is formed in the shape of a corrugated plate having an arbitrary radiation absorption that is lower than the radiation absorption of the flat plate. are arranged as spacers, and the radiation picture formed by integrating them is a collimator for the device.