JPS61275683A - Semiconductor radiation position detecting device - Google Patents

Abstract

PURPOSE:To improve counting rate characteristics by grouping radiation detecting elements arrayed in a matrix on condition that adjacent elements belong to different groups and providing independent signal processing circuits corresponding to the groups. CONSTITUTION:Many semiconductor radiation detecting elements in the semiconductor radiation detecting element array 1 are divided into groups A, B, C, and D on condition that mutually adjacent elements belong to different groups. Respectively elements in the group A are connected to a signal processing circuit 21 and elements in the group B are connected to a signal processing circuit 22; and elements in the group C are connected to a signal processing circuit 23, and elements in the group D are connected to a signal processing circuit 24 respectively. Output signals of the circuits 21-24 are sent to an image generating device 3 to constitute the whole image. Thus, counting rate characteristics are improved even on RI station condition as well as on uniform irradiation condition.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to an improvement in a semiconductor radiation position detection device, which can be used, for example, in a scintillation camera or an emissive seal commonly used in nuclear medicine diagnosis. A specific RI (radioisotope)
It is useful for obtaining distribution images of nuclides, and is also used in other fields such as science and engineering.

2. Description of the Related Art Conventionally, semiconductor radiation position detection devices have been known that detect the two-dimensional position of radiation by arranging a large number of semiconductor radiation detection elements in a matrix (for example, Japanese Patent Application No. 1982-
247109, Japanese Patent Application No. 59-135493).To briefly explain, as shown in FIG. For simplicity, the diagram shows a semiconductor radiation detection element array l in which elements are arranged in an 8x8 arrangement. , the signals from each element are input to the signal processing circuit 2, where position detection, energy signal waveform shaping processing, wave height analysis, etc. are performed for each radiation incident event, and position signals x, Y, energy signal Z, and UNBLANK signal are processed. is output.

Although various types of signal processing circuit 2 are conceivable, for example, the signal processing circuit 2 is configured as shown in diagram Is4. The signals for each row arranged in the X direction are sent to the discriminator and encoder 13 via the preamplifier 11, and a position signal X (digital signal) corresponding to the row generating a signal greater than the threshold level is output. . On the other hand, the signals for each column arranged in the Y direction are sent via the preamplifier 12 to the discriminator and encoder 14, and a position signal Y (
digital signal) is output. The row signal that has passed through the preamplifier 11 is sent to a delay and multiplexer 16, and based on the output signal of the discriminator and encoder 13, the row signal that has generated a signal greater than the threshold override level is selected. This signal is amplified by the main amplifier 17 to become an energy signal Z, and the pulse height is analyzed by the pulse height analyzer 18. Based on this wave height analysis result, the timing control circuit 15 outputs the UNBLANK signal.

Note that here, preamplifiers ll and 12 are provided for each row and each column.
However, a preamplifier can also be provided for each element.

Problems to be Solved by the Invention By the way, when there is only one signal processing circuit 2, there is a problem that the count rate characteristic is low. Therefore, conventionally, the fifth
As shown in the figure, it is possible to divide the matrix-like semiconductor radiation detection element array l into multiple regions (four regions A, B, C, and D in the figure) and provide an independent signal processing circuit in each region. It is considered.

By dividing the area in this way and providing an independent signal processing circuit for each area, it is true that under uniform radiation irradiation conditions, the overall count rate characteristics will apparently be improved by a magnification corresponding to the number of divisions. Ru.

However, in applications such as nuclear medicine diagnosis, especially cardiac examination, high concentration of RI is often localized, and under such conditions, only the signal processing circuit for a specific region operates mainly. become.

Count rate characteristics are not improved.

An object of the present invention is to provide a semiconductor radiation position detection device that can improve count rate characteristics under conditions where high concentration RI is localized in the same way as under uniform irradiation conditions with a simple circuit configuration. With the goal.

Means for Solving the Problems In the semiconductor radiation position detection device according to the present invention, a large number of semiconductor radiation detection elements are divided into a plurality of groups according to the rule that mutually adjacent elements or element groups belong to different groups, Mutually independent signal processing circuits are provided corresponding to each of these groups.

Function: A large number of semiconductor radiation detection elements are divided into multiple groups according to the rule that adjacent elements or element groups belong to different groups, so even if the RI distribution is localized, it is difficult to separate the areas. Unlike in the previous case, most of the light does not always enter only one group, but instead enters each group on average. Therefore, the signal processing circuits provided in each group operate at the same frequency, and the count rate characteristics under conditions where high concentration of RI is localized are improved to the same extent as under uniform irradiation conditions. be able to.

Embodiment In FIG. 1, each of the large number of semiconductor radiation detection elements in the semiconductor radiation detection element array 1 is divided into a plurality of groups, four groups A in this figure, according to the rule that adjacent elements belong to different groups. , B, C, and D. Each element belonging to group A is connected to the signal processing circuit 21, each element belonging to group B is connected to the signal processing circuit 22, each element belonging to group C is connected to the signal processing circuit 23, and each element belonging to group D is connected to the signal processing circuit 21. circuit 24
are connected to each other. As the signal processing circuits 21 to 24, the signal processing circuit shown in FIG. 4 above or other signal processing circuits can be used. Each output signal of these signal processing circuits 21 to 24 is sent to the image creation device 3.
The entire image is constructed. This image creation device 3 includes, for example, an image memory (RAM), an image display device, and the like. Note that it is also possible to provide an independent image memory for each group and to transfer the contents of each image memory to another overall image memory at appropriate time intervals.

In this way, a large number of semiconductor radiation detection elements constituting the semiconductor radiation detection element array 1 are arranged according to the rule that adjacent elements or element groups belong to different groups.
Since it is divided into four groups A to D, even if the RI force distribution is localized, it will not always be incident on only one group, but will be incident on each group on average. Therefore, the signal processing circuit 2 provided in each group A to D
1 to 24 will operate at about the same frequency.

The count rate characteristics under conditions where high concentration of RI is localized are also
Improvements can be made similar to those under uniform irradiation conditions.

FIG. 2 shows a second embodiment. In this figure, a large number of semiconductor radiation detection elements of a semiconductor radiation detection element array l are arranged in element groups adjacent to each other (element groups in units of one row in the figure).
With the rule that they belong to different groups, multiple
Here, they are classified into four groups A, B, C, and D. The configuration, such as sending the output signals of each group A to D to four mutually independent signal processing circuits, is the same as that in FIG. 1.

In Fig. 2, the count rate characteristic is inferior to that in Fig. 1 when the RI force distribution is localized in the longitudinal direction, but when using a signal processing circuit as shown in Fig. 2, This has the advantage that signal extraction from the electrodes of each detection element is simplified and can be easily applied.

Note that the present invention can be modified in various ways without departing from the spirit thereof. For example, other groupings than those shown in FIGS. 1 and 2 are also possible. Moreover, for convenience of explanation, the case of an 8×8 matrix has been described above, but it goes without saying that the case of other arrangements can be similarly applied. Further, as the signal processing circuit, circuit configurations other than the signal processing circuit shown in FIG. 4 are also possible.

Further, the present invention can be applied not only to a two-dimensional radiation detection device such as a normal gamma camera but also to a multilayer slice emission CT device.

Effects of the Invention According to the present invention, count rate characteristics can be improved with a simple circuit configuration without deterioration of physical characteristics such as position resolution and energy resolution. High count rate characteristics can be obtained not only under conditions of uniform RI force distribution but also under conditions of localized RI.

[Brief explanation of drawings]

FIG. 1 is a block diagram of one embodiment of the present invention, FIG. 2 is a block diagram of a second embodiment, and FIGS. 3, 144, and 5 are block diagrams of conventional examples. l...Semiconductor radiation detection element array 2.21-24...Signal processing circuit 3...Image creation device 11.12...Preamplifier 13.14...Discriminator and encoder 15...・Timing control circuit 16... Delay and multiplexer 17... Main amplifier 18... Pulse height analyzer Answer 1 note Z

Claims (1)

[Claims] (1) In a semiconductor radiation position detection device that performs two-dimensional position detection of radiation by arranging a large number of semiconductor radiation detection elements in a matrix, each of the above-mentioned detection elements is classified into adjacent elements or element groups that belong to different groups. A semiconductor radiation position detection device characterized in that it is divided into a plurality of groups according to the rule, and a mutually independent signal processing circuit is provided corresponding to each of these groups.