JPS63167248A - Industrial ct scanner - Google Patents

Abstract

PURPOSE:To eliminate a part where radiation can not be detected by a separator by laminating plural detection parts where detecting elements and separators are arranged alternately, and arranging the detecting elements of the respective layers so that they shift in position. CONSTITUTION:A radiation beam from a radiation generator 11 is collimated by a slit 15 into a fan-shaped beam 14, which is projected on a sample 12. A radiation detector group 13 have detection parts 13a and 13b laminated. The detection part 13a has detecting elements 1 at positions obtained by dividing a fan angle alpha equally and separators 2 between them respectively, and the detection part 13b have an arrangement in the opposite relation from the detection part 13a. The quantity of radiation transmission is detected by respective detecting elements 1 of the detection part 13a by arrangement positions. While a turntable 16 is rotated by a specific angle, the sample is rotated by at least 180 deg.+alpha and data corresponding to respective angles are collected. Then the detector group 13 is lowered until the detection part 13b reaches the same plane with the fan-shaped beam and transmission data corresponding to the arrangement positions of the respective detecting elements of the detection part 13b, i.e. >=180 deg.+alpha are collected similarly.

Description

Detailed Description of the Invention [Objective of the Invention] (Industrial Application Field) The present invention performs image reconstruction processing based on transmission data obtained by irradiating fan-shaped radiation onto a specific cross section of an object, and Regarding industrial CT scanners that obtain cross-sectional tomographic images,
In particular, it relates to improvements in the detection configuration of nine radiations that pass through a subject.

(Prior Art) FIG. 8 shows a schematic configuration of a radiation detection section of a conventional industrial eT scanner as viewed from the radiation incident direction.

In the figure, 1 is a detection element in which a scintillation crystal or the like is formed into a rectangular parallelepiped shape, and 2 is a separator arranged between each detection element 1 to insulate the light emitted by the scintillation phenomenon when each element 1 detects radiation.

The detection element 1 and the separator 2 are arranged alternately along the fan-shaped radiation receiving surface, and the amount of light emitted when the detection element 1 detects the radiation is converted into electricity by the nine photoelectric conversion parts arranged on the side of the detection element 1. It is converted into a signal and output as transparent data.

(Problems to be solved by the invention) In an industrial CT scanner, the mounting density of the detection element 1, that is,
The resolution of the reconstructed tomographic image is determined by the fineness of the arrangement interval between the elements 1. However, in the conventional detection section, the separator 2 disposed between the detection elements 1 creates a portion where radiation cannot be detected, which limits the mounting density of the radiation detection surface of the detection elements 1, and thus limits the resolution.

The present invention has been made to solve the above-mentioned problems, and provides an industrial CT scanner that can significantly improve the packaging density without significantly changing the configuration of the radiation detection section.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above object, the present invention has a radiation detection section of an industrial CT scanner in which a plurality of detection sections in which detection elements and separators are arranged alternately are stacked. By shifting the detection elements of each layer and arranging them, the area where radiation cannot be detected due to the separator is eliminated.

(Function) The radiation dose transmitted through a specific cross section of the object is sequentially detected for each layer by using multiple radiation detectors stacked with the detection elements of each layer shifted in position. The resolution of transmission data detection can be improved, and scattering of light and radiation between each detection element can be effectively blocked.

(Example) Hereinafter, the present invention will be described using an example with reference to the drawings. 1 and 2 show the radiation generator 11 and the subject 1.
2 and the radiation detector group.
The figure is a plan view thereof, and FIG. 3 is a side view thereof. Note that this embodiment will be described using an example in which two radiation detection units are stacked, and the same components as in FIG. 3 are denoted by the same reference numerals, and the explanation will be omitted.

The radiation generator 11 emits a high-energy radiation beam, and is fixedly installed at a predetermined position in a fixed direction. This radiation beam is collimated by a slit 15 into a fan-shaped beam 14 corresponding to the desired slice thickness. The fan-shaped beam 14 is a beam that spreads like a door at a fan angle α, and is irradiated onto the subject 12.

The subject 12 is placed on a turntable 16 and rotates at a predetermined number of rotations as the table rotates. The transmission dose of the fan-shaped beam 14 irradiated onto a plane along a specific cross section of the subject 12 is detected by the radiation detector group 13 and acquired as transmission data.

As shown in FIG. 3, the radiation detector group 13 includes a first detecting section 13a and a second detecting section 13b stacked so as to face each other in the direction of incidence of the fan-shaped beam 14. In the first detection unit 13a, the detection elements 1 are arranged at positions equally divided by the fan angle α on the same plane as the fan-shaped beam, and between each detection element 1, the shape of the detection element 1 and the beam incidence surface are the same. A separator 2 is arranged.

- The second detection section 13b is the detection element 1 of the first detection section 13a.
, the separator 2 is arranged in a relationship opposite to that of the separator 2, that is, the separator 2 is arranged to face the detection element 1, and the detection element 1 is arranged to face the separator IK.

A photoelectric converter 13C*1 is installed on the side of each detection element 1.
3d are arranged respectively, and output an electrical signal with the next luminescence amount as transmission data corresponding to the radiation dose within the ζ detection element 1.

Next, FIG. 5 shows the turntable 16 and the radiation detector group 1.
The turntable 16 is controlled by a table controller 21, and the table controller 21 transmits rotation to rotate the turntable 16 by a predetermined angle every time an external signal is input, for example. It is equipped with gears etc.

Further, the radiation detector group 13 is controlled by a detector group drive control section 22, and this control section 22 controls the vertical movement of the first detection section 13a and the second detection section 13b according to a table control command from the table control section 21. It is something.

FIG. 6 is a block diagram showing the overall configuration of this embodiment. In the figure, 25 is a radiation control section, which controls the radiation generator 11 to emit a radiation beam. 21 is a table control section, 22 is a detector drive control section, and 26 is a data collection section, which independently collects the video data detected by the detector group 13 for each slice, that is, the rows of detectors 13a and 13b. ℃ is collected and stored as data. 27 is an image reconstruction device which inputs the transmission data from the data collection unit 26 and reconstructs the image so that it becomes a tomographic image. 28 is an image memory that stores transmission data for each slice from the data collection unit 26 and reconstructed data. 29 is a CRT display console;
It receives commands and signals from the outside and displays reconstructed images in response to requests.

Next, the operation of the apparatus configured as described above will be explained.

First, when an operation command signal is output from the CRT display console 29 through an operation by an operator or the like, the radiation control section 25 receives this signal and controls the radiation generator 11 to emit a radiation beam. This radiation beam is collimated into a fan-shaped beam 14 by a slit 15 and irradiated onto a specific cross section of the subject 12. The amount of radiation transmitted through this object 12 is now the fan-shaped beam 1
The detection elements of the first detecting section 13a arranged on the same plane as the first detecting section 4 detect each position of the first detecting section 13a, and output the transmitted data to the data collecting section 26 as transmission data.

When the data collection section 26 finishes collecting the transmission data of the first detection section 13a, it outputs an end signal to the console 29.

In response to this, the console 29 operates the table drive control section 21 to rotate the turntable 16 by a predetermined angle.

When this rotation is completed, the radiation control unit 25 is operated,
A radiation beam 15 is generated, and the first detection unit 13a detects transmission data at that angle.

When the subject is thus rotated by at least 1800+α angles and the first detection section 13a finishes collecting data for each angular opening, the console 29 gives a signal to operate the detector drive section 22. In response to this, the drive unit 22 moves the radiation detector group 13 to the second detection unit 1 as shown in FIG.
3b is lowered until it is flush with the fan beam. When this movement is completed, the connor moves to the first detection unit 13.
The rotational direction of the turntable 16 is reset so that it is the same direction as the direction in which the fan-shaped beam 14 was irradiated at time a. As in the case of the first detection section 13a, the radiation machine control section 25 and the table drive control section 21 are connected to the radiation generator 1.
The rotation of the first radiation irradiation turntable 16 is controlled to obtain transmission data corresponding to the arrangement position of each detection element of the second detection unit 13 at least at an angle of 180°+α or more, and output to the data collection unit 26.

The data collection unit 26 includes a first detection unit 13a1 and a second detection unit 1.
Transmission data corresponding to each angle from each 3b is subjected to preprocessing such as A/D conversion and 10g conversion, and is stored in the image memory 26.

The image reconstruction device 27 uses the first image stored in the image memory 26.
The transmission data of the detection unit 13a1 and the second detection unit 13b are read out independently, and known image reconstruction processing such as convolution processing and back projection processing is independently performed on each transmission data, and the obtained reconstructed image is The images are stored independently in the image memory 28.

The reconstructed image data of the first detection section 13a1 and the second ejection section 13b in the image memory 28 is read out by the console 29 in response to an operator's request, and displayed on the CRT display either individually or by combining the two images. be done.

In this way, in this embodiment, when the radiation detector is arranged in an alternating combination of the detection elements 1 and separators 2, the parts of the radiator that cannot be detected by the separators 2 are detected by the other laminated detection element 2. can be detected without changing the internal configuration or connection relationships of the detector.
The mounting density of the detection element 1 can be doubled.

Furthermore, when receiving a high-energy radiation beam from the radiation generator 11, crosstalk occurs due to scattering i(A, B) generated from the detection element 1 itself as shown in FIG. Since 30,000 of each detection element 1 is intercepted by a separator 2, the scattered radiation is absorbed by the separator and does not affect adjacent detection elements 1.

In addition, in the embodiment, the case where the detection element 1 and the separator 2 have the same beam incident surface shape was explained, but in the present invention, the portion where the radiation cannot be detected by the separator 2 is stacked in multiple stages. Any device may be used as long as it is configured so that radiation can be detected by the detection element 1 . For example, if you want to detect with high resolution using a low-energy radiation beam, the entrance surface of the separator 20 will be thicker than the entrance surface of the detection element 1, so the entrance surface of the separator 2 will need to be detected until the entrance surface of the separator 2 has the same width. Detectors 13a, b for the number of elements
The detection elements 1 may be stacked and the positions of the detection elements 1 between the stacked layers may be shifted from each other.

Further, in one embodiment, the first detection section 13a and the second detection section 13
The explanation was given using an example of collecting transmission data for one slice of a progressive image in combination with b, but as shown in Figure WIJ7,
By repeating the vertical movement of the turntable 16 or the vertical movement of the radiation detector group 13, N tomographic images can be obtained.

Furthermore, in one embodiment, after the first detection unit 13a finishes collecting transmission data for at least an angle of 180°+α, the second detection unit 13a
After shifting to the detection section 13b and resetting it, the 18
Data was collected for the 0°+α angle.

However, in the present invention, the first detection section 13a and the second detection section 13a are connected to each other at the same angle.
Transmission data may be collected by moving the detection unit 13b up and down.

〔Effect of the invention〕

As explained above, according to the present invention, a plurality of radiation detecting units in which detecting elements and separators are arranged alternately are stacked, and transmission data corresponding to areas where radiation cannot be detected by the separators is transmitted by detecting elements in other layers. Since the detection elements of each layer are arranged offset from each other for detection, the efficiency of arrangement of the detection elements in the radiation beam plane is improved, and the resolution of the reconstructed image can be significantly improved.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing the configuration of an embodiment of the present invention, and FIG.
The figure is a side view showing the configuration of an embodiment of the invention, FIGS. 3 and 4 are schematic configuration diagrams for explaining the configuration of an embodiment of the invention, and FIG. 5 is an embodiment of the invention. FIG. 6 is a schematic diagram for explaining the operation of one embodiment of the invention, FIG. 7 is a flowchart showing the structure of another embodiment of the invention, and FIG. 1 is a schematic configuration diagram showing a conventional example of the invention. 1...Detection element 2...Separator 11...Radiation generator 13...Radiation detector group 15...Slit 16...Turntable 22...Detector ...Data collection unit 27...Image reconstruction device 29...Console agent Patent attorney Nori Chika Nori Yudo Hirofumi Mitsumata Figure 4 Figure 5

Claims (1)

[Scope of Claims] Radiation generating means for irradiating fan-shaped radiation at least 180°+fan angle or more to a specific cross section of the subject;
a radiation detection means for detecting the transmitted dose of the radiation generated by the means to the subject and outputting it as transmission data; and a tomographic image for a specific cross section of the subject that performs image reconstruction processing based on the transmitted data from this means. In the industrial CT scanner, the radiation detection means includes a detection element that emits light according to the transmitted dose, and a separator that blocks light and scattered rays from the detection element, which are arranged alternately in a straight line. The detected part is
The detection elements in each layer are stacked with the arrangement relationship shifted,
An industrial CT scanner characterized in that the amount of radiation transmitted from the radiation generating means through the subject is sequentially detected for each layer.