JP2003098261A - X-ray ct apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multi-slice type X-ray CT apparatus capable of preventing lowering of detection sensitivity and resolution. SOLUTION: A detection block 20 of an X-ray detector 10 contains a photoelectric transfer substrate 23 formed with a plurality of photoelectric transfer elements 59, a detection block substrate 25, and a scintillator element 22. The photoelectric transfer substrate 23 or the detection block substrate 25 has an element selecting part for selecting the plurality of photoelectric transfer elements 59 to conduct switching for reading-out of output electric signals from the selected photoelectric transfer elements 59. A wiring 71 for the selection for supplying a signal for selecting the photoelectric transfer elements 59 to the element selecting part, and a wiring 70 for an output for outputting the output electric signals from the photoelectric transfer elements 59 are formed in the first face of the detection block substrate 25. The signal for selecting the photoelectric transfer elements 59 is input from a control circuit 15 to the wiring 71 for the selection, and the output electric signals from the group of the photoelectric transfer elements 59 common to the second direction are output from the wiring 70 for the output. A reading circuit is prevented from increasing in its scale in this way.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray CT apparatus for obtaining an X-ray tomographic image, and more particularly to a multi-slice X-ray CT apparatus.

[0002]

2. Description of the Related Art There is a third scanning method for an X-ray CT apparatus.
There are a generation method and a fourth generation method. In the third generation system, X
An X-ray detector composed of a plurality of X-ray detection elements is arranged in an arc shape centered on the radiation source, and the X-ray source and the X-ray detector are opposed to each other and rotated to measure an X-ray projection image of the inspection target object. To do. In the 4th generation method, an X-ray detector including a plurality of X-ray detection elements is arranged on the entire circumference centered on the inspection object, and the X-ray source is rotated to measure an X-ray projection image of the inspection object. To do.

An X-ray CT apparatus has a plurality of Xs arranged in a plurality of rows in the axial direction (rotation of an X-ray source and an X-ray detector in the third generation system, rotation of an X-ray source in the fourth generation system). It is roughly classified by the number of array rows of the line detection elements (hereinafter, the number of array rows of the X-ray detection elements is referred to as the number of stages of the X-ray detector). That is, the case where the number of stages is one is called a single slice system, and the case where there are a plurality of stages is called a multi-slice system for distinction.

In the tomographic imaging by the single-slice type X-ray CT apparatus, only one tomographic image on one slice plane perpendicular to the rotation axis can be obtained at the same time. In order to obtain a plurality of tomographic images, the bed top plate on which the object to be inspected is mounted is moved in the rotation axis direction to select a plurality of slice planes, and tomographic images are sequentially taken in time series.

In the single-slice type X-ray CT apparatus, at the same time as the rotation (the rotation of the X-ray source and the X-ray detector in the third generation method, the rotation of the X-ray source in the fourth generation method), the bed top plate is rotated. 3) by performing tomography while continuously moving in the direction and performing scanning (spiral scanning).
It is possible to obtain a dimensional tomographic image.

In the multi-slice type X-ray CT apparatus,
Even if the spiral scanning is not performed, tomography can be performed on a plurality of slice planes. When performing tomography by combining the multi-slice method and spiral scanning, compared to the case of using a single-slice method X-ray CT apparatus,
There is an advantage that tomography can be performed on a plurality of slice planes in a short time with a fine sampling interval. Due to this advantage, a multi-slice type X-ray CT apparatus is widely used. In recent years, a multi-slice X-ray CT apparatus having three or more X-ray detector stages has also appeared, and the number of X-ray detector stages tends to further increase.

As the X-ray detector of the X-ray CT apparatus described above, an X-ray solid-state detector composed of a scintillator element and a photoelectric conversion element is usually used.

[0008]

A plurality of photoelectric conversion elements are manufactured on one substrate to manufacture a photoelectric conversion element substrate having a plurality of stages, and an X-ray solid-state detector having a plurality of stages (hereinafter,
When obtaining an X-ray detector), a large-area semiconductor substrate is required. However, as the area of the semiconductor substrate increases, the cost of the substrate increases and the X-ray detector becomes expensive.

As a method for solving this problem, a photoelectric conversion element substrate having a small number of stages is manufactured at a low cost, and a plurality of the substrates having a small number of stages are arranged close to each other in the stage direction (rotation axis direction). There is a method of substituting a photoelectric conversion element substrate having multiple stages. However, in this method, the method of reading the output signal from the photoelectric conversion element substrate becomes a problem. Conventionally, in order to solve this problem, a lap joint method (US Pat. No. 4,467,342),
Two-layer tile array method (US Pat. No. 5,105,0)
No. 87) has been proposed, but these methods have a problem in that detection sensitivity and resolution are deteriorated.

As the number of stages of the X-ray detector is increased, the scale of the read-out circuit is greatly increased, the detection circuit becomes large, and the manufacturing cost of the X-ray detector becomes high. There is a problem that the number of stages of the X-ray detector that can be performed is limited.

Therefore, an object of the present invention is to use an X-ray detector capable of preventing a decrease in detection sensitivity and resolution without increasing the scale of the readout circuit in the X-ray detector having another number of stages. It is to provide a slice X-ray CT apparatus.

[0012]

In the X-ray detector of the X-ray CT apparatus of the present invention, the X-rays that have passed through the object to be detected enter the scintillator element and are converted into light, and this light is converted into the photoelectric conversion element. The light enters, is photoelectrically converted, and is output as an electric signal from the photoelectric conversion element.

According to the present invention, a photoelectric conversion element substrate is formed by arranging a plurality of photoelectric conversion elements on a semiconductor substrate in a plurality of stages. A signal reading substrate for reading an output electric signal from the photoelectric conversion element substrate is arranged on the side opposite to the side), and an output electric signal from the photoelectric conversion element substrate is supplied from the back side of the photoelectric conversion element substrate. Take it out.

The output electric signal is read in parallel with respect to a group of a plurality of photoelectric conversion elements, and the group of photoelectric conversion elements is sequentially switched two-dimensionally to read the output electric signal. Each of the plurality of photoelectric conversion element groups is formed on a plurality of sub-boards, and the plurality of sub-boards are brought into close proximity to each other and are jointly arranged on a signal reading board for reading an electric signal, and the above-described multi-stage configuration An electric signal (photoelectric conversion signal) may be output from the back side of the photoelectric conversion element substrate.

The detection block constituting the X-ray detector in the X-ray CT apparatus of the present invention includes a photoelectric conversion substrate on which a plurality of photoelectric conversion elements are arrayed, a detection block substrate, and a plurality of scintillator elements. The detection block includes a plurality of X-ray detection elements (hereinafter simply referred to as detection elements) formed of scintillator elements and photoelectric conversion elements. The plurality of scintillator elements are optically bonded to the photoelectric conversion substrate. The photoelectric conversion substrate is electrically bonded to the detection block substrate.
The photoelectric conversion substrate or the detection block substrate has an element selection unit that selects a photoelectric conversion element and switches reading of an electric signal. On the front surface (first surface) side of the detection block substrate, a selection wiring for supplying an element selection signal for selecting a photoelectric conversion element from which an output electric signal is to be read to an element selection unit, output electricity from the photoelectric conversion element An output wiring for outputting a signal is formed. The selection wiring and the output wiring are formed by a multi-layer wiring structure in which each layer is insulated.

The output wiring is formed commonly to the photoelectric conversion elements arranged in a row in the first direction (slice direction or channel direction), and the selection wiring is arranged in the second direction orthogonal to the first direction. It is formed commonly to the photoelectric conversion elements forming a row. A selection signal for selecting a photoelectric conversion element is input from the control circuit to the selection wiring, and an output electric signal from the group of photoelectric conversion elements in which the selection wiring is commonly wired in the second direction is used for the output. It is output from the wiring. The rows of photoelectric conversion elements to be selected are switched to sequentially switch the group of photoelectric conversion elements in the first direction to read the output electric signal.

By the detector configuration according to the present invention described above,
Since the output electric signals of the photoelectric conversion elements belonging to the same column can be read by the common read circuit, it is possible to suppress the increase in the circuit scale of the read circuit for reading the output electric signals from the photoelectric conversion elements and reduce the circuit scale. Can be planned.

Further, since the output electric signal is output onto the detection block substrate from the back side of the photoelectric conversion substrate, a wiring space for forming a wiring for signal output is required around the photoelectric conversion element forming region. Since it does not, detection sensitivity,
The decrease in resolution can be prevented. This is because if the space between the photoelectric conversion elements becomes large and the element arrangement interval becomes large, the detection sensitivity and resolution will be reduced.

In the X-ray detector of the X-ray CT apparatus of the present invention,
X-ray detection having a plurality of detection stages by using a photoelectric conversion element substrate in which a plurality of photoelectric conversion elements are formed by a plurality of sub-boards to form a plurality of detection stages without using a large semiconductor substrate Blocks can be realized.

When a plurality of photoelectric conversion substrates are arranged in the channel direction (row direction) in which a plurality of detection elements are arranged, a plurality of element selection units extending over the plurality of photoelectric conversion substrates are electrically connected by a common selection wiring. It is possible to reduce the number of wirings connected to select the photoelectric conversion element from which the output electric signal is to be read.

When a plurality of photoelectric conversion substrates are arranged in the slice direction (column direction), a plurality of detection elements extending across the plurality of photoelectric conversion substrates are electrically connected by a common signal wiring, so that reading is performed. The scale of the circuit can be reduced.

In the X-ray detector of the X-ray CT apparatus of the present invention,
At least one of the photoelectric conversion substrate and the detection block substrate,
An amplifier circuit for amplifying the output electric signal from the photoelectric conversion element is arranged. The noise generated in the read circuit causes a decrease in the S / N ratio, but the noise generated in the lower side of the amplifier circuit makes a small contribution to the S / N ratio.

In the X-ray detector of the X-ray CT apparatus of the present invention,
At least one of the photoelectric conversion substrate and the detection block substrate is composed of a plurality of substrates. For example, the detection block substrate is composed of a selection wiring substrate having a selection element and a selection wiring formed thereon, and an output wiring substrate having an output wiring for reading an electric signal. An amplifier circuit is arranged on the wiring board.

In the X-ray CT apparatus of the present invention, the photoelectric conversion substrate is formed on the first surface (light incident surface) side of the selection element for switching on / off the electric signal output. A transparent electrode, an output terminal formed on the second surface (surface opposite to the light incident surface) side for outputting an electric signal, and a signal formed on the second surface side for controlling the selection element are input. The detection block substrate has a reference potential wiring electrically connected to the transparent electrode, and the output wiring is electrically connected to the output terminal. Of the connection output terminal formed on the first surface side of the, and the connection output terminal and the connection output terminal are formed at a position not electrically contacting the photoelectric conversion substrate and electrically connected to the signal collection circuit. Has an external output terminal to be connected and a signal line,
The connection output terminals to which the group of detection elements forming a row in the first direction (slice direction or channel direction) correspond are electrically connected by a common output line, and the selection wiring is electrically connected to the selection terminal. A selection terminal for connection which is connected and formed on the first surface, an external selection terminal which is electrically connected to the control circuit and formed at a position not in contact with the photoelectric conversion substrate, a selection terminal for connection and an external selection terminal And a selection line for electrically connecting to each other, and the connection selection terminal corresponding to the group of detection elements corresponding to the row in the second direction (rotational axis direction) orthogonal to the first direction is common. The reference potential wiring is electrically connected by the selection line, and the reference potential wiring is for connection to be electrically connected to the reference potential input terminal formed at a position not in contact with the photoelectric conversion substrate and the reference potential input terminal and the transparent electrode. And a reference potential terminal. Furthermore, a surface electrode terminal electrically connected to the connection reference potential terminal is formed on the second surface of the photoelectric conversion substrate.

Alternatively, in the X-ray detector of the X-ray CT apparatus according to the present invention, the photoelectric conversion substrate is formed on the transparent electrode formed on the first surface side and the electric signal is output on the second surface side. The detection block substrate has a selection element formed on the first surface side thereof for switching ON / OFF of an electric signal output, and a reference potential electrically connected to the transparent electrode. The selection element has an input electrode for inputting the electric signal, an output electrode for outputting the electric signal input to the input electrode, and ON / OFF switching of the electric signal output. And a control output electrode, the output wiring is electrically connected to the input electrode, and a connection output terminal is formed on the first surface.
An external output terminal formed at a position not in contact with the photoelectric conversion substrate electrically connected to the output electrode by the output line and electrically connected to the signal collection circuit, and a signal line, The output electrodes of the selection elements corresponding to the group of detection elements arranged in a row in the first direction are electrically connected to each other by a common output line, and the selection wiring is electrically connected to the control circuit to perform photoelectric conversion. A group of detection elements, which has an external selection terminal formed at a position not in contact with the substrate and a selection line electrically connecting the control electrode and the external selection terminal, and which forms a row in the second direction. The control electrodes of the corresponding selection elements are electrically connected to each other by a common selection line, and the reference potential wiring is electrically connected to the reference potential input terminal formed at a position not in contact with the photoelectric conversion substrate and the transparent electrode. With the reference potential terminal for connection It is. Furthermore, a surface electrode terminal electrically connected to the connection reference potential terminal is formed on the second surface of the photoelectric conversion substrate.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, an X-ray detector is constructed by arranging detection blocks in an arc shape in the circumferential direction, and the X-ray source and the X-ray detector are surrounded by a rotating means around an object to be inspected. 3rd generation X-ray CT apparatus for rotating by X, and an X-ray detector is constructed by arranging detection blocks in a circular shape in the circumferential direction, and an X-ray source is arranged around an object to be inspected by rotating means. It is applied to a rotating fourth generation X-ray CT apparatus.

Embodiments of the present invention will be described below in detail with reference to the drawings. (Embodiment 1) FIG. 1 shows an X-ray CT according to Embodiment 1 of the present invention.
The basic configuration of the device is shown. This X-ray CT system has a bed top plate 1
2, X-ray source 11, X-ray detector 10, rotating body 16, signal acquisition circuit 90, arithmetic processing unit 13, display unit 14, and
It is composed of a control circuit 15. The inspection target object S is mounted on the bed top plate 12, and the X-ray source 11 and the X-ray detector 10 are arranged to face each other with the inspection target object S interposed therebetween. The X-ray source 11 and the X-ray detector 10 are fixedly held on the rotating body 16. The rotating body 16 rotates in the rotation direction 18 with the inspection target object S as a substantial center. In X-ray tomography in which the inspection target object S is irradiated with X-rays from the X-ray source 11 and the transmitted X-rays are detected, a projection image is detected at each rotation angle of the rotating body 16. At each rotation angle, the X-ray transmitted through the inspection object S is detected by the X-ray detector 10 and converted into an electric signal (projection image). This electric signal is collected and stored by the signal collecting circuit 90. For example, when the projected image is detected at every rotation angle of the rotating body 16 of 0.4 °, one rotation of the rotating body 16 (3
The number of detected projection images during the rotation of 60 ° is 900.

The detection data of these projection images are transferred to the arithmetic processing unit 13 placed in the stationary system. Processor 1
In 3, the convolution (convolution) processing and the back projection (back projection) processing are performed on the detection data of these projection images to obtain an image (tomographic image) of the X-ray absorption coefficient distribution on the desired cross section of the inspection object S. ) Is reconfigured. This reconstructed tomographic image is displayed on the display device 14. The control circuit 15 controls the X-ray irradiation timing and the X-ray detector 1
The control of the read timing of the electric signal from 0 is performed.

FIG. 2 is a perspective view showing the structure of the detection block used in the X-ray CT apparatus according to the first embodiment. Also, FIG.
In the X-ray incident direction 92 of the detection block 20 shown in FIG.
The circuit configuration viewed from is shown.

The X-ray detector shown in FIG. 1 has a structure in which a plurality of (K) detection blocks 20 are fixedly arranged in an arc shape on the detection block fixing plate 91 in the channel direction 21. The detection block 20 is fixed on the fixing plate 91 by screws through the fixing screw holes 46. Here, k
Let (= 1, 2, ..., K) be the number of each detection block,
The kth detection block 20 is represented by 20-k.

Each detection block 20 includes a scintillator element 22, a photoelectric conversion substrate 23, and a detection block substrate 25. The photoelectric conversion substrate 23 is arranged in contact with the detection block substrate 25, and the scintillator element 22 is disposed on the photoelectric conversion substrate 23.
It is placed on top of. The detection element includes a scintillator element 22 that converts X-rays into light and a photoelectric conversion element 59 that converts the light into an electric signal. Each scintillator element 22 is optically divided corresponding to each photoelectric conversion element 59.

The number of detecting elements is, for example, the detecting block 2
16 in the direction parallel to the channel direction 21 of 0 (hereinafter referred to as the row direction) and the direction parallel to the slice direction 26 (hereinafter
There are 24 in the column direction). That is, the detection block is composed of 16 rows and 24 columns of detection elements. In FIG. 2, in order to simplify the drawing, a case of 4 rows and 2 columns is shown as an example. The photoelectric conversion element 59-k-i-j indicates the photoelectric conversion element in the i-th column and the j-th row in the detection block 20-k. Photoelectric conversion element 59-
The k-i-j and the scintillator element 22-k-i-j correspond to the same i-th column and j-th row on the same detection block 20-k. The photoelectric conversion substrate 23-km is the m-th photoelectric conversion substrate (sub substrate). Note that i = 1, 2, ..., I,
, j, m = 1, 2, ..., M. The detection block substrate 25 has a function of selecting which photoelectric conversion element to read an electric signal from and a function of actually reading the electric signal.

As shown in FIG. 3, the detection block 20 is
It includes a photoelectric conversion circuit 41, a selection element 43, a selection line 61, a signal line 60, an external selection terminal 53, an external output terminal 52, and a reference potential input terminal 54. The selection element 43 is, for example, a MOS type transistor. Photoelectric conversion element 59-k-i-j
Is a photoelectric conversion circuit 41-k-i-j and a selection element 43-k.
-I-j is included. The photoelectric conversion circuit 41 and the selection element 43 are provided on the photoelectric conversion substrate 23. The selection line 61, the signal line 60, the external selection terminal 53, the external output terminal 52, and the reference potential input terminal 54 are provided on the detection block substrate 25.

The photoelectric conversion elements 59k-i on the same j-th row
The gate electrode of the selection element 43-k-i-j of -j is connected to the common selection line 61-k-j, and the photoelectric conversion element 59k.
-I-j is selected row by row. In addition, the selection elements 43-k-i of the photoelectric conversion elements 59k-i-j on the same i-th column.
The source electrode of −j is connected to the common signal line 60-ki. The readout of the detection signal from the photoelectric conversion elements 59k-i-j is performed using a readout circuit common in the column direction. Next, details of the reading method will be described.

The X-rays incident on the detection block 20 are converted into light by the scintillator element 22, this light is converted into an electric signal by the photoelectric conversion elements 59k-i-j, and this electric signal is accumulated therein. . When a signal for selecting the photoelectric conversion element from which the accumulated electric signal is to be read is input from the control circuit 15 to the external selection terminal 53-k-j, the selection element 43-k-i-j of the same j row is input. Is turned on. Thereby, the photoelectric conversion elements 59k-i-of the same j-th row
The electric signal stored in j is the external output terminal 52-k.
-I is simultaneously output to the signal acquisition circuit 90. Next, when a signal for selecting a photoelectric conversion element from which an electric signal is to be read is input to the external selection terminal 53-k- (j + 1), the photoelectric conversion element 59k-i- (j) of the same (j + 1) th row.
The electrical signal stored in (+1) is the signal collection circuit 90.
Are output simultaneously.

In this way, by sequentially switching the rows of photoelectric conversion elements from which the stored electric signals should be read, the stored electric signals can be read from all the photoelectric conversion elements of the detection block 20. In this way, the X-ray projection image from one direction can be acquired. Next, the detailed structure of each substrate will be described.

FIG. 4 shows the detailed structure of the photoelectric conversion substrate 23 in the first embodiment of the present invention. The photoelectric conversion substrate 23 is composed of a silicon substrate 140, and photoelectric conversion elements are formed on the substrate.
It is formed dimensionally. FIG. 4 illustrates the case where the photoelectric conversion elements 59 of 2 rows and 2 columns are formed. Note that reference numeral 141 in the figure denotes the projection surface of the photoelectric conversion substrate 23.

FIG. 5 shows a circuit configuration of the photoelectric conversion substrate 23 in the first embodiment of the present invention. The photoelectric conversion substrate 23 includes a photoelectric conversion circuit 41, a selection element 43, a transparent electrode 42, a transparent electrode terminal 38, an output terminal 45, and a selection terminal 44.
The photoelectric conversion circuit 41 and the selection element 43 are provided for each photoelectric conversion element. The transparent electrode 42 is formed on the first surface (light incident surface) 32 of the photoelectric conversion substrate 23. First surface 32
Is a surface to be joined to the scintillator element 22. The selection terminal 44-k-j is electrically connected to the gate electrode of the selection element 43-k-i-j.

The output terminal 45-ki is electrically connected to the source electrode. The transparent electrode terminal 38-km is electrically connected to the transparent electrode 42. These terminals are formed on the second surface 33 of the photoelectric conversion substrate 23. Second surface 33
Is a surface to be joined to the detection block substrate 25. In this way, the photoelectric conversion substrate 2 bonded to the detection block substrate 25
Since the terminals connected to the respective electrodes are provided on the second surface 33 of No. 3, it is not necessary to provide a space for the read circuit with the detection block substrate 25.

FIG. 6 is a perspective view showing the structure of the detection block substrate 25 in the first embodiment of the present invention. The detection block substrate 25 supports the photoelectric conversion substrate 23. The detection block substrate 25-k is connected to the photoelectric conversion substrate 23-km and the junction region 2
It is joined at 20-km.

FIG. 7 shows the circuit configuration of the detection block substrate 25 in the first embodiment of the present invention. Detection block board 2
Reference numeral 5 includes an output wiring 70, a selection wiring 71, and a reference potential wiring 72. The output wiring 70 is connected to the output terminal 5
5-k-i, signal line 60-k-i and external output terminal 52
-Ki is included. The connection output terminal 55-k-i and the external output terminal 52-k-i are electrically connected by the signal line 60-k-i. The selection wiring 71 is connected to the selection terminal 5
6-k-j, selection line 61-k-j, external selection terminal 53-
Including k-i. The reference potential wiring 72 includes a connection reference potential terminal 57-km, a reference potential input terminal 54-k, and a signal line 62 (62-k).

The connection output terminal 55-k-i connected to the photoelectric conversion element 59k-i-j in the same column i is electrically connected to the external output terminal 52-k-i by the common signal line 60-k-i. Connected. The connection selection terminal 56-k-i and the external selection terminal 53-k-i are electrically connected by the selection line 61-k-i. The photoelectric conversion element 59k-i- of the same row j
The connection selection terminal 56-k-j connected to j is electrically connected to the external selection terminal 53-k-j by the common selection line 61-k-j. Reference potential terminal for connection 57-km
Are electrically connected to the reference potential input terminal 54-k.
Output terminal 55-k-i for connection, selection terminal 56-k for connection
-J and the connection reference potential terminal 57-km are provided inside the junction region 220-km.

Output terminal 55-ki for connection and output terminal 4
5-k-i electrically connects the selection terminal 56-k-j and the selection terminal 44-k-j, and the connection reference potential terminal 57-km and the transparent electrode terminal 38-km electrically. Connected to the detection block substrate 25 and the photoelectric conversion substrate 23-
Join with km. By inputting a signal from the control circuit 15 to the external selection terminal 53-ki, the same row j
The electric signal of the photoelectric conversion element 59k-i-j of
The read electrical signal can be output in parallel from the external output terminal 52-ki to the signal collection circuit 90.

FIG. 8 shows the cross-sectional structure of the multilayer wiring of the detection block substrate 25 which constitutes the detection block in the first embodiment of the present invention. The detection block substrate 25 has the output wiring 7
0, an upper layer 230 that configures 0, an intermediate layer 231 that configures the reference potential wiring 72, and a lower layer 232 that configures the selection wiring 71.
3 and an insulating layer 233 between the layers. Connection selection terminal 56-k-j, connection output terminal 55-k-
i and the reference potential terminal 57-km for connection penetrate from the above layers to the surface of the first surface 34 of the detection block substrate 25, and are electrically connected to the photoelectric conversion substrate 23. The external selection terminal 53-k-i, the external output terminal 52-k-i, and the reference potential input terminal 54-k penetrate from the above layers to the surface of the first surface 34 of the detection block substrate 25, and the control circuit 15 and the signal collection circuit. It is electrically connected to the circuit 90.

9 to 12 are perspective views illustrating a method of manufacturing the detection block 20-k according to the first embodiment of the present invention. As shown in FIG. 9, the photoelectric conversion substrate 23 is bonded to the detection block substrate 25. In the example shown in FIG. 9, two rows and two columns of photoelectric conversion substrates 23-km (m = 1, 2) are used to fabricate a four rows and two columns detection block 20-k.

Output terminals 45-km-i formed on the second surface side of the photoelectric conversion board 23-km and connection output terminals 55-k- formed on the detection block board 25-k. m
-I is a selection terminal 44-km-j formed on the second surface side of the photoelectric conversion substrate 23-km and a connection selection terminal 56- formed on the detection block substrate 25-k. km-
j is a transparent electrode terminal 38-km formed on the end surface (side surface) of the photoelectric conversion substrate 23-km and a connection reference potential terminal 57-km formed on the detection block substrate 25-k.
And are electrically connected by soldering.

As shown in FIG. 10, the scintillator 22-
k is on the first surface 32 of the photoelectric conversion substrate 23-km,
Optical bonding is performed using a translucent adhesive that can transmit the light generated by the scintillator 22. In addition, as shown in FIG. 11, the groove 1 is formed in the scintillator 22 and the photoelectric conversion substrate 23.
Form 50. Of these, the groove parallel to the slice direction penetrates the scintillator 22 and extends to a part of the photoelectric conversion substrate 23. Further, the groove parallel to the channel direction is formed almost penetrating the scintillator 22, but is not formed so as to extend to the photoelectric conversion substrate 23.

As shown in FIG. 12, a separator 27 made of Cu or Mo on which a light reflecting film is formed is inserted into the groove 150. The scintillator elements 22-k-i-j are optically separated from each other by the separator 27.

A possible modification of the first embodiment will be described below. (1) Third generation X-ray CT described above
It can be applied to a fourth-generation X-ray CT apparatus instead of the apparatus. (2) Instead of reading the electric signals in parallel in the column direction and sequentially switching in the row direction, the electric signals may be read in parallel in the row direction and sequentially switching in the column direction. (3) Instead of arranging a plurality of photoelectric conversion substrates (sub substrates) in the slice direction 26, a plurality of photoelectric conversion substrates (sub substrates) are arranged in the channel direction 21, or a plurality of photoelectric conversion substrates (sub substrates) are arranged in both directions 26, 21. A conversion board (sub-board) can be arranged.
(4) Instead of one signal line 60 being electrically connected to the connection output terminal 55 across a plurality of photoelectric conversion substrates (sub substrates), one selection line 61 is a plurality of photoelectric conversion substrates (sub substrates). ) May be electrically connected to the connection selection terminal 56. (5) Instead of dividing the transparent electrodes 42 into columns, the transparent electrodes 42 are divided into rows, or the transparent electrodes 42 are divided into rows and columns, or alternatively, the transparent electrodes 42 are divided. It is also possible to adopt a configuration in which is not divided into both rows and columns.
(6) Instead of constructing the scintillator elements 22-k-i-j two-dimensionally, the scintillator element 22-k-i-j is divided in one direction of the channel direction 21 or the slice direction 26, or is not divided in any direction. (Scintillator plate structure in which scintillator elements are continuous) can also be used. (7) Instead of electrically connecting the transparent electrode 42 and the connection reference potential terminal 57 via the transparent electrode terminal 38, the transparent electrode 42 and the connection reference potential terminal 57 are directly electrically connected by bonding. You can also (8) Instead of forming the wiring connecting the transparent electrode terminal 38 and the transparent electrode 42 on the end face (side surface) of the photoelectric conversion substrate 23, the transparent electrode terminal 38 and the transparent electrode 42 are penetrated through the photoelectric conversion substrate 23. It is also possible to form a wiring for connecting the above. (9) The transparent electrode may be commonly provided over a plurality of photoelectric conversion substrates. (10) The transparent electrodes of the plurality of photoelectric conversion substrates may be in electrical contact with the adjacent surfaces of the photoelectric conversion substrates. (Embodiment 2) An X-ray CT apparatus according to Embodiment 2 has a photoelectric conversion substrate 23 having a circuit configuration shown in FIG. 13 and a detection circuit having a circuit configuration shown in FIG. The container block substrate 25 is used.

As shown in FIG. 13, the photoelectric conversion substrate 23
Is a photoelectric conversion circuit 41, a transparent electrode 42, a transparent electrode terminal 3
8 and an output terminal 45. The photoelectric conversion circuit 41 and the output terminal 45 are arranged for each photoelectric conversion element. The transparent electrode 42 is formed on the first surface (light incident surface) 32 of the photoelectric conversion substrate that is bonded to the scintillator element 22. The transparent electrode 42 is one electrode in the photoelectric conversion circuit 41.

The output terminal 45-k-i-j is electrically connected to the electrode of the photoelectric conversion circuit 41-k-i-j. The transparent electrode terminal 38-km is electrically connected to the transparent electrode 42. Output terminal 45-k-i-j and transparent electrode terminal 38-
km is formed on the second surface (back surface) 33 of the photoelectric conversion substrate that is bonded to the detection block substrate 25. Since each terminal is formed on the back surface (second surface) of the photoelectric conversion substrate bonded to the detection block substrate 25 in this manner, a space for forming a read circuit is provided between the photoelectric conversion substrate 23 and the detection block substrate 25. There is no need to secure in between.

As shown in FIG. 14, the detection block substrate 2
5 is a selection element 43, an output wiring 70, a selection wiring 7
1, including a reference potential wiring 72. The output wiring 70 includes connection output terminals 55-k-i-j, signal lines 60-k-i,
The external output terminal 52-k-i is included. The selection wiring 71 is
The selection line 61-k-j and the external selection terminal 53-k-i are included. The reference potential wiring 72 is connected to the reference potential terminal 57-
KM and a reference potential input terminal 54-k are included. The selection element 43, the output wiring 70, the selection wiring 71, and the reference potential wiring 72 are the first surface (upper surface) 3 of the detection block substrate 25.
4 is formed. Selection element 43 and connection output terminal 55
Are arranged for each photoelectric conversion element.

The connection output terminal 55-k-i-j includes the output terminal 45-k-i-j and the selection element 43-k-i-j.
Is electrically connected to the drain electrode of. Selection element 43-
k-i-j source electrode and external output terminal 52-k-i
Are electrically connected by signal lines 60-k-i. The source electrode of the selection element 43-k-i-j connected to the photoelectric conversion element 59k-i-j of the same column i is the common signal line 6
They are electrically connected to each other by 0-ki.

The gate electrode of the selection element 43-k-i-j and the external selection terminal 53-k-i are electrically connected by the selection line 61-k-i. Photoelectric conversion element 59k in the same row j
The gate electrodes of the selection elements 43-k-i-j connected to -i-j are electrically connected to each other by a common selection line 61-k-i.

The connection reference potential terminal 57-km is electrically connected to the reference potential input terminal 54-k. The connection output terminal 55-k-i, the connection selection terminal 56-k-j, and the connection reference potential terminal 57-km are connected to the junction area 220-k.
It is placed inside -m.

Output terminal for connection 55-ki and output terminal 4
5-k-i electrically connects the connection selection terminal 56-k-j and the selection terminal 44-k-j, and the connection reference potential terminal 57-km and the transparent electrode terminal 38-km electrically. Connected to the detection block substrate 25-k and the photoelectric conversion substrate 2
Join with 3-km. By inputting the signal from the control circuit 15 to the external selection terminal 53-k-i, the electric signal of the photoelectric conversion element 59k-i-j in the same row j is read, and the electric signal is output to the external output terminal 52-k-. i can be output in parallel to the signal acquisition circuit 90. (Embodiment 3) The X-ray CT apparatus according to the third embodiment has the detection block 20 shown in FIG.
To use. The photoelectric conversion board 23 of the detection block 20 is
Photoelectric conversion element substrate 200 having a function of performing photoelectric conversion
And a switching module substrate 201 having a function of selecting a photoelectric conversion element to output an electric signal.

As shown in FIG. 16, the photoelectric conversion element substrate 2
The second surface (rear surface) 35 of 00 is bonded to the first surface (upper surface) 36 of the switching module substrate 201. The first surface (light incident surface) 32 of the photoelectric conversion element substrate 200 is bonded to the lower surface of the scintillator element 22. The second surface (lower surface) 33 of the switching module substrate 201 is bonded to the detection block substrate 25.

FIG. 17 shows the circuit configuration of the photoelectric conversion element substrate 200 according to the third embodiment. Photoelectric conversion element substrate 200
Includes a photoelectric conversion circuit 41, a transparent electrode 42, a second connecting transparent electrode terminal 204, and a second connecting output terminal 202. The transparent electrode 42 is the first electrode of the photoelectric conversion element substrate 200.
Is formed on the surface 32 (light incident surface). The second connecting transparent electrode terminal 204 and the second connecting output terminal 202 are formed on the second surface (lower surface) 35 of the photoelectric conversion element substrate 200. The second connecting transparent electrode terminal 204 is electrically connected to the transparent electrode 42. Second connection output terminal 20
The 2-k-i-j is electrically connected to the output electrode of the photoelectric conversion circuit 41-k-i-j.

FIG. 18 shows a circuit configuration of the switching module board 201 in the third embodiment. The switching module board 201 includes a selection element 43 and a selection terminal 4.
4, an output terminal 45, a transparent electrode terminal 38, a second connecting transparent electrode terminal 205, and a second connecting output terminal 203. Selection terminal 44, output terminal 45, transparent electrode terminal 38
Is the second surface 33 of the switching module substrate 201.
Formed on.

The second connecting transparent electrode terminal 205 and the second connecting output terminal 203 are formed on the first surface 36 of the switching module substrate 201. The second connection output terminal 203-k-i-j is connected to the selection element 43-k-i-
It is electrically connected to the drain electrode of j. The second connection output terminal 203 is electrically connected to the transparent electrode terminal 38. The selection terminal 44-k-i-j is the selection element 43-k-
It is electrically connected to the gate electrode of ij.

The output terminal 45-k-i-j is the selection element 43.
-K-i-j is electrically connected to the source electrode. Second
Connection transparent electrode terminal 205-k-i-j and second connection transparent electrode terminal 204-k-i-j of the second connection output terminal 203-k-i-j and second Output terminal 2 for connection
The photoelectric conversion element substrate 200-km and the switching module substrate 201-km are bonded so that 02-k-i-j are electrically connected to each other. Example 3
The detection block 20 used in this X-ray CT apparatus is the detection block substrate 25 of the detection block in the second embodiment.
Can be regarded as one composed of a substrate having two functions. (Embodiment 4) The X-ray CT apparatus of Embodiment 4 is the same as the apparatus configuration of Embodiment 1 described above, but further provided with a function of amplifying an electric signal generated in the photoelectric conversion substrate 23.

FIG. 19 shows the circuit configuration of the photoelectric conversion substrate 23 in the third embodiment. The photoelectric conversion board 23 includes an amplifier circuit 164, a reset power terminal 163, a reset selection terminal 167, and a constant voltage input terminal 166 in addition to the configuration of the photoelectric conversion board 23 in the first embodiment. Amplifier circuit 1
64 is arranged for each photoelectric conversion circuit 41. The reset power terminal 163, the reset selection terminal 167, and the constant voltage input terminal 166 are formed on the second surface (lower surface) 33 of the photoelectric conversion substrate.

FIG. 20 shows an amplifier circuit 1 according to the fourth embodiment.
The circuit configuration of 64 and its peripherals is shown. The amplifier circuit 164 includes a transistor 165 and a reset selection element 168. The drain electrode 160 of the transistor 165 is connected to the constant voltage input terminal 166, and the source electrode 161 is connected to the selection element 43.
Is electrically connected to the drain electrode of. Transistor 1
The gate electrode 162 of 65 is connected to the electrode for outputting an electric signal of the photoelectric conversion circuit 41, and is connected to the reset selection element 16
8 is electrically connected to the constant voltage input terminal 171 for connection.

The reset selection electrode 169 is electrically connected to the reset selection terminal 167, and the reset power electrode 170 is electrically connected to the reset power terminal 163. Amplifier circuit 16 connected to photoelectric conversion elements 59k-i-j in the same row j
4-k-i-j reset selection electrodes 169-k-i-j
Are electrically connected to a common reset selection terminal 167-k-j.

In the photoelectric conversion substrate 23 of the fourth embodiment, the electric signal reading and resetting operations are performed as follows. First, a signal for selecting a photoelectric conversion element from which an electric signal is to be read is input to the reset selection terminal 167-k-j. At this time, if a certain voltage is bias-applied to the reset power terminal 163-k, the photoelectric conversion circuit 41-
The potential difference between the k-i-j electrodes can be uniquely determined.

Next, the signal for selecting the photoelectric conversion element from which the electric signal input to the reset selection terminal 167-k-j is selected is turned off (input is turned off). This time,
When an X-ray enters the photoelectric conversion circuit 41-k-i-j, the electric signal generated by photoelectric conversion is accumulated,
The potential of the gate electrode 162 changes. Therefore, when a constant voltage is biased to the constant voltage input terminal 166-km, a current depending on the generated electric signal causes the source electrode 16 to flow.
1-k-i-j.

In reading the electric signal, the selection terminal 44-
A signal for selecting a photoelectric conversion element from which an electric signal is to be read is input to k-ij, and the accumulated current is output from the output terminal 45-k-i. Next, select terminal 4
The signal input to 4-k-i-j is cut off, and a signal for selecting a photoelectric conversion element from which an electric signal is to be read is input to the reset selection terminal 167-k-j. Accordingly, the potential difference between the electrodes of the photoelectric conversion circuit 41-k-i-j can be returned to the original and reset. Repeat the above operation,
The electrical signal depending on the incident X-ray dose is repeatedly acquired.

FIG. 21 shows the circuit configuration of the detection block substrate 25 in the fourth embodiment. Detection block substrate 25
Is the detection block substrate 25 shown in the first embodiment.
In addition to the above configuration, a constant voltage input terminal for connection 171, an external constant voltage input terminal 172, a reset power terminal for connection 173,
An external reset power terminal 174, a connection reset selection terminal 175, and an external reset selection terminal 176 are included. The connection constant voltage input terminal 171, the connection reset power terminal 173, and the connection reset selection terminal 175 are connected to the junction area 220-.
It is located inside km. Junction area 220-km
Is a position to be joined to the photoelectric conversion substrate 23-km.

The connection constant voltage input terminal 171 is electrically connected to the external constant voltage input terminal 172, the connection reset power terminal 173 is electrically connected to the external reset power terminal 174, and the connection reset selection terminal 175 is electrically connected to the external reset selection terminal 176. Connected to. The connection constant voltage input terminal 171 is connected to the constant voltage input terminal 166, the connection reset power terminal 173 is connected to the reset power terminal 163, and the connection reset selection terminal 17 is connected.
5 are electrically connected to the reset selection terminals 167, respectively. The external constant voltage input terminal 172, the external reset power terminal 174, and the external reset selection terminal 176 are connected to the control circuit 15.

In the detection block 20-k of the fourth embodiment,
The read operation is performed as follows. First, the control circuit 15
From the above, a signal for selecting a photoelectric conversion element from which an electric signal is to be read is input to the selection terminal 44-k-j. Accordingly, the photoelectric conversion circuits 41-k-i- belonging to the same row j
The output signal from j can be taken out in parallel from the output terminal 45-ki. Next, while changing the row of the photoelectric conversion element from which the electric signal is to be read from j to (j + 1),
A signal for selecting a photoelectric conversion element from which an electric signal is to be read is input to the reset selection terminal 167-k-ij. At this time, the signal of the photoelectric conversion circuit 41-k-i- (j + 1) is read, and at the same time, the potential difference between the electrodes of the photoelectric conversion circuit 41-k-i-j is reset. 2 electric signals
While sequentially reading out dimensionally, resetting is performed sequentially.

In this embodiment, the amplification factor of the amplifier circuit 164 is changed depending on the position of the photoelectric conversion element. This amplification factor is
It is the ratio of the current flowing through the source electrode 161 of the transistor 165 with respect to the electric signal generated in the photoelectric conversion circuit 41. For example, a direct X-ray that does not pass through the inspection object S is X
When entering the line detector 10, the amplification factor of the amplifier circuit 164 at the position of the photoelectric conversion element where the direct X-ray enters is made low. At the position of the photoelectric conversion element where the weak X-rays transmitted through the center of the inspection object S enter, the amplification circuit 16
Increase the amplification factor of 4.

As a result, at the position where the strong X-ray is incident, signal saturation in the readout circuit can be prevented, and at the position of the photoelectric conversion element where the weak X-ray is incident, the noise of the subsequent readout circuit affects the S / N ratio. Can be made smaller. Moreover, the same effect as the above can be realized by making the amplification factor of the amplifier circuit 164 different for each photoelectric conversion substrate 23 or for each detection block.

In the fourth embodiment, the photoelectric conversion substrate 23 may be composed of a plurality of substrates having different functions. In particular, the photoelectric conversion substrate 23 includes the substrate on which the photoelectric conversion circuit 41 is formed and the substrate on which the amplifier circuit 164 and the selection element 43 are formed.
Is desirable. (Fifth Embodiment) In the X-ray CT apparatus according to the fifth embodiment, the photoelectric conversion elements are arranged at equal intervals by the plurality of photoelectric conversion substrates 23 in the device configuration shown in the first to fourth embodiments.

FIG. 22 shows the arrangement positional relationship of the photoelectric conversion substrate 23 in the fifth embodiment. The distance between the photoelectric conversion elements of two adjacent photoelectric conversion substrates 23, and the photoelectric conversion substrate 2
3 is a diagram illustrating the relationship between the distance between the end face of No. 3 and the end of the photoelectric conversion element 59. FIG.

The two photoelectric conversion substrates 23 are adjacent to each other on the adjacent surface 212 in the slice direction 26. Adjacent surface 212
The distance 211 between the photoelectric conversion element 59k-2-2 and the photoelectric conversion element 59k-2-2 is equal to the distance between the photoelectric conversion element 59k-2-1 and the photoelectric conversion element 59k-2-2.
It is arranged so that it is (1/2) of the distance 210 between.
Photoelectric conversion element 59k-2-2 and photoelectric conversion element 59k-3
The interval 213 with -2 is set equal to the interval 210 described above.

As described above, since the intervals between the photoelectric conversion elements are set equal regardless of the positions of the photoelectric conversion elements,
The decrease in resolution can be prevented. Note that the interval 211 is replaced by the interval 2
2 at the adjacent surface 212 as less than (1/2) of 10
Adjust the distance between the end faces (side faces) of the two photoelectric conversion boards,
Even if the space 213 is made equal to the space 210, the same effect as described above can be obtained.

[0077]

As described above, according to the present invention,
A multi-slice X-ray C capable of preventing a reduction in detection sensitivity and resolution by suppressing an increase in the scale of a readout circuit.
A T device can be realized.

[Brief description of drawings]

FIG. 1 is a diagram showing a basic configuration of an X-ray CT apparatus according to a first embodiment of the present invention.

FIG. 2 is a diagram showing the structure of a detection block used in the X-ray CT apparatus according to the first embodiment.

FIG. 3 is a diagram showing a circuit configuration of a detection block used in the X-ray CT apparatus according to the first embodiment.

FIG. 4 is a diagram showing a structure of a photoelectric conversion substrate used in the X-ray CT apparatus according to the first embodiment.

FIG. 5 is a diagram showing a circuit configuration of a photoelectric conversion substrate used in the X-ray CT apparatus according to the first embodiment.

FIG. 6 is a diagram showing the structure of a detection block substrate used in the X-ray CT apparatus according to the first embodiment.

FIG. 7 is a diagram showing a circuit configuration of a detection block substrate used in the X-ray CT apparatus according to the first embodiment.

FIG. 8 is a diagram showing a multilayer wiring structure of a detection block substrate used in the X-ray CT apparatus according to the first embodiment.

FIG. 9 is a diagram illustrating a procedure for manufacturing a detection block used in the X-ray CT apparatus according to the first embodiment.

FIG. 10 is a diagram illustrating a procedure for manufacturing a detection block used in the X-ray CT apparatus according to the first embodiment.

FIG. 11 is a diagram illustrating a procedure for manufacturing a detection block used in the X-ray CT apparatus according to the first embodiment.

FIG. 12 is a diagram illustrating a procedure for manufacturing a detection block used in the X-ray CT apparatus according to the first embodiment.

FIG. 13 is a diagram showing a circuit configuration of a photoelectric conversion substrate in a detection block used in an X-ray CT apparatus according to a second embodiment of the present invention.

FIG. 14 is a diagram showing a circuit configuration of a detection block substrate in a detection block used in the X-ray CT apparatus according to the second embodiment.

FIG. 15 is a diagram showing a configuration of a detection block used in an X-ray CT apparatus according to a third embodiment of the present invention.

FIG. 16 is a diagram showing a structure of a photoelectric conversion element substrate used in an X-ray CT apparatus according to a third embodiment.

FIG. 17 is a diagram showing a circuit structure of a photoelectric conversion element substrate used in an X-ray CT apparatus according to a third embodiment.

FIG. 18 is a diagram showing a circuit configuration of a switching module substrate used in the X-ray CT apparatus according to the third embodiment.

FIG. 19 is a diagram showing a circuit configuration of a photoelectric conversion substrate in a detection block used in an X-ray CT apparatus according to a fourth embodiment of the present invention.

FIG. 20 is a diagram showing an amplifier circuit used in the X-ray CT apparatus according to the fourth embodiment and a circuit configuration around the amplifier circuit.

FIG. 21 is a diagram showing a circuit configuration of a detection block substrate in a detection block used in the X-ray CT apparatus according to the fourth embodiment.

FIG. 22 is a diagram illustrating the arrangement relationship of photoelectric conversion substrates in a detection block used in the X-ray CT apparatus according to the fifth embodiment of the present invention.

[Explanation of symbols]

10 ... X-ray solid state detector, 11 ... X-ray source, 12 ... Bed top, 13 ... Arithmetic processing device, 14 ... Display device, 15 ... Control circuit, 16 ... Rotating body, 18 ... Rotation direction, 20 ... Detection block , 21 ... Channel direction, 22 ... Scintillator element,
23 ... Photoelectric conversion substrate, 25 ... Detection block substrate, 26 ...
Slice direction, 27 ... Separator, 32 ... First surface (light incident surface) of photoelectric conversion substrate, 33 ... Second surface (back surface) of photoelectric conversion substrate, 34 ... First surface (upper surface) of detection block substrate , 35 ... Second surface (lower surface) of photoelectric conversion element substrate, 3
6 ... the first surface (upper surface) of the switching module substrate,
38 ... Transparent electrode terminal, 41 ... Photoelectric conversion circuit, 42 ... Transparent electrode, 43 ... Selection element, 44 ... Selection terminal, 45 ... Output terminal, 46 ... Fixing screw hole, 52 ... External output terminal, 53 ...
External selection terminal, 54 ... Reference potential input terminal, 55 ... Connection output terminal, 56 ... Connection selection terminal, 57 ... Connection reference potential terminal, 59 ... Photoelectric conversion element, 60 ... Signal line, 61 ... Selection line, 62 ... signal line, 70 ... output wiring, 71 ... selection wiring, 72 ... reference potential wiring, 90 ... signal collecting circuit, 9
1 ... Detection block fixing plate, 92 ... X-ray incident direction, 140
... Silicon substrate, 141 ... Projection surface of photoelectric conversion substrate, 15
0 ... groove, 160 ... drain electrode, 161 ... source electrode,
162 ... Gate electrode, 163 ... Reset power terminal, 16
4 ... Amplifier circuit, 165 ... Transistor, 166 ... Constant voltage input terminal, 167 ... Reset selection terminal, 168 ... Reset selection element, 169 ... Reset selection electrode, 170 ... Reset power electrode, 171 ... Connection constant voltage input terminal, 172
... external constant voltage input terminal, 173 ... connection reset power terminal, 174 ... external reset power terminal, 175 ... connection reset selection terminal, 176 ... external reset selection terminal, 20
0 ... Photoelectric conversion element substrate, 201 ... Switching module substrate, 202 ... Second connection output terminal, 203 ... Second
Output terminals for connection, 204 ... Second transparent electrode terminals for connection, 205 ... Second transparent electrode terminals for connection, 210 ... Interval, 211 ... Interval, 212 ... Adjacent surface, 213 ... Interval, 2
20 ... Bonding area, 230 ... Upper layer, 231 ... Middle layer, 232
... Lower layer, 233 ... Insulating layer, S ... Object to be inspected.

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 2G088 EE02 FF02 GG19 JJ02 JJ05                       JJ09 JJ33 JJ37                 4C093 AA22 CA32 EB12 EB18 EB20                 5F088 BB07 EA04 JA17 KA08 LA08

Claims (5)

[Claims] 1. An X for generating an X-ray that irradiates an object to be inspected
A radiation source, an X-ray detector that irradiates the inspection target object with the X-rays from a plurality of directions to detect transmitted X-rays that have passed through the inspection target object, and the X-ray source around the inspection target object. Rotation means, a signal collecting circuit for collecting the output signal of the X-ray detector, a control circuit for controlling the X-ray detector and the signal collecting circuit, and an arithmetic processing of the output signal. An X-ray detector for calculating a tomographic image of a sliced surface of an object to be inspected,
The detection blocks are arranged in a circumferential direction of the rotation and configured to detect the transmitted X-rays, and the detection blocks are separated from each other in a first direction and a second direction orthogonal to the first direction. A detection element including a scintillator element for converting the transmitted X-rays into light and a photoelectric conversion element for converting the light into an electric signal is provided. The detection elements are arranged in a two-dimensional manner and a plurality of detection elements are arranged in a two-dimensional manner. The scintillator element is composed of a photoelectric conversion substrate on which the photoelectric conversion element is formed, and a detection block substrate on which wiring for reading the electric signal from the detection element is formed, and the scintillator element and a first surface of the photoelectric conversion substrate. Electrically, the second surface of the photoelectric conversion substrate is electrically bonded to the first surface of the detection block substrate, and the photoelectric conversion substrate or the detection block substrate is connected to the detection element from the detection element. The detection block substrate has an element selection unit that switches reading of an electric signal, and the detection block substrate supplies a selection signal for selecting the detection element for reading the electric signal to the element selection unit; and the electric signal. For outputting to the signal collecting circuit, the selection wiring and the output wiring are provided on the first surface, and the output wiring forms a row in the first direction. The selection wiring is formed in common for the detection elements, and the selection wiring is formed in common for the detection elements forming a row in the second direction, and the control circuit inputs the selection signal to the selection wiring. Then, the detection element that outputs the electric signal is selected for each row, and the row to be selected is switched,
The signal collecting circuit collects the electric signal from the detection element in each row from the output wiring for each column, and the arithmetic unit uses the output signal collected by the signal collecting circuit. Then, the X-ray CT apparatus is characterized in that the tomographic images at the positions of the plurality of slice planes are obtained. 2. The X-ray CT apparatus according to claim 1,
An X-ray CT apparatus, wherein the photoelectric conversion substrate comprises a plurality of photoelectric conversion sub-substrates. 3. The X-ray CT apparatus according to claim 1,
An X-ray CT apparatus, wherein the photoelectric conversion substrate or the detection block substrate includes an amplifier that amplifies the electric signal for each of the detection elements. 4. The X-ray CT apparatus according to claim 2,
An X-ray CT apparatus, wherein a plurality of the detection elements that straddle the plurality of photoelectric conversion sub-boards are electrically connected by a common signal wiring. 5. The X-ray CT apparatus according to claim 2,
In at least one of the first direction and the second direction, the distance between the end surface of the photoelectric conversion sub-board and the end surface of the photoelectric conversion element closest to the end surface is
An X-ray CT apparatus, characterized in that the distance between the facing end faces of the photoelectric conversion elements adjacent to each other in the photoelectric conversion sub-substrate is ½ or less.