WO2006112320A1

WO2006112320A1 - X-ray plane detector and x-ray image diagnosing device

Info

Publication number: WO2006112320A1
Application number: PCT/JP2006/307730
Authority: WO
Inventors: Shigeyuki Ikeda
Original assignee: Hitachi Medical Corporation
Priority date: 2005-04-15
Filing date: 2006-04-12
Publication date: 2006-10-26
Also published as: JPWO2006112320A1

Abstract

An X-ray plane detector comprising, disposed as a circuit pattern formed on a circular semiconductor wafer, a storing means for storing charges corresponding to entered X-ray energy, and a switching means for outputting, as an X-ray image signal, charges stored by the storing means.

Description

Specification

X-ray flat panel detector and X-ray diagnostic imaging system

Technical field

TECHNICAL FIELD [0001] The present invention relates to an X-ray flat panel detector comprising an X-ray conversion unit and a detection unit using a two-dimensional semiconductor detection element array, and an X-ray image diagnostic apparatus using the same.

[0002] This application is a patent application claiming priority based on Japanese Patent Application No. 2005-117853 under Japanese Patent Law, and is incorporated by reference to enjoy the benefits of Japanese Patent Application No. 2005-117853. It is an application to receive.

Background art

In recent years, an X-ray diagnostic imaging apparatus using a semiconductor digital X-ray detector capable of obtaining a digital X-ray image in real time has been put into practical use.

[0004] This semiconductor digital X-ray detector is called an X-ray flat panel detector (FPD). In the FPD, the X-ray converter and the detector are electrically connected. The X-ray converter converts the X-ray energy indirectly into light or directly into the charge amount. The detection unit is formed by a two-dimensional semiconductor detection element array, and detects a value obtained by converting the light converted by the X-ray conversion unit into a charge or a value obtained by directly converting the X-ray energy into a charge. Then, the electric charge detected by the detection unit is read as an electric signal, and the read electric signal is imaged by an image processing unit for diagnosis.

[0005] In an FPD having such a configuration, for example, in order to obtain a light-receiving unit having a visual field size capable of photographing the body of a patient (subject), a plurality of rectangular small silicon substrates are bonded together like a tile. It is manufactured by the ring method.

[0006] An FPD manufactured by the above-described tiling method is disclosed in Patent Document 1! In this patent document 1, there is a set of light receiving elements formed from a photodiode corresponding to a pixel and a switch element such as a MOS transistor having an input terminal connected to the photodiode, and the light receiving elements are arranged in a matrix. They are arranged to form a set of detection element array sections, and a plurality of detection element array sections are combined to obtain a field of view of a required size.

[0007] Patent Document 1: Japanese Patent Laid-Open No. 9 326479 Disclosure of the invention

Problems to be solved by the invention

[0008] However, the FPD manufactured by the tiling method has variations in the quality of the silicon substrate for each tile and the accuracy when bonding multiple tiles together, and the variation is the image quality of X-ray images. The power that did not consider the point that may affect the.

[0009] On the other hand, it is known that in order to image a specific part such as a head blood vessel or a cardiac blood vessel of a subject, the specific part can be imaged with a circular visual field size of approximately 8 inches. . Because this specific part of the image diagnosis deals with fine blood vessels, FPD based on the tiling method may not be able to clearly visualize the blood vessels, or may result in false images. For this reason, there is a demand for a single-piece FPD with a uniform field-of-view size that allows radiography of a specific part and X-ray electrical signal conversion characteristics (X-ray conversion characteristics).

[0010] An object of the present invention is to provide an FPD and an X-ray image diagnostic apparatus having uniform X-ray conversion characteristics for imaging a specific part.

Means for solving the problem

[0011] In the FPD of the present invention, an accumulation unit that accumulates charges corresponding to incident X-ray energy and a switch unit that outputs the charges accumulated by the accumulation unit as an X-ray image signal are circular. It is arranged as a circuit pattern formed on the semiconductor wafer.

[0012] Further, the X-ray diagnostic imaging apparatus of the present invention includes an X-ray source that irradiates a subject with X-rays, and an X-ray plane detection that is disposed opposite to the X-ray source and detects transmitted X-rays of the subject. Means and display means for displaying an image of transmitted X-ray information detected by the X-ray plane detection means, wherein the X-ray plane detection means is the FPD.

The invention's effect

[0013] According to the present invention, it is possible to provide an FPD and an X-ray diagnostic imaging apparatus having uniform X-ray conversion characteristics for imaging a specific part.

Brief Description of Drawings

FIG. 1 is a schematic explanatory diagram of an FPD based on an indirect conversion method according to a first embodiment of the present invention.

FIG. 2 is an image obtained by performing head angiography using the FPD according to the first embodiment of the present invention. FIG.

FIG. 3 is an explanatory diagram of a main part of an indirect conversion type FPD according to a second embodiment of the present invention.

FIG. 4 is an explanatory diagram of a main part of an indirect conversion type FPD according to a third embodiment of the present invention.

FIG. 5 is an internal configuration diagram of a read row selection circuit in a third embodiment of the present invention.

FIG. 6 is an internal configuration diagram of a read circuit in a third embodiment of the present invention.

FIG. 7 is a schematic configuration diagram of an X-ray diagnostic imaging apparatus employing FPDs according to the first to third embodiments of the present invention.

Explanation of symbols

[0016] 1 phosphor layer, 3 pixel array group, 4 photodiode, 5 FET switch, 6 pixel, 7 switch control line, 8 signal readout line, 9 silicon wafer, 10 FET switch drive circuit, 11 readout row selection Signal input terminal, 12 electric signal amplifier, 13 column output terminal, 14 through-hole, 15 readout row selection circuit, 16 readout circuit, 17 readout circuit output terminal, 18 counter, 19 decoder, 20 multiplexer, 21 AZD converter , 22 Normal R Z serial conversion, 31 Subject, 32 X-ray source, 33 X-ray flat panel detector, 34 X-ray detector control unit, 35 Sensitivity and offset information storage unit, 36 Sensitivity and offset correction unit, 37 Corrected image storage unit, 38 display unit, 39 sensitivity and offset information collection control unit, 40 console

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic explanatory diagram of an X-ray flat panel detector according to the indirect conversion method according to the first embodiment of the present invention. As shown in Fig. 1 (a), the X-ray flat panel detector converts X-ray energy incident on the phosphor layer 1 such as Csl (Cesium iodide) into light, and the converted light is a circular silicon wafer. The pixel array group 3 formed in 9 circuit patterns converts the charges. Here, the power of explaining an example of a semiconductor using silicon, and other semiconductors that can be used for FPD as well as silicon are also included in the practice of the present invention.

[0018] The pixel array group 3 is configured by arranging a plurality of pixel arrays in which the photodiode 4 and the FET switch 5 shown in FIG. . The FET switch 5 of each pixel 6 is connected to the switch control line 7 and the signal readout line. A signal for selecting a pixel to be read is transmitted to the switch control line 7, and the FET switch 5 is turned on by this signal. When the FET switch 5 is turned on, the signal is read out by the signal readout line 8 via the charge force SFET switch 5 accumulated in the photodiode 4.

The pixel 6 including the photodiode 4 and the FET switch 5 is formed by an amorphous silicon layer on a glass substrate layer.

Here, the size of the circular silicon wafer 9 is determined as a basic size manufactured by a manufacturing line such as 8 inches or 12 inches. For this reason, for example, when a rectangular silicon substrate is produced using a circular 8-inch wafer, a rectangular silicon substrate with a side of about 14 cm inscribed in the 8-inch (about 20.32 cm) circular silicon substrate is the largest. It becomes size.

[0022] However, an FPD having a square field of view of 14 cm on a side is insufficient for use in diagnosis of the entire head angiography image, and a circular field of approximately 8 inches without cutting into a square. If it is the size, the entire head blood vessel image can be imaged.

[0023] Therefore, the present invention is to obtain a light-receiving unit having a visual field size necessary for head angiography and cardiovascular imaging using the circular silicon wafer itself of 8 inches, 12 inches or the like.

FIG. 1 (c) is an explanatory view of the main part of the indirect conversion type X-ray flat panel detector according to the first embodiment of the present invention. In FIG. 1 (c), a plurality of pixels 6 shown in FIG. 1 (b) are arranged in a matrix on a circular silicon wafer 9, and switch control lines 7 and signal readout lines are connected to the pixels 6 arranged in this matrix. Wire 8

Further, on the silicon wafer 9, an FET switch driving circuit 10, a read row selection signal input terminal 11, an electric signal amplifier 12, and a column output terminal 13 are arranged. The FET switch drive circuit 10 drives the FET switch 5 that reads out charges from the photodiode 4 of the pixel 6. Further, the readout row selection signal input terminal 11 is output from a readout row selection circuit (not shown in FIG. 1 (c)) arranged outside the silicon wafer 9 and supplied to the FET switch drive circuit 10. A read row selection signal is input.

[0026] The electric signal amplifier 12 amplifies the read electric charge of the photodiode 4 to a required value. Further, the output signal of the electric signal amplifier 12 is supplied from the column output terminal 13 to a readout circuit (not shown in FIG. 1 (c)) arranged outside the silicon wafer 9.

The switch 6 is controlled by a readout row selection circuit (not shown), so that the pixel 6 Selected. In other words, when the selection signal for the pixel 6 is input to the readout row selection signal input terminal 11 in the row direction, the FET switch 5 for the pixel 6 in the row direction is turned on all at once by the FET switch drive circuit 10, and the signal in the column direction The X-ray information stored in the photodiode 4 is output to the readout line 8. The X-ray information is supplied to the electric signal amplifier 12 through the signal readout line 8, amplified by the amplifier 12, and inputted to a readout circuit (not shown).

[0028] The above operation is repeated in order for all the rows of the plurality of pixels 6 arranged in a matrix, and an electrical signal to be a two-dimensional image data sequence is collected by a readout circuit. It is imaged by the processing unit.

In the first embodiment of the present invention, as shown in FIG. 1 (c), the FET switch drive circuit 10, the input terminal 11, the electric signal amplifier 12, and the column output terminal 13 are circular. The silicon wafer 9 is placed on the periphery.

[0030] Normally, the peripheral area corresponding to about 10% of the surface of the silicon wafer 9 cannot be a pixel area due to the limitation of the area where the wiring pattern is exposed, and is effective as a pixel area. The area is at most 90% of the surface of the silicon wafer 9. For this reason, the drive circuit 10, the input terminal 11, the electric signal amplifier 12, and the column output terminal 13 are arranged on the peripheral edge of the circular silicon wafer 9, so that the central area is the entire pixel arrangement area, and the circular shape is obtained. Silicone, 90% of 9 can be used as pixel area.

[0031] Therefore, a large detection area can be secured, an image having a visual field size necessary for head blood vessel and cardiovascular diagnosis can be obtained, and the X-ray flat panel detector can be made inexpensive.

In addition, since the input terminal 11 and the output terminal 12 are arranged at the peripheral edge of the circular silicon wafer 9, the connection between the ends 11 and 12 and the outside can be easily performed. it can.

[0033] Further, since the light receiving unit is only one circular silicon wafer 9, there is no problem due to bonding, and a highly reliable X-ray image diagnostic apparatus can be provided.

FIG. 2 shows an image obtained by performing head angiography using the X-ray flat panel detector according to the first embodiment of the present invention described above. In FIG. 2, a rectangular image area indicated by a solid line indicates an area corresponding to a square silicon substrate having a side of 14 cm created from an 8-inch silicon wafer 9, and an area indicated by a solid circle indicates an image according to the present invention. It is an area. [0035] As shown in FIG. 2, it can be seen that in the image region using the above-described rectangular silicon substrate, an insufficiently imaged portion occurs in the blood vessel necessary for diagnosis, and the image region of the head blood vessel is insufficient.

On the other hand, in the X-ray flat panel detector of the present invention that can obtain a circular image region, a wide and region blood vessel image can be obtained, and an image region sufficient for diagnosing head blood vessels and cardiovascular blood vessels is obtained. can get.

Note that the read row selection circuit and the read circuit are arranged on the back surface of the base for fixing the circular silicon wafer 9. By doing so, the distance between the read row selection circuit and the read circuit and the input terminal 11 and the column output terminal 13 is shortened, the mounting is simplified, and the introduction of external noise can be prevented.

[0038] Fig. 3 is an explanatory diagram of a main part of an indirect conversion type X-ray flat panel detector according to a second embodiment of the present invention. The difference between the second embodiment and the first embodiment is that the readout row selection signal input terminal 11 is disposed on the surface opposite to the surface on which the pixel 6 is disposed, and the through hole 14 is interposed. Thus, the input terminal 11 and the FET switch drive circuit 10 are connected. Since other configurations are the same as those in the first embodiment and the second embodiment, detailed description thereof is omitted.

In the first embodiment shown in FIG. 1, when the pixel size is small because the readout row selection signal input terminal 11 and the column output terminal 13 are both arranged at the lower left corner of the silicon wafer 9. In this case, the space between the row and the column becomes small, and the area necessary for bonding the terminals 11 and 13 cannot be secured! / ヽ case is considered.

Therefore, in the second embodiment of the present invention shown in FIG. 3, the reading row selection signal input terminal 11 for inputting the selection signal of the pixel 6 is arranged on the surface opposite to the surface on which the pixel 6 is arranged. It is arranged (not shown) and connected to the FET switch drive circuit 10 through the through hole 14.

Therefore, according to the second embodiment of the present invention, the same effects as those of the first embodiment can be obtained, and the area necessary for bonding the terminals 11 and 13 even when the pixel size is small. Can be secured.

In the second embodiment, the column output terminal 13 is also disposed on the surface opposite to the surface on which the pixels 6 are disposed, and is connected to the electric signal amplifier 12 through a through hole. You can do that. [0043] Further, only a part of the terminals 11 and 13 is disposed on the surface opposite to the surface on which the pixel 6 is disposed, and the FET switch driving circuit 10 or the electric signal amplifier 12 is connected to the terminal 11 and 13 through the through hole. It is also possible to connect.

FIG. 4 is an explanatory diagram of a main part of an indirect conversion type X-ray flat panel detector according to a third embodiment of the present invention. The difference between the third embodiment and the first embodiment is that, in the third embodiment, the read row selection circuit 15 and the read circuit 16 are arranged on the periphery of the circular silicon wafer 9. It is that you are. Since other configurations are the same as those of the first embodiment and the third embodiment, detailed description thereof is omitted. Reference numeral 17 denotes a read output terminal of the read circuit 16.

The read row selection circuit 15 includes a counter 18 and a decoder 19 as shown in FIG. When a detection signal read command is also input to the force counter 18, the counter 18 inputs a count value corresponding to the number of rows of the light receiving unit to the decoder 19. The decoder 19 decodes the input count value and inputs it as a read row selection signal to the read row selection signal input terminal 11 of each row of the light receiving unit.

As shown in FIG. 6, the read circuit 16 includes a multiplexer 20, an AZD (analog Z digital) conversion 21, and a normal / serial conversion 22. The column output of the electric signal amplifier 12 is input to the multiplexer 20, and all the electric signals input to the multiplexer 20 are sequentially converted into digital values by the AZD converter 21.

[0047] From this AZD transformation ^^ 21, the power to output parallel data of all pixels. When this parallel data is converted into serial data and sent to an image processing device (not shown), the parallel Z serial transformation 22 is used. Convert to serial data. The serial data converted signal is output from the read output terminal 17.

If the data to be sent to the image processing apparatus is parallel data, the parallel data output from the AZD converter output is supplied as it is to the output terminal 17.

[0049] According to the third embodiment of the present invention, the same effect as in the first embodiment can be obtained. Further, according to the third embodiment, since the read row selection circuit 15 and the read circuit 16 are provided on the peripheral edge of the circular silicon wafer 9, these circuits 15 and 16 are provided close to the light receiving portion. Read row selection signal input than the first embodiment and the second embodiment The distances between the terminal 11 and the column output terminal 13 and the circuit 15 and the circuit 16 are further shortened, which can be more effective in mounting and preventing external noise from being mixed.

[0050] The above is an example in which the present invention is applied to an indirect conversion type X-ray flat panel detector, but the present invention is not limited to an indirect conversion type X-ray flat panel detector. It can also be applied to an X-ray flat panel detector.

[0051] In the case of a direct conversion type X-ray flat panel detector, the phosphor layer 1 in FIG. 1 becomes an X-ray detection film (amorphous selenium), and the photodiode 4 shown in FIG. It becomes. About another structure, an indirect conversion system and a direct conversion system become the same.

FIG. 7 is a schematic configuration diagram of an X-ray image diagnostic apparatus employing the FPD of the first to third embodiments of the present invention.

In FIG. 7, the X-ray diagnostic imaging apparatus includes an X-ray source 32 that irradiates a subject 31 with X-rays, and an X-ray plane that is disposed opposite to the X-ray source 32 and detects X-rays transmitted through the subject 31 A detector 33 and an X-ray detector control unit 34 for controlling reading of image information output from the X-ray flat panel detector 33 are provided.

In addition, the X-ray diagnostic imaging apparatus includes a sensitivity and offset information storage unit 35 that stores the output of each channel force of the X-ray flat panel detector 33 as sensitivity and offset information, and this sensitivity and offset information storage. Sensitivity and offset correction unit 36 for performing sensitivity correction and offset correction of image information read from the X-ray flat panel detector 33, and the sensitivity and offset correction unit stored in the unit 35. 36 includes a corrected image storage unit 37 for storing the image information subjected to sensitivity and offset correction, and a display unit 38 for displaying the stored image information.

[0054] Further, the X-ray diagnostic imaging apparatus performs control for reading an image from the X-ray plane detector 33 to collect sensitivity and offset information, and is read from the X-ray plane detector 33. Sensitivity and offset information storage unit 35 for storing information as sensitivity and offset information, and sensitivity and offset information collection control unit 39 for storing information, and a signal for the operator to start collecting sensitivity and offset information. It is equipped with a console 40 to be sent to part 39.

The X-ray flat panel detector 33 is one of the above-described first to third embodiments of the present invention. Any circular silicon wafer 9 is used, and this silicon wafer 9 is supported by a pedestal.

Therefore, the X-ray diagnostic imaging apparatus of the present invention can obtain an image data detection unit having a necessary visual field size without bonding a plurality of detection element arrays, and is an inexpensive X-ray flat detector. An X-ray diagnostic imaging apparatus using can be provided.

Industrial applicability

[0057] The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

Claims

The scope of the claims

[1] Accumulation means (4) for accumulating charges corresponding to incident X-ray energy and switch means (5) for outputting the charges accumulated by the accumulation means as X-ray image signals are circular. An X-ray flat panel detector arranged as a circuit pattern formed on a semiconductor wafer (9).

[2] The storage means (4) is a photodiode that converts X-ray energy converted into light into electric charges, and the switch means (5) is a semiconductor switch connected to a photodiode, and The X-ray flat panel detector according to claim 1, wherein the photodiode and the semiconductor switch are arranged as a circuit pattern arranged in a matrix on the silicon wafer (9).

[3] The accumulating means (4) is a capacitor for accumulating charges converted from X-ray energy, and the switch means (5) is a semiconductor switch connected to a photodiode. 2. The X-ray flat panel detector according to claim 1, wherein the switch is arranged as a circuit pattern arranged in a matrix on the silicon wafer.

[4] The control signal input terminal (11) for outputting the charge accumulated in the accumulation means (4) and the charge outputted from the switch means (5) are outputted to the outside of the semiconductor wafer (9). 2. The X-ray flat panel detector according to claim 1, wherein an external output terminal (13) is arranged in a peripheral area of the semiconductor wafer (9).

[5] The control signal input terminal is supplied with a read selection signal for selecting which of the plurality of storage means is to read the charge, and the storage means selected by this selection signal is input to the control signal input terminal. A plurality of semiconductor switch driving means (10) for driving the corresponding semiconductor switch and the selected storage means force Amplifying the electric signal of the read electric charge, and a plurality of electric switches connected to the external output terminal 5. The signal amplifying means (12), wherein the semiconductor switch driving means (10) and the electric signal amplifying means (12) are arranged in a peripheral region of the circular silicon wafer. X-ray flat panel detector.

[6] The storage means, the semiconductor switch driving means (10), and the electric signal amplifying means (12) of the silicon wafer (9) are arranged in part or all of the control signal input terminal and the external output terminal. It is formed on the surface opposite to the surface and is formed on the silicon wafer (9). 6. The X-ray flat panel detector according to claim 5, wherein the X-ray flat panel detector is connected to the semiconductor switch driving means (10) or the electric signal amplifying means (12) through a hole.

[7] The storage means arranged in which row of the plurality of pixel storage means arranged in a matrix form The readout row selection means (15) for selecting whether to read out the charges, and the readout row selection means A plurality of semiconductor switch driving means (10) for driving the semiconductor switch of the storage means connected to the selected row; and an electric signal of the electric charge read from the storage means of the selected row is amplified, and 3. A plurality of electric signal amplifying means (12) connected to the output terminal, and a reading means (16) for collecting an output signal of the electric signal amplifying means power. X-ray flat panel detector.

[8] Semiconductor switch driving means (10), electric signal amplifying means (12), readout row selecting means

8. The X-ray flat panel detector according to claim 7, wherein (15) and the reading means (16) are arranged in a peripheral region of the circular silicon wafer.

[9] The readout row selection means (15) decodes the count value (18) for counting the count value corresponding to the number of rows of the pixel means arranged in a matrix, and the value counted by the count means. And a decoding means (19) for inputting the decoded signal to a plurality of semiconductor switch driving means, and the reading means (16) inputs an output signal of the plurality of electric signal amplifying means (12). Then, the multiplexer (20) that sequentially outputs, the analog Z digital conversion means (21) that converts the electrical signal output from the multiplexer (20) into a digital value, and the converted parallel digital signal in serial 8. The X-ray plane inspection unit according to claim 7, further comprising: a parallel Z-serial conversion unit (22) for converting the signal into an output; and an output terminal for outputting the parallel signal or the serial signal. Vessel.

[10] The X-ray plane detection according to claim 7, wherein the readout row selection means (15) and the readout means (16) are arranged on a back surface of a pedestal supporting a circular silicon wafer.

[11] An X-ray source (32) for irradiating the subject with X-rays, an X-ray plane detection means (33) disposed opposite to the X-ray source to detect the transmitted X-rays of the subject, and the X-rays X-ray diagnostic imaging apparatus having display means (38) for displaying the transmitted X-ray information detected by the plane detection means (33). 11. The X-ray image diagnostic apparatus according to claim 1, wherein the X-ray plane detection means (33) is the X-ray plane detector according to any one of claims 1 to 10.