JP2012042301A - Cassette for radiograph - Google Patents

Abstract

An object of the present invention is to reduce the influence on a radiographic image obtained by FPD.
A cassette 13 includes a housing 26 that houses a detection panel 16 that functions as radiation detection means. The casing 26 is a rectangular surface plate disposed so as to cover the detection range 16a at a position facing the radiation detection range 16a of the front panel 30, the rear surface 31, and the detection panel 16 that covers the detection panel 16. 32. The front surface part 30 has a rectangular opening 30a. The surface plate 32 is attached to the front surface 30 from the inside of the housing 26 so as to cover the opening 30a. The surface plate 32 includes a plurality of carbon prepregs 32a in which carbon fibers are impregnated with a resin, and a metal foil 32b is stacked on the carbon prepreg 32a by pressure bonding. The carbon prepreg 32a and the metal foil 32b are integrally formed by an autoclave.
[Selection] Figure 3

Description

  The present invention relates to a radiographic cassette.

  A radiation imaging system that obtains a radiation image by irradiating radiation such as X-rays from a radiation generator toward a subject is known. The radiation imaging system includes a radiation detector that detects radiation transmitted through a subject. In recent years, a radiation detector using a flat panel detector (FPD) instead of a radiation film or an imaging plate (IP) has become widespread. The FPD is accommodated in a rectangular parallelepiped housing. The FPD accommodated in the housing is called a radiographic FPD cassette (hereinafter simply referred to as a cassette).

  The casing constituting the cassette is configured with a surface plate made of a carbon-based material having a low radiation absorption rate such as carbon fiber at least on the side facing the FPD radiation detection surface (see, for example, Patent Document 1). ). Thereby, the radiation efficiently passes through the housing and is reliably detected by the FPD.

  On the other hand, the face plate scatters low-energy radiation and affects the radiation image obtained by FPD. In view of this, the cassette of Patent Document 1 has a metal foil attached to the surface plate to remove radiation scattered by the surface plate.

JP 2003-185753 A

  In the cassette of patent document 1, metal foil is affixed by fixing means, such as a double-sided tape and an adhesive agent. As the fixing means, a polyester resin having a high radiation transmittance is selected, but there is a problem that the fixing means affects the radiation image obtained by the FPD.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a radiographic cassette with less influence on a radiographic image obtained by FPD.

  In order to achieve the above object, a radiographic cassette according to the present invention comprises a radiation detecting means for detecting radiation to generate a radiation image, a driving means for driving the radiation detecting means, and a carbon fiber. It has a surface plate which permeate | transmits, It is provided with the housing | casing which accommodates the said radiation detection means and the said drive means, and the metal foil crimped | bonded to the said surface plate.

  The metal foil is preferably pressure-bonded so as to cover a part of the surface plate to protect the driving means from radiation.

  The surface plate is preferably formed from a carbon prepreg obtained by impregnating a carbon fiber with a resin.

  According to the present invention, since the metal foil is pressure-bonded to the surface plate formed of carbon fiber and transmitting radiation, the radiation scattered by the surface plate is removed by the metal foil, and the radiation image obtained by the radiation detection means is obtained. Less influence. Further, since the metal foil is fixed without using a fixing means such as an adhesive, the radiation image is not affected by the fixing means.

It is a figure which shows the structure of a radiography system roughly. It is a disassembled perspective view of a cassette. It is sectional drawing of a cassette. It is sectional drawing of another form of cassette.

  As shown in FIG. 1, the radiation imaging system 11 includes a radiation generator 12 that irradiates a subject H with radiation (X-rays) X, a cassette 13 that detects the radiation X transmitted through the subject H, and radiation. A system controller 14 that controls the generator 12 and the cassette 13, and a console 15 that inputs imaging conditions such as tube voltage, tube current, exposure time, and operation instructions such as imaging instructions to the system controller 14. Yes.

  The radiation generator 12 includes a radiation tube 12a that generates radiation X, and a collimator 12b that limits an irradiation range of the radiation X. The radiation generator 12 is movably supported by a support device (not shown). For example, the radiation generator 12 is moved by a support device (not shown) so as to face the cassette 13, and the irradiation range of the radiation X is changed according to the imaging region set by the system controller 14.

  The cassette 13 is a box shape that is large enough to cover the chest of the subject H, and has high handleability and portability. The cassette 13 is disposed under the subject H lying on a bed when used in an examination room, a hospital room, or the like. The cassette 13 performs wireless communication with the system controller 14 and is controlled based on a signal from the system controller 14.

  The system controller 14 controls the radiation generator 12 and the cassette 13 to operate synchronously based on the imaging conditions and imaging instructions received from the console 15. The radiation image data output from the cassette 13 is transferred to the console 15 via the system controller 14.

  The console 15 outputs the received radiation image data to a monitor or a data storage device (such as an image server connected via a local hard disk or a communication network).

  As shown in FIGS. 2 and 3, the cassette 13 includes a detection panel 16 that functions as a radiation detection unit, various circuit boards 17, 18, 19, and 20, and a detection panel 16 and various circuit boards 17 to 20. A base plate 21 serving as a base, flexible cables 22 and 23 for connecting the circuit boards 17 and 18 to the detection panel 16, IC chips 24 and 25 mounted on the flexible cables 22 and 23, and a casing 26 for housing these. And.

  The detection panel 16 is a flat panel detector (FPD) in which a glass substrate 27, a detection element array 28, and a scintillator 29 are stacked in this order. The detection panel 16 is fixed to the base plate 21 from the scintillator 29 side.

  The glass substrate 27 has radiation transparency and insulating properties. In the detection element array 28, detection elements including thin film transistors (TFTs) as switching elements and photodiodes as photoelectric conversion elements are arranged on a glass substrate 27 in a matrix. The glass substrate 27 and the detection element array 28 constitute a so-called active matrix substrate.

  The photodiode is made of amorphous silicon (a-Si), for example, and generates electric charges in response to visible light emitted from the scintillator 29. When the TFT is turned on, the charge generated by the photodiode is read out to a signal line (not shown) provided for each column of the detection element array 28.

  The scintillator 29 is made of a phosphor such as cesium iodide (CsI) or gadolinium oxysulfide (GOS), and emits visible light corresponding to the amount of incident radiation. The scintillator 29 is formed by adhering a sheet coated with a phosphor to the detection element array 28 or depositing a phosphor on the detection element array 28.

  The detection panel 16 is a so-called back-illuminated type in which radiation is incident on the scintillator 29 through the glass substrate 27 and the detection element array 28. The light detection surface of the detection element array 28 is arranged to face the scintillator 29. The light emission amount of the scintillator 29 is the largest on the side where the radiation is incident, but since the detection element array 28 is arranged on the side where the light emission amount is large, high detection efficiency can be obtained.

  A circuit for driving the TFTs of the detection element array 28 is formed on the circuit board 17. The circuit board 17 and the IC chip 24 functioning as a shift register constitute a drive circuit.

  An A / D conversion circuit is formed on the circuit board 18. The A / D conversion circuit converts an analog signal output from the IC chip 25 into a digital signal. The IC chip 25 is an ASIC that constitutes a readout circuit, and sequentially selects a charge amplifier that converts the signal charge read from the detection panel 16 into a voltage signal and a signal line formed for each column of the detection element array 28. And a multiplexer that outputs voltage signals to the A / D conversion circuit one column at a time.

  A control circuit is formed on the circuit board 19. The control circuit controls each part of the cassette 13 and controls communication with an external device.

  A power supply circuit is formed on the circuit board 20. The power supply circuit is composed of circuit elements such as an AC / DC converter that converts alternating current into direct current and a DC / DC converter that converts direct current voltage into a voltage necessary for the operation of each circuit, and supplies power to each section.

  The various circuit boards 17 to 20 are fixed on the side of the base plate 21 opposite to the side on which the detection panel 16 is fixed.

  The housing 26 includes a front surface portion 30 that covers the detection panel 16 from the glass substrate 27 side on which radiation is incident, a rear surface portion 31 that covers the detection panel 16 from the scintillator 29 side, and a radiation detection range 16a on the detection panel 16. A rectangular surface plate 32 disposed so as to cover the detection range 16a is provided at the facing position.

  The front surface portion 30 has a rectangular opening 30a. The surface plate 32 is attached to the front surface portion 30 from the inside of the housing 26 so as to cover the opening 30a.

  The surface plate 32 includes a plurality of carbon prepregs 32a in which carbon fibers are impregnated with a resin, and a metal foil 32b is stacked on the carbon prepreg 32a by pressure bonding. The carbon prepreg 32a and the metal foil 32b are integrally formed by an autoclave. The metal foil 32b has a function of removing radiation scattered by the carbon prepreg 32a, a function of releasing heat in the housing 26, a function of protecting the IC chip 24 from radiation, and the like. The metal foil 32b may be laminated on the intermediate layer, but is preferably laminated on the outermost layer on the detection panel 16 side as shown.

  The front surface portion 30, the back surface portion 31, and the base plate 21 are formed of a metal having a relatively low radiation transmittance, such as stainless steel, to reduce the influence of radiation on various circuit boards 17 to 20. On the other hand, the surface plate 32 has a relatively high radiation transmittance and functions as a transmission surface that transmits the radiation. Since the surface plate 32 functions as a transmission surface, the detection panel 16 efficiently detects radiation.

  Hereinafter, the operation of the above configuration will be described. The cassette 13 is placed under the subject H in the prone position by a medical radiographer or the like. The positions of the radiation generator 12 and the cassette 13 are adjusted so that the irradiation range of the radiation generator 12 and the detection range 16a of the detection panel 16 substantially coincide.

  By setting imaging conditions using the console 15 and giving an imaging start instruction, the radiation generator 12 emits radiation and the detection panel 16 detects radiation according to the control of the system controller 14. Thus, a radiation image of the subject H is obtained. This radiation image is displayed on a monitor.

  Since the metal foil 32b is pressure-bonded to the surface plate 32 on which the carbon prepreg 32a is laminated, the radiation scattered by the carbon prepreg 32a is removed by the metal foil 32b, and the influence on the radiation image is reduced. Further, since the metal foil 32b is fixed without using a fixing means such as an adhesive, the radiation image is not affected by the fixing means. For this reason, the risk of overlooking the presence of the affected area when radiographic images are interpreted is reduced. Further, since the metal foil 32b is integrally formed with the carbon prepreg 32a by pressure bonding, it is difficult to peel off and is excellent in durability.

  In the above embodiment, the metal foil 32b is pressure-bonded so as to cover the entire surface plate 32, but may be pressure-bonded so as to cover a part thereof. In the cassette 13 shown in FIG. 4, the metal foil 32 b is laminated so as to cover a portion along the upper end of the surface plate 32, that is, a portion facing the IC chip 24.

  Since the metal foil 32b has a lower radiation transmittance than the carbon prepreg 32a, the influence of the radiation on the IC chip 24 is reduced. On the other hand, since the metal foil 32b is not laminated on the portion facing the detection range 16a, the detection of the radiation by the detection panel 16 is not affected.

  In each of the above embodiments, the indirect conversion type FPD that converts radiation into visible light using a phosphor and converts the visible light into electric charge using a photoelectric conversion element has been described as an example of the detection panel 16. Instead of the type FPD, a direct conversion type FPD that directly converts radiation into charges by a photoconductive layer such as amorphous selenium (a-Se) may be used.

13 cassette 16 detection panel 17 circuit board 24 IC chip 26 housing 32 surface plate 32a carbon prepreg 32b metal foil X radiation

Claims (3)

Radiation detecting means for detecting radiation and generating a radiation image;
Drive means for driving the radiation detection means;
A housing that is formed of carbon fiber and has a surface plate that transmits radiation, and that houses the radiation detecting means and the driving means;
A radiographic cassette, comprising: a metal foil pressure-bonded to the surface plate.   The radiographic cassette according to claim 1, wherein the metal foil is pressure-bonded so as to cover a part of the surface plate to protect the driving unit from radiation.   The radiographic cassette according to claim 1, wherein the surface plate is made of a carbon prepreg obtained by impregnating a carbon fiber with a resin.

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