JP2012066060A - Radiographic image capturing system and radiographic image capturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily expand the irradiation range of radiation and apply an optimal dose of radiation to a subject in the case of photographing the subject with a short SID using a field electron emission type radiation source.SOLUTION: In the radiographic image capturing system and radiographic image capturing method, at least three radiation sources (18a-18g) are divided into at least three groups (54-58) including one or more radiation sources. The doses of respective radiation (16a-16g) are weighted so that the doses of radiation (16c-16e) output from the radiation sources (18c-18e) belonging to the group (56) in the vicinity of the geometric center position of the radiation sources (18a-18g) are maximum doses, and the doses of radiation (16a, 16b, 16f, 16g) output from the radiation sources (18a, 18b, 18f, 18g) belonging to the other groups (54, 58) in the vicinity of the geometric center position are low.

Description

  The present invention relates to a radiation imaging system and a radiation imaging method in which a subject is irradiated with radiation from a plurality of radiation sources accommodated in a radiation output device, each radiation transmitted through the subject is detected by a radiation detection device and converted into a radiation image. About.

  In the medical field, radiation imaging systems that acquire radiation images of a subject by irradiating the subject with radiation from a radiation source and detecting the radiation transmitted through the subject with a radiation detection device are widely used. For example, in a radiographic system installed in a hospital (medical institution), a relatively large and heavy thermoelectron emission type radiation source is usually used.

  However, such a radiographic system can be used for radiographic imaging during rounds in hospitals, radiographic imaging outside hospitals, for example, taking pictures with examination cars, natural disasters and other disaster sites and home medical care. If it is applied as it is to on-site imaging, it takes a large and heavy radiation source to the site to perform imaging, increasing the burden on the doctor or radiologist. Therefore, Patent Document 1 proposes a field electron emission type radiation source that is smaller and lighter than a thermionic emission type radiation source.

JP 2007-103016 A

  When a field electron emission type radiation source is operated on site, it is assumed that it is difficult to secure a power source. Therefore, it is desirable that the field electron emission type radiation source is a battery-driven radiation source. Therefore, the field electron emission type radiation source used in the field is a radiation source that outputs a small dose of radiation as well as a small and lightweight radiation source. Therefore, a doctor or a radiographer brings the field electron emission type radiation source as close to the subject as possible at the site, and sets the distance between the radiation source and the radiation detection apparatus (distance between source images) (SID). It is necessary to take a radiographic image of the subject in a short setting. As a result, the irradiation range of the radiation output from the field electron emission radiation source is narrowed, and the radiation dose (exposure dose) irradiated to the subject is small. A radiation image of radiation dose cannot be obtained.

  In order to solve such a problem, a plurality of field electron emission type radiation sources are prepared, and the subject is irradiated with radiation from each of the radiation sources so as to cover a desired irradiation range (imaging region of the subject). Alternatively, it may be possible to cover the irradiation range by irradiating the subject with radiation from the moved position while moving one field electron emission type radiation source.

  By the way, when irradiating a subject with radiation, if the subject can be irradiated with an optimal dose (exposure dose) according to the subject, a radiation image with an exposure dose suitable for a doctor's interpretation diagnosis can be obtained. In addition, inadvertent exposure of the subject can be avoided.

  However, as described above, it is impossible to irradiate the subject with an optimal dose of radiation simply by irradiating the subject with radiation from a field electron emission type radiation source so as to cover a desired irradiation range.

  The present invention has been made to solve the above-described problems, and easily expands the radiation irradiation range when a radiographic image is taken on a subject with a short SID using a field electron emission type radiation source. Another object of the present invention is to provide a radiation imaging system and a radiation imaging method capable of irradiating the subject with an optimal dose of radiation.

In order to achieve the above object, a radiographic system according to the present invention includes:
A radiation output device that accommodates at least three radiation sources that output radiation, and when each of the at least three radiation sources irradiates a subject with radiation, the radiation transmitted through the subject is detected and converted into a radiation image. A radiation detection device, and a control device for controlling the radiation output device and the radiation detection device,
The controller is
Dividing the at least three radiation sources into at least three groups comprising one or more radiation sources;
Among the divided groups, the radiation dose output from the radiation source belonging to the group in the vicinity of the geometric center position of the at least three radiation sources becomes the maximum dose, and the geometric center position Weighting the dose of each radiation output from the at least three radiation sources so that the radiation dose output from a radiation source belonging to a group other than the neighboring group is a small dose that supplements the maximum dose. Done in groups,
The radiation output device is controlled to irradiate the subject with radiation from the at least three radiation sources according to the weighting.

Further, the radiographic method according to the present invention includes:
When at least three radiation sources outputting radiation are accommodated in the radiation output device, the at least three radiation sources are divided into at least three groups including one or more radiation sources;
Among the divided groups, the radiation dose output from the radiation source belonging to the group in the vicinity of the geometric center position of the at least three radiation sources becomes the maximum dose, and the geometric center position Weighting the dose of each radiation output from the at least three radiation sources so that the radiation dose output from a radiation source belonging to a group other than the neighboring group is a small dose that supplements the maximum dose. Done in groups,
Subject the subject to radiation from the at least three radiation sources according to the weighting;
Each radiation transmitted through the subject is detected by a radiation detection device and converted into a radiation image.

  According to the present invention, at least three radiation sources accommodated in the radiation output device are divided into at least three groups, and among these groups, the radiation sources belonging to a group near the geometric center position of each radiation source. Each of the radiation doses output from a radiation source belonging to a group other than the group in the vicinity of the geometric center position is a small dose. The dose of each radiation output from the radiation source is weighted in groups.

  Thus, in the present invention, instead of simply setting the radiation irradiation range so that the desired irradiation range (imaging region of the subject) can be covered, the radiation sources are divided into at least three groups, Since the dose of each radiation output from the radiation source is weighted for each group, the radiation irradiation range can be obtained even if a radiographic image of a subject is taken with a short SID using a field electron emission type radiation source. Can be easily enlarged, and the subject can be irradiated with an optimal dose of radiation (exposure dose). Therefore, in the present invention, since the subject can be irradiated with an optimal dose of radiation according to the subject, a radiographic image suitable for a doctor's interpretation diagnosis can be obtained, and inadvertent exposure of the subject can be avoided. can do.

  In the present invention, when a subject is arranged between a radiation output device and a radiation detection device and the subject is positioned so as to face the geometric center position, the group near the geometric center position is used. The radiation dose output from the radiation source belonging to the group becomes the maximum dose, and the radiation dose output from the radiation source belonging to the other group becomes a small dose. ) Can be efficiently taken.

  In addition, when there is a group to which two or more radiation sources belong, if further weighting of the dose of the radiation output from each radiation source in the group is performed, irradiation of the subject with the optimal dose is performed. It becomes possible to carry out with high accuracy. Further, when the radiation output device and the radiation detection device are opposed to each other, if the at least three radiation sources are arranged one-dimensionally or two-dimensionally with respect to the irradiation surface of the radiation detection device irradiated with radiation Therefore, radiographic images can be efficiently captured for any imaging region.

It is a block diagram of the radiography system which concerns on this embodiment. 2A is a perspective view in which the radiation output device and the radiation detection device of FIG. 1 are integrated, and FIG. 2B is a perspective view showing a state in which the radiation output device and the radiation detection device are separated from each other. 3A and 3B are plan views showing the positioning of the imaging region of the subject with respect to the radiation detection apparatus. 4A and 4B are perspective views of the radiation output apparatus. FIG. 5A and FIG. 5B are side views showing radiation irradiation to the imaging region of the subject. It is a block diagram of the radiation output device and radiation detection device of FIG. It is a block diagram of the control apparatus of FIG. It is a circuit block diagram of the radiation detection apparatus of FIG. It is explanatory drawing which shows an example of the table stored in the database of FIG. It is explanatory drawing which shows an example of the table stored in the database of FIG. It is a flowchart for demonstrating operation | movement of the radiography system of FIG. 12A and 12B are side views showing a first modified example of the present embodiment. 13A and 13B are side views showing a second modified example of the present embodiment. 14A and 14B are perspective views illustrating a third modification of the present embodiment. 15A and 15B are perspective views showing a fourth modification of the present embodiment. It is sectional drawing which shows the 5th modification of this embodiment. It is sectional drawing which showed roughly the structure of the signal output part of 1 pixel part of the radiation detector of FIG. FIG. 18A is a schematic explanatory diagram schematically illustrating a sixth modification of the present embodiment, and FIG. 18B is a schematic explanatory diagram schematically illustrating an example of the scintillator of FIG. 18A.

  A preferred embodiment of the radiation imaging system according to the present invention will be described below in detail with reference to FIGS.

[Configuration of this embodiment]
As shown in FIG. 1, the radiation imaging system 10 according to the present embodiment accommodates a plurality of radiation sources 18 a to 18 g capable of irradiating radiation 16 a to 16 g to a subject 14 lying on an imaging table 12 such as a bed. A radiation output device 20, a radiation detection device 22 that detects radiations 16 a to 16 g transmitted through the subject 14 and converts them into a radiation image, and a control device 24 that controls the radiation output device 20 and the radiation detection device 22. In this case, transmission / reception of signals between the control device 24 and the radiation output device 20 and the radiation detection device 22 is performed by, for example, UWB (Ultra Wide Band), IEEE802.11. Signals may be transmitted and received by wireless communication using a / b / g / n, wireless communication using millimeter waves, or by wired communication using a cable.

  The radiation imaging system 10 also captures a radiographic image of a subject 14 (patient) in a radiology room in a hospital (medical institution) or a radiographic image of a subject 14 (patient) in a hospital room during a round-trip in the hospital. The present invention can be applied to imaging of radiographic images of the subject 14 outside the hospital. As imaging outside the hospital, for example, imaging for the subject 14 (examined person) at the time of a health examination in a medical examination car, imaging for the subject 14 (injured person) at a disaster site such as a natural disaster, or in the field of home medical care There is shooting for a subject 14 (at-home person).

  In order to realize such various applications, in the radiation imaging system 10 according to the present embodiment, it is desirable that the radiation sources 18a to 18g are field electron emission type radiation sources as disclosed in Patent Document 1. In addition, a doctor or a radiologist (hereinafter simply referred to as a doctor) 26 holds the part opposite to the output part of the radiations 16a to 16g in the radiation output device 20 that accommodates the radiation sources 18a to 18g. A handle 28 is provided. Therefore, the radiation output device 20 is a portable device.

  The radiation detection device 22 temporarily converts the radiations 16a to 16g into visible light using a scintillator, and the converted visible light is electrically converted by a solid detection element (hereinafter also referred to as a pixel) made of a substance such as amorphous silicon (a-Si). Built-in indirect conversion type radiation detector that converts to signal, or direct conversion type radiation detector that converts radiation 16a-16g directly into electrical signal by solid state detection element made of material such as amorphous selenium (a-Se) It is a portable electronic cassette.

  The control device 24 is preferably a portable information terminal (for example, a notebook personal computer (PC), a tablet PC, or a personal digital assistant (PDA)). When the radiation imaging system 10 is applied to a radiology room, the control device 24 may be a stationary console, and the radiation output device 20 and the radiation detection device 22 may be portable devices.

  As shown in FIGS. 2A and 2B, the radiation detection device 22 includes a rectangular housing 30 made of a material that can transmit the radiations 16a to 16g (see FIG. 1), and the subject 14 is positioned (positioned). The surface (upper surface) to be irradiated is an irradiation surface 32 irradiated with radiation 16a to 16g. On the irradiation surface 32, an imaging area for the radiation 16a to 16g and a guide line 34 serving as a reference for the imaging position are formed, and an outer frame portion of the guide line 34 is an area where the radiation 16a to 16g can be irradiated. Region 36 is designated.

  Also, on one side of the housing 30, a switch 38 for turning on or off the radiation detection device 22, a card slot 40 for loading a memory card (not shown), an input terminal 42 of an AC adapter, and not shown A USB terminal 44 to which a USB cable is connected is provided.

  Further, holding portions 35 and 37 that protrude outward are provided on the side surface opposite to the side surface on which the switch 38, the card slot 40, the input terminal 42, and the USB terminal 44 are disposed. The holding portion 35 is provided with a convex connection terminal 39 so as to face the holding portion 37, while the holding portion 37 is provided with a concave connection terminal 41 so as to face the connection terminal 39. (See FIGS. 2B to 3B). In addition, a concave connection terminal 43 that can be fitted to the connection terminal 39 and a convex connection that can be fitted to the connection terminal 41 are provided at both ends of the cylindrical casing 46 constituting the radiation output device 20 described above. Terminals 45 are provided (see FIGS. 2B, 4A, and 4B).

  Here, by fitting the connection terminal 39 and the connection terminal 43 and fitting the connection terminal 41 and the connection terminal 45, the radiation output device 20 is placed between the holding portions 35 and 37 as shown in FIG. 2A. The connection terminal 39 and the connection terminal 43 are electrically connected, and the connection terminal 41 and the connection terminal 45 are electrically connected. Thus, in a state where the radiation output device 20 and the radiation detection device 22 are integrated, the doctor 26 can hold the handle 28 and carry the radiation output device 20 and the radiation detection device 22, for example. . In the integrated state of the radiation output device 20 and the radiation detection device 22, the output locations of the radiations 16 a to 16 g in the radiation output device 20 are directed to the side surface of the housing 30 of the radiation detection device 22.

  On the other hand, by releasing the holding state of the radiation detection device 22 by the holding portions 35 and 37 and the connection terminals 39, 41, 43 and 45 and separating the radiation detection device 22 from the radiation output device 20, the radiation output device 20 and The integrated state of the radiation detector 22 is canceled, and the electrical connection state between the connection terminal 39 and the connection terminal 43 and the electrical connection state between the connection terminal 41 and the connection terminal 45 are released.

  As shown in FIGS. 3A and 3B, when positioning the subject 14, the center position of the imaging region of the subject 14 and the center position of the imageable region 36 (intersection of the guide line 34) are seen in plan view. The imaging region is positioned so that the imaging regions substantially coincide with each other and the imaging region falls within the imageable region 36. 3A illustrates a case where the chest of the subject 14 is positioned as an imaging region, and FIG. 3B illustrates a case where the right hand of the subject 14 is positioned as an imaging region.

  As shown in FIGS. 4A and 4B, the radiation output device 20 has a cylindrical housing 46 made of a material that can transmit the radiations 16a to 16g. Field electron emission type radiation sources 18a to 18g are arranged (one-dimensional array) along one direction. In addition, a USB terminal 50 to which a USB cable (not shown) is connected and the connection terminal 43 described above are provided at one end of the housing 46, and the connection terminal 45 described above is provided at the other end. . Further, the handle 28 described above is disposed on the side surface of the housing 46, and the handle 28 has a built-in touch sensor 52 (gripping state detection sensor).

  The touch sensor 52 is a capacitance type or resistance type contact sensor. When the doctor 26 holds the handle 28 and the hand of the doctor 26 touches an electrode (not shown) constituting the touch sensor 52, the touch sensor 52 is touched. 52 outputs a detection signal indicating that the hand and the electrode are in contact with each other. The touch sensor 52 may be a mechanical switch such as a push switch. In this case, when the doctor 26 grasps the handle 28 and contacts the mechanical switch, the touch sensor 52 outputs a signal indicating that the mechanical switch is turned on or off as a detection signal.

  Here, when the doctor 26 holds the handle 28 and directs the radiation output device 20 toward the subject 14, the radiation output device 20 causes each radiation source 18 a to 18 g due to the output of the detection signal from the touch sensor 52. The radiations 16a to 16g can be output all at once or sequentially (see FIG. 4B). When the radiation output device 20 and the radiation detection device 22 are integrated with the holding portions 35 and 37 and the connection terminals 39, 41, 43, and 45, the radiation output device 20 even if the doctor 26 holds the handle 28. Does not allow (inhibit) the output of radiation 16a-16g from each radiation source 18a-18g.

  FIG. 5A illustrates a case where the chest of the subject 14 which is a relatively large imaging region is imaged, and FIG. 5B illustrates a case where the hand of the subject 14 which is a relatively small imaging region is imaged. is there.

  In the housing 46 of the radiation output apparatus 20, seven radiation sources 18a to 18g are arranged along the left-right direction (the longitudinal direction of the housing 46) of FIGS. 5A and 5B. The geometric center position is the position of the central radiation source 18d (the center position of the housing 46). Moreover, in the radiation output device 20, each radiation source 18a-18g is divided into three groups 54-58. In this case, the two radiation sources 18a and 18b belong to the group 54, the three radiation sources 18c to 18e belong to the group 56, and the two radiation sources 18f and 18g belong to the group 58. Therefore, the group 56 to which the central radiation source 18d belongs is a central group including the geometric center position, while the other groups 54 and 58 are groups at both ends with respect to the geometric center position. .

  By the way, when the portable radiation output device 20 is operated in a hospital or a field outside the hospital, it is assumed that it is difficult to secure a power source. Therefore, each radiation source 18a to 18g of the radiation output device 20 is a battery. A driven radiation source is desirable. That is, the field electron emission type radiation sources 18a to 18g are smaller and lighter than the thermal electron emission type radiation source disposed in the radiology room, and emit a small dose of radiation. The radiation source to output.

  In this case, the doctor 26 brings the radiation output device 20 as close as possible to the subject 14 at the site, and the distance between the radiation sources 18a to 18g and the radiation detector 60 in the radiation detection device 22 (line source image). It is necessary to take a radiographic image of the subject 14 with the distance (SID) set short. As a result, the radiation range of the radiations 16a to 16g output from the radiation sources 18a to 18g is narrowed, and the dose of the radiation 16a to 16g (exposure dose) irradiated to the subject 14 is small. In some cases, it becomes impossible to obtain a radiation image having an exposure dose suitable for diagnosis.

  Therefore, in the present embodiment, at least three radiation sources (seven radiation sources 18a to 18g in FIGS. 4A to 5B) are arranged in the radiation output device 20, and radiation output from adjacent radiation sources (FIG. 4B to FIG. 4B). In FIG. 5B, the radiation ranges of the radiations 16a to 16g) are partially overlapped with each other so that the radiation part is irradiated to the imaging region of the subject 14 without any gap.

  Further, if the subject 14 can be irradiated with an optimal dose (exposure dose) of radiation according to the imaging region of the subject 14 and its thickness, a radiation image with an exposure dose suitable for the diagnostic interpretation of the doctor 26 can be obtained. In addition, inadvertent exposure to the subject 14 can be avoided.

  Therefore, in the present embodiment, all the radiation sources built in the radiation output apparatus 20 are divided into at least three groups (three groups 54 to 58 in FIGS. 5A and 5B) that always include one radiation source. The radiation dose is weighted in units of groups in accordance with at least the imaging region of the subject 14, and then the radiation to the subject 14 is irradiated from each radiation source according to the weighting.

  Specifically, in radiographic imaging of a relatively large imaging region (chest) shown in FIG. 5A, radiation is applied over a relatively wide range (the entire imaging region 36) such that the radiation 16a to 16g is applied to the entire chest. It is necessary to irradiate 16a-16g. In addition, the cumulative exposure dose to the subject 14 in the imaging needs to be an optimum dose according to the chest and its thickness (exposure dose suitable for the interpretation diagnosis of the doctor 26).

  Therefore, in the present embodiment, in imaging for a relatively large imaging region as shown in FIG. 5A, the radiations 16a, 16b, 16f, and 16g output from the radiation sources 18a, 18b, 18f, and 18g of the groups 54 and 58 at both ends. The dose of the radiation 16c to 16e output from each of the radiation sources 18c to 18e in the central group 56 becomes the maximum dose (schematically illustrated by the thick dashed line in FIG. 5A). The dose is weighted for each group (in units of groups) so that the dose is small enough to be supplemented (schematically illustrated by the thin one-dot chain line in FIG. 5A). Irradiate 16g all at once, sequentially irradiate, or sequentially irradiate every group.

  On the other hand, in radiographic image capturing for a relatively small imaging region (right hand) shown in FIG. 5B, the right hand is arranged in the central portion in the imageable region 36, so that only within a relatively narrow range including the central portion, It suffices if radiation is reliably applied. Even in this case, the cumulative exposure dose to the subject 14 in the imaging needs to be an optimal dose according to the right hand and the thickness thereof (an exposure dose suitable for the interpretation diagnosis of the doctor 26).

  Therefore, in the present embodiment, in imaging with respect to a relatively small imaging region as shown in FIG. 5B, the doses of the radiations 16c to 16e output from the radiation sources 18c to 18e in the central group 56 are the maximum doses (in FIG. 5B). The doses of the radiations 16a, 16b, 16f, and 16g output from the radiation sources 18a, 18b, 18f, and 18g of the groups 54 and 58 at both ends are the maximum doses. The dose is weighted for each group (in units of groups) so that the dose is small enough to be supplemented (schematically illustrated by the thin one-dot chain line in FIG. 5B), and the radiations 16a to 16a are emitted from the radiation sources 18a to 18g. Irradiate 16g all at once, sequentially irradiate, or sequentially irradiate every group.

  In the above description, the maximum dose refers to the relatively largest dose when the doses of the respective radiations 16a to 16g are compared, and the small dose refers to the dose of each of the radiations 16a to 16g. When compared, it refers to a relatively small dose, and any dose should not exceed the optimum dose. That is, in the present embodiment, in one imaging in FIGS. 5A and 5B, the cumulative exposure dose when the subject 14 is exposed by the irradiation of each of the radiations 16a to 16g is the optimal dose. The doses of the radiations 16a to 16g output from the radiation sources 18a to 18g belonging to the groups 54 to 58 are weighted in units of groups.

  In addition, when dose weighting is performed in units of groups, for groups including two or more radiation sources, dose weighting may be further performed for each radiation source belonging to the group. That is, in this embodiment, a single dose weighting is performed on all radiation sources in one group, or different dose weights are individually applied to the radiation sources constituting one group. It is also possible to do this. By further weighting the dose for each radiation source, it is possible to accurately irradiate the subject 14 with radiation.

  Further, it is preferable to irradiate the radiation 16a to 16g from the radiation sources 18a to 18g at the same time because the time required for photographing the subject 14 is shortened. However, simultaneous irradiation of the radiations 16a to 16g may be difficult depending on the power supply capability (consumption of power in the radiation output device 20) to each of the radiation sources 18a to 18g and the imaging conditions (number of images) of the subject 14.

  In such a case, the radiation images 16a to 16g may be sequentially irradiated from the radiation sources 18a to 18g so as to surely capture the radiation image on the subject 14. In the case of sequentially irradiating the radiation 16a to 16g, for the purpose of reducing the blur of the radiographic image due to the movement of the imaging part during imaging, the irradiation to the center position of the positioned imaging part is prioritized, and thereafter Irradiation with respect to these points may be performed sequentially. Alternatively, the irradiation with the radiation illustrated by the thick dashed line in FIG. 5A and FIG. 5B may be performed preferentially, and then the irradiation illustrated by the thin dashed line may be sequentially performed.

  Therefore, in the present embodiment, simultaneous irradiation or sequential irradiation may be selected according to the power supply capability for each of the radiation sources 18a to 18g and the imaging conditions of the subject 14.

  When the radiations 16a to 16g weighted in this way are irradiated onto the imaging region of the subject 14, the radiations 16a to 16g transmitted through the imaging region are transmitted to the surface of the housing 30 of the radiation detection device 22 ( It passes through the imageable area 36) shown in FIGS. 2A to 3B and is guided to the radiation detector 60 built in the housing 30. The radiation detector 60 is the above-described indirect conversion type radiation detector or direct conversion type radiation detector, and detects each radiation 16a to 16g and converts it into a radiation image.

  Here, the internal configurations of the radiation output device 20, the radiation detection device 22, and the control device 24 constituting the radiation imaging system 10 will be described with reference to the block diagrams of FIGS. 6 and 7 and the circuit configuration diagram of FIG. explain in detail.

  The radiation output device 20 includes a communication unit 64 that transmits and receives signals by wireless communication with the control device 24 via the antenna 62, and a radiation source control unit that controls the radiation sources 18a to 18g individually or in groups. 66 and a battery 68 for supplying power to each part in the radiation output apparatus 20.

  The battery 68 constantly supplies power to the touch sensor 52, the communication unit 64, and the radiation source control unit 66. Here, when a detection signal is output from the touch sensor 52 to the radiation source control unit 66 due to the grasping of the handle 28 by the doctor 26, the radiation source control unit 66 supplies power to each unit in the radiation output device 20. The battery 68 is controlled to supply.

  Further, the connection terminal 39 and the connection terminal 43 are electrically connected, and the connection terminal 41 and the connection terminal 45 are electrically connected, so that the radiation output device 20 and the radiation detection device 22 are integrated. In this case, it is possible to charge the battery 68 from the battery 76 of the radiation detection device 22. In this case, even if the detection signal from the touch sensor 52 is input, the radiation source controller 66 does not permit (inhibit) power supply from the battery 68 to the radiation sources 18a to 18g. Therefore, the radiation source control unit 66 releases the electrical connection between the connection terminal 39 and the connection terminal 43 and releases the electrical connection between the connection terminal 41 and the connection terminal 45, so that the radiation output When a detection signal is output from the touch sensor 52 in a state where the device 20 and the radiation detection device 22 are separated from each other, power supply from the battery 68 to the radiation sources 18a to 18g is started for the first time.

  In the radiation output device 20, when a cable (not shown) (communication cable, USB cable, cable according to the IEEE 1394 standard) is connected, signals are transmitted to and received from the outside via the cable, or It is also possible to receive power supply. For example, when a USB cable (not shown) is connected to the USB terminal 50, the battery 68 can be charged from the outside, while the communication unit 64 is connected to the outside via the USB cable. It is possible to transmit and receive signals.

  The radiation detection device 22 includes a communication unit 72 that transmits and receives signals to and from the control device 24 via the antenna 70 by wireless communication, a cassette control unit 74 that controls the radiation detector 60, and a radiation detection device 22. A battery 76 that supplies power to each unit is further included.

  The battery 76 always supplies power to the cassette control unit 74 and the communication unit 72. When the switch 38 is operated (turned on) by the doctor 26, each unit in the radiation detection device 22 is supplied. It is possible to start supplying power.

  In the radiation detection device 22 as well, when a cable (not shown) (communication cable, USB cable, IEEE1394 standard cable, etc.) is connected, signals are transmitted to and received from the outside via the cable. Alternatively, it is possible to receive power supply. For example, when a USB cable (not shown) is connected to the USB terminal 44, the battery 76 can be charged from the outside, while the communication unit 72 is connected to the outside via the USB cable. It is possible to transmit and receive signals.

  The cassette control unit 74 includes an address signal generation unit 78 that supplies an address signal for reading out a radiation image to the radiation detector 60, an image memory 80 that stores the radiation image read out from the radiation detector 60, and And a cassette ID memory 82 for storing cassette ID information for specifying the radiation detection device 22.

  Here, as an example, the circuit configuration of the radiation detection apparatus 22 when the indirect conversion type radiation detector 60 is employed will be described in detail with reference to FIG.

  The radiation detector 60 has a structure in which a photoelectric conversion layer 96 in which each pixel 90 made of a substance such as a-Si that converts visible light into an electrical signal is formed is arranged on an array of matrix-shaped TFTs 98. In this case, in each pixel 90 to which the bias voltage Vb is supplied from the battery 76 (see FIG. 6), electric charges generated by converting visible light into an electric signal (analog signal) are accumulated, and the TFT 98 is sequentially set for each row. By turning it on, the charge can be read out as an image signal.

  A gate line 92 extending in parallel to the row direction and a signal line 94 extending in parallel to the column direction are connected to the TFT 98 connected to each pixel 90. Each gate line 92 is connected to the line scan driver 100, and each signal line 94 is connected to the multiplexer 102. Control signals Von and Voff for on / off control of the TFTs 98 arranged in the row direction are supplied to the gate line 92 from the line scan driving unit 100. In this case, the line scan driving unit 100 includes a plurality of switches SW1 for switching the gate lines 92 and an address decoder 104 for outputting a selection signal for selecting one of the switches SW1. An address signal is supplied to the address decoder 104 from an address signal generator 78 (see FIG. 6) of the cassette controller 74.

  Further, the charge held in each pixel 90 flows out to the signal line 94 through the TFTs 98 arranged in the column direction. This charge is amplified by the amplifier 106. A multiplexer 102 is connected to the amplifier 106 via a sample and hold circuit 108. The multiplexer 102 includes a plurality of switches SW2 that switches the signal line 94 and an address decoder 110 that outputs a selection signal for selecting one of the switches SW2. An address signal is supplied to the address decoder 110 from the address signal generator 78 of the cassette controller 74. An A / D converter 112 is connected to the multiplexer 102, and a radiographic image converted into a digital signal by the A / D converter 112 is supplied to the cassette control unit 74.

  Note that the TFT 98 functioning as a switching element may be realized in combination with another imaging element such as a CMOS (Complementary Metal-Oxide Semiconductor) image sensor. Furthermore, it can be replaced with a CCD (Charge-Coupled Device) image sensor that transfers charges while shifting charges by a shift pulse corresponding to a gate signal referred to in the TFT 98.

  As shown in FIG. 7, the control device 24 includes a communication unit 122, a control processing unit 124, a display unit 126 such as a display, an operation unit 128 such as a keyboard and a mouse, an exposure switch 130, and order information storage. Unit 132, database 134, imaging condition storage unit 136, image memory 138, and power supply unit 140.

  The communication unit 122 transmits and receives signals to and from the communication unit 64 of the radiation output device 20 and the communication unit 72 of the radiation detection device 22 by wireless communication via the antennas 62, 70, and 120. The control processing unit 124 executes predetermined control processing for the radiation output device 20 and the radiation detection device 22. The exposure switch 130 is a switch for the doctor 26 to instruct the start of output of the radiation 16a to 16g from the radiation sources 18a to 18g. The order information storage unit 132 stores order information for requesting radiographic imaging of the subject 14. The database 134 stores various data relating to the weighting of the radiation doses 16a to 16g. The imaging condition storage unit 136 stores imaging conditions for irradiating the imaging parts with the radiations 16a to 16g. The image memory 138 stores the radiation image distributed from the radiation detection device 22 by wireless communication. The power supply unit 140 supplies power to each unit in the control device 24.

  Note that the order information is a radiology information system (RIS) (not shown) that centrally manages radiographic images and other information handled in the radiology department in the hospital, or in the hospital connected to the RIS. In the medical information system (HIS) that comprehensively manages medical information, it is created by the doctor 26. In this order information, in addition to subject information for specifying the subject 14 such as the name, age, and sex of the subject 14, information on the radiation output device 20 and the radiation detection device 22 used for radiographic image capturing, 14 imaging regions and the like are included. The imaging conditions are necessary for irradiating the imaging region of the subject 14 with the radiation 16a to 16g, such as the tube voltage and tube current of each radiation source 18a to 18g, the exposure time of the radiation 16a to 16g, and the like. There are various conditions.

  Further, when the control device 24 is a console provided in the radiology room, the console (control device 24) acquires the order information from the RIS or the HIS and stores it in the order information storage unit 132. On the other hand, when the control device 24 is a portable terminal that is transported to the site and used, (1) the order information is simply registered by the doctor 26 operating the operation unit 128 on the site to register the order information. Is stored in the order information storage unit 132, or (2) the order information is acquired from the RIS or HIS at the hospital and stored in advance in the order information storage unit 132 before being transported to the site, or (3 ) Preferably, the received order information is stored in the order information storage unit 132 by forming a wireless link between the on-site control device 24 and the hospital and receiving the order information from the hospital via the radio. .

  The control processing unit 124 includes a database search unit 150, an imaging condition setting unit 152, and a control signal generation unit 154.

  The database search unit 150 searches the database 134 for desired data corresponding to the imaging region or the like of the subject 14. The shooting condition setting unit 152 sets shooting conditions based on the data searched by the database search unit 150 and the order information. The control signal generation unit 154 generates an exposure control signal for starting output of the radiation 16a to 16g from the radiation sources 18a to 18g when the doctor 26 operates the exposure switch 130.

  9 and 10 illustrate tables in which various data related to the weighting of the radiation doses 16a to 16g are stored in the database 134. FIG.

  FIG. 9 shows a table storing a plurality of imaging regions, the thickness of each imaging region, imaging techniques for each imaging region, and the optimal dose (optimum dose data) according to these contents. . The imaging technique is information indicating the direction of the imaging region with respect to the radiation detection device 22 and the irradiation direction of the radiation 16a to 16g with respect to the imaging region. In FIG. 9, typically, regarding a chest that is a relatively large imaging region and a hand that is a relatively small imaging region, these imaging regions (chest, hand) and imaging techniques (imaging on the front of the chest, on the back of the hand) The case where various types of data such as (imaging), the thickness of the imaging region, and the optimum dose data are stored in the database 134 is illustrated.

  FIG. 10 shows a plurality of imaging regions and imaging techniques, the number of radiation sources accommodated in the radiation output apparatus 20, the number of radiation sources assigned to each group (grouping data), and the weighting of the dose in each group. A table storing (weighting data) is shown. Note that, in FIG. 10, as corresponding to FIG. 9, representatively, data regarding the chest and hands, and data when the number of radiation sources is 3 and 7 are illustrated.

  In FIG. 10, as an example, the number of groups is three (A, B, C), and weighting data for these three groups is stored. For example, A corresponds to the group 54, B corresponds to the group 56, and C corresponds to the group 58.

  Here, when the number of radiation sources is 3, one radiation source belongs to each of the groups 54 to 58. When the number of radiation sources is 7, two radiation sources belong to the group 54, three radiation sources belong to the group 56, and two radiation sources belong to the group 58. become.

  Furthermore, when the number of groups is 3 or more, it goes without saying that the number of grouping data and weighting data in the table of FIG. 10 increases according to the number of groups. In addition, when the dose is weighted for each radiation source even in the same group, it goes without saying that the number of weighting data increases according to the number of radiation sources to be weighted.

  Since the database 134 (see FIG. 7) can store various types of data related to imaging that can be executed by the radiation imaging system 10, the subject 14 to be imaged can be changed, or the imaging region of the subject 14 can be changed. Alternatively, the data in the database 134 can also be used when photographing a plurality of subjects 14 sequentially.

  Further, the imaging region of the subject 14, the thickness of the imaging region, and the imaging technique may be input by the doctor 26 by operating the operation unit 128 at the time of imaging, or may be included in the order information of the subject 14 in advance. Good. The imaging information, the thickness, and the imaging technique input using the operation unit 128 are stored in the order information storage unit 132 as a part of the order information, so that the order information is edited.

  Here, when a radiographic image is captured with respect to the imaging region (imaging technique) of the subject 14 indicated in the order information, the database search unit 150 performs the following processing.

  The database search unit 150 automatically searches the table of FIG. 9 for the optimum dose data corresponding to the imaging region of the subject 14, its thickness, and the imaging technique. Further, the database search unit 150 automatically searches for optimum grouping data and weighting data according to the imaging region and imaging technique of the subject 14 and the number of radiation sources in the radiation output device 20. Then, the database search unit 150 uses the searched optimum dose data, grouping data, and weighting data, and the imaging condition setting unit 152 including order information including the imaging region of the subject 14, the thickness of the imaging region, and the imaging technique used for the search. Output to.

  When the database search unit 150 searches the database 134 for a plurality of candidates as the optimum dose data, grouping data, and weighting data, the database search unit 150 may display the plurality of candidates and order information on the display unit 126. In this case, if the doctor 26 confirms the display content of the display unit 126 and operates the operation unit 128 to select data that seems to be optimal for imaging of the subject 14, the database search unit 150 selects the selected optimal dose. Data, grouping data, weighting data, and order information are output to the imaging condition setting unit 152.

  The imaging condition setting unit 152 automatically sets imaging conditions for the imaging region of the subject 14 based on the order information and the optimal dose data, grouping data, and weighting data (selected by the doctor 26) searched by the database search unit 150. The set shooting conditions are stored in the shooting condition storage unit 136.

  Note that the imaging condition setting unit 152 may display the order information and the optimum dose data, grouping data, and weighting data searched by the database search unit 150 on the display unit 126. In this case, the doctor 26 operates the operation unit 128 while confirming the display content of the display unit 126, so that the optimum dose data, grouping data, and weighting data are obtained according to the order information, the state of the subject 14, or the imaging technique. The imaging condition setting unit 152 sets the imaging conditions based on the changed optimal dose data, grouping data, and weighting data.

[Operation of this embodiment]
The radiation imaging system 10 according to the present embodiment is basically configured as described above. Next, the operation (radiation imaging method) will be described with reference to the flowchart of FIG. In this description of the operation, it will be described with reference to FIGS. 1 to 10 as necessary.

  First, in step S <b> 1 of FIG. 11, the control processing unit 124 (see FIG. 7) of the control device 24 acquires order information from the outside, and stores the acquired order information in the order information storage unit 132. In the case where the control device 24 is a console in the radiographing room, order information may be acquired from RIS or HIS via the antenna 120 and the communication unit 122. When the control device 24 is a portable portable terminal that can be transported to the site, registration of order information by operating the operation unit 128 by the doctor 26 (see FIGS. 1 and 4B to 5B) at the site. Orders can be obtained by acquiring order information from RIS or HIS in the hospital before transporting to the site, or receiving order information via a wireless link formed with the hospital after transporting to the site. What is necessary is just to acquire information.

  In step S <b> 2, the database search unit 150 specifies the imaging region of the subject 14, the thickness of the imaging region, and the imaging technique necessary for searching the database 134.

  If the order information stored in the order information storage unit 132 includes the imaging region of the subject 14, the thickness of the imaging region, and the imaging technique, the database search unit 150 uses these information for the imaging region in the current imaging. The thickness and the shooting technique are specified.

  In addition, when the doctor 26 operates the operation unit 128 and inputs the imaging region, thickness, and imaging technique of the subject 14, the database search unit 150 displays the input imaging region, thickness, and imaging technique of the subject 14 this time. This is specified as the imaging part, thickness, and imaging technique in the imaging. As a result, the specified imaging region, thickness, and imaging technique are stored in the order information storage unit 132 as part of the order information, and the order information in the order information storage unit 132 is edited.

  In the next step S3, the database search unit 150 captures the imaging region of the subject 14 identified in step S2, the imaging region corresponding to the thickness and imaging procedure, the thickness and imaging procedure, and the optimum dose data corresponding to these pieces of information. Are automatically retrieved from the database 134. The database search unit 150 also automatically searches the database 134 for grouping data and weighting data corresponding to the imaging region and imaging technique of the subject 14 specified in step S2. Then, the database search unit 150 needs the optimal dose data, grouping data, and weighting data that can be searched, and order information including the imaging part, the thickness, and the imaging technique of the subject 14 used for the search, to capture the radiographic image. Is output to the imaging condition setting unit 152 as various data (step S4).

  In step S3, when searching for a plurality of candidates for the optimum dose data, grouping data, and weighting data, the database search unit 150 displays these candidates and order information on the display unit 126. The doctor 26 confirms the display content of the display unit 126 and selects a candidate (data) that seems to be optimal for photographing the subject 14 by operating the operation unit 128. As a result, the database search unit 150 regards the optimal dose data, grouping data, and weighting data candidates selected by the doctor 26 and the order information as various data necessary for radiographic imaging, and the imaging condition setting unit 152. (Step S4).

  In step S5, the imaging condition setting unit 152 sends radiations 16a to 16g from the radiation sources 18a to 18g to the imaging region of the subject 14 based on the input optimum dose data, grouping data, weighting data, and order information. Set the shooting conditions for irradiation.

  When the imaging region of the subject 14 is the chest as shown in FIG. 5A, the imaging condition setting unit 152 outputs the radiation sources 18a, 18b, 18f, and 18g of the groups 54 and 58 at both ends in accordance with the contents of the above-described data. The doses of radiation 16a, 16b, 16f, and 16g to be performed become the maximum dose, and the doses of the radiations 16c to 16e output from the radiation sources 18c to 18e in the central group 56 supplement the maximum dose. The imaging conditions (tube voltage, tube current, irradiation time) are set so that the following conditions are satisfied, and the set imaging conditions are stored in the imaging condition storage unit 136.

  When the imaging region of the subject 14 is a hand (right hand) as shown in FIG. 5B, the imaging condition setting unit 152 performs radiation output from the radiation sources 18c to 18e of the central group 56 in accordance with the above data. The doses of 16c to 16e are the maximum dose, and the doses of the radiations 16a, 16b, 16f, and 16g output from the radiation sources 18a, 18b, 18f, and 18g of the groups 54 and 58 at both ends are the maximum doses. Imaging conditions (tube voltage, tube current, irradiation time) are set so that a small dose can be supplemented, and the set imaging conditions are stored in the imaging condition storage unit 136.

  In step S5, the imaging condition setting unit 152 may display the input optimum dose data, grouping data, weighting data, and order information on the display unit 126. In this case, the doctor 26 confirms the display content of the display unit 126 and operates the operation unit 128 according to the content of the order information, the state of the subject 14, or the imaging technique of the subject 14, thereby obtaining the optimum dose data. It is also possible to change the contents of the grouping data and the weighting data and set desired photographing conditions according to the contents of the changed data. Even in this case, the shooting condition setting unit 152 stores the set shooting condition in the shooting condition storage unit 136.

  In step S5, the imaging condition setting unit 152 further weights different radiation doses to the radiation sources in the group in order to realize highly accurate radiation 16a to 16g, and further weights. The desired shooting conditions may be set according to the above, and the set shooting conditions may be stored in the shooting condition storage unit 136.

  Next, when the doctor 26 turns on the switch 38 (see FIGS. 2A, 2B and FIGS. 5A to 6) of the radiation detection device 22 in step S <b> 6, the battery 76 supplies power to each part in the radiation detection device 22. Then, the entire apparatus is activated. Thereby, the cassette control unit 74 wirelessly transmits an activation notification signal for notifying that the radiation detection device 22 has been activated to the control device 24 (see FIGS. 1 and 7). The bias voltage Vb is also supplied from the battery 76 to each pixel 90 (see FIG. 8) of the radiation detector 60.

  Based on the reception of the activation notification signal via the antenna 120 and the communication unit 122, the control processing unit 124 of the control device 24 wirelessly transmits the imaging conditions stored in the imaging condition storage unit 136 to the radiation detection device 22. To do. The cassette control unit 74 registers the imaging conditions received via the antenna 70 and the communication unit 72.

  By the way, when the radiation output device 20 and the radiation detection device 22 are transported to the site, the radiation output device 20 is connected by the fitting of the connection terminal 39 and the connection terminal 43 and the fitting of the connection terminal 41 and the connection terminal 45. It is hold | maintained between the holding parts 35 and 37 of the radiation detection apparatus 22, and the radiation output device 20 and the radiation detection apparatus 22 are an integrated state (refer FIG. 2A). In this case, the battery 76 charges the battery 68 via the connection terminals 39, 41, 43, 45.

  Therefore, the doctor 26 releases the fitting state between the connection terminal 39 and the connection terminal 43 and releases the fitting state between the connection terminal 41 and the connection terminal 45 in order to position the imaging region of the subject 14. Then, the radiation output device 20 is separated from the radiation detection device 22, and the integrated state of the radiation output device 20 and the radiation detection device 22 is released (see FIG. 2B). Thereby, the charging from the battery 76 to the battery 68 is also stopped.

  Next, the doctor 26 positions the imaging region so that the center position of the imaging region of the subject 14 and the center position of the imaging region 36 are substantially coincident and the imaging region is within the imaging region 36 ( FIG. 3A and FIG. 3B). Thereafter, with the doctor 26 holding the handle 28, the radiation output device 20 is directed toward the imaging region of the subject 14 so that the distance between the radiation output device 20 and the radiation detection device 22 is a distance corresponding to the SID. The touch sensor 52 outputs a detection signal to the radiation source controller 66. Based on the input of the detection signal, the radiation source control unit 66 controls the battery 68 so as to supply power to each unit in the radiation output device 20 to activate the radiation output device 20 as a whole. Further, the radiation source control unit 66 transmits an activation notification signal for notifying that the radiation output device 20 has been activated to the control device 24 by radio.

  Based on the reception of the activation notification signal via the antenna 120 and the communication unit 122, the control processing unit 124 wirelessly transmits the imaging conditions stored in the imaging condition storage unit 136 to the radiation output apparatus 20. The radiation source control unit 66 registers the imaging conditions received via the antenna 62 and the communication unit 64.

  On the premise that the above preparation for imaging is completed, the doctor 26 turns on the exposure switch 130 with the other hand while holding the handle 28 with one hand (step S7). Thereby, the control signal generation unit 154 generates an exposure control signal for starting output of the radiation 16a to 16g from each of the radiation sources 18a to 18g, and transmits to the radiation output device 20 and the radiation detection device 22 by radio. To do. The exposure control signal is synchronized with the start of the output of the radiation 16a to 16g from the radiation sources 18a to 18g and the detection of the radiation 16a to 16g in the radiation detector 60 and the conversion to the radiation image. 3 is a synchronization control signal for executing radiographic image capturing for an imaging region of the subject.

  When receiving the exposure control signal, the radiation source controller 66 controls the radiation sources 18a to 18g so as to irradiate the subject 14 with the radiation 16a to 16g having a predetermined dose according to the imaging conditions. Thereby, each radiation source 18a-18g outputs radiation 16a-16g, respectively, and each said radiation 16a-16g is output outside from the radiation output device 20, and predetermined exposure time (irradiation based on the said imaging conditions) The imaging part of the subject 14 is irradiated for the time (step S8).

  In this case, if the imaging region is the chest shown in FIGS. 3A and 5A, a large dose of radiation 16a, 16b, 16f, 16g is emitted from each of the radiation sources 18a, 18b, 18f, 18g of the groups 54, 58 at both ends. On the other hand, the chest of the subject 14 is irradiated, while the radiation sources 18c to 18e of the central group 56 irradiate the imaging region with small doses of radiation 16c to 16e that supplement the large dose.

  If the imaging region is the right hand shown in FIG. 3B and FIG. 5B, a large dose of radiation 16c to 16e is emitted from the radiation sources 18c to 18e of the central group 56 to the imaging region of the subject 14, while From the radiation sources 18a, 18b, 18f, and 18g of the groups 54 and 58 at both ends, a small dose of radiation 16a, 16b, 16f, and 16g that supplements the large dose is irradiated to the right hand of the subject 14.

  In step S9 in which each of the radiations 16a to 16g passes through the subject 14 and reaches the radiation detector 60 in the radiation detection device 22, the radiation detector 60 is an indirect conversion type radiation detector. The scintillator constituting the detector 60 emits visible light having an intensity corresponding to the intensity of the radiation 16a to 16g, and each pixel 90 constituting the photoelectric conversion layer 96 (see FIG. 8) converts the visible light into an electrical signal. And accumulates as electric charge. Next, the charge information that is the radiation image of the subject 14 held in each pixel 90 is read according to the address signal supplied from the address signal generation unit 78 constituting the cassette control unit 74 to the line scanning drive unit 100 and the multiplexer 102. .

  That is, the address decoder 104 of the line scan driver 100 outputs a selection signal according to the address signal supplied from the address signal generator 78 to select one of the switches SW1, and the TFT 98 connected to the corresponding gate line 92. A control signal Von is supplied to the gates of the two. On the other hand, the address decoder 110 of the multiplexer 102 outputs a selection signal in accordance with the address signal supplied from the address signal generation unit 78, sequentially switches the switch SW2, and is connected to the gate line 92 selected by the line scan driving unit 100. The radiographic image as the charge information held in each pixel 90 is sequentially read out via the signal line 94.

  The radiation image read out from each pixel 90 connected to the selected gate line 92 is amplified by each amplifier 106, then sampled by each sample hold circuit 108, and A / D converter via the multiplexer 102. 112 and is converted into a digital signal. The radiographic image converted into the digital signal is temporarily stored in the image memory 80 of the cassette control unit 74 (step S10).

  Similarly, the address decoder 104 of the line scan driver 100 sequentially switches the switch SW1 according to the address signal supplied from the address signal generator 78, and the charge held in each pixel 90 connected to each gate line 92. A radiation image as information is read out through the signal line 94 and stored in the image memory 80 of the cassette control unit 74 through the multiplexer 102 and the A / D converter 112 (step S10).

  The radiographic image stored in the image memory 80 is transmitted to the control device 24 by wireless communication through the communication unit 72 and the antenna 70 together with the cassette ID information stored in the cassette ID memory 82. The control processing unit 124 of the control device 24 stores the radiographic image and cassette ID information received via the antenna 120 and the communication unit 122 in the image memory 138 and displays the radiographic image on the display unit 126 (step S11). .

  The doctor 26 visually confirms the display content of the display unit 126 and confirms that a radiographic image has been obtained. Then, the doctor 26 releases the subject 14 from the positioning state, and then releases the handle 28. Thereby, since the output of the detection signal from the touch sensor 52 is stopped, the radiation source control unit 66 stops the power supply from the battery 68 to each unit in the radiation output device 20. As a result, the radiation output apparatus 20 reaches a sleep state or a stop state. Further, when the doctor 26 presses (turns off) the switch 38, the power supply from the battery 76 to each part in the radiation detection device 22 is stopped, so that the radiation detection device 22 also enters the sleep state or the stop state.

  Then, the doctor 26 holds the radiation output device 20 between the holding portions 35 and 37 by fitting the connection terminal 39 and the connection terminal 43 and fitting the connection terminal 41 and the connection terminal 45 together. The radiation output device 20 and the radiation detection device 22 are integrated (see FIG. 2A).

[Effect of this embodiment]
As described above, according to the radiation imaging system 10 and the radiation imaging method according to the present embodiment, at least three radiation sources (seven radiation sources 18a to 18g in FIGS. 4A to 5B) accommodated in the radiation output device 20. ) Are divided into at least three groups (three groups 54 to 58 in FIGS. 5A and 5B).

  Then, as shown in FIG. 5A, the subject 14 is disposed between the radiation output device 20 and the radiation detection device 22 and is relatively opposed to the geometric center position of each radiation source (position of the radiation source 18d). In the case of positioning a large imaging region (for example, the chest of the subject 14), in this embodiment, among these groups, they belong to groups at both ends (groups 54 and 58) with respect to the geometric center position of each radiation source. The radiation dose output from the radiation source is the maximum dose, while the radiation dose output from the radiation source belonging to the group near the geometric center position (group 56) is a small dose. The dose of each radiation (radiation 16a to 16g) output from each radiation source is weighted in groups.

  On the other hand, as shown in FIG. 5B, the subject 14 is disposed between the radiation output device 20 and the radiation detection device 22, and a relatively small imaging region (for example, the subject) is disposed so as to face the geometric center position of each radiation source. In this embodiment, the radiation dose output from the radiation source belonging to the group (group 56) in the vicinity of the geometric center position of each radiation source is the maximum. On the other hand, it is output from each radiation source so that the radiation dose output from the radiation source belonging to the group (group 54, 58) other than the group near the geometric center position becomes a small dose. The dose of each radiation (radiation 16a to 16g) is weighted in groups.

  As described above, in the present embodiment, instead of simply setting the radiation irradiation range so as to cover the imaging region of the subject 14, each radiation source is divided into at least three groups and output from each radiation source. The dose of each radiation is weighted for each group. Therefore, even if a radiographic image of the subject 14 is taken with a short SID using a field electron emission type radiation source, the radiation irradiation range can be easily expanded, and an optimal dose for the subject 14 can be obtained. It becomes possible to irradiate (exposure dose) of radiation. Therefore, in the present embodiment, by irradiating the subject 14 with the optimal dose of radiation according to the subject 14, a radiographic image suitable for the interpretation diagnosis of the doctor 26 is obtained, and inadvertent exposure of the subject 14 is avoided. can do.

  In the example of FIG. 5A, the doses of the radiations 16a, 16b, 16f, and 16g output from the radiation sources 18a, 18b, 18f, and 18g belonging to the groups 54 and 58 at both ends with respect to the geometric center position are maximum. Since the radiation doses of the radiations 16c to 16e output from the radiation sources 18c to 18e belonging to the group 56 near the geometric center position are small doses, it is efficient to capture a radiation image on a relatively large imaging region. It can be done well. In the example of FIG. 5B, the radiation doses of the radiations 16c to 16e output from the radiation sources 18c to 18e belonging to the group 56 in the vicinity of the geometric center position become the maximum doses, and belong to the other groups 54 and 58. Since the doses of the radiations 16a, 16b, 16f, and 16g output from the radiation sources 18a, 18b, 18f, and 18g are small doses, it is possible to efficiently capture a radiation image for a relatively small imaging region. .

  Further, the database search unit 150 searches the database 134 for optimal dose data corresponding to the imaging region, thickness, and imaging technique of the subject 14, and grouping data corresponding to the imaging region, thickness, and imaging technique of the subject 14. Since the weighted data is searched and the searched optimum dose data, grouping data, weighted data, and order information are output to the imaging condition setting unit 152, the setting of the imaging conditions in the imaging condition setting unit 152 is accurately and efficiently performed. Can be done. Accordingly, the radiation output device 20 irradiates the imaging portions of the subject 14 with the radiations 16a to 16g from the radiation sources 18a to 18g according to the imaging conditions, so that a radiographic image is obtained with an optimal exposure dose to the imaging portion of the subject 14. Can be taken.

  Furthermore, the imaging condition setting unit 152 changes the contents of the optimum dose data, grouping data, and weighting data searched by the database search unit 150 according to the order information, the state of the subject 14 or the shooting technique of the subject 14, More accurate shooting conditions can be set according to the actual shooting technique of the subject 14.

  Furthermore, when there is a group to which two or more radiation sources belong, by further weighting the dose of the radiation output from each radiation source in the group, the radiation of the subject 14 at the optimum dose can be weighted. Irradiation can be performed with high accuracy.

  Furthermore, by providing the handle 28 at a location opposite to the output location of the radiation 16a to 16g in the radiation output device 20, the doctor 26 grasps the handle 28 with one hand and moves the radiation output device 20 over. While facing the subject 14 and the radiation detection device 22, it is possible to check the display content of the display unit 126, operate the operation unit 128 with the other hand, or operate the exposure switch 130 with the other hand. It becomes. Moreover, even when the radiation 16a to 16g is output while the doctor 26 is holding the handle 28, irradiation of the radiation 16a to 16g (exposure to the doctor 26) to the doctor 26 can be reliably avoided. .

  Further, by fitting the connection terminal 39 and the connection terminal 43 and fitting the connection terminal 41 and the connection terminal 45, the radiation output device 20 is held between the holding portions 35 and 37, and the radiation output device 20 and By bringing the radiation detection device 22 into an integrated state, the radiation output device 20 and the radiation detection device 22 can be easily transported. Furthermore, the connection terminal 39 and the connection terminal 43 are electrically connected, and the connection terminal 41 and the connection terminal 45 are electrically connected, so that the radiation output device 20 can be connected to the radiation output device 20 from the battery 76 of the radiation detection device 22. The battery 68 can also be charged.

  Furthermore, in the integrated state of the radiation output device 20 and the radiation detection device 22, the radiation source control unit 66 prohibits power supply from the battery 68 to each of the radiation sources 18a to 18g, whereby the radiation output device 20 and the radiation detection device. Thus, erroneous exposure of the radiations 16a to 16g during the transportation of 22 can be avoided. Moreover, in the integrated state of the radiation output device 20 and the radiation detection device 22, the radiation 16 a to 16 g output positions of the radiation output device 20 are directed to the side surface of the housing 30 of the radiation detection device 22, thereby Even if erroneous exposure occurs, exposure of the doctor 26 can be avoided reliably.

  Note that signals are transmitted and received wirelessly between the control device 24 and the radiation output device 20 and the radiation detection device 22. In this way, the radiation output device 20, the radiation detection device 22, and the control device 24 are connected wirelessly in the same link, and a cable (USB cable) for transmitting and receiving signals is not necessary. There is no risk of disturbing work. Therefore, the doctor 26 can perform his / her work efficiently. Further, since the cable is not required, the number of parts of the radiation imaging system 10 is reduced. In this embodiment, signals may be transmitted and received by optical wireless communication using infrared rays or the like instead of wireless communication.

  Furthermore, in this embodiment, it is also possible to transmit and receive signals between the control device 24, the radiation output device 20, and the radiation detection device 22 by wire. For example, if the control device 24 and the radiation output device 20 and the radiation detection device 22 are electrically connected via a USB cable (not shown), the battery 68 and the radiation of the radiation output device 20 from the power supply unit 140 of the control device 24. The battery 76 of the detection device 22 can be reliably charged. In addition, it is possible to reliably transmit an exposure control signal and imaging conditions from the control device 24 to the radiation output device 20 and the radiation detection device 22, and transmit a radiation image from the radiation detection device 22 to the control device 24. Therefore, in the wired connection, signal transmission / reception and charging of the batteries 68 and 76 can be performed reliably.

  In addition, when charging the batteries 68 and 76, it is sufficient that the batteries 68 and 76 can be charged by a charge amount corresponding to at least the number of photographed objects 14. Thereby, it is possible to reliably perform shooting for the number of shots during shooting.

  In this case, the batteries 68 and 76 may be charged in a time zone other than when radiographic images are captured. As a result, the batteries 68 and 76 are not charged at the time of imaging and at the time of transmission of the radiographic image after imaging, so that a charge signal (analog signal) is caused due to charging of the batteries 68 and 76 during imaging. It can be avoided that noise is superimposed on the radiographic image or that the noise is superimposed on the radiographic image during transmission of the radiographic image.

  Here, charging and noise will be described in more detail. A period (accumulation period) in which the radiations 16a to 16g transmitted through the subject 14 are converted into electric signals by the radiation detector 60 and then accumulated as charges in each pixel 90. ), A period during which the charge accumulated in each pixel 90 is read (reading period), and a period during which the read charge (analog signal) is converted into a digital signal by the A / D converter 112 It is only necessary that the batteries 68 and 76 can be charged in the time period excluding the period, the period obtained by combining the periods, or the period excluding the period including all the periods.

  In other words, these three periods are particularly affected by noise superimposed on the image signal (radiation image). In the accumulation period and the reading period, the influence of noise is large because the charge is very small, and in the conversion period to the digital signal, an analog signal having lower noise resistance than the digital signal is used before the A / D conversion. Furthermore, the noise superimposed on the analog signal is easily converted into a digital signal and appears in the image data as it is.

  The part of the accumulation period includes the time for irradiating the radiations 16a to 16g from the radiation sources 18a to 18g. In other words, the operation after the reading should be performed immediately after the accumulation is started, the irradiation is started at the earliest possible timing, the irradiation is stopped, and the time lag in each of these operations is minimized. Then, it is suitable for suppression of so-called dark current, and the quality of the obtained radiographic image can be further improved. The reading period is a period in which the TFT 98 is turned on and a signal flows to the A / D converter 112 via each amplifier 106 and the like. The reading period and the conversion period to the digital signal are on the time axis. At substantially the same time, the reading period (start of) actually occurs slightly earlier.

  Therefore, by prohibiting the charging of the batteries 68 and 76 at the time of imaging and at the time of transmission of the radiographic image after imaging, the radiation detector 60 can detect the radiation 16a to 16g with high quality.

  In addition, the amount of power supplied to the batteries 68 and 76 during the time zone other than the time of radiographic image capture may be predicted as follows, and by charging the batteries 68 and 76 with the predicted amount of power, Radiation images (for the required number of sheets) can be reliably taken.

  That is, the power consumption of the radiation output device 20 and the radiation detection device 22 used for imaging is calculated from the charging conditions of the batteries 68 and 76 and the current or previous imaging conditions (number of images to be taken, mAs value, etc.). Based on the power consumption amount, each power amount of the radiation output device 20 and the radiation detection device 22 that will be consumed in the current imaging, or the radiation output device 20 and radiation detection that would have been consumed in the previous imaging. Each power amount of the device 22 is predicted.

  The batteries 68 and 76 are charged by the amount of power that will be consumed in the current shooting, or the batteries 68 and 76 are charged by the amount of power that will be consumed in the previous shooting. This makes it possible to reliably perform the current shooting.

  In addition, when charging a plurality of images, when charging the batteries 68 and 76 during shooting, shooting has already been completed among the charging conditions and the current shooting conditions (number of shots, mAs value, etc.). The power consumption of the radiation output device 20 and the radiation detection device 22 is calculated from the imaging conditions of the imaging to be performed in the future, excluding the minutes, and based on the calculated power consumption, the energy consumed in the imaging to be performed in the future is calculated. Predict.

  Even in this case, by charging the batteries 68 and 76 with the amount of power that will be consumed in the shooting to be performed in the future, it is possible to reliably perform shooting for the remaining number of sheets.

  Furthermore, in the present embodiment, signal transmission / reception by wireless communication and / or wired communication has been described. However, when the subject 14 is in contact with the radiation output device 20 and the radiation detection device 22 and the SID is set shorter. Signals may be transmitted and received between the radiation output device 20 and the radiation detection device 22 by human body communication via the subject 14. In addition, when the doctor 26 is in contact with both the radiation output device 20 and the control device 24, transmission / reception of signals between the radiation output device 20 and the control device 24 is performed by human body communication via the doctor 26. You may go.

  In the present embodiment, the control signal generation unit 154 synchronizes the output of the radiations 16a to 16g from the radiation sources 18a to 18g and the conversion from the radiations 16a to 16g to the radiation image in the radiation detector 60. The communication unit 122 transmits the exposure control signal to the radiation output device 20 and the radiation detection device 22. Thereby, the time synchronization with each radiation source 18a-18g and the radiation detector 60 at the time of imaging | photography of a radiographic image can be taken reliably.

  Furthermore, although the radiation detection apparatus 22 has the shape of a housing | casing, about the location of the radiation detector 60, it is good also as a sheet-like shape which has flexibility. Since the sheet can be wound into a roll, the radiation detector 22 can be made compact.

  Furthermore, the present embodiment can also be applied to a case where a radiation image is acquired using an optical readout radiation detector. In this light readout type radiation detector, when radiation enters each solid detection element, an electrostatic latent image corresponding to the dose is accumulated and recorded in the solid detection element. When reading the electrostatic latent image, the radiation detector is irradiated with reading light, and the value of the generated current is acquired as a radiation image. Note that the radiation detector can erase and reuse the radiation image, which is the remaining electrostatic latent image, by irradiating the radiation detector with erasing light (see Japanese Patent Application Laid-Open No. 2000-105297).

  Furthermore, in the radiation imaging system 10, in order to prevent the possibility of blood and other germs adhering, for example, the radiation output device 20 and the radiation detection device 22 have a waterproof and sealing structure, and if necessary, By sterilizing and cleaning, one radiography system 10 can be used repeatedly.

  In addition, the present embodiment is not limited to the above-described medical radiographic image capturing, and can be applied to, for example, radiographic image capturing in various nondestructive inspections.

[Modification of this embodiment]
Next, modified examples (first to seventh modified examples) of the present embodiment will be described with reference to FIGS. 12A to 18B.

  In these modified examples, the same components as those in FIGS. 1 to 11 are described with the same reference numerals, and detailed description thereof is omitted.

[First Modification]
The first modified example illustrates a case where one radiation source 18a to 18c belongs to three groups 54 to 58, as shown in FIGS. 12A and 12B. In this case, the geometrical center position of the three radiation sources 18a to 18c is the position of the central radiation source 18b. Therefore, the central group 56 is a group including the geometrical center position, and the other groups. 54 and 58 form groups at both ends with respect to the geometric center position.

  In the first modification, in the chest imaging shown in FIG. 12A, the radiation doses of the radiations 16a and 16c output from the radiation sources 18a and 18c to which the groups 54 and 58 belong are set to the maximum doses, and Dose weighting is performed so that the dose of the radiation 16b output from the radiation source 18b to which it belongs is set to a small dose. On the other hand, in the hand imaging shown in FIG. 12B, the radiation 16b output from the radiation source 18b belonging to the group 56 is set to the maximum dose, and is output from the radiation sources 18a and 18c belonging to the groups 54 and 58. The doses are weighted so that the doses of the radiations 16a and 16c are small.

  Thus, even in the case of the first modified example in which only one radiation source 18a to 18c is assigned to the three groups 54 to 58, each effect of the present embodiment can be obtained by performing the above-described dose weighting. Of course, is obtained.

[Second Modification]
As shown in FIGS. 13A and 13B, the second modification illustrates a case where one radiation source 18a to 18d belongs to four groups 156 to 162, respectively. In this case, the geometric center position of the four radiation sources 18a to 18d is an intermediate position between the two radiation sources 18b and 18c. Therefore, the groups 158 and 160 to which the radiation sources 18b and 18c belong respectively are groups near the geometric center position not including the geometric center position, and the other groups 156 and 162 are the geometric groups. It becomes a group of both ends with respect to the center position.

  In the second modification, in the chest imaging shown in FIG. 13A, the radiation doses of the radiations 16a and 16d output from the radiation sources 18a and 18d to which the groups 156 and 162 belong are set as the maximum doses, and the group 158 and The doses are weighted so that the doses of the radiations 16b and 16c output from the radiation sources 18b and 18c to which 160 belongs are small. On the other hand, in the hand imaging shown in FIG. 13B, the radiation doses of the radiations 16b and 16c output from the radiation sources 18b and 18c to which the groups 158 and 160 belong is set to the maximum dose, and the radiation sources to which the groups 156 and 162 belong. Dose weighting is performed so that the doses of the radiations 16a and 16d output from 18a and 18d are small.

  Thus, even in the case of the second modification in which one radiation source 18a to 18d is assigned to each of the four groups 156 to 162, each dose of the present embodiment can be obtained by performing the above-described dose weighting. Of course, the effect is obtained.

  As described above, in the present embodiment and the first modified example, the dose weighting for the three groups 54 to 58 has been described as an example, but an odd number (3, 5, 7,. However, if the concept of weighting of doses in the present embodiment and the first modification is applied, the effects of the present embodiment and the first modification can be easily obtained. In the second modification, the dose weighting for the four groups 156 to 162 has been described as an example. However, even if the number of groups is an even number (4, 6, 8,...) Of 4 or more, By applying the concept of dose weighting in the second modification, the effects of the second modification (and this embodiment) can be easily obtained.

[Third Modification]
As shown in FIGS. 14A and 14B, in the third modification, a recess 164 is formed at a location opposite to the output location of the radiations 16 a to 16 g in the housing 46 of the radiation output device 20, and is stored in the recess 164. An expression handle 166 is provided. In this case, the touch sensor 52 is also incorporated in the handle 166.

  Here, in a state where the doctor 26 does not have the radiation output device 20, the handle 166 is stored in the recess 164 as shown in FIG. 14A. On the other hand, when the doctor 26 rotates the handle 166 around the proximal end side of the handle 166, the handle 166 is pulled out from the recess 164, so that the doctor 26 can hold the handle 166. (See FIG. 14B). Even in this case, the same effects as those obtained by the handle 28 and the touch sensor 52 described above can be obtained. Further, when the handle 166 is stored, the electrode of the touch sensor 52 and the hand of the doctor 26 do not come into contact with each other. Therefore, the radiation 16a to 16g is erroneously transmitted from the radiation sources 18a to 18g with the radiation output device 20 activated. The output can be avoided.

[Fourth Modification]
As shown in FIGS. 15A and 15B, in the fourth modification, the casing 46 of the radiation output apparatus 20 is formed in a rectangular shape having substantially the same plane area as that of the radiation detection apparatus 22, and the casing 46 includes, for example, Nine radiation sources 18a to 18i are incorporated. Note that the number of radiation sources incorporated in the housing 46 is not limited to nine, and may be at least three.

  In this case, the radiation sources 18a to 18i are two-dimensionally arranged with respect to the irradiation surface 32, and are one-dimensionally arranged with respect to the irradiation surface 32 of the above-described radiation sources 18a to 18g (FIGS. 1, 5A, 5B and FIG. 12A to 13B).

  A handle 28 is provided on the upper surface of the housing 46, and openings formed at four corners of the upper surface of the housing 30 of the radiation detection device 22 are formed on one side surface and the other side surface of the housing 46. A lock release button 167 for releasing the engagement between the H.163 and the hook 165 provided on the bottom surface of the housing 46 is provided.

  Further, on the outside of the shootable area 36 in the housing 30, connection terminals 173 and 175 as jacks that can be fitted to pin-shaped connection terminals 169 and 171 provided on the bottom surface of the housing 46 are also arranged. Yes.

  Therefore, in the state shown in FIG. 15A, the hooks 165 and the openings 163 are engaged with each other, and the connection terminals 169 and 171 and the connection terminals 173 and 175 are engaged with each other. The device 22 is integrated. Accordingly, the doctor 26 easily holds the radiation output device 20 and the radiation detection device 22 in an integrated state while holding the handle 28 or inserting the hand between the handle 28 and the upper surface of the housing 46. Can be transported. In this integrated state, the battery 76 (see FIG. 6) of the radiation detection apparatus 22 can also charge the battery 68 via the connection terminals 169, 171, 173, and 175.

  On the other hand, the doctor 26 presses each lock release button 167 to release the engagement state between each hook 165 and each opening 163 and grips the handle 28 or between the handle 28 and the upper surface of the housing 46. When the radiation output device 20 is moved away from the radiation detection device 22 with the hand inserted into the device, the fitting state between the connection terminals 169 and 171 and the connection terminals 173 and 175 is also released. The integrated state of 20 and the radiation detector 22 is released. As a result, the charging from the battery 76 to the battery 68 is also stopped, and the radiation from each of the radiation sources 18a to 18i can be output.

  In the fourth modified example, the radiation sources 18a to 18i are two-dimensionally arranged, so that radiographic images can be efficiently captured for any imaging region. In addition, the shape of the housing 46 of the radiation output device 20 is substantially the same rectangular shape as that of the housing 30 of the radiation detection device 22, thereby allowing portability when the radiation output device 20 and the radiation detection device 22 are integrated. In addition, the radiation output device 20 can be easily positioned with respect to the radiation detection device 22.

  Furthermore, in the fourth modification, it is needless to say that the effects of the present embodiment and the first to third modifications can be easily obtained.

[Fifth Modification]
In the above description, an example in which the photoelectric conversion layer 96, which is one of the components of the radiation detector 60, is formed of a substance such as a-Si is shown. However, in the present embodiment, an organic photoelectric conversion material is included. It is also possible to use a photoelectric conversion layer.

  Here, as a fifth modification, an example of a radiation detector using a photoelectric conversion layer containing an organic photoelectric conversion material will be described with reference to FIGS. 16 and 17.

  As shown in FIG. 16, the radiation detector 170 includes a signal output unit 174, a sensor unit 176, and a scintillator 178 sequentially stacked on an insulating substrate 172, and the pixel unit is formed by the signal output unit 174 and the sensor unit 176. Is configured. A plurality of pixel portions are arranged on the substrate 172, and the signal output portion 174 and the sensor portion 176 in each pixel portion are configured to overlap each other.

  That is, the radiation detector 170 shown in FIGS. 16 and 17 has a back surface reading method (PSS method, PSS) in which a scintillator 178, a sensor unit 176, and a signal output unit 174 are arranged in order along the irradiation direction of the radiation 16a to 16g. : Penetration Side Sampling) radiation detector. Note that a radiation detector of the surface reading method (ISS method, ISS: Irradiation Side Sampling) in which the signal output unit 174, the sensor unit 176, and the scintillator 178 are sequentially arranged along the irradiation direction of the radiation 16a to 16g will be described later. .

  The scintillator 178 is formed on the sensor unit 176 via the transparent insulating film 180, and the radiations 16a to 16g (FIGS. 1, 4B, and 5A to 6) entering from above (opposite the substrate 172). And FIG. 12A to FIG. 14B) are converted into light, and a phosphor that emits light is formed into a film. By providing such a scintillator 178, the radiation 16a to 16g transmitted through the subject 14 can be absorbed and emitted.

  The wavelength range of light emitted by the scintillator 178 is preferably the visible light range (wavelength 360 nm to 830 nm), and in order to enable monochrome imaging by the radiation detector 170, the wavelength range of green is included. Is more preferable.

Specifically, the phosphor used in the scintillator 178 preferably contains cesium iodide (CsI) when imaging using X-rays as the radiation 16a to 16g, and the emission spectrum upon X-ray irradiation is 420 nm to It is particularly preferable to use CsI (Tl) (cesium iodide with thallium added) at 700 nm. Note that the emission peak wavelength of CsI (Tl) in the visible light region is 565 nm. The phosphor is not limited to CsI (Tl), and materials such as CsI (Na) (sodium-activated cesium iodide) and GOS (Gd ₂ O ₂ S: Tb) may be used.

  The sensor unit 176 includes an upper electrode 182, a lower electrode 184, and a photoelectric conversion film 186 disposed between the upper and lower electrodes 182 and 184. The photoelectric conversion film 186 absorbs light emitted from the scintillator 178 and is charged. It is comprised with the organic photoelectric conversion material which generate | occur | produces.

Since the upper electrode 182 needs to cause the light generated by the scintillator 178 to be incident on the photoelectric conversion film 186, it is preferable that the upper electrode 182 be made of a conductive material that is transparent at least with respect to the emission wavelength of the scintillator 178. It is preferable to use a transparent conductive oxide (TCO) that has a high transmittance for visible light and a small resistance value. Note that a metal thin film such as Au can be used as the upper electrode 182; however, the TCO is preferable because the resistance value is likely to increase when the transmittance of 90% or more is obtained. For example, ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), AZO (Aluminum doped Zinc Oxide), FTO (Fluorine doped Tin Oxide), SnO ₂ , TiO ₂ , ZnO _{2 and the} like can be used preferably. ITO is most preferable from the viewpoints of stability, low resistance, and transparency. Note that the upper electrode 182 may have a single configuration common to all pixel portions, or may be divided for each pixel portion.

  The photoelectric conversion film 186 may be formed of a material that absorbs visible light and generates charges, and the above-described amorphous silicon (a-Si), organic photoelectric conversion material (OPC), or the like can be used.

  In the case where the photoelectric conversion film 186 is formed of amorphous silicon, visible light emitted from the scintillator 178 can be configured to be absorbed over a wide wavelength range. However, the formation of the photoelectric conversion film 186 made of amorphous silicon requires vapor deposition. When the substrate 172 is made of a synthetic resin, the heat resistance of the substrate 172 needs to be considered.

  On the other hand, when the photoelectric conversion film 186 is composed of a material containing an organic photoelectric conversion material, it has a sharp absorption spectrum in the visible range, and electromagnetic waves other than light emitted by the scintillator 178 are hardly absorbed by the photoelectric conversion film 186. Noise generated when the radiations 16a to 16g such as X-rays are absorbed by the photoelectric conversion film 186 can be effectively suppressed.

  In addition, the photoelectric conversion film 186 made of an organic photoelectric conversion material can be formed by depositing an organic photoelectric conversion material on an object to be formed using a droplet discharge head such as an ink jet head. Heat resistance to the body is not required.

  The organic photoelectric conversion material constituting the photoelectric conversion film 186 preferably has an absorption peak wavelength that is closer to the emission peak wavelength of the scintillator 178 in order to absorb light emitted by the scintillator 178 most efficiently. Ideally, the absorption peak wavelength of the organic photoelectric conversion material matches the emission peak wavelength of the scintillator 178. However, if the difference between the two is small, the light emitted from the scintillator 178 can be sufficiently absorbed. . Specifically, the difference between the absorption peak wavelength of the organic photoelectric conversion material and the emission peak wavelength of the scintillator 178 with respect to the radiations 16a to 16g is preferably within 10 nm, and more preferably within 5 nm.

  Examples of organic photoelectric conversion materials that can satisfy such conditions include quinacridone organic compounds and phthalocyanine organic compounds. For example, since the absorption peak wavelength of quinacridone in the visible region is 560 nm, if quinacridone is used as the organic photoelectric conversion material and CsI (Tl) is used as the material of the scintillator 178, the difference in peak wavelength may be within 5 nm. Thus, the amount of charge generated in the photoelectric conversion film 186 can be substantially maximized.

  Next, the photoelectric conversion film 186 applicable to the radiation detector 170 described above will be specifically described.

  The electromagnetic wave absorption / photoelectric conversion site in the radiation detector 170 can be composed of an organic layer including a pair of electrodes 182 and 184 and a photoelectric conversion film 186 sandwiched between the electrodes 182 and 184. More specifically, this organic layer is a part that absorbs electromagnetic waves, a photoelectric conversion part, an electron transport part, a hole transport part, an electron blocking part, a hole blocking part, a crystallization preventing part, an electrode, and an interlayer contact. It can be formed by stacking or mixing improved parts.

  The organic layer preferably contains an organic p-type compound or an organic n-type compound.

  The organic p-type semiconductor (compound) is a donor organic semiconductor (compound) mainly represented by a hole-transporting organic compound and refers to an organic compound having a property of easily donating electrons. More specifically, an organic compound having a smaller ionization potential when two organic materials are used in contact with each other. Therefore, any organic compound can be used as the donor organic compound as long as it is an electron-donating organic compound.

  An organic n-type semiconductor (compound) is an acceptor organic semiconductor (compound) mainly represented by an electron-transporting organic compound and refers to an organic compound having a property of easily accepting electrons. More specifically, the organic compound having the higher electron affinity when two organic compounds are used in contact with each other. Accordingly, as the acceptor organic compound, any organic compound can be used as long as it is an electron-accepting organic compound.

  Since the materials applicable as the organic p-type semiconductor and the organic n-type semiconductor and the configuration of the photoelectric conversion film 186 are described in detail in Japanese Patent Application Laid-Open No. 2009-32854, description thereof is omitted.

  The sensor unit 176 constituting each pixel unit may include at least the lower electrode 184, the photoelectric conversion film 186, and the upper electrode 182, but in order to suppress an increase in dark current, the electron blocking film 188 and the hole blocking film are included. It is preferable to provide at least one of 190, and it is more preferable to provide both.

  The electron blocking film 188 can be provided between the lower electrode 184 and the photoelectric conversion film 186, and when a bias voltage is applied between the lower electrode 184 and the upper electrode 182, the lower electrode 184 to the photoelectric conversion film 186. It is possible to prevent the dark current from being increased due to the injection of electrons.

  For the electron blocking film 188, an electron donating organic material can be used.

  The material actually used for the electron blocking film 188 may be selected according to the material of the adjacent electrode, the material of the adjacent photoelectric conversion film 186, and the like, and 1.3 eV or more from the work function (Wf) of the material of the adjacent electrode. A material having a large electron affinity (Ea) and an Ip equivalent to or smaller than the ionization potential (Ip) of the material of the adjacent photoelectric conversion film 186 is preferable. Since the material applicable as the electron donating organic material is described in detail in Japanese Patent Application Laid-Open No. 2009-32854, description thereof is omitted.

  The thickness of the electron blocking film 188 is preferably 10 nm or more and 200 nm or less, more preferably 30 nm or more and 150 nm or less, and particularly preferably, in order to reliably exhibit the dark current suppressing effect and prevent a decrease in the photoelectric conversion efficiency of the sensor unit 176. It is 50 nm or more and 100 nm or less.

  The hole blocking film 190 can be provided between the photoelectric conversion film 186 and the upper electrode 182, and when a bias voltage is applied between the lower electrode 184 and the upper electrode 182, the photoelectric conversion film is formed from the upper electrode 182. It can be suppressed that holes are injected into 186 and the dark current increases.

  An electron-accepting organic material can be used for the hole blocking film 190.

  Further, the thickness of the hole blocking film 190 is preferably 10 nm or more and 200 nm or less, more preferably 30 nm or more and 150 nm or less, in order to reliably exhibit the dark current suppressing effect and prevent a decrease in the photoelectric conversion efficiency of the sensor unit 176. Especially preferably, they are 50 nm or more and 100 nm or less.

  The material actually used for the hole blocking film 190 may be selected according to the material of the adjacent electrode, the material of the adjacent photoelectric conversion film 186, etc., and 1.3 eV from the work function (Wf) of the material of the adjacent electrode. As described above, it is preferable that the ionization potential (Ip) is large and the Ea is equal to or larger than the electron affinity (Ea) of the material of the adjacent photoelectric conversion film 186. Since the material applicable as the electron-accepting organic material is described in detail in Japanese Patent Application Laid-Open No. 2009-32854, description thereof is omitted.

  In the case where the bias voltage is set so that holes move to the upper electrode 182 and electrons move to the lower electrode 184 among the charges generated in the photoelectric conversion film 186, the electron blocking film 188 and the hole blocking are set. The position of the film 190 may be reversed. Further, it is not necessary to provide both the electron blocking film 188 and the hole blocking film 190, and if either one is provided, a certain dark current suppressing effect can be obtained.

  A signal output unit 174 is formed on the surface of the substrate 172 below the lower electrode 184 of each pixel unit. FIG. 17 schematically shows the configuration of the signal output unit 174 (see FIG. 16).

  The signal output unit 174 corresponds to the lower electrode 184, a capacitor 192 that accumulates the charge transferred to the lower electrode 184, and a field effect thin film transistor (Thin) that converts the charge accumulated in the capacitor 192 into an electric signal and outputs it. A film transistor (hereinafter sometimes simply referred to as a thin film transistor or a TFT) 194 is formed. The region where the capacitor 192 and the thin film transistor 194 are formed has a portion that overlaps with the lower electrode 184 in a plan view. With such a structure, the signal output unit 174 and the sensor unit 176 in each pixel unit are connected to each other. There will be overlap in the thickness direction. In order to minimize the plane area of the radiation detector 170 (pixel portion), it is desirable that the region where the capacitor 192 and the thin film transistor 194 are formed is completely covered with the lower electrode 184.

  The capacitor 192 is electrically connected to the corresponding lower electrode 184 through a conductive material wiring formed through an insulating film 196 provided between the substrate 172 and the lower electrode 184. Thereby, the electric charge collected by the lower electrode 184 can be moved to the capacitor 192.

  As shown in FIG. 17, the thin film transistor 194 includes a gate electrode 198, a gate insulating film 200, and an active layer (channel layer) 202, and a source electrode 204 and a drain electrode 206 are formed on the active layer 202. It is formed with a gap. Further, in the radiation detector 170, the active layer 202 can be formed of any one of amorphous silicon, amorphous oxide, organic semiconductor material, carbon nanotube, and the like, but the active layer 202 can be formed. The material is not limited to these.

As the amorphous oxide constituting the active layer 202, an oxide containing at least one of In, Ga, and Zn (for example, In—O-based) is preferable, and at least two of In, Ga, and Zn are used. An oxide containing In (eg, In—Zn—O, In—Ga—O, or Ga—Zn—O) is more preferable, and an oxide containing In, Ga, and Zn is particularly preferable. As the In—Ga—Zn—O-based amorphous oxide, an amorphous oxide whose composition in a crystalline state is represented by InGaO ₃ (ZnO) _m (m is a natural number less than 6) is preferable, and InGaZnO is particularly preferable. ₄ is more preferable. Note that the amorphous oxide capable of forming the active layer 202 is not limited thereto.

  Examples of the organic semiconductor material capable of forming the active layer 202 include, but are not limited to, phthalocyanine compounds, pentacene, vanadyl phthalocyanine, and the like. In addition, about the structure of a phthalocyanine compound, since it demonstrates in detail by Unexamined-Japanese-Patent No. 2009-212389, description is abbreviate | omitted.

  If the active layer 202 of the thin film transistor 194 is formed of any one of an amorphous oxide, an organic semiconductor material, a carbon nanotube, etc., the radiation 16a to 16g such as X-rays is not absorbed or even if it is absorbed. Since the amount remains small, generation of noise in the signal output unit 174 can be effectively suppressed.

  In the case where the active layer 202 is formed using carbon nanotubes, the switching speed of the thin film transistor 194 can be increased, and the degree of light absorption in the visible light region of the thin film transistor 194 can be reduced. Note that in the case where the active layer 202 is formed of carbon nanotubes, the performance of the thin film transistor 194 is remarkably deteriorated only by mixing a very small amount of metallic impurities into the active layer 202. The active layer 202 needs to be separated and extracted for use.

  Moreover, since the film | membrane formed with the organic photoelectric conversion material and the film | membrane formed with the organic-semiconductor material have sufficient flexibility, the photoelectric conversion film 186 formed with the organic photoelectric conversion material, and the active layer 202 are used. Is combined with a thin film transistor 194 formed of an organic semiconductor material, it is not always necessary to increase the rigidity of the TFT substrate 208 to which the weight of the body of the subject 14 is applied as a load.

  Here, any of the amorphous oxide forming the active layer 202 of the thin film transistor 194 and the organic photoelectric conversion material forming the photoelectric conversion film 186 can be formed at a low temperature. Therefore, the substrate 172 is not limited to a substrate having high heat resistance such as a semiconductor substrate, a quartz substrate, and a glass substrate, and a flexible substrate such as plastic, aramid, or bionanofiber can also be used. Specifically, flexible materials such as polyesters such as polyethylene terephthalate, polybutylene phthalate, polyethylene naphthalate, polystyrene, polycarbonate, polyethersulfone, polyarylate, polyimide, polycycloolefin, norbornene resin, poly (chlorotrifluoroethylene), etc. A conductive substrate can be used. If such a plastic flexible substrate is used, it is possible to reduce the weight, which is advantageous for carrying around, for example.

  In addition, the substrate 172 is provided with an insulating layer for ensuring insulation, a gas barrier layer for preventing permeation of moisture and oxygen, an undercoat layer for improving flatness or adhesion to electrodes, and the like. May be.

  Since aramid can be applied at a high temperature process of 200 ° C. or more, the transparent electrode material can be cured at a high temperature to reduce the resistance, and can also be used for automatic mounting of a driver IC including a solder reflow process. Moreover, since aramid has a thermal expansion coefficient close to that of ITO (Indium Tin Oxide) or a glass substrate, warping after manufacturing is small and it is difficult to crack. In addition, aramid can form a substrate thinner than a glass substrate or the like. Note that the substrate 172 may be formed by stacking an ultrathin glass substrate and aramid.

  The bionanofiber is a composite of a cellulose microfibril bundle (bacterial cellulose) produced by bacteria (acetobacterium Xylinum) and a transparent resin. The cellulose microfibril bundle has a width of 50 nm and a size of 1/10 of the visible light wavelength, and has high strength, high elasticity, and low thermal expansion. By impregnating and curing a transparent resin such as acrylic resin and epoxy resin in bacterial cellulose, a bio-nanofiber having a light transmittance of about 90% at a wavelength of 500 nm can be obtained while containing 60% to 70% of the fiber. Bionanofiber has a low coefficient of thermal expansion (3-7 ppm) comparable to silicon crystals, is as strong as steel (460 MPa), has high elasticity (30 GPa), and is flexible, compared to glass substrates, etc. Thus, a thin substrate 172 can be formed.

  In the radiation detector 170, the photoelectric conversion film 186 is made of an organic photoelectric conversion material, and the radiations 16a to 16g are hardly absorbed by the photoelectric conversion film 186. For this reason, the above-described PSS radiation detector 170 has a small amount of absorption of the radiations 16a to 16g by the photoelectric conversion film 186 even when the radiations 16a to 16g are transmitted through the TFT substrate 208, and thus the sensitivity to the radiations 16a to 16g. Can be suppressed. In the PSS method, the radiations 16a to 16g pass through the TFT substrate 208 and reach the scintillator 178. Thus, when the photoelectric conversion film 186 of the TFT substrate 208 is formed of an organic photoelectric conversion material, the photoelectric conversion film 186 Is hardly absorbed, and attenuation of the radiations 16a to 16g can be suppressed to a low level, which is suitable for the PSS system.

  Further, the amorphous oxide constituting the active layer 202 of the thin film transistor 194 and the organic photoelectric conversion material constituting the photoelectric conversion film 186 can be formed at a low temperature. For this reason, the board | substrate 172 can be formed with a plastic resin, aramid, and bionanofiber with little absorption of the radiation 16a-16g. Since the substrate 172 formed in this manner has a small amount of absorption of the radiations 16a to 16g, even when the radiations 16a to 16g are transmitted through the TFT substrate 208 by the PSS method, it is possible to suppress a decrease in sensitivity to the radiations 16a to 16g. it can.

  In the fifth modification, the radiation detector 170 may be configured as follows.

  (1) The sensor unit 176 may be configured including the photoelectric conversion film 186 of an organic photoelectric conversion material, and the signal output unit 174 may be configured using a CMOS sensor. In this case, since only the sensor unit 176 is made of an organic material, the signal output unit 174 including the CMOS sensor may not have flexibility. In addition, since the sensor part 176 comprised including an organic photoelectric conversion material and a CMOS sensor are described in Unexamined-Japanese-Patent No. 2009-212377, the detailed description is abbreviate | omitted.

(2) The sensor unit 176 is configured including the photoelectric conversion film 186 made of an organic photoelectric conversion material, and a flexible signal output unit 174 is realized by a CMOS circuit including a thin film transistor (TFT) 194 made of an organic material. Also good. In this case, pentacene may be adopted as the material of the p-type organic semiconductor used in the CMOS circuit, and copper fluoride phthalocyanine (F ₁₆ CuPc) may be adopted as the material of the n-type organic semiconductor. As a result, a flexible TFT substrate 208 that can have a smaller bending radius can be realized. In addition, by configuring the TFT substrate 208 in this way, the gate insulating film 200 can be significantly thinned, and the driving voltage can be lowered. Furthermore, the gate insulating film 200, the semiconductor, and each electrode can be manufactured at room temperature or 100 ° C. or lower. Furthermore, a CMOS circuit can be directly formed over the flexible substrate 172. In addition, the thin film transistor 194 made of an organic material can be miniaturized by a manufacturing process in accordance with a scaling law. Note that the substrate 172 can be realized by applying a polyimide precursor onto a thin polyimide substrate by a spin coating method and heating the substrate, so that the polyimide precursor is changed to polyimide, so that a flat substrate without unevenness can be realized.

  (3) Applying a self-alignment arrangement technique (Fluidic Self-Assembly method) in which a plurality of micron-order device blocks are arranged at specified positions on the substrate, a sensor unit 176 and a signal output unit 174 made of crystalline Si are You may arrange | position on the board | substrate 172 which consists of a board | substrate. In this case, the sensor unit 176 and the signal output unit 174 as micro device blocks of micron order are fabricated in advance on another substrate and then separated from the substrate, and the sensor unit 176 and the signal output unit 174 are used as a target substrate in a liquid. It is distributed on the substrate 172 and statistically arranged. The substrate 172 is processed in advance to be adapted to the device block, and the device block can be selectively disposed on the substrate 172. Therefore, an optimal device block (sensor unit 176 and signal output unit 174) made of an optimal material can be integrated on an optimal substrate (substrate 172), and the sensor is mounted on a non-crystal substrate 172 (resin substrate). The unit 176 and the signal output unit 174 can be integrated.

[Sixth Modification]
Next, as a sixth modification, an example of an ISS radiation detector 300 including a CsI (Tl) scintillator 500 will be described with reference to FIGS. 18A and 18B.

  The radiation detector 300 is substantially the same as the TFT substrate 208 including the signal output unit 174 and the sensor unit 176 with respect to the irradiation surface 32 irradiated with the radiations 16a to 16g (along the irradiation direction of the radiations 16a to 16g). It is an ISS radiation detector in which a radiation detection unit 502 having a function and a CsI (Tl) scintillator 500 are arranged in order.

  The scintillator 500 emits light more strongly on the irradiation surface 32 side on which the radiations 16a to 16g are incident. In the ISS system, the light emission position in the scintillator 500 is close to the radiation detection unit 502. Therefore, the ISS method has a higher resolution of a radiographic image obtained by imaging, and the amount of visible light received by the radiation detection unit 502 is larger than that of the PSS method. Therefore, the sensitivity of the radiation detector 300 (radiation detection device 22) can be improved in the ISS method than in the PSS method.

  FIG. 18B illustrates, as an example, a case where a scintillator 500 including a columnar crystal region is formed by evaporating a material containing CsI on a deposition substrate 504.

  Specifically, in the scintillator 500 of FIG. 18B, a columnar crystal region composed of columnar crystals 500a is formed on the irradiation surface 32 side (radiation detection unit 502 side) on which the radiations 16a to 16g are incident, and is opposite to the irradiation surface 32 side. A non-columnar crystal region composed of a non-columnar crystal 500b is formed on the side. Note that the vapor deposition substrate 504 is preferably made of a material having high heat resistance. For example, aluminum (Al) is preferable from the viewpoint of low cost. In the scintillator 500, the average diameter of the columnar crystals 500a is approximately uniform along the longitudinal direction of the columnar crystals 500a.

  As described above, the scintillator 500 has a structure formed of a columnar crystal region (columnar crystal 500a) and a non-columnar crystal region (noncolumnar crystal 500b), and a columnar crystal 500a that can emit light with high efficiency. The crystal region is disposed on the radiation detection unit 502 side. Therefore, visible light generated by the scintillator 500 travels through the columnar crystal 500 a and is emitted to the radiation detection unit 502. As a result, diffusion of visible light emitted to the radiation detection unit 502 side is suppressed, and blurring of the radiation image detected by the radiation detection device 22 is suppressed. Further, the visible light reaching the deep part (non-columnar crystal region) of the scintillator 500 is also reflected by the non-columnar crystal 500b toward the radiation detection unit 502, so that the amount of visible light incident on the radiation detection unit 502 (in the scintillator 500) (Detection efficiency of emitted visible light) can also be improved.

  Note that if the thickness of the columnar crystal region located on the irradiation surface 32 side of the scintillator 500 is t1, and the thickness of the non-columnar crystal region located on the vapor deposition substrate 504 side of the scintillator 500 is t2, the interval between t1 and t2 , 0.01 ≦ (t2 / t1) ≦ 0.25 is preferably satisfied.

  Thus, when the thickness t1 of the columnar crystal region and the thickness t2 of the non-columnar crystal region satisfy the above relationship, a region (columnar crystal region) that has high luminous efficiency and prevents the diffusion of visible light, and visible light The ratio along the thickness direction of the scintillator 500 to the region that reflects the light (non-columnar crystal region) is a suitable range, the light emission efficiency of the scintillator 500, the detection efficiency of visible light emitted by the scintillator 500, and the radiation image Improve the resolution.

  In addition, if the thickness t2 of the non-columnar crystal region is too thick, a region with low light emission efficiency increases and the sensitivity of the radiation detection device 22 is decreased. Therefore, (t2 / t1) is 0.02 or more and 0.1 or less. A range is more preferable.

  In the above description, the scintillator 500 having a structure in which a columnar crystal region and a non-columnar crystal region are continuously formed has been described. For example, instead of the noncolumnar crystal region, a light reflection made of Al or the like is used. A layer may be provided so that only the columnar crystal region is formed, or another configuration may be used.

  The radiation detection unit 502 detects visible light emitted from the light emission side (columnar crystal 500a) of the scintillator 500, and in the side view of FIG. 18A, the irradiation surface along the irradiation direction of the radiations 16a to 16g. 32, an insulating substrate 508, a TFT layer 510, and a photoelectric conversion unit 512 are sequentially stacked. A planarization layer 514 is formed on the bottom surface of the TFT layer 510 so as to cover the photoelectric conversion portion 512.

  The radiation detection unit 502 includes a pixel unit 520 including a photoelectric conversion unit 512 including a photodiode (PD), a storage capacitor 516, and a thin film transistor (TFT) 518 on an insulating substrate 508 in a plan view. A plurality of TFT active matrix substrates (hereinafter also referred to as TFT substrates) are formed in a matrix.

  Further, the photoelectric conversion unit 512 is configured by disposing a photoelectric conversion film 512c between a lower electrode 512a on the scintillator 500 side and an upper electrode 512b on the TFT layer 510 side.

  Furthermore, in the TFT 518 of the TFT layer 510, a gate electrode, a gate insulating film, and an active layer (channel layer) are stacked, and a source electrode and a drain electrode are formed on the active layer at a predetermined interval. .

  In addition, a planarization layer 514 for flattening the radiation detection unit 502 is formed on the opposite side (scintillator 500 side) of the radiation 16a to 16g in the radiation detection unit 502 as a TFT substrate. .

  Here, when the radiation detector 300 of the sixth modification is compared with the radiation detector 170 of the fifth modification, each component of the radiation detector 300 includes each component of the radiation detector 170 as described below. Corresponds to each element.

  First, the insulating substrate 508 corresponds to the substrate 172. However, the insulating substrate 508 may be any substrate as long as it has light transparency and absorbs little radiation 16a to 16g.

  When a glass substrate is used as the insulating substrate 508, the thickness of the radiation detection unit 502 (TFT substrate) as a whole is about 0.7 mm, for example. In the sixth modification, the radiation detection device 22 is thinned. Considering this, as the insulating substrate 508, a thin substrate made of a light-transmitting synthetic resin is used. As a result, the thickness of the radiation detection unit 502 as a whole can be reduced to, for example, about 0.1 mm, and the radiation detection unit 502 can be flexible. Further, by providing the radiation detection unit 502 with flexibility, the impact resistance of the radiation detection device 22 is improved, and even when an impact is applied to the radiation detection device 22, it is difficult to be damaged. In addition, plastic resin, aramid, bionanofiber, etc. all absorb less radiation 16a to 16g, and when the insulating substrate 508 is formed of these materials, the amount of radiation 16a to 16g absorbed by the insulating substrate 508 is also large. Therefore, even if the radiation detection unit 502 is configured to transmit the radiation 16a to 16g by the ISS method, it is possible to suppress a decrease in sensitivity to the radiation 16a to 16g.

  In the radiation detection device 22, it is not essential to use a synthetic resin substrate as the insulating substrate 508. Although the thickness of the radiation detection device 22 increases, a substrate made of another material such as a glass substrate is insulated. The conductive substrate 508 may be used.

  The pixel unit 520 corresponds to the signal output unit 174, and the photoelectric conversion unit 512 corresponds to the sensor unit 176. Therefore, the storage capacitor 516 of the pixel portion 520 corresponds to the capacitor 192 of the signal output portion 174, and the TFT 518 corresponds to the thin film transistor 194. The lower electrode 512a of the photoelectric conversion unit 512 corresponds to the upper electrode 182 of the sensor unit 176, the photoelectric conversion film 512c corresponds to the photoelectric conversion film 186, and the upper electrode 512b corresponds to the lower electrode 184.

  That is, each component of the ISS radiation detector 300 shown in the sixth modification generally corresponds to each component of the PSS radiation detector 170 shown in the fifth modification. Therefore, if the material of the component of the radiation detector 170 described in FIGS. 16 and 17 is applied as the material of the corresponding component in the radiation detector 300 of the sixth modified example, it will be described with reference to FIGS. Of course, the effect of each material can be easily obtained.

  However, unlike the PSS system, the ISS system transmits the radiation 16a to 16g through the radiation detection unit 502 and reaches the CsI (Tl) scintillator 500. Therefore, the insulating substrate 508, the pixel unit 520, and the photoelectric conversion unit 512 are used. It is necessary that the radiation detection unit 502 including the entire material is made of a material that absorbs less radiation 16a to 16g.

  Therefore, in the sixth modification, when the photoelectric conversion film 512c is made of an organic photoelectric conversion material, the radiation detection unit 502 transmits the radiations 16a to 16g because the photoelectric conversion film 512c hardly absorbs the radiations 16a to 16g. In the ISS system in which is disposed, the attenuation of the radiations 16a to 16g transmitted through the radiation detection unit 502 can be suppressed, and a decrease in sensitivity to the radiations 16a to 16g can be suppressed. Therefore, it is particularly suitable for the ISS system to configure the photoelectric conversion film 512c with an organic photoelectric conversion material.

[Seventh Modification]
By the way, in imaging with respect to the subject 14, the imaging region is positioned so that the center position of the imaging region of the subject 14 and the center position of the imaging region 36 are substantially coincident and the imaging region is within the imaging region 36. Therefore, the region of interest (ROI) is often located at the center of the imageable region 36.

  Therefore, in this embodiment, the radiation dose from the radiation source (radiation source belonging to the group 56 or the group 158, 160) in the vicinity of the geometric center position in the radiation output device 20 is increased, and the radiation at both ends is increased. The radiation dose from the source (the radiation source belonging to the group 54, 58 or the group 156, 162) is set to a small dose so as to supplement the radiation from the radiation source in the vicinity of the geometric center position. More will be done.

  In other words, in actual imaging, the control processing unit 124 has a maximum radiation dose from the radiation source near the geometric center position or the central radiation source, and is output from each radiation source at both ends. The respective doses are weighted so that the dose of the radiation to be obtained is a small dose that is sufficient to compensate for the maximum dose, and the radiation is simultaneously irradiated from the respective radiation sources according to this weighting or sequentially irradiated.

  If each of the radiation sources 18a to 18i is continuously driven in accordance with such weighting, only the radiation source near the geometric center position or the central radiation source is deteriorated. Therefore, from the viewpoint of life management of the radiation output device 20, each radiation is managed by performing dose management so that the cumulative irradiation dose (cumulative exposure dose) from each of the radiation sources 18a to 18i becomes the same. It is desirable that the life of the radiation output device 20 including the sources 18a to 18i can be extended.

  Therefore, in the seventh modification, for example, in step S4 or step S11 of FIG. 11 in the present embodiment, dose data (weighting is performed on each radiation) according to the optimum dose data searched by the database search unit 150. Dose data) may be stored in the database 134, and the stored dose data may be used for dose management and lifetime management of the radiation sources 18a to 18i.

  Thereby, about the cumulative exposure dose of the radiation output from each radiation source 18a-18i, the cumulative exposure dose of the radiation output from the geometrical center position vicinity or the radiation source of the center is both ends. When projecting from the cumulative exposure dose of radiation output from other radiation sources, the radiation source near the geometric center position or the central radiation source can deteriorate faster than the radiation sources at both ends. There is sex. Therefore, based on the comparison of the accumulated exposure doses, the control processing unit 124, for example, for imaging with a large SID, the radiation dose output from each radiation source at both ends is the maximum dose. The weighting of each dose is changed so that the radiation dose near the geometric center position or the radiation dose output from the central radiation source is a dose that is small enough to supplement the maximum dose.

  In this way, by using each accumulated exposure dose as a judgment material, by changing the weighting of the dose of the radiation output from each radiation source 18a to 18i, the radiation source near the geometric center position or the central radiation is changed. It is possible to avoid the deterioration of only the source and to extend the life of the radiation output apparatus 20 including the radiation sources 18a to 18i.

  Note that the present invention is not limited to the above-described embodiment, and it is needless to say that various configurations can be adopted without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 10 ... Radiography system 14 ... Subject 16a-16g ... Radiation 18a-18i ... Radiation source 20 ... Radiation output device 22 ... Radiation detection device 24 ... Control device 26 ... Doctor 28, 166 ... Handle 52 ... Touch sensor 54-58, 156 -162 ... groups 60, 170, 300 ... radiation detector 66 ... radiation source control unit 74 ... cassette control unit 124 ... control processing unit 132 ... order information storage unit 134 ... database 136 ... imaging condition storage unit 150 ... database search unit 152 ... Shooting condition setting unit 154 ... Control signal generation unit

Claims (13)

A radiation output device containing at least three radiation sources for outputting radiation;
A radiation detection device that detects each of the radiation transmitted through the subject and converts it into a radiation image when the at least three radiation sources respectively irradiate the subject with radiation; and
A control device for controlling the radiation output device and the radiation detection device;
With
The controller is
Dividing the at least three radiation sources into at least three groups comprising one or more radiation sources;
Among the divided groups, the radiation dose output from the radiation source belonging to the group in the vicinity of the geometric center position of the at least three radiation sources becomes the maximum dose, and the geometric center position Weighting the dose of each radiation output from the at least three radiation sources so that the radiation dose output from a radiation source belonging to a group other than the neighboring group is a small dose that supplements the maximum dose. Done in groups,
The radiation imaging system, wherein the radiation output device is controlled to irradiate the subject with radiation from the at least three radiation sources according to the weighting. The system of claim 1, wherein
The controller is
A database for storing grouping data indicating grouping of the radiation sources according to the number of radiation sources that can be accommodated in the radiation output device, and weighting data indicating weighting of dose for each group according to the grouping data;
A database search unit that searches the database for grouping data and weighting data corresponding to the imaging region of the subject;
An imaging condition setting unit that sets imaging conditions for irradiating the imaging region with radiation based on the imaging region of the subject and the grouping data and weighting data searched by the database search unit;
A control processing unit for controlling the radiation output device and the radiation detection device according to the imaging conditions;
A radiation imaging system comprising: The system of claim 2, wherein
The database further stores optimal dose data indicating an optimal dose corresponding to a plurality of imaging regions and the thickness of each imaging region,
The database search unit includes, in the database, an imaging part of the subject and an optimum dose data of the imaging part and thickness that match the thickness of the imaging part, grouping data and weighting data of the imaging part that matches the imaging part of the subject And search for
The imaging condition setting unit sets the imaging condition based on the imaging region of the subject and the thickness of the imaging region, and the optimum dose data, grouping data, and weighting data searched by the database search unit. Radiation imaging system. The system of claim 3, wherein
The optimum dose data is associated with an imaging technique indicating the plurality of imaging regions, the thickness of each imaging region, and the direction of each imaging region with respect to the radiation detection apparatus and the radiation irradiation direction with respect to each imaging region. Stored in the database,
The grouping data and the weighting data are stored in the database in association with the plurality of imaging regions and imaging techniques corresponding to the imaging regions,
In the database, the database search unit matches the imaging region of the subject, the imaging region that matches the imaging region thickness and imaging technique, the optimal dose data of the thickness and imaging procedure, and the imaging region and imaging technique of the subject. Search the imaging part and imaging technique grouping data and weighting data to be performed,
The imaging condition setting unit sets the imaging condition based on the imaging region of the subject, the thickness and imaging technique of the imaging region, and the optimum dose data, grouping data, and weighting data searched by the database search unit. A radiation imaging system characterized by that. The system of claim 4, wherein
The imaging condition setting unit includes the optimum dose data, grouping data, and weighting data searched by the database search unit, order information for requesting imaging of the radiographic image of the subject, the subject, or imaging of the subject. A radiography system that can be changed according to the procedure. The system according to any one of claims 2 to 5,
The radiation imaging system, wherein the imaging region is a hand of the subject. The system according to any one of claims 1 to 6,
The radiation output device irradiates the subject with radiation simultaneously from the at least three radiation sources, sequentially irradiates the subject with radiation from the at least three radiation sources, or radiates the subject on a group basis. Radiation imaging system characterized by sequentially irradiating. The system according to any one of claims 1 to 7,
The controller is
When the number of the groups is an odd number of 3 or more, the dose of radiation output from the radiation source of the group including the geometric center position is the maximum dose,
On the other hand, when the number of the groups is an even number of 4 or more, the radiation dose output from the radiation sources of two groups close to the geometric center position is set to a maximum dose. Radiography system. The system according to any one of claims 1 to 8,
The control apparatus further weights a dose of radiation output from each radiation source in the group to a group to which two or more radiation sources belong. The system according to any one of claims 1 to 9,
When the radiation output device and the radiation detection device are opposed to each other, the at least three radiation sources are one-dimensionally within the radiation output device with respect to the irradiation surface of the radiation detection device irradiated with the radiation. A radiographic system characterized by being arranged or two-dimensionally arranged. The system according to any one of claims 1 to 10,
The radiation output device and the radiation detection device are portable devices,
The radiographic imaging system, wherein the control device is a portable portable terminal or a console provided in a medical institution. The system according to any one of claims 1 to 11,
A handle is provided at a location opposite to the output location of each radiation in the radiation output device,
The grip is provided with a gripping state detection sensor capable of outputting a detection signal indicating that the grip is gripped,
The radiation output system, wherein the radiation output device permits the output of radiation from the at least three radiation sources when the detection signal is output from the gripping state detection sensor. When at least three radiation sources outputting radiation are accommodated in the radiation output device, the at least three radiation sources are divided into at least three groups including one or more radiation sources;
Among the divided groups, the radiation dose output from the radiation source belonging to the group in the vicinity of the geometric center position of the at least three radiation sources becomes the maximum dose, and the geometric center position Weighting the dose of each radiation output from the at least three radiation sources so that the radiation dose output from a radiation source belonging to a group other than the neighboring group is a small dose that supplements the maximum dose. Done in groups,
Subject the subject to radiation from the at least three radiation sources according to the weighting;
A radiation imaging method, wherein each radiation transmitted through the subject is detected by a radiation detection device and converted into a radiation image.

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