CN1317568C - Optical detecting device x-ray photographic method and apparatus and photo-electric conversion components - Google Patents

Abstract

The present invention provides a photodetection device, an X-ray imaging method and device, and a photoelectric conversion element capable of saving electric energy in driving an X-ray sensor. The X-ray imaging device includes: an imaging device composed of a plurality of photoelectric conversion elements for converting radiation into electrical signals; a plurality of amplification devices for amplifying the electrical signals output from the plurality of photoelectric conversion elements; The drive of the device performs on/off control of the drive device.

Description

Photodetection device, X-ray photography method and device, and photoelectric conversion element

technical field

The present invention relates to an X-ray imaging method, an X-ray imaging device, and a photoelectric conversion element that control the driving of a photoelectric conversion element, and more particularly, to an X-ray imaging method, an X-ray imaging device, and Photoelectric conversion element.

Background technique

In the conventional X-ray imaging device, the X-ray beam is irradiated from the X-ray source through the analyzed object such as the medical patient. (Computed Radiography), FPD (Flat Panel Detector), etc. for photography.

In X-ray radiography, a high-resolution solid-state X-ray detector using an FPD has been proposed. This detector has a two-dimensional array using 3,000 to 4,000 photoelectric conversion elements represented by photodiodes in each dimension. X-ray sensor. Each photoelectric conversion element generates an electrical signal corresponding to the amount of X-rays projected onto the X-ray sensor. Thus, the object to be photographed is placed between the X-ray source and the X-ray sensor, and the amount of X-rays transmitted through the object to be photographed is converted into an electrical signal to obtain an X-ray image of the object to be photographed. In addition, the signals from the respective photoelectric conversion elements are read out, digitized, image processed, stored, and displayed. Such a detector is disclosed, for example, in Japanese Patent Application Laid-Open No. Hei 9-257944.

Furthermore, solid-state X-ray detectors using FPDs are also becoming smaller and thinner like X-ray screen film cassettes, along with improvements in thickness reduction and high-reliability technology.

However, in the solid-state X-ray detector using the FPD, there is a problem that a large amount of power is consumed for driving the photoelectric conversion elements in the X-ray sensor. In particular, for example, when a battery is mounted in a thin and small X-ray digital imaging device, it is necessary to drive to reduce the power consumed by the thin X-ray digital imaging device during normal imaging.

Contents of the invention

An object of the present invention is to provide an X-ray imaging device, an X-ray imaging method, and a photoelectric conversion element capable of driving an X-ray sensor that saves power.

In order to achieve the above object, the present invention provides a photoelectric conversion element, comprising: a photodetection device that converts light into an electrical signal; an amplifying device that amplifies the electrical signal output by the photodetection device; Off-control drives.

Furthermore, the present invention provides an X-ray imaging device including: an imaging device composed of a plurality of photoelectric conversion elements for converting radiation into electrical signals; an amplifying device; and a driving device for on/off controlling the drive of the amplifying device.

In addition, the present invention provides an X-ray imaging device including: an imaging device composed of a plurality of photoelectric conversion elements for converting light into electrical signals; a drive range specifying device for a range; a drive device for driving the photoelectric conversion elements in a range specified by the drive range specifying device; and a signal reading device for reading the output of the photoelectric conversion elements driven by the drive device; wherein, The driving range designating means designates a range in which the photoelectric conversion element is driven by a coordinate input device attached to the imaging device.

Other objects, features, and advantages of the present invention will be clarified through detailed description with reference to the accompanying drawings. In these drawings, the same reference numerals denote the same or similar parts.

Description of drawings

FIG. 1 is a structural diagram of an X-ray imaging system.

FIG. 2 is an equivalent circuit diagram of a photoelectric conversion element.

FIG. 3 shows a configuration example of an imaging device.

Fig. 4 is a configuration example of a display device for operating an X-ray imaging device.

Fig. 5 is a configuration diagram when the X-ray image capturing area is designated in cooperation with the diaphragm.

FIG. 6 shows a calculation method of the device that designates an X-ray imaging area in cooperation with the diaphragm.

FIG. 7 is a configuration diagram when specifying an X-ray imaging area by a device attached to the X-ray imaging device.

Fig. 8 is a device for specifying an X-ray image shooting area by the irradiation field recognition device at the time of the previous shooting.

FIG. 9 is a diagram illustrating a method of specifying an X-ray imaging region by using relative position information between an object to be imaged and an X-ray imaging device.

FIG. 10 is a schematic diagram of the power saving effect produced by the present invention.

FIG. 11 is a flowchart showing the flow of selecting an imaging area.

Detailed ways

Preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

first embodiment

Hereinafter, Embodiment 1 of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing the configuration of an X-ray imaging system according to an embodiment of the present invention. 10 is an X-ray room, 12 is an X-ray control room, and 14 is a diagnosis room and other operating rooms.

In the X-ray control room 12, a system controller 20 for controlling the overall operation of the X-ray imaging system is disposed. The operator interface 22 composed of an X-ray exposure request SW, a touch panel, a mouse, a keyboard, an operation room, and a foot switch is used when the operator inputs various commands to the system controller 20 . The content of instructions from the operator 21 includes, for example, imaging conditions (still images/moving images, X-ray tube voltage, tube current, and X-ray irradiation time, etc.), imaging timing, image processing conditions, examinee ID, and processing methods for read images. etc. In addition to these, there are methods for setting the imaging area, confirmation of the imaging area, and the like.

The imaging control circuit 24 of the system controller 20 controls the X-ray imaging system placed in the X-ray room 10 , and the image processing circuit 26 performs image processing on images generated by the X-ray imaging system of the X-ray room 10 . Image processing in the image processing circuit 26 includes, for example, irradiation field recognition, image data correction, spatial filtering, recursive processing, tone processing, scattered ray correction, and dynamic range compression processing. The large-capacity and high-speed storage device 28 stores the basic image data processed by the image processing circuit 26, and is constituted by, for example, a hard disk array (RAID). 30 is a monitor display (hereinafter referred to as monitor) for displaying images, 32 is a display controller that controls monitor 30 to display various characters and images, 34 is a large-capacity external storage device (such as a magnetic disk), and 36 is a connection The device in the X-ray control room 12 and the diagnosis room or the device in the operation room 14 transmit the photographed images in the X-ray room 10 to the LAN board of the diagnosis room and other devices in the operation room 14 .

In the X-ray room 10, an X-ray generator 40 that generates X-rays is placed. The X-ray generator 40 is controlled by the X-ray tube 42 that generates X-rays, and the high-voltage power supply 44 that drives the X-ray tube 42 is controlled by the imaging control circuit 24, and the X-ray beam that is generated by the X-ray tube 42 is reduced to a desired value. The X-ray aperture 46 in the imaging area is constituted. 47 is a CCD camera. In this embodiment, it is arranged according to an adjustment and positioning that is optically equal to the focus of the X-ray tube. .

A subject 50 as a patient lies on the imaging bed 48 . The imaging bed 48 is driven in accordance with a control signal from the imaging control circuit 24 , and can change the orientation of the subject with respect to the X-ray beam from the X-ray generator 40 . An X-ray detector 52 for detecting X-ray beams transmitted through the subject 50 and the imaging bed 48 is disposed under the imaging bed 48 .

The configuration of the X-ray detector 52 in FIG. 1 will be described. The X-ray detector 52 is composed of a grid 54, a scintillator 56, an X-ray sensor (imaging device) 58 constituted as a two-dimensional array of a plurality of photoelectric conversion elements, and a laminated body that drives the X-ray exposure amount monitor 60, and X-ray exposure amount monitor 60. The drive circuit 62 of the radiation sensor (imaging device) 58 constitutes. The grid 54 is provided to reduce the influence of scattering of X-rays transmitted through the object 50 to be inspected. The grid 54 is composed of X-ray low-absorption members and high-absorption members, for example, a stripe structure of Al and Pb. During X-ray irradiation, the X-ray detector 52 vibrates the grid 54 according to the setting from the imaging control circuit 24, so that moiré will not be generated due to the relationship between the X-ray sensor (imaging device) 58 and the grid ratio of the grid 54. stripe.

Whether to vibrate the grid 54 is selected by the photographer, and the grid 54 may be fixed for photography. When imaging is performed with the grid 54 fixed, it is preferable to set such that moiré fringes such as aliasing or beating do not easily occur due to the grid ratio relationship between the X-ray sensor (imaging device) 58 and the grid 54 . In addition, the grid stripe itself is reflected in the image, and it is preferable to perform processing such as reducing the frequency of the grid stripe itself by image processing.

In the scintillator 56 , the host substance of the phosphor is excited (absorbed) by high-energy X-rays, and fluorescence in the visible region is generated by its recombination energy. That is, X-rays are converted into visible light. The fluorescence is generated by the matrix itself such as CaWo4 or CdWo4, or by the luminescent center substance added to the matrix of CsI:Tl or ZnS:Ag. The X-ray sensor (imaging device) 58 converts the visible light generated by the scintillator 56 into an electric signal.

In addition, in this embodiment, the scintillator 56 and the X-ray sensor (imaging device) 58 are made into separate structures, but it is also applicable to an X-ray sensor (imaging device) composed of a photoelectric conversion element that directly converts X-rays into electrons. device) 58. For example, it is a photoelectric conversion element composed of a photosensitive part such as amorphous Se or PbI2, and an amorphous silicon TFT.

The X-ray exposure dose monitor 60 is arranged for the purpose of monitoring the transmitted X-ray dose. The X-ray exposure monitor 60 may directly detect X-rays using a crystalline silicon photosensitive element or the like, or may detect fluorescence generated by the scintillator 56 . In this embodiment, the X-ray exposure monitor 60 is composed of an amorphous silicon photosensitive element formed on the back surface of the substrate of the X-ray sensor (imaging device) 58, and detects visible light transmitted through the X-ray sensor (imaging device) 58. (proportional to the amount of X-rays), and the light amount information is sent to the imaging control circuit 24 . The imaging control circuit 24 controls the high-voltage power supply 44 based on the information from the X-ray exposure monitor 60 to adjust the X-ray dose. The drive circuit 62 drives the photoelectric conversion elements constituting the photodetector array 58 under the control of the imaging control circuit 24 to read out signals from the respective pixels.

The thin X-ray detector 152 in FIG. 1 will be described. One thin X-ray detector 152 is shown as a representative of various sensors, but sensors with different spatial resolutions or different sizes of the thin X-ray detector 152 , that is, different sizes of imaging areas, etc. can be used instead. The difference between the X-ray detector 52 and the thin X-ray detector 152 is that the thickness of the first thin X-ray detector 152 is about 20 mm or less which corresponds to a film screen type cassette. This is the biggest difference. In addition, in the thin X-ray detector 152, the grid 54 is not installed inside, and a simple power supply and a large-capacity (more than 10 images and less than 20 images) memory are installed inside, so that it can communicate with the repeater 153 without cables. There are many points such as the exchange of image signals and control signals. Likewise, a scintillator 56 , an X-ray sensor (imaging device) 58 , a laminate for driving an X-ray exposure level monitor 60 , and a drive circuit 62 for the X-ray sensor (imaging device) 58 are mounted inside. It can be operated with or without the cable 154. In the case of using the cable 154, since the image can be transmitted at high speed, the operations of image acquisition, processing, and confirmation after X-ray imaging can be realized in a shorter time. . This thin X-ray detector 152 is used, for example, to photograph limbs, and other thin X-ray detectors 152 are connected to the system controller 20 through a repeater 153 .

The diagnosis room and other operating rooms 14 in FIG. 1 are explained. In the diagnostic room and other operation rooms 14, HIS/LIS etc. connected to the information and imaging methods for instructing the subject to be examined via the LAN board are installed, and the images from the LAN board 36 are image-processed and diagnosed. Supported image processing terminal 70, monitor 72 for displaying images (moving images/still images) from LAN board 36, image printer 74, and file server 76 for storing image data.

In addition, signals from the system controller 20 for each device can occur according to instructions from the operator interface 22 in the X-ray control room 12 , or the image processing terminal 70 located in the diagnostic or other operating room 14 .

The basic operation of the system controller 20 shown in FIG. 1 will be described. The drive controller 20 instructs the imaging control circuit 24 of the program controlling the X-ray imaging system to capture the imaging conditions according to the instructions of the operator 21, and the imaging control circuit 24 drives the X-ray generator 40, the imaging bed 48 and the X-ray detection system according to the instructions. device 52 to take X-ray images. The X-ray image signal output from the X-ray detector 52 is supplied to the image processing circuit 26, the image processing specified by the operator 21 is performed, and the image is displayed on the monitor 30 and stored in the storage device 28 as basic image data. The signal controller 20 also executes re-image processing and image display of the result thereof, transmission of image data to devices on the network, storage, image display, and film printing, etc., according to instructions from the operator 21 .

The basic operation of the system shown in FIG. 1 will be described in terms of signal flow. The high voltage source 44 of the X-ray generator 40 applies a high voltage for generating X-rays to the X-ray tube 42 according to a control signal from the imaging control circuit 24 . Thus, the X-ray tube 42 generates X-ray beams. The generated X-ray beams pass through the X-ray aperture 46 and are irradiated to the subject 50 which is a patient. The X-ray aperture 46 is controlled by the imaging controller 24 according to the position of the X-ray beam to be irradiated. That is, the X-ray aperture 46 shapes the X-ray beam so as not to irradiate unnecessary X-rays as the imaging area is changed.

The X-ray beam output from the X-ray generator 40 in FIG. 1 passes through the subject 50 lying on the X-ray transparent imaging bed 48 and the imaging bed 48 , and enters the X-ray detector 52 . In addition, the imaging control circuit 24 controls the imaging bed 48 so that the X-ray beams are transmitted to different parts or directions of the subject 50 . In addition, in the case of using the thin X-ray detector 152, the operator 21 adjusts the thin X-ray detector 152 and the object 50 so that the X-ray beam output from the X-ray generator 40 passes through the object 50 and enters the X-ray beam. Thin X-ray detector. At this time, in order to limit the imaging area, it is preferable to add an imaging area specifying device (not shown) to the thin X-ray detector 152 so that an imaging area can be specified. Also, when it is preset that the X-ray imaging area can be specified in cooperation with the X-ray tube diaphragm 46, it is preferable to place an imaging area display device (not shown) on the surface of the thin X-ray detector 152 or the like.

The grid 54 of the X-ray detector 52 in FIG. 1 reduces the influence of X-ray scattering caused by passing through the object 50 to be inspected. The imaging control circuit 24 vibrates the grid 54 during X-ray irradiation so that moiré fringes are not generated due to the grid ratio relationship between the photodetector array 58 and the grid 54 . In the scintillator 56, the host material of the phosphor is excited by high-energy X-rays (absorbs X-rays), and fluorescence in the visible region is generated by recombination energy generated at this time. An X-ray sensor (imaging device) 58 disposed adjacent to the scintillator 56 converts fluorescence generated by the scintillator 56 into an electrical signal. The X-ray exposure monitor 60 detects visible light (proportional to the X-ray dose) transmitted through the X-ray sensor (imaging device) 58 , and supplies the detected amount information to the imaging controller 24 . The imaging control circuit 24 controls the high-voltage power supply 44 according to the X-ray exposure amount information to block or adjust the X-rays. The drive circuit 62 drives the X-ray sensor (imaging device) 58 under the control of the imaging control circuit 24 to read pixel signals from the respective photodetectors.

Pixel signals output from the X-ray detector 52 and the thin X-ray detector 152 in FIG. 1 are output to the image processing circuit 26 in the X-ray control room 12 . Since the noise generated with X-rays in the X-ray room 10 is large, the signal channel from the X-ray detector 52 to the image processing circuit 26 needs to be a channel with high noise resistance. Digital transmission systems with error correction, or shielded twisted pair wires or optical fibers using differential drivers.

The image processing circuit 26 in FIG. 1 switches the display form of the image signal according to the instruction from the system controller 20. In addition, it can also correct the image signal in real time, perform spatial filtering processing, recursive processing, etc., and can perform color tone processing. , scatter ray correction and DR compression processing, etc. The image processed by the image processing circuit 26 is displayed on the screen of the monitor 30 . Simultaneously with real-time image processing, only image information (basic image) subjected to image correction is stored in the storage device 28 . In addition, according to the instructions of the operator 21, the image information stored in the storage device 28 is reconstructed so as to meet a predetermined standard (for example, Image Save & Carry (IS & C)), and then stored in the external storage device 34 and the file server 76 internal hard disk, etc.

The devices of the X-ray control room 12 in FIG. 1 are connected to a LAN (or WAN) via a LAN board 36 . On the LAN, it is of course possible to connect a plurality of radiographing systems. The LAN board 36 outputs image data according to a predetermined protocol (for example, Digital Imaging and Communications in Medicine (DICOM)). Displaying X-ray images as high-resolution still images and moving images on the screen of the monitor 72 connected to (or WAN) enables real-time remote diagnosis by doctors almost simultaneously with X-ray photography.

FIG. 2 shows an example of an equivalent circuit of a photoelectric conversion element that is a constituent unit of the X-ray sensor (imaging device) 58 . One photoelectric conversion element is composed of a photodetection unit 80 and a switching thin film transistor (TFT) 82 that controls charge storage and readout, and is generally formed of amorphous silicon (a-Si) on a glass substrate. The photodetection unit 80 is also composed of a parallel circuit of a photodiode 80a and a capacitor 80b, which is used as a constant current source 81 to write charges generated by the photoelectric effect. The capacitor 80b may be a parasitic capacitance of the photodiode 80a, or may be a capacitor added to improve the dynamic range of the photodiode 80a. The cathode of the photodetection unit (photodiode 80a) is connected to a bias power supply 85 via a bias wiring Lb serving as a common electrode (D electrode). The anode of the photodetection unit 80 (photodiode 80a) is connected to a capacitor 86 and a charge readout preamplifier (amplifying device) 88 via a switching TFT 82 from a gate electrode (G electrode). The input of the preamplifier (amplifier) 88 is also connected to a ground point via a reset switch 90 and a signal line bias power supply 91 . In this embodiment, in FIG. 2 , the power supply of the preamplifier (amplifying device) 88 is adjusted, or the power of the portion designated as the imaging area is adjusted based on a control signal from a driving circuit not shown that performs ON/OFF. Power supply for photoelectric conversion elements. By adjusting the power supply of the preamplifier (amplifier) 88, the power consumption of the photoelectric conversion element can be suppressed. Especially when the photoelectric conversion elements are used to form a large-area X-ray sensor (imaging device) 58, the effect of reducing power consumption by adjusting the power supply of the photoelectric conversion elements in a range not required for imaging is particularly remarkable. This is because tens of thousands of units of photoelectric conversion elements are used in the X-ray sensor (imaging device) 58 .

Next, the readout method of the photoelectric conversion imaging device will be described using FIG. 2 . The sequence in the figure is roughly divided into three stages: reset, storage, and readout.

Reset: Temporarily bring the switch TFT 82 and the reset switch 90 into conduction, and reset the capacitance line 80b.

Storage: Next, the switching TFT 82 and the reset switch 90 are turned off. Then, X-rays are generated and irradiated on the object 50 to be inspected. The scintillator 56 converts the X-ray image transmitted through the object 50 into a visible ray image, and the photodiode 80a is turned on by the visible ray image to discharge the charge of the capacitor 80b.

Read: The switching TFT 82 is turned on, and the capacitor 80b and the capacitor 86 are connected. Accordingly, information on the discharge amount of the capacitor 80 b is also transmitted to the capacitor 86 . The voltage generated by the charge stored in the capacitor 86 is amplified by a preamplifier (amplifying means) 88, or the charge-voltage conversion is performed by a capacitor 89 indicated by a dotted line, and output to the outside.

Next, the photoelectric conversion operation when the photoelectric conversion element shown in FIG. 2 is extended to a two-dimensional configuration will be described using FIG. 3 . FIG. 3 is an equivalent circuit of an X-ray sensor (imaging device) 58 including photoelectric conversion elements arranged two-dimensionally. Since the two-dimensional readout operation is the same as in the two equivalent circuits described above, FIG. 3 is realized using the equivalent circuit shown in FIG. 2 .

The X-ray sensor (imaging device) 58 in FIG. 3 is composed of about 2000×2000 to 4000×4000 photoelectric elements, and the array area is about 200mm×200mm to 500mm×500mm. The output of one photoelectric conversion element corresponds to one pixel. That is, in FIG. 2 , the X-ray sensor (imaging device) 58 is composed of 4096×4096 pixels, and the array area is 430 mm×430 mm. Therefore, the size of one pixel is approximately 105×105 μm. 4096 pixels arranged in the horizontal direction are regarded as one block, and 4096 blocks are arranged in the vertical direction to form a two-dimensional structure.

As explained in FIG. 2 , one photoelectric conversion element is composed of one photodetection unit 80 and a switching TFT 82. In FIG. 3 , photoelectric conversion elements ( 1 , 1 ) to ( 4096 , 4096 ) and transmission switches SW ( 1 , 1 ) to ( 4096 , 4096 ), which are switching TFTs, are shown. The gate electrode (G electrode) of the photoelectric conversion element PD(m,n) is connected to the column signal line Lcm common to the column via the corresponding switch SW(m,n). For example, the photoelectric conversion elements PD ( 1 , 1 ) to ( 4096 , 1 ) in the first column are connected to the signal line Lc1 in the first column. All the common electrodes (D electrodes) of the respective photoelectric conversion elements PD(m,n) are connected to the bias power source 85 via the bias unit Lb.

The control terminals of the switches SW(m,n) of the same row are connected to a common row selection line Lrn. For example, the switches SW (1, 1) to (1, 4096) of the first row are connected to the row selection line Lr1. The row selection lines Lr1 to 4096 are connected to the imaging control circuit 24 via a row selector (reading range specifying means) 92 . The row selector (reading range specifying device) 92 is composed of an address decoder 94 that decodes the control signal from the imaging control circuit 24 to determine the signal charge of the photoelectric conversion element of which row to read, and decodes the signal charge according to the address. 4096 switching elements 96-1 to 96-4096 for switching the output of the device 94. According to this configuration, it is possible to read the signal charge of the photoelectric conversion element PD(m,n) connected to the switch SW(m,n) connected to an arbitrary row Lrn. Thereby, signal reading can be performed only from the target photoelectric conversion element.

The row selector (means for specifying the reading range) 92 may only be constituted by a shift register used in a liquid crystal display or the like as the simplest structure. In the present embodiment, there is an effect of shortening the reading time of stored charges by selecting the region of the imaging row by the row decoder 94 . This is an effect that is particularly required in a medical field where a short-time display is required. Furthermore, when the X-ray sensor (imaging device) 58 is used for moving images, there is an effect of increasing the frame rate.

The column signal lines Lc1 to 4096 are connected to the signal readout circuit 100 controlled by the imaging control circuit 24 . In the signal readout circuit 100, 102-1 to 4096 are reset switches, which respectively reset the column signal lines Lc1 to 4096 to the reset reference potential 101. 106-1 to 4096 respectively amplify signals from the column signal lines Lc1 to 4096 The preamplifier (amplifying device) of electric potential, 108-1～4096 is the sample and hold (S/H) circuit of the output of sample and hold preamplifier 106-1～4096 respectively, and 110 is the sample and hold (S/H) circuit An analog multiplexer for multiplexing the outputs of 108-1 to 4096 on the time axis, and 112 is an A/D converter for digitizing the analog output of the multiplexer 110 . The output of the A/D converter 112 is supplied to the image processing circuit 26 . In addition, by controlling the power sources (not shown) for driving the preamplifiers (amplifiers) 106-1 to 4096 by signals controlled by the imaging control circuit 24, only the target photoelectric conversion element can be driven. In this configuration, the photoelectric conversion elements arranged in the column direction are controlled, but it is also possible to adjust the driving of each photoelectric conversion element by individually controlling the driving of each photoelectric conversion element.

In the photodetector array shown in Figure 3, 4096×4096 pixels are divided into 4096 columns through the column signal lines Lc1~4096, and the signal charges of the 4096 pixels in each column are read out at the same time, and passed through the column signal lines Lc1~4096. 4096, preamplifiers (amplifying devices) 106-1~4096 and S/H circuits 108-1~4096 are sent to the analog multiplexer 110, where time axis multiplexing is performed, and the A/D converter 112 into a digital signal. That is, the signal is read out for each column, but by providing the switches 96-1 to 96-4096 in the respective photoelectric conversion elements, it is also possible to select the readout of individual photoelectric conversion elements.

In the present invention, by using the switch 98 for adjusting the power supply of the preamplifier (amplifier) 88 of each photoelectric conversion element, only the photoelectric conversion elements in the imaging range are brought into the ready state. In FIG. 3, the preamplifiers (amplifiers) 88 of 106-1 to 106-4096 in FIG. power input to achieve. This driving device is controlled by the imaging control circuit 24 .

In addition, in order to limit the vertical imaging range of FIG. 3 , the row selector (reading range specifying device) 92 decodes the control signal from the imaging control circuit 24, and determines the signal charge of the read conversion element through the address decoder 94. OK. As a result, switching elements (96-1 to 96-4096) corresponding to the range specified as the imaging range are opened and closed.

2nd embodiment

FIG. 4 shows a display device for designating an X-ray image imaging area by means of operating the X-ray imaging device. Using FIG. 4 , a method of designating a range to drive a photoelectric conversion element and calling an output signal range of a photoelectric conversion element from an operating device of an X-ray imaging apparatus will be described. 1101 is an example of a display screen. As the display device, a touch panel type display device that allows input by directly touching the screen with a finger, a pen, or the like is used. 1102 is the reduced simplified image display area of the acquired image. When the thin X-ray detector 152 is used, the image transmitted by the previous wireless communication is reprocessed, and the image is displayed in the display area 1102 . 1103 is a button for displaying an imaging target portion corresponding to each X-ray detector 52 or thin X-ray detector 152 , and the imaging target is specified by selecting the button 1103 before imaging. 1104 is an effective X-ray detector display area. In the effective X-ray detector display area 1104, icons representing the X-ray detectors 52 or the thin X-ray detectors 152 in the controllable state of the system controller 20 are displayed. 1105 is an image of the CCD camera 47, and 1106 is a driving range of the photoelectric conversion element or a signal readout range of the photoelectric conversion element. Using the CCD camera mounted on the X-ray tube, the imaging device and the patient to be photographed are projected on the image 1105 through an imaging path adjusted and positioned almost equal to the X-ray output from the X-ray tube. On the image 1105 , the imaging area can be specified by pointing the driving range of the photoelectric conversion element or the signal readout range 1106 of the photoelectric conversion element with a finger or a pen on the touch panel as a display device displayed on the touch panel.

In this case, for example, predetermined coordinates (for example, coordinates of the four corners of the X-ray sensor) of the X-ray sensor (imaging device) 58 displayed on the display screen 1105 are indicated in advance, and the coordinates are calculated in advance from the indicated coordinates and saved for display. The coordinates on the image 105 and the positional relationship on the X-ray sensor (imaging device). Thereby, the imaging control circuit 24 calculates the coordinates on the X-ray sensor (imaging device) 58 from the coordinates of the area 1106 indicated with a finger or a pen on the touch panel.

In addition, when the X-ray sensor (imaging device) 58 of the first embodiment is used, the driving range of the photoelectric conversion element or the signal readout range of the photoelectric conversion element are specified simultaneously by the indication area 1106 . Thus, by using the image of the CCD camera 47 adjusted and positioned almost the same as the X-rays emitted from the X-ray tube, there is an effect that the area on the X-ray sensor (imaging device) 58 can be easily indicated from the display device 1101 . Furthermore, since the area on the X-ray sensor (imaging device) 58 can be indicated while actually checking the imaging target on the display device 1101, there is an effect that the minimum required area can be indicated with high accuracy.

Then, by pressing the button 1103 , the object information of the selected imaging target is read from the storage device 28 into the imaging control circuit 24 . Here, the subject information refers to patient information such as physique, imaging site, patient's sex, age, nationality, and race. In this case, instead of allocating the test object information to the button 1103 , an item for inputting the patient's test object information may be added to the display screen 1101 . For example, based on patient information such as physique, the range used for imaging is roughly determined based on the imaging areas used for children and adult men. Therefore, if the center of the region to be photographed is indicated on the touch panel, the driving range of the photoelectric conversion element on the X-ray sensor (imaging device) 58 or the signal readout range of the photoelectric conversion element can be indicated. When such a configuration is adopted, there is an effect of being able to indicate an area suitable for the subject when the same type of subject is photographed multiple times. This is because if the type of the object to be photographed is identified based on the object to be inspected information, the region required for imaging can be specified statistically or empirically.

3rd embodiment

FIG. 5 is a block diagram of a device for specifying an X-ray image capturing area in cooperation with the aperture, and FIG. 6 shows a calculation method of the device for specifying an X-ray image capturing area in cooperation with the aperture. A specific method when the method of specifying the imaging range is coordinated with the aperture of the X-ray generator will be described with reference to FIGS. 5 and 6 .

As shown in Figure 5, the X-ray generator 40 is controlled by the X-ray tube 42 that generates X-rays, and is controlled by the imaging control circuit 24 to drive the high-voltage power supply 44 of the X-ray tube 42 to reduce the X-ray beam generated by the X-ray tube 42. An X-ray aperture 46 is configured to reach the desired imaging area. Here, the X-ray diaphragm generally uses lead or the like to block X-rays. The X-ray generator 40 includes a visible light source 201 such as a light bulb in order to display an imaging area narrowed by the X-ray diaphragm 46 . The positional relationship between the visible light source 201 and the X-ray aperture 46 is optically almost equal to the positional relationship between the focal point 203 of the X-ray tube 42 and the X-ray aperture 46 . Therefore, the range irradiated with visible light 202 is almost equal to the range irradiated with X-rays.

An embodiment in which the imaging area is calculated based only on the amount of the X-ray tube and the X-ray aperture and the geometric relationship of the X-ray imaging device will be described. The information needed when calculating the imaging area is the distance between the X-ray tube and the X-ray imaging device (L1+L2), the distance from the center of each collimating lens (Lx1, Lx2, Ly1, Ly2), and the distance from the X-ray imaging device. The positional information (SCx, SCy) where the center point of the X-rays generated by the tube reaches the X-ray imaging device, and the inclination angle (θx, θy) between the X-ray tube and the surface of the X-ray imaging device.

In addition, the distance L1 from the focal point of the X-ray tube to the collimator lens is information required when setting up the device. If according to these information, the range that the X-ray arrives in the X-ray imaging device is used as the range surrounded by (Ssx1, Ssy1), (Ssx1, Ssy2), (Ssx2, Ssy1), (Ssx2, Ssy2), then the calculation is

S sx1＝SCx-(L1+L2) Lx1 cosθx/L1 (Formula 1)

S sy1＝SCy-(L1+L2) Ly1 cosθy/L1 (Formula 2)

S sx2＝SCx+(L1+L2)·Lx2·cosθx/L1 (Formula 3)

S sy2＝SCy+(L1+L2) Ly2 cosθy/L1 (Formula 4)

In addition, the above calculation assumes that the range of X-ray irradiation limited by the collimator lens is rectangular or square, and the range of X-ray irradiation limited by the collimator lens can pass through the same even if it is elliptical or circular. Calculate the X-ray range of X-ray exposure. Among them, the inclination angle (θx, θy) between the X-ray tube and the surface of the X-ray imaging device is preferably placed on the surface of the X-ray imaging device in advance, so that θx and θy are simultaneously 0 by utilizing the reflection irradiated by the light bulb. .

Using the range including the X-ray imaging range obtained above, the range in which the row selection line or the power supply of the preamplifier (amplifier) is driven is determined. In this case, by setting, it is possible to select the X-ray imaging range to use a range larger than the X-ray irradiation range, or to use a range smaller than the X-ray irradiation range. Thereby, if the necessary information is measured in advance, it is possible to determine the drive range or the readout range of the X-ray sensor only by measuring the aperture amount of the X-ray tube.

4th embodiment

FIG. 7 is a configuration example in which an X-ray image imaging area is designated by devices 210 and 211 attached to an X-ray sensor (imaging device) 58 . That is, a method for specifying the drive range or readout range of the X-ray sensor (imaging device) 58 by the devices 210 and 211 in the X-ray imaging device will be described. Attachments 210 and 211 of the imaging device located in the designated X-ray imaging range in the X-ray imaging device are configured as shown in Figure 7 to be located outside the imaging range (for example, the peripheral area of the imaging device, where there is no photoelectric conversion element). area), and this position is easy to understand intuitively from the relationship with the X-ray image imaging area. In FIG. 7 , there is a button 210 as an accessory corresponding to each photoelectric conversion element, and only the photoelectric conversion element used is turned on. The state of being lit by an LED or the like is the button 211 as an accessory device. A shooting area 212 can be imagined from the button 211 that is lit. This is because in this case, for example, the imaging range (for example, 212(A)) can be determined from the vertical and horizontal AND relationship of the lit buttons 211 .

However, for example, when a plurality of shooting areas such as 212(A) and 212(D) are taken, 212(C) and 212(B) may be thought of as ghosting areas. Therefore, when a plurality of areas are indicated, as indicated by 215 , the button 210 located in the horizontal axis direction of the peripheral area may be further subdivided to indicate the coordinates in the vertical axis direction.

By pressing the button 210 as an accessory device, the button 211 is turned on and the driving range or readout range on the X-ray sensor (imaging device) 58 is indicated. In this way, the imaging control circuit 24 analyzes and determines the drive range or readout range from the position information of the button 211 . In addition, as another configuration, it may also be configured so that the switch 96 of the row selector (reading range specifying device) 92 is adjusted, or the not-shown ON/OFF of the driving device for power input of the preamplifier (amplifying device) 88 The OFF switch is mechanically linked.

fifth embodiment

Fig. 8 is for explaining the method of specifying the X-ray image shooting area by the irradiation field recognition device in the previous shooting. Using FIG. 8 , a method of specifying the X-ray imaging range using the irradiation field information at the time of the previous imaging will be described. The exposure field range of the previous image is directly used, or a range shifted by a predetermined distance based on information on the exposure field range of the previous image is used as the driving range or reading range (photographing range) of the X-ray sensor (imaging device) 58 . Such irradiation field identification can be extracted by implementing, for example, the irradiation field identification method disclosed in Japanese Patent Application Laid-Open No. 2000-271107 in the image processing circuit 26 . The imaging control circuit 24 analyzes and determines the drive range or the readout range based on the irradiation field identification result of the image processing circuit 26 .

Next, when it is known that the irradiation field area (imaging area) moves according to a certain rule, the imaging control circuit 24 can sequentially set the driving range or the readout range in accordance with the movement of the irradiation field area. For example, in the X-ray inspection of cargo at an airport, when the cargo placed on the conveyor belt is moved along the imaging area of the two-dimensional planar radiation detection device while taking pictures, it has the effect of saving power and reading in a short time.

In addition, even in the case where the imaging area itself is fixed, when the subject itself is known to move according to a certain rule, the imaging control circuit 24 may sequentially set the driving range or The structure of the read range. Even in this case, when shooting is performed while moving along the shooting area, there are effects of power saving and short-time readout.

FIG. 8 shows an example of an imaging flow. When specifying the imaging range using the previous irradiation field identification information, it is firstly selected whether the same imaging range as that in the previous imaging can be used, and then whether the imaging range obtained in the previous imaging can be directly used or not is selected. In the negative case, it is advantageous that the irradiation field identification information at the time of the previous imaging can be used by changing the size, position, and shape. In addition, the so-called "previous" exposure field identification information refers to an image captured before the desired image, not necessarily the image just captured.

sixth embodiment

When using the sensor (imaging device) 88 to capture a moving image, in the image of the subject obtained from the CCD camera 47, the difference between the captured images over time is calculated, and the photographing control circuit 24 calculates the occurrence of the subject. moving parts. Next, the imaging control circuit 24 regards only the moved portion as the driving range or the reading range of the sensor (imaging device) 88, or the driving range and the reading range. Thereby, there is an effect that it is possible to shorten the time for image readout and the like, and to reduce the image capacity. It can be said that it is as if hardware-based moving image compression processing has been performed.

Seventh embodiment

FIG. 9 is used to explain a method of indicating a driving range or a readout range, or a driving range and a readout range, of the sensor (imaging device) 58 by using relative position information between the inspected object and the X-ray imaging device. Using FIG. 9 , a method of using relative positional information between the object to be inspected and the X-ray imaging apparatus will be described.

Regarding the relative position information between the inspected object and the X-ray imaging device, the purpose is to know the imaging range in the X-ray imaging device, so it is not necessary to know the three-dimensional position information, preferably such as on the focal point optics with the X-ray tube A small camera such as a CCD is installed in a close position.

Eighth embodiment

A method of determining the X-ray imaging range using the CCD camera 47 will be described. The image captured by the CCD camera is displayed on the monitor, and the operator knows the geometric relationship between the X-ray imaging device viewed from the X-ray transmitting device and the object to be photographed before taking the X-ray. The operator first designates the range of the X-ray imaging device with a mouse or the like, and then designates the range used for imaging with the mouse or the like. These pieces of information can also be automatically obtained by image processing. In addition, when automatically obtained by this image processing, input information outside the imaging range, such as the imaging site designated by the device operating the X-ray imaging device, the patient's sex, age, and sensor tube distance, may be used. Based on the relative positional relationship between the range of the X-ray imaging device and the range desired to be captured on the image captured by the designated and selected CCD camera, information on the used amplifier photoelectric conversion element and the like can be obtained. At this time, by using the inverse function of the geometrical positional relationship (Equation (1) to Equation (4)) described in FIG. The minimum required X-rays can therefore be configured to automatically change the aperture 10 of the X-ray generator device.

The range showing the imaging area in FIG. 9 is illuminated by a light bulb, and the image is acquired by the CCD camera 47 attached to the X-ray tube. In order to designate the position of the two-dimensional flat sensor used in imaging, it may also be calculated by performing image processing.

The calculation procedure at this time will be described below. First step: search for an X-ray imaging device through parameter identification or the like from a CCD camera attached to an X-ray tube. At this time, in addition to the image selected from the CCD camera, for example, additional information such as the distance between the X-ray tube and the sensor, and the type or size of the X-ray imaging device used can be used to increase the speed and accuracy of the calculation. In addition to automatic recognition, for example, the range used for imaging can be specified by showing the range of the X-ray imaging device and the range of the X-ray imaging device illuminated by visible light on the image.

Second step: Calculate the imaging area by finding the range whose tone information is changed by visible light from the selected X-ray image imaging device position according to the image processing.

Step 3: Designate the photoelectric conversion element block used for imaging from (1) the obtained imaging region and (2) the photoelectric conversion element block information at the time of arrival of the X-ray imaging apparatus.

Step 4: Change the parameters so that only the ranges used in each stage of shooting, such as blank reading, reading during shooting, reading after shooting, amplifier photoelectric conversion element, etc., are used in the control device.

In addition, when the present two-dimensional planar radiation detection device is used for moving images or the like, only a part may be captured, and the other range may not be used for imaging. For example, the case where it is desired to confirm the insertion position of a catheter in a cardiac paravalve surgery using the present two-dimensional planar radiation detection device, and the like. In such a case, only the first frame is photographed in the entire photographing range, and in the second and subsequent frames, the required part can be photographed and combined. In particular, when performing partial preparation or partial readout of the shooting area during movie shooting, the effect of increasing the shooting speed can be increased by changing the shooting area every frame. For example, when shooting a moving image at 30 frames per second, it is preferable to capture the entire shooting range only once per second, and to combine the partial shooting area with the entire shooting range for the other 29 times per second.

In addition, when it is known that the partial imaging area has moved, the area may be controlled to move. For example, in the X-ray inspection of cargo at an airport, it is effective to save power when imaging while moving cargo on a conveyor belt along the imaging area of a two-dimensional planar radiation detection device.

FIG. 10 shows a schematic diagram of the power saving effect of the present invention. The area of the portion schematically shown by the time-power straight line in FIG. 10 corresponds to the total power consumption. According to the present invention, the area of the portion surrounded by oblique lines has the effect of saving power. The power saving effect is divided into two types. One is to reduce the electric power on the vertical axis by only inputting power to the photoelectric conversion elements corresponding to the portion designated as the imaging drive range.

Another point is that by using the address decoder 94 to select only the row corresponding to the designated portion of the imaging drive range, the time to read the charge after X-ray irradiation (main read) and the charge for correction (post-read) are read. The time to take) is shortened, so the time to input the power supply of the photoelectric conversion element of the amplifier is shortened. Based on these two effects, it is a feature of the present invention that the area of the hatched portion in FIG. 10 is reduced in terms of electric power and time.

In addition, in the partial designation of the imaging area performed by the present invention, a readout method combining digital zooming by sampling or pixel averaging for the purpose of speeding up data readout may be used in combination with these operations.

Fig. 11 shows the flow in the embodiment of the present invention. Firstly, the positions of the X-ray generating device and the X-ray imaging device are set. Next, it is selected whether to designate the X-ray imaging range, and if no designation is made, the entire range of the X-ray imaging device is driven. When specified, select (i) the aperture of the X-ray tube, (ii) the device attached to the X-ray imaging device, (iii) the irradiation field identification information at the time of the previous imaging, (iv) the subject and the imaging device Relative positional information between, (v) one or more devices operating the X-ray imaging device to determine the imaging range. As an imaging device attached to (ii), for example, as shown in FIG. 11 , buttons located on the surface of the housing of the X-ray imaging device are shown. In addition to (ii), for the case of operating on the operator interface 22, since there is a device for specifying the imaging range on the X-ray detector 52 and the thin X-ray detector 152 in (ii), it is preferable to use it with other related devices. Comparison has priority so that specification can be made without going through the flow of FIG. 11 . That is, when the entire range of the X-ray imaging device is used or a partial imaging is designated using (i) to (v), the X-ray detector 52 or the thin X-ray detector 152 shows which part is to be imaged. Since the amount of exposure will be excessive if shooting fails or re-shooting is unavoidable, it is preferable to always refer to the display of the shooting range before shooting. When it is desired to change the shooting range, it is preferable to use the priority of (ii) to change. In addition, the priority is given in (v), for example, when designation is made using an image obtained from a CCD camera or the like, or when designation is made on a monitor.

other embodiments

By supplying a storage medium storing program codes of software for implementing the functions of the apparatus or system according to the first or second embodiment to an apparatus or system, a computer (CPU, MPU, etc.) The object of the present invention can also be achieved by fetching and executing the program code stored in the storage medium.

In this case, the program code itself read from the storage medium realizes the functions of the first or second embodiment, and thus the storage medium storing the program code and the program code itself constitute the present invention.

The storage medium storing the program code may be, for example, ROM, floppy disk (registered trademark), hard disk, optical disk, magneto-optical disk, CD-ROM, CD-R, magnetic tape, non-volatile memory card, etc.

In addition, not only can the functions of the first or second embodiment be realized by reading and executing the program code by a computer, but also by executing part or all of the processing by the computer using the OS or the like running on the computer according to the instructions of the program code, it will also realize function of the first or second embodiment. The latter is also an embodiment of the present invention.

In addition, the program code read from the storage medium can be written into a memory of a function expansion board inserted into the computer or a function expansion unit connected to the computer. The functions of the first or second embodiment can also be realized by performing part or all of the processing by the CPU of the function expansion board or the function expansion unit according to the instructions of the program code. This is also one of the present invention

Example.

The present invention can be applied to a program or a storage medium storing the program.

The present invention can also be applied to a system including a plurality of devices (for example, a radiation generating device, an X-ray generating device, an image processing device, and an interface device, etc.) and a single device capable of realizing the functions of these devices. When the present invention is applied to a system comprising a plurality of devices, the devices communicate with each other, eg, by electrical, optical, and/or mechanical means, and/or other means.

Furthermore, the present invention can also be applied to an image diagnosis assistance system including a network (LAN and/or WAN, etc.).

The present invention thus achieves the above objects.

The present invention is not limited to the above-described embodiments, and various changes and modifications can be made within the spirit and scope of the present invention. Therefore, the following claims are appended to apprise the public of the scope of the invention.

Claims (5)

1. components of photo-electric conversion comprise:

Light is transformed to the optical detection device of electric signal;

Amplification is by the multiplying arrangement of the electric signal of this optical detection device output; And

The driving of this multiplying arrangement is carried out the drive unit of ON/OFF control.

2. X ray camera comprises:

By being used for that radioactive ray are transformed to the camera head that a plurality of components of photo-electric conversion of electric signal constitute;

A plurality of multiplying arrangements that electric signal from above-mentioned a plurality of components of photo-electric conversion output is amplified;

The driving of above-mentioned multiplying arrangement is carried out the drive unit of ON/OFF control.

3. X ray camera according to claim 2 is characterized in that, also comprises:

The read range specified device of the scope of the components of photo-electric conversion that appointment will be driven by this drive unit; And

Read signal reader by the output of the components of photo-electric conversion in the specified scope of this read range specified device.

4. X ray camera according to claim 3 is characterized in that:

Above-mentioned read range specified device shows the image that is photographed by above-mentioned camera head, and specifies the scope that reads the above-mentioned components of photo-electric conversion from shown image.

5. X ray camera comprises:

By being used for that light is transformed to the camera head that a plurality of components of photo-electric conversion of electric signal constitute;

Be used to specify the driving scope specified device of the scope that each components of photo-electric conversion that constitute above-mentioned camera head are driven;

The drive unit that the components of photo-electric conversion by the scope of above-mentioned driving scope specified device appointment are driven; And

Read the signal reader of the output of the components of photo-electric conversion that driven by above-mentioned drive unit;

Wherein, above-mentioned driving scope specified device is specified the scope that drives the above-mentioned components of photo-electric conversion by accompanying the coordinate entering device of above-mentioned camera head.

Images