JP2005296115A - Mammographic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To select the control of an irradiation condition depending on the kind of a radiation image detector. <P>SOLUTION: A mammographic apparatus 1 is provided with a radiation source 7, an object base 4 for supporting an object so as to face the radiation source 7, the radiation image detector facing the radiation source 7 through the object base 4 for detecting radiation transmitted through the object H by photographing, a discrimination means 100 for discriminating the kind of the radiation image detector, and a selection means 101 for selecting the control of the irradiation condition depending on the discriminated kind of the radiation image detector. The radiation image detector can be set to a close photographing position and an enlarged photographing position. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a mammography apparatus that selects an irradiation condition control method according to the type of radiation image detector.

  2. Description of the Related Art Conventionally, there is a mammography apparatus as an apparatus for performing image diagnosis in the medical field. This mammography apparatus irradiates radiation from a radiation source toward a subject, that is, a breast, so as not to harm the health of the subject, and detects radiation transmitted through the subject by a radiation image detector to acquire radiation image information. (For example, refer to Patent Document 1).

This mammography apparatus is equipped with a control device that controls the dose of radiation emitted from a radiation source. Specifically, the control device controls the radiation dose of the radiation source based on the radiation dose detected by a radiation dose detector, a so-called phototimer. The phototimer is arranged in a state fixed to the opposite side of the radiation source with respect to the radiation image detector, and detects the amount of radiation transmitted through the subject and the radiation image detector, that is, the transmitted dose. It has become.
JP 2001-238871 A (page 1 to page 12, FIGS. 1 to 10)

  However, in the conventional mammography apparatus, since the radiographic image detector has been switched from, for example, a screen film system (SF) to a computed radiography (CR), the phototimer table may be recreated. In addition, when the radiation image detector is a flat panel detector (FPD), for example, a photo timer is not used. Therefore, when the radiation image detector is used in combination with a screen film system or a computed radiography, aside from completely changing to a flat panel detector. Therefore, it is necessary to switch the method of controlling the irradiation dose, in other words, whether or not a phototimer is used.

  The present invention has been made in view of such circumstances, and it is an object of the present invention to provide a breast imaging apparatus capable of selecting an irradiation condition control method according to the type of radiation image detector.

  In order to solve the above-described problems and achieve the object, the present invention is configured as follows.

The invention according to claim 1 is a radiation source;
A subject table that supports the subject so as to face the radiation source;
A radiographic image detector for detecting radiation transmitted through the subject by imaging, facing the radiation source via the subject table;
Discriminating means for discriminating the type of the radiation image detector;
A mammography apparatus, comprising: selection means for selecting a control method of an irradiation condition according to the type of the determined radiographic image detector.

  The invention according to claim 2 is the breast image capturing apparatus according to claim 1, wherein the radiographic image detector can be set at a close contact photographing position and a phase contrast photographing position.

  According to a third aspect of the present invention, in the breast image photographing apparatus according to the second aspect, the close contact photographing position is a cassette insertion type holder to which the radiation image detector can be attached and detached.

  A fourth aspect of the present invention is the breast image photographing apparatus according to the second aspect, wherein when the cassette insertion type holder is set at the close-contact photographing position, the phototimer is controlled.

  According to a fifth aspect of the present invention, when an integrated holder to which the radiation image detector is directly attached is set at the phase contrast imaging position, the pre-exposure method is automatically controlled. The mammography apparatus described in 1. above.

  The invention described in claim 6 is characterized in that when the cable from the radiological image detector is attached, the pre-exposure method is automatically controlled. An image capturing device.

In the invention according to claim 7, the cassette insertion type holder has an identification means,
5. The mammography apparatus according to claim 3 or 4, wherein the apparatus main body is provided with a reader for the identification means.

  The invention according to claim 8 is the mammography apparatus according to any one of claims 1 to 7, wherein the selection unit is provided in an operation unit of the apparatus main body.

  The invention according to claim 9 is the mammography apparatus according to any one of claims 1 to 7, wherein the selection means is provided in a control device of the apparatus main body.

  With the above configuration, the present invention has the following effects.

  According to the first aspect of the present invention, it is possible to photograph under the optimum irradiation condition by determining the type of the radiation image detector and selecting the control method of the irradiation condition according to the determined type of the radiation image detector. Under optimal irradiation conditions, for example, there is too much irradiation dose so that unnecessary exposure does not occur, and too little irradiation dose prevents image quality from deteriorating and diagnostic ability to deteriorate.

  According to the second aspect of the present invention, the radiation image detector can be set at the close contact photographing position and the phase contrast photographing position, and a high quality image can be obtained by the phase contrast photographing. Since patients such as wheelchairs are difficult to photograph, close contact photography can be performed for such a case. In phase contrast photography, it is desirable to use a flat panel detector capable of actual print output and computed radiography, and in close-contact photography, it is preferred to use a screen film system with good image quality.

  According to the third aspect of the present invention, the close-contact photographing position is a cassette insertion type holder. For example, when a patient such as a wheelchair patient needs to be photographed in close contact, a screen film system with better image quality is used. Since it is preferable, the cassette insertion type holder which can insert a screen film system is used.

  According to the fourth aspect of the present invention, when the cassette insertion type holder is set at the close-contact photographing position, the control of the phototimer is performed. Images can be taken using a screen film system.

  According to the invention described in claim 5, when the integrated holder is set at the phase contrast photographing position, the pre-exposure method is automatically controlled, and when a flat panel detector is used, it is not necessary to set each time, There will be no mistakes.

  According to the invention described in claim 6, when the cable from the radiation image detector of the flat panel detector is attached, the pre-exposure method is automatically controlled. When the flat panel detector is used, it is set each time. There is no need to make a mistake and no mistakes are made.

  According to the seventh aspect of the present invention, the cassette insertion type holder has the identification means, the apparatus main body is provided with the reader of the identification means, and can be set without error by reading the reading apparatus.

  According to the eighth aspect of the present invention, the selecting means is provided in the operation unit of the apparatus main body, and can be set without mistake, and the automatically set one can be changed manually.

  According to the ninth aspect of the present invention, the selection means is provided in the control device of the apparatus main body, and can be set without error, and the automatically set one can be changed manually.

  Hereinafter, embodiments of the mammography apparatus of the present invention will be described. However, the present invention is not limited to these embodiments. The embodiment of the present invention shows the most preferable mode of the present invention, and the terminology of the present invention is not limited to this.

  FIG. 1 is a schematic diagram showing the configuration of the main part of a breast image photographing apparatus according to the first embodiment. The breast image capturing apparatus 1 is an apparatus that captures an absorption contrast image in the normal capturing mode and captures a phase contrast image in the phase contrast image capturing mode.

  In the breast image photographing apparatus 1, the photographing unit 2 having a substantially seven letter shape in a side view is disposed in a state of being supported by a columnar support base 20. At the lower end of the imaging unit 2, a subject table 4 that supports the subject H is provided horizontally, and a support shaft 3 that supports the radiation image detectors 26, 29, etc. protrudes downward. Is provided with a radiation source 7 for irradiating the subject table 4 with radiation.

  The subject table 4 is movable up and down, and the distance R1 between the subject table 4 and the radiation source 7 is 50 [cm] ≦ R1 ≦ 100 [cm]. This interval R1 is one of the parameters for changing the exposure dose of the subject H, and is one of the control conditions for controlling the irradiation dose of the radiation source 7.

  Above the subject table 4, a plate-shaped compression plate 30 is disposed substantially parallel to the subject table 4. The compression plate 30 extends up and down and can move up and down along a rail (measuring device) 31 provided in the photographing unit 2. The pressure is about 150 [N], for example, 100 [N]. The rail 31 also functions as an electrical resistor and detects a resistance value corresponding to the position of the compression plate 30. Thereby, the distance R3 between the lower surface of the compression plate 30 and the upper surface of the subject table 4, that is, the thickness of the subject H in the state sandwiched between the compression plate 30 and the subject table 4 is measured. This interval R3 is one of the parameters for changing the exposure dose of the subject H, and is one of the control conditions for controlling the irradiation dose of the radiation source 7.

  A radiographic image detector 23 used in the normal imaging mode is provided below the subject table 4. The subject table 4 is also used as a cassette insertion type holder to which the radiation image detector 23 can be attached and detached. The radiation image detector 23 can be rotated from the horizontal position to the A position about the first rotation shaft 90. The radiation image detector 23 is in the horizontal position in the normal imaging mode and in the phase contrast image imaging mode. It is arranged at the A position. More specifically, when the radiation image detector 23 is in the horizontal position, the upper surface of the subject table 4, that is, the distance between the subject H and the radiation image detector 23 becomes zero.

  Although the configuration in which the radiation image detector 23 is rotated from the horizontal position to the A position around the first rotation shaft 90 is automatically performed, it may be performed manually. Further, the radiation image detector 23 is configured to be out of the irradiation field of the radiation source 7 when it is at the A position. The radiation image detector 23 may be provided so as to be removable from the subject table 4.

  The support shaft 3 is provided extending in the vertical direction. The support shaft 3 is detachably provided with radiation image detectors 26 and 29 used in the phase contrast image photographing mode.

  The radiation image detector 26 is located below the subject table 4 and is rotatable from the horizontal position to the B position around the second rotation shaft 24. When the radiation image detector 26 is in the horizontal position, a phase contrast image can be taken. At this time, the distance R2 between the radiation image detector 26 and the upper surface of the subject table 4 is within a range of 15 [cm] ≦ R2 ≦ 100 [cm], preferably 25 [cm] ≦ R2 ≦ 80 [cm]. Yes. The distance R21 between the radiation source 7 and the radiation image detector 26 is 75 [cm] ≦ R21 ≦ 200 [cm], preferably 100 [cm] ≦ R21 ≦ 160 [cm]. When the radiographic image detector 26 is in the normal imaging mode or when the radiographic image detector 29 is used, the radiographic image detector 26 moves to the B position and retracts from the irradiation field of the radiation source 7. Yes.

  The radiographic image detector 29 is located below the radiographic image detector 26 and is rotatable from the horizontal position to the C position around the third rotation shaft 27. The radiation image detector 29 slides and expands at the horizontal position, and slides and contracts at the C position. The radiation image detector 29 is removed when the normal imaging mode or the radiation image detector 26 is used. At this time, the radiation image detector 29 slides and contracts to move to the C position.

  The distance R22 between the upper surface of the subject table 4 and the radiation image detector 29 is set larger than the distance R2 between the upper surface of the subject table 4 and the radiation image detector 26. Therefore, an image with a higher magnification can be obtained when the radiographic image detector 29 is used for imaging than when the radiographic image detector 26 is used for imaging. Here, the relationship between the distance R21 between the radiation source 7 and the radiation image detector 26 and the distance R2 between the subject table 4 and the radiation image detector 26 will be described. A larger R2 is preferable because the edge effect due to the phase contrast becomes larger, but if R2 is too large with respect to R21, sharpness is deteriorated due to the influence of the blur of the penumbra. Therefore, it is desired from the aspect of image quality improvement that both R21 and R2 are long. However, when actually using the mammography apparatus in the imaging room, there is a problem that the apparatus may be rotated and used. There is a point. Therefore, the desirable sizes of R21 and R2 are determined in terms of image quality and ease of use.

  Next, the radiation image detectors 23, 26, and 29 will be described. The radiation image detectors 23, 26, and 29 detect the radiation transmitted through the subject H. Specifically, a. A combination of a radiation fluorescent intensifying screen and a silver halide photographic film; b. A fluorescent plate emitting stimulable light, c. A radiation image information reading device in which a scintillator for converting radiation energy into light and an optical semiconductor element for reading the light are two-dimensionally arranged; d. A radiographic image information reading device in which a photoconductor for directly converting radiation energy into an electric signal and a semiconductor element for reading the electric signal are two-dimensionally arranged; e. A radiographic image information reading apparatus in which a combination of a scintillator for converting radiation into light and a lens for condensing the light on a CCD, CMOS, or the like is arranged in one or more sets, or f. A scintillator that converts radiation into light and a radiation image information reading device that guides the light to a CCD or CMOS with an optical fiber and replaces it with an electrical signal can be used.

  Here, the radiation image detectors 23, 26, and 29, which are an assembly of an X-ray fluorescent intensifying screen and a silver halide photographic film as shown in a, are also referred to as an SF system (screen film system). The X-ray fluorescent intensifying screen has a rare earth phosphor such as calcium tungstate or gadolinium oxysulfide, and replaces X-ray energy with blue or green light emission. In particular, for an intensifying screen using a rare earth phosphor, the technique disclosed in Japanese Patent Laid-Open No. 6-67365 may be used. In addition, it is preferable to use a silver halide photographic film in which a photosensitive emulsion is coated only on one side of the support or a photosensitive emulsion coated on both sides of the support. In particular, in the case of a double-sided film, it is a preferred embodiment to use a photographic light-sensitive material in which the photographic characteristics of the respective emulsion layers sandwiching the film support are different. It is also preferred to use a photographic film having a layer that absorbs crossover light between the emulsion surfaces of the double-sided film. The size of the single-sided and double-sided film used in the present invention can be any size from six-cut size to half-cut size. These silver halide photographic light-sensitive materials are outlined in Japanese Patent Application Laid-Open No. 6-67365, for example, “Basics of Revision Photographic Engineering—Silver Salt Photo Edition” (Corona Company, 1998, edited by the Japan Photographic Society). For photographic film development processing, the average gradation can be increased by raising the development temperature or extending the processing time, but in principle when developing automatically, the development conditions specified by the film manufacturer It is preferable to treat with.

  The stimulable phosphor referred to in b above is one in which visible light emission corresponding to the X-ray intensity already irradiated is induced by irradiation with visible light after irradiation. That is, after the X-ray irradiation, this phosphor is transferred to a laser reader to read out the stimulated emission, and the read emission is replaced with an electric signal by a photomultiplier tube to obtain an X-ray image electric signal. This electric signal is subjected to appropriate image processing and then displayed on an image display means such as a monitor, or a hard copy of an X-ray image is obtained using an image output means such as a laser imager. At this time, in the case of an image taken by phase contrast, it is a preferable aspect that the image is automatically returned to the actual size by inputting an enlargement magnification in advance and displayed on a monitor or output to a hard copy. Regarding the radiation image detector using the photostimulable phosphor, it is preferable to use the phosphor disclosed in Japanese Patent Application No. 2000-245721 and image visualization technology such as photostimulated luminescence reading in this invention. It is.

  For the reading device for converting the radiation described in the above cf into an electrical signal, refer to “Handbook of Medical Imaging” Vol. It is a preferred embodiment to use the technique disclosed in Chapter 1, “Flat panel images for digital radio graphics” (ed. R. V. Matter et al., SPIE Press, Bellingham, 2000). In these cases, the electrical signals of the X-ray images obtained by the radiation image detectors 23, 26, and 29 are appropriately processed, and the images are drawn on a monitor or on a hard copy for use in image diagnosis or the like.

  In the case of using the radiation image detector to which these cf are applied, in the normal imaging mode, 18 [cm] × 24 [cm] or 24 [cm] × 30 [cm], which has been mainly used conventionally. A radiographic image detector of the size is used. On the other hand, in the phase contrast image photographing mode, since it is phase contrast photographing, it is preferable to use a large one. Specifically, the size of the radiation image detector is preferably 25 [cm] × 32 [cm] or more, and considering the ease of handling, the size is preferably about 35 [cm] × 43 [cm].

  As the radiation source 7, a radiation tube having a focal size of 300 [μm] and a radiation tube having a focal size of 100 [μm] are provided to be switchable. Specifically, a radiation tube with a focal size of 300 [μm] is used in the normal imaging mode, and a radiation tube with a focal size of 100 [μm] is used in the phase contrast image imaging mode. Note that the focal point of the radiation source is, for example, a window viewed from the direction of the subject from which radiation generated by electrons colliding with the rotating anode of the radiation tube is taken out. In general, the focal point is a square, and the length of one side is the focal point size D. When the focus is circular, the diameter is the focus size D, and when the focus is rectangular, the short side is the focus size D. As a method for measuring the focus size D, a method using a pinhole camera and a method using a micro test chart are described in JIS Z 4704.

  As these radiation tubes, radiation tubes that irradiate radiation having a wavelength of about 0.1 to 1 [１] are used. The radiation tube accelerates electrons generated by thermal excitation with a high voltage and collides with the cathode. As a result, the kinetic energy of the electrons is converted into radiant energy, and radiation is emitted from the focal point. When a radiation image is taken, the acceleration voltage is set as a tube voltage, the amount of electrons generated is set as a tube current, and the radiation irradiation time is set as an exposure time. The anode (counter cathode) with which the electrons collide is formed of copper, molybdenum, rhodium, tungsten, or the like. In addition, if the kind of anode changes, the energy spectrum of the irradiated radiation will change. In this embodiment, among these anodes, anodes such as copper, molybdenum, and rhodium are used, and a radiation spectrum having a narrow energy distribution and a relatively low energy is obtained. . Further, this anode is a so-called rotating anode, and the collision position with the electrons can be dispersed by rotating. Since such an anode can disperse the heat generation position due to the collision, it has an advantage that it is difficult to melt.

  The support base 20 is provided with a power supply unit 56 and a control device 11 that controls the operation of the imaging unit 2. As shown in FIG. 2, the control device 11 includes a CPU 40 that controls all operations of the control device 11. A system bus 41, an image bus 42, and an input interface 43 are connected to the CPU 40, and the operation of each unit is controlled via the system bus 41, and radiation image information between each unit via the image bus 42. Is transferred. The system bus 41 and the image bus 42 include a shooting control unit 44, a switching unit 45, a frame memory control unit 50, a disk control unit 48, an output interface 51, an image processing unit 49, an input interface 43, a memory 47, a control device 60, and the like. It is connected.

  The imaging control unit 44 reads out radiation image information from the radiation image detectors 23, 26, and 29 and supplies it to the frame memory control unit 50. Further, the imaging control unit 44 rotates the radiological image detector 23 from the horizontal position to the A position in the phase contrast image imaging mode, and when the radiographic image detector 26 is not in the horizontal position, the support base 25 is moved. When the support base 28 does not support the radiation image detector 29, the support base 28 is rotated from the horizontal position to the C position. Although the rotation of the radiation image detectors 23, 26, and 29 is automatically performed, it may be performed manually or may be manually attached or detached.

  The switching unit 45 is switching means for switching between the phase contrast image shooting mode and the normal shooting mode. Note that the switching instruction may be input from the input device 12 of the input interface 43.

  A frame memory 52 is connected to the frame memory control unit 50, and the radiation image information generated by the radiation image detectors 23, 26, and 29 is stored in the frame memory 52. The radiation image information stored in the frame memory 52 is read out and supplied to the disk control unit 48. The frame memory 52 may store radiation image information supplied from the radiation image detectors 23, 26, and 29 and processed by the image processing unit 49.

  When supplying radiation image information from the frame memory 52 to the disk control unit 48, the radiation image information is continuously read out and written to the FIFO memory in the disk control unit 48, and then sequentially stored in the disk device 53. It has become so. The disk device 53 stores the radiation image information stored in the frame memory 52, that is, the radiation image information supplied from the radiation image detectors 23, 26, and 29 and processed by the image processing unit 49 together with management information and the like. Can be done. The management information is information including subject identification information for identifying the subject H, information for identifying radiation image information, information related to imaging such as an enlargement rate of an X-ray image, and the like.

  The radiation image information read from the frame memory 52 and the radiation image information read from the disk device 53 are supplied to the image output device 54 and the monitor (notification unit) 13 as image output means via the output interface 51. Then, it is provided to the user as a visible image. This monitor 13 notifies the operator of an abnormality in the irradiation dose of the radiation to be irradiated.

  The image processing unit 49 performs irradiation field recognition processing, region of interest setting, normalization processing, gradation processing, and the like of the radiation image information supplied from the radiation image detectors 23, 26, and 29 via the imaging control unit 44. The image processing unit 49 performs frequency enhancement processing, dynamic range compression processing, and the like. Further, the image processing unit 49 returns an image captured at an enlargement of 1x or more to the same magnification based on the shooting mode information, and automatically displays or outputs a display close to the actual size via the monitor 13 or the image output device 54. Can be done automatically. In addition, it is also possible to perform image processing or the like in a configuration in which the CPU 40 serves as the image processing unit 49.

  The mammography apparatus 1 of this embodiment includes a determination unit 100 and a selection unit 110. The discriminating means 100 discriminates the types of the radiation image detectors 23, 26 and 29. As described above, the types of the radiation image detectors 23, 26, and 29 include a. A combination of a radiation fluorescent intensifying screen and a silver halide photographic film; b. A fluorescent plate emitting stimulable light, c. A radiation image information reading device in which a scintillator for converting radiation energy into light and an optical semiconductor element for reading the light are two-dimensionally arranged; d. A radiographic image information reading device in which a photoconductor for directly converting radiation energy into an electric signal and a semiconductor element for reading the electric signal are two-dimensionally arranged; e. A radiographic image information reading apparatus in which a combination of a scintillator for converting radiation into light and a lens for condensing the light on a CCD, CMOS, or the like is arranged in one or more sets, or f. A scintillator that converts radiation into light and a radiation image information reading device that converts the light to a CCD or CMOS with an optical fiber and replaces it with an electrical signal.

  As shown in FIGS. 3 (a) and 3 (b), the flat panel detectors cf of this radiographic image detector can be attached to and detached from the cassette integrated type to which the radiographic image detector is directly attached. There is a cassette insertion type. Moreover, as shown in FIG.3 (c), the computed radiography of b and the screen film system of a are cassette insertion types which can attach or detach a radiographic image detector. As described above, the radiation detector includes a to f types, and c and d among c to f are preferable as the flat panel detector used in the present invention.

  Such a radiation image detector can be set at the close contact photographing position and the phase contrast photographing position. When photographing a normal mammo, photographing at the phase contrast photographing position can improve the image quality and can reduce the exposure dose. Therefore, it is preferable. At the phase contrast imaging position, since a large image is captured for phase contrast imaging, it is preferable to use a digital radiation image detector to output the actual size. Among digital radiographic image detectors, a flat panel detector capable of confirming a captured image instantly after imaging is preferable. In close-contact photography, it is preferable to use a screen film system with the best image quality.

  1 has a subject table 4, and as shown in FIG. 4, a radiation image detector 23 is set on the subject table 4 located at the close-up position. In this set of radiographic image detectors 23, as shown in FIG. 4A, when the radiographic image detector 23 is attached to the subject table 4 at the close-contact photographing position, and as shown in FIG. In some cases, the radiological image detector 23 that has been used is positioned at the close-contact imaging position, which is the use position.

  The subject table 4 has a cassette insertion function. When the subject table 4 is located at the close-contact photographing position, the cassette upper plate also serves as the subject table 4. The subject table 4 has a flat panel detector cassette insertion type shown in FIG. 3B as a radiation image detector 23, and a computed radiography and screen film system cassette insertion type shown in FIG. 3C. A radiation image detector is set. In this case, since the subject table 4 itself has a cassette insertion function, a radiographic image detector 23 of a flat panel detector or a radiographic image detector 23 of a computed radiography or screen film system is inserted. For example, when a patient in a wheelchair or the like has to shoot closely, it is preferable to use a screen film system with better image quality.

  In this way, the close contact imaging position is a cassette insertion type holder to which the radiation image detector 3 can be attached and detached, and when the cassette insertion type holder configured by the subject table 4 having the cassette insertion function is set at the close contact imaging position. The photo timer is controlled to control the irradiation conditions.

  At the phase contrast imaging position shown in FIG. 1, as shown in FIG. 5, a cassette integrated type of flat panel detectors cf is set as the radiation image detectors 26 and 29. When the cassette-integrated type is set at the phase contrast imaging position, the radiation image detector used in the cassette-integrated type is a flat panel detector. For this reason, it is not necessary to set each time, and there is no mistake.

  Further, when the cassette insertion type of the flat panel detectors cf is set and a cable from the cassette insertion type is attached, the pre-exposure method is automatically controlled. Thus, when using a flat panel detector, it is not necessary to set each time, and there is no mistake.

  Also, when setting the radiation image detector at the phase contrast imaging position, if the cassette insertion type holder and the subject table are integrated in the close-contact imaging position, replace with the subject table only, leaving the subject table and the cassette insertion type. If only the holder can be removed, remove only the holder. In the claims, setting the integrated holder to which the radiation image detector is directly attached may mean that it is actually attached to the phase contrast imaging position, or moved from the position retracted from the phase contrast imaging position to the position at the time of imaging. It may mean attaching, including doing, and the word removing is also the same.

  In this embodiment, as shown in FIG. 4, the cassette insertion type holder constituted by the subject table 4 includes an identification unit 151, and the apparatus main body includes a reader 152 of the identification unit 151. The identification unit 151 is configured by, for example, a barcode or a wireless tag. When the cassette insertion type holder is set, the reader 152 of the apparatus body reads the type of the radiation image detector from the identification means 151. In this embodiment, it is read that the cassette insertion type of the flat panel detector shown in FIG. 3 (b) and the computed radiography and the cassette insertion type of the screen film system shown in FIG. 3 (c) are set. Setting can be made without error by reading the reading device 152.

  The selection unit 110 selects an irradiation condition control method according to the determined type of the radiation image detector. As shown in FIGS. 1 and 2, the selection unit 110 is provided in the operation unit 111 of the apparatus main body, and includes, for example, an SF button 110a, an FPD button 110b, and a CR button 110c. By operating the SF button 110a, the FPD button 110b, and the CR button 110c, an irradiation condition control method is selected according to the type of radiation image detector, a selection signal is input via the input interface 44, and is sent to the control device 60. The control device 60 can be set without error by the irradiation condition control method depending on the type of radiation image detector. Further, the automatically set one may be changed manually.

  The operation unit 111 is provided in the control device 11 in the embodiment of FIGS. 1 and 2, but may be provided in the support base 20 or may be provided in the photographing unit 2.

  Moreover, the selection means 110 is provided in the control apparatus 11, as shown in FIG. The selection unit 110 selects an irradiation condition control method according to the determined type of the radiation image detector based on the determination signal from the determination unit 100, and sends the selection signal to the control device 60. The control device 60 detects the radiation image. The irradiation conditions can be controlled according to the type of vessel and can be set without mistake. Further, the automatically set one may be changed manually.

  As described above, by determining the type of the radiation image detector and selecting the control method of the irradiation condition according to the determined type of the radiation image detector, it is possible to photograph under the optimal irradiation condition. Under optimal irradiation conditions, for example, there is too much irradiation dose so that unnecessary exposure does not occur, and too little irradiation dose prevents image quality from deteriorating and diagnostic ability to deteriorate. In the case of the computed radiography and screen film system, the radiation dose of the radiation source is controlled based on the radiation dose detected by the phototimer. This phototimer is arranged in a state fixed to the opposite side of the radiation source with respect to the radiation image detector, and detects the amount of radiation that has passed through the subject and the radiation image detector, that is, the transmitted dose. It has become.

  FIG. 7 shows an example in which the radiation dose of the radiation source is controlled based on the radiation dose detected by the phototimer. For example, three phototimer light receiving units 203a to 203c are arranged on the subject table 4 on which the radiation image detector is installed. These phototimer light receiving sections 203a to 203c are arranged in a line from the near side, which is the insertion direction of the radiation image detector, to the back. Each of the phototimer light receiving sections 203a to 203c is a radiation detector including a scintillator and a photoelectric converter such as a photomultiplier tube or a photodiode, and outputs the intensity of the radiation incident on the light receiving surface as a radiation received signal. It is supposed to be.

  The radiation light receiving signals output from the phototimer light receiving units 203a to 203c are input to the selector 204, respectively. The selector 204 is a circuit that selects only one of the radiation received light signals from the phototimer light receiving units 203 a to 203 c according to the selection signal and sends it to the imaging control unit 44. The imaging control unit 44 controls the radiation blocking signal to the radiation high voltage generator 216 via the radiation source controller 55 when the integrated value of the radiation received light signal reaches the reference value, thereby blocking radiation irradiation. Control the automatic irradiation dose.

  A touch panel 209 is attached to the entire bottom surface of the compression plate 30 as a compression surface. The touch panel 209 is a position detection panel that detects a pressed position using, for example, a resin whose electrical resistance changes according to pressure. That is, the touch panel 209 outputs a pressing position signal indicating whether or not pressure is applied to each area by dividing the panel surface into a large number of areas in a matrix and sequentially scanning these areas by the touch panel driver 210. To do. Therefore, when the subject H is compressed with the compression plate 30, it is possible to detect which region of the touch panel 209 is in contact with and pressed by the subject H.

  The pressed position signal output from the touch panel 209 via the touch panel driver 210 is input to the light receiving unit selection unit 211. The light receiving unit selection unit 211 selects one of the phototimer light receiving units 203a to 203c in accordance with the pressed position signal. That is, the light receiving unit selection unit 211 first checks whether or not the area on the touch panel 209 corresponding to the position where the light receiving surface is arranged is pressed for each phototimer light receiving unit 203a to 203c. Of the photo timer light receiving portions 203a to 203c that are all pressed, the one located on the farthest side is selected.

  Then, when any one of the phototimer light receiving units 203a to 203c is selected in this way, a selection signal corresponding to this is sent to the selector 204, so that only the radiation received light signal from the selected phototimer light receiving unit is obtained. The image is sent to the imaging control unit 44.

  For example, when radiography of a large subject H is performed, when the subject H is compressed with the compression plate 30, a pressing position signal indicating that a region within a wide range has been pressed is output from the touch panel 209. Therefore, the light receiving unit selection unit 211 selects the phototimer light receiving unit 203c arranged on the innermost side, and only the radiation received light signal from the phototimer light receiving unit 203c is sent to the imaging control unit 44 via the selector 204. Therefore, in the case of the subject H having such a large size, accurate automatic control is performed according to the incident amount of the photographing control unit 44 that is incident on the phototimer light receiving unit 203c arranged at the innermost side. When radiography is performed on a subject H having a small size, a touch position signal indicating that a region within a narrow range has been pressed when the subject H is compressed with the compression plate 30 is output from the touch panel 209. Therefore, the light receiving unit selection unit 211 selects the phototimer light receiving unit 203a arranged on the front side, and only the radiation light reception signal from the phototimer light receiving unit 203a is sent to the imaging control unit 44 via the selector 204. Accordingly, in the case of the subject H having such a small size, accurate automatic irradiation dose control is performed in accordance with the amount of radiation incident on the phototimer light receiving unit 203a arranged on the most front side. Similarly, in the case of the subject H having an intermediate size, accurate automatic irradiation dose control is performed according to the amount of radiation incident on the phototimer light receiving unit 203b disposed in the center in the same manner.

  The selection process of the phototimer light receiving units 203a to 203c is not limited to these methods. For example, the area of the pressed area indicated by the pressed position signal, the position of the innermost side among the pressed areas, and the like are selected. By detecting, the subject H can be classified into three types of sizes, and any one of the phototimer light receiving units can be selected according to the classified sizes. Further, various image processing such as feature extraction may be performed based on the pressed position signal, and an optimal phototimer light receiving unit may be selected by an appropriate algorithm based on the processing result.

  Furthermore, although the case where three phototimer light receiving units are arranged is shown, a plurality of other phototimer light receiving units can also be arranged. Moreover, although the touch panel 209 that detects the pressed position is used as the position detection panel, a position detection panel that detects the contact position of the subject H can be used instead.

  Further, regarding detection of radiation by a phototimer, arrangement of a phototimer, and a method of controlling the radiation dose of a radiation source based on the detected radiation dose, JP-A Nos. 2003-290184 and 2003-287830 are disclosed. , JP-A-2002-45354, JP-A-2003-290184, JP-A-2003-302716, JP-A-2000-173895, JP-A-8-238237, etc. It is a preferred embodiment to use this technique in the present invention.

  For the control in the case of a flat panel detector, a pre-exposure method from a radiation image detector is used, and the irradiation condition of the main exposure is determined from image information by this pre-exposure. Specifically, imaging is performed with a very small amount of radiation before actual imaging, and conditions for actual imaging are determined based on the signal and histogram information at that time. For example, photographing is performed by determining tube voltage, mAs value, target, and (if there are a plurality of filters) as photographing conditions for the main photographing.

  In the case of flat panel detectors and computed radiography, the irradiation conditions may be set by referring to the data table, the exposure dose of the subject can be estimated quickly, images can be taken, and In comparison, radiation with a safe irradiation dose can be reliably and promptly irradiated.

  This invention irradiates the subject with radiation that does not harm the health of the subject, toward the subject, that is, the breast, detects radiation transmitted through the subject with a radiation image detector, acquires radiation image information, and performs image diagnosis It can be applied to a mammography apparatus for performing the above.

It is the schematic which showed the principal part structure of the mammography apparatus. It is a block diagram showing the main structures of a control part. It is a figure which shows the kind of radiographic image detector. It is a figure which shows the set of the radiographic image detector in a close_contact | adherence imaging position. It is a figure which shows the set of the radiographic image detector in a phase contrast imaging position. It is a block diagram of other embodiments showing the main composition of a control part. It is a figure which shows an example of implementation which controls the irradiation dose of a radiation source based on the irradiation dose of the radiation detected by the phototimer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Breast imaging device 4 Subject stand 7 Radiation source 11 Control device 12 Input device (age input device, density information input device)
13 Monitor (notification part)
23, 26, 29 Radiation image detector 30 Compression plate 31 Rail (measuring device)
47 memory (first storage unit, second storage unit)
100 Discrimination means 101 Selection means 140 Flat panel detector cassette integrated type 141 Flat panel detector cassette insertion type 142 Computed radiography, cassette insertion type of screen film system 150 Cassette insertion type holder 151 Identification means 152 Reader H Subject R3 Distance between the lower surface of the compression plate and the upper surface of the subject table (subject thickness)
R1 Distance between radiation source and subject table

Claims (9)

A radiation source;
A subject table that supports the subject so as to face the radiation source;
A radiographic image detector for detecting radiation transmitted through the subject by imaging, facing the radiation source via the subject table;
Discriminating means for discriminating the type of the radiation image detector;
A mammography apparatus, comprising: selection means for selecting a method for controlling an irradiation condition according to the determined type of the radiation image detector. The mammography apparatus according to claim 1, wherein the radiation image detector can be set at a contact imaging position and a phase contrast imaging position. The mammography apparatus according to claim 2, wherein the close-contact imaging position is a cassette insertion type holder to which the radiation image detector can be attached and detached. The mammography apparatus according to claim 2, wherein when the cassette insertion type holder is set at the close-contact imaging position, the phototimer is controlled. The mammography apparatus according to claim 2, wherein when an integrated holder for directly attaching the radiation image detector is set at the phase contrast imaging position, the pre-exposure method is automatically controlled. 5. The mammography apparatus according to claim 3, wherein when the cable from the radiological image detector is attached, the pre-exposure method is automatically controlled. The cassette insertion type holder has an identification means,
The mammography apparatus according to claim 3 or 4, wherein the apparatus main body is provided with a reader for the identification means. The mammography apparatus according to claim 1, wherein the selection unit is provided in an operation unit of the apparatus main body. The mammography apparatus according to claim 1, wherein the selection unit is provided in a control device of the apparatus main body.

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