JP2009240467A - Image pickup device for breasts - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To display a mark at an accurate position regardless of the height and distortion of a pressurizing plate, in an image pickup device for breasts capable of imaging the radiation image of an object and displaying a mark in the region of interest on the object using a laser beam or the like. <P>SOLUTION: In the image pickup device for breasts capable of imaging the radiation image of the breast B and also displaying a mark M in the region of interest on the breast B using the laser beam or the like, the height h from an imaging table part 5b of the pressurizing plate 7 and the inclination (distortion) of the pressurizing plate 7 in the state of pressurizing the breast B onto the imaging table part 5b by the pressurizing plate 7 are detected by a pressurizing plate position information detection means, and the position of the mark M displayed by a laser beam irradiation device 13 is corrected by a correction means on the basis thereof. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a breast image capturing apparatus capable of capturing a radiographic image of a subject and displaying a region of interest on the subject using, for example, a laser beam.

  2. Description of the Related Art Conventionally, in the medical field and the like, various types of radiation detectors that record a radiation image related to a subject by irradiation with radiation that has passed through the subject have been proposed and put into practical use.

  As the radiation detector, for example, as described in Patent Document 1, there is a radiation detector using a semiconductor such as amorphous selenium that generates a charge by irradiation of radiation, and as such a radiation detector, a so-called radiation detector is used. An optical reading type and a TFT reading type have been proposed.

  If such a radiation detector is used, image information obtained by imaging can be acquired as digital data, so that affinity with a diagnosis support apparatus using a computer can be increased.

On the other hand, as described in Patent Document 2, a breast imaging apparatus that displays a mark on a region of interest of a subject using a laser marker has been proposed. This is because, for example, when a part having an abnormality such as cancer is found in a radiographic image taken, a mark is displayed by irradiating a part on the breast corresponding to that area with a laser marker from above the pressing plate. Thus, a doctor or the like can puncture the needle with respect to the anomalous part to obtain a biological sample.
JP 2000-105297 A International Publication No. WO2007702050

  In the breast imaging apparatus provided with the laser marker as described above, the laser beam depends on the height or distortion of the pressing plate that presses the breast unless the laser marker emission point is aligned with the focal point of the radiation irradiation means or the virtual image position of the focal point. The irradiation position of the marker changes, and the marker cannot be displayed at an accurate position.

  However, if the laser marker emission point is set to the focal point of the radiation irradiation means or the virtual image position of the focal point, the operator's hand or the like is hindered when the needle is punctured, and the laser marker can be displayed normally. It may be lost.

  Therefore, it is conceivable to arrange the emission point of the laser marker at a position different from the focal point of the radiation irradiating means or the virtual image position of the focal point so as not to be hindered by the operator's hand, etc. As described above, there arises a problem that the irradiation position of the laser marker changes depending on the height and strain of the pressing plate.

  The present invention has been made in view of the above circumstances, and in a breast imaging apparatus capable of capturing a radiographic image of a subject and displaying a mark on a region of interest on the subject using a laser beam or the like. An object of the present invention is to provide a breast imaging apparatus capable of displaying a mark at an accurate position regardless of the height and distortion of the plate.

  An image capturing apparatus for breast according to the present invention includes a radiation irradiating unit that irradiates a subject with radiation, a radiation image detecting unit that receives radiation irradiated through the subject and records a radiation image of the subject, and a radiation image detecting unit. A radiographic image display unit, a pressing plate for pressing a subject on the imaging table, an image display unit for displaying a radiographic image, a designation unit for designating a region of interest on the radiographic image, and designation on the radiographic image by the designation unit A region-of-interest display means for displaying a mark on a portion on the subject corresponding to the region of interest, and the height of the pressing plate from the imaging table when the pressing plate presses the subject on the imaging table; The region-of-interest display means displays based on the pressure plate position information detection means for detecting the distortion, the height of the pressure plate from the imaging table detected by the pressure plate position information detection means, and the distortion of the pressure plate. And is characterized in by comprising a correction means for performing correction of the position.

  Here, the “radiation image detecting means” obtains an image signal representing a radiographic image related to a subject by converting incident radiation directly or once into light and then converting it into electric charge and outputting the electric charge to the outside. Can be used.

  There are various types of solid-state detectors. For example, from the aspect of the charge generation process that converts radiation into electric charge, the photoconductive layer detects fluorescence emitted from the phosphor when irradiated with radiation. The signal charge obtained in this way is temporarily stored in the power storage unit, the stored charge is converted into an image signal (electrical signal) and output, or the photoconductive layer is irradiated with radiation. The signal charge generated in step 1 is collected by the charge collection electrode, temporarily stored in the power storage unit, and the stored charge is converted into an electrical signal and output, or the direct conversion type solid state detector that reads the stored charge to the outside From the aspect of the reading process, a TFT reading method that scans and reads a TFT (thin film transistor) connected to a power storage unit, or an optical reading method that reads a reading light (reading electromagnetic wave) by irradiating a detector to the detector. Such as those of news, there is such an improved direct conversion type which is proposed in the Patent Document 1 filed by the present applicant that combines the direct conversion type and the optical readout type.

  In addition, the “height of the pressing plate from the imaging stand” is a height from a predetermined reference surface such as the upper surface of the imaging stand to a predetermined reference position of the pressing plate such as a mounting base of the pressing plate. The “distortion of the pressing plate” is an error between the parallel surface with the reference surface including a predetermined reference position of the pressing plate and the pressing surface of the pressing plate.

  In the radiographic image capturing apparatus according to the present invention, the pressing plate may be provided with a sensor that detects an inclination with respect to a pressing surface on which the subject of the imaging table is pressed.

  Moreover, it is good also as what detects the distortion of a press plate based on the image | video of the press plate image | photographed with the camera provided with the camera which image | photographs a press plate.

  Further, a reference point that is non-transparent and can be detected by the radiation image detection means may be provided between the radiation irradiation means and the radiation image detection means.

  In addition, the reference point on the radiographic image is designated as the region of interest by the designating means, and the region of interest is displayed based on the error between the mark position displayed by the region of interest display means and the actual position of the reference point. The means may be calibrated.

  Further, the position information on the radiographic image of the reference point may be automatically performed based on the shape recognition of the reference point.

  Furthermore, you may provide the light detection means which detects the position of the mark which a region-of-interest display means displays.

  According to the radiographic image capturing apparatus of the present invention, in the breast image capturing apparatus capable of capturing a radiographic image of a subject and displaying a mark on a region of interest on the subject using a laser beam or the like, the pressing plate position information detecting means Detects the height of the pressing plate from the imaging table and the distortion of the pressing plate in a state where the pressing plate presses the subject on the imaging table, and corrects the height of the pressing plate from the imaging table and the distortion of the pressing plate. Based on the correction of the position of the mark displayed by the region-of-interest display means, the mark can be displayed at an accurate position regardless of the height and distortion of the pressing plate.

  In addition, a reference point that is opaque to radiation and can be detected by the radiation image detection means is provided between the radiation irradiation means and the radiation image detection means, and the reference point on the radiation image is designated as a region of interest by the designation means. Accordingly, the position of the region of interest is automatically displayed by calibrating the region of interest displaying means based on the error between the position of the mark displayed by the region of interest displaying means and the actual position of the reference point. The accuracy can be improved.

  In this case, the position information on the radiation image of the reference point is automatically performed based on the recognition of the shape of the reference point, or the light detection means for detecting the position of the mark displayed by the region of interest display means is provided. By automatically detecting the position, it is possible to save the user's trouble and improve convenience.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic diagram showing a breast imaging system as an example of a preferred embodiment of the present invention, FIG. 2 is a schematic diagram of the inside of a main body of a breast imaging apparatus of this system, and FIG. FIG. 4 is a schematic diagram of a solid state detector used in the apparatus, and FIG.

  The breast image capturing system 1 includes a breast image capturing apparatus 2, a computer 3 connected to the breast image capturing apparatus 2, and a monitor 4 connected to the computer 3.

  The breast image pickup apparatus 2 includes a main body 5 and a base 6 that rotatably supports the main body 5.

  The main body 5 is connected to a radiation source storage unit 5a that stores therein a radiation source 11 and the like, an imaging table unit 5b that stores a solid detector 20 and the like, and the radiation source storage unit 5a and the imaging table unit 5b. The connecting portion 5c is attached to the base 6 and configured.

  As shown in FIG. 2, the radiation source storage unit 5 a of the main body 5 includes an illumination light source 12 for illuminating a subject, a mask 14 for limiting a radiation irradiation field, in addition to the radiation source 11 described above. A mirror 15 for reflecting the light emitted from the illumination light source 12 and a CCD 16 as a light detection means for detecting the position of the laser light irradiated on the imaging table 5b are provided. The mirror 15 is configured to be retractable to a position that does not hinder radiation irradiation when the radiation source 11 emits radiation.

  Further, a pressing plate 7 for pressing and holding the breast B of the subject from above and a laser beam irradiation device 13 as a region of interest display means are attached to the connecting portion 5c. The laser light irradiation device 13 includes a laser light source and a direction adjusting mechanism for changing the irradiation direction of the laser light.

  As shown in FIG. 3, the solid state detector 20 includes a first conductive layer 24 made of an a-si TFT on a glass substrate 25, a photoconductivity that generates electric charge by receiving radiation and exhibits conductivity. The layer 23, the second conductive layer 22, and the insulating layer 21 are laminated in this order.

  The first conductive layer 24 is formed with a TFT corresponding to each pixel, the output of each TFT is connected to an IC chip 26, and the IC chip 26 is an image signal processing unit (not shown) on the printed circuit board 27. It is connected to the.

  When the solid state detector 20 irradiates the photoconductive layer 23 with radiation when an electric field is formed between the first conductive layer 24 and the second conductive layer 22, the solid state detector 20 enters the photoconductive layer 23. Charge pairs are generated, and latent image charges corresponding to the amount of the charge pairs are accumulated in the first conductive layer 24. When reading the accumulated latent image charge, the TFTs of the first conductive layer 24 are sequentially driven to output an analog signal corresponding to the latent image charge corresponding to each pixel, and this analog signal is processed by image signal processing. The detection is performed for each pixel in the unit, and the analog signals detected for each pixel are combined in the pixel arrangement order. The combined analog signal is AD converted by an AD converter (not shown) to generate a digital image signal. The generated digital image signal is transmitted from the image signal processing unit to the computer 3 via the memory.

  As shown in FIG. 4, two reference points R <b> 1 and R <b> 2 that are non-transparent and can be detected by the solid state detector 20 are provided on the imaging table unit 5 b.

  Further, in the image capturing apparatus for breast 2 of the present embodiment, the height of the pressing plate 7 from the upper surface of the imaging table portion 5b and the pressing plate when the pressing plate 7 presses the breast B on the imaging table 5b. 7 is provided with pressing plate position information detecting means for detecting the distortion 7. The pressing plate position information detecting means will be described in detail. FIG. 5 is a side view of the main body of the breast image pickup apparatus, and FIG. 6 is a top view of the imaging table and the pressing plate of the breast image pickup apparatus.

  The pressing plate 7 is configured to be movable in the vertical direction in FIG. 5 with respect to the connecting portion 5c, and is configured to be able to detect the height h of the connecting portion 5c side base.

  However, when the breast B of the subject is pressed and held on the imaging table 5b by the pressing plate 7, the pressing plate 7 may be inclined (distorted) with respect to the upper surface of the imaging table 5b. Therefore, in order to detect this inclination (distortion), as shown in FIG. 5, two displacement sensors 17a and 17b for detecting the height from the upper surface of the imaging table 5b are attached to the side surface of the pressing plate 7. The inclination (distortion) of the pressing plate 7 with respect to the upper surface of the imaging table 5b can be obtained from the difference between the detection signals of the two displacement sensors 17a and 17b.

  In this embodiment, the distortion of the pressing plate is detected one-dimensionally. However, the detection of the distortion of the pressing plate is not limited to one-dimensional detection, and may be detected two-dimensionally or three-dimensionally.

  For example, when detecting the distortion of the pressing plate in two dimensions, it is sufficient to provide two displacement sensors not only on the side surface of the pressing plate but also on the front surface. As shown in FIG. 6, a grid pattern P is printed on the upper surface of the pressing plate 7, the grid pattern P of the pressing plate 7 is photographed by the CCD 16, and the distortion of the grid pattern P in the photographed image is obtained. What is necessary is just to obtain | require the state of the distortion of the press plate 7 based on this state.

  The radiation source 11, illumination light source 12, laser light irradiation device 13, mask 14, mirror 15, CCD 16, solid state detector 20, pressing plate position information detection means are all integrated and controlled by a control means (not shown). Is.

  In addition, the control means detects the position of the mark displayed by the laser light irradiation device 13 on the basis of the height of the pressing plate 7 from the imaging table 5b detected by the pressing plate position information detecting means and the distortion of the pressing plate 7. It also has a function as correction means for correcting the above.

  Here, the processing of the correcting means will be described with reference to FIG. FIG. 5 shows a state in which a mark M is displayed on the surface of the breast B in a line connecting the region SC where a part having an abnormality such as cancer is detected in the solid state detector 20 and the focal point F of the radiation source 11. ing.

  When the irradiation direction of the laser beam of the laser beam irradiation device 13 is constant, the irradiation position of the laser beam on the surface of the breast B is changed by changing the height of the pressing plate 7 from the imaging table 5b and the distortion of the pressing plate 7. Will change.

  If a specific example is given, if the height h from the imaging stand part 5b of the press plate 7 will become low in the state of FIG. 5, the irradiation position of a laser beam will move to the chest wall side more. Further, when the inclination (distortion) of the pressing plate 7 is further increased (when the chest wall side end portion is further lifted), the irradiation position of the laser beam is further moved to the breast tip side.

  In consideration of such characteristics, the position of the mark displayed by the laser beam irradiation device 13 can be displayed at the position where it is originally desired to display based on the height of the pressing plate 7 from the imaging base 5b and the distortion of the pressing plate 7. Control to correct the irradiation direction of the laser beam.

  Next, the operation of the breast imaging system 1 configured as described above will be described. FIG. 7 is a top view showing a state where the breast is sandwiched on the imaging table by the pressing plate, and FIG. 8 is a diagram showing an image taken in the state of FIG.

  When a radiation exposure switch (not shown) is pressed by the user while the pressing plate 7 is moved to a position where the breast B is pressed and the breast B is fixed on the imaging table 5b, solid detection is performed from the radiation source 11. Radiation is irradiated toward the container 20.

  When radiation is irradiated, latent image charges carrying radiation image information are accumulated in the solid state detector 20. Since the amount of accumulated latent image charge is substantially proportional to the amount of radiation transmitted through the subject (breast B), the latent image charge carries an electrostatic latent image.

  After the predetermined time elapses, recording on the solid state detector 20 is stopped and photographing is finished. Then, an analog signal corresponding to the latent image charge is output from the solid state detector 20, and AD conversion is performed in the image signal processing unit to convert the digital image signal. Generate. The generated digital image signal is transmitted from the image signal processing unit to the computer 3 via the memory.

  When the computer 3 receives the digital image signal from the breast image pickup device 2, the computer 3 displays an image as shown in FIG. 8 on the monitor 4.

  When the user sees an image displayed on the monitor 4 and finds a part having an abnormality such as cancer (GC in FIG. 8), the user designates the region using an input device such as a mouse.

  When the computer 3 receives the designation of the region of interest from the user, the computer 3 transmits coordinate information of the designated position on the image to the breast image capturing apparatus 2.

  When receiving the coordinate information of the region of interest, the breast image capturing device 2 controls the laser beam irradiation device 13 so that the laser beam is irradiated to the position on the subject corresponding to the region of interest specified on the radiographic image. To do.

  At this time, the control means applies the laser light irradiation position in the laser light irradiation device 13 based on the height of the pressing plate 7 detected by the pressing plate position information detecting means from the upper surface of the imaging table and the distortion of the pressing plate 7. Correction is performed, and control is performed so that the laser beam is accurately applied to the position on the subject corresponding to the region of interest specified on the radiographic image. As a result, a mark M is displayed on the subject as shown in FIG.

  If it is known in advance that the mark M is displayed on the subject, the pressing plate 7 is transparent, or a hole is made in the pressing surface, and a mark is directly written on the breast B with a marker. It is preferable that a doctor or the like punctures the anomalous part to directly obtain a biological sample.

  Next, the calibration operation of the laser beam irradiation device 13 (region of interest display means) of the breast imaging system 1 will be described. FIG. 9 is a diagram showing an image photographed in a state where nothing is placed on the photographing table portion, and FIG. 10 shows a state in which a mark is displayed on the photographing table portion corresponding to the reference point in the image of FIG. FIG.

  First, an image is obtained by taking an image without placing anything on the imaging table. Since two reference points R1 and R2 that are opaque to radiation and can be detected by the solid state detector 20 are provided on the imaging table unit 5b, two reference points R1 and R2 in the image as shown in FIG. R2 images GR1 and GR2 are displayed.

  By making the reference point R into a shape such as a + -shaped mark that can be easily recognized in the shape of the image, the reference point R is automatically selected by the computer 3 without the user manually selecting the image GR of the reference point R. The coordinate information of the R image GR can be acquired.

  In addition, when calibrating the laser beam irradiation apparatus 13, both the two reference points R1 and R2 may be used, or only one of them may be used. Here, a case where calibration is performed using the reference point R1 will be described.

  The computer 3 transmits the acquired coordinate information of the image GR1 of the reference point R1 to the breast image capturing apparatus 2.

  When receiving the coordinate information of the reference point R1, the breast image pickup device 2 controls the laser light irradiation device 13 so that the laser beam is irradiated to the position corresponding to the reference point R1 designated on the radiographic image. . As a result, as shown in FIG. 10, the mark M is displayed on the imaging platform 5b.

  At this time, if the accuracy of the laser beam irradiation device 13 is high, the mark M should be displayed at the position of the reference point R1 on the imaging table 5b. When the accuracy is lowered, as shown in FIG. 10, the mark M is displayed at a position deviated from the reference point R1 on the imaging platform 5b.

  Since the mark M is a bright spot irradiated by the laser beam, it can be automatically detected by the CCD 16, and based on the error between the detected position of the mark M and the position of the reference point R1, the laser is detected. The laser light irradiation device 13 can be calibrated by adjusting the light irradiation device 13.

  The preferred embodiment of the present invention has been described above, but the present invention is not limited to the above-described breast image capturing system, and may be applied to any photographing system such as a chest image capturing system.

  In addition, although a TFT readout type is used as the solid state detector, the present invention is not limited to this, and the same effect can be obtained even with other types of individual detectors such as an optical readout type. Can be obtained.

Schematic showing a breast imaging system according to the invention Schematic view of the inside of the main body of the breast imaging apparatus of the above system Schematic diagram of a solid state detector used in the breast imaging apparatus Top view of the imaging table of the breast imaging apparatus Side view of the main body of the breast imaging apparatus Top view of imaging stand and pressing plate of image imaging apparatus for breast The top view which shows the state which pinched | interposed the breast on the imaging stand part with the press board in the said image pick-up device for breasts The figure which shows the image image | photographed in the state of FIG. The figure which shows the image image | photographed in the state which puts nothing on an imaging stand part in the said image pick-up device for breasts The figure which shows the state which displayed the mark on the imaging stand part corresponding to the reference point in the image of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Breast imaging system 2 Breast imaging system 3 Computer 4 Monitor 5 Main body 6 Base 7 Press plate 11 Radiation source 12 Illumination light source 13 Laser light irradiation device 14 Mask 15 Mirror 16 CCD
20 Solid state detector

Claims (7)

Radiation irradiating means for irradiating the subject with radiation;
Radiation image detection means for recording a radiation image of the subject under irradiation of radiation transmitted through the subject;
An imaging table containing the radiation image detecting means;
A pressing plate for pressing the subject on the photographing table;
Image display means for displaying the radiation image;
Designating means for designating a region of interest on the radiation image;
A region of interest display means for displaying a mark on a part on the subject corresponding to the region of interest designated on the radiographic image by the designation means;
Pressure plate position information detecting means for detecting the height of the pressure plate from the imaging table and the distortion of the pressure plate in a state where the pressure plate presses the subject on the imaging table;
Correction means for correcting the position of the mark displayed by the region-of-interest display means based on the height of the pressure plate detected by the pressure plate position information detection means from the imaging stand and the distortion of the pressure plate. A breast imaging apparatus characterized by comprising:   2. The breast image pickup apparatus according to claim 1, wherein the pressing plate is provided with a sensor that detects an inclination of the imaging stand with respect to a pressing surface against which the subject is pressed.   The breast imaging apparatus according to claim 1, further comprising a camera that photographs the pressing plate, and detecting distortion of the pressing plate based on an image of the pressing plate captured by the camera. .   4. The reference point according to claim 1, wherein a reference point that does not transmit radiation and is detectable by the radiation image detection unit is provided between the radiation irradiation unit and the radiation image detection unit. 5. Breast imaging device.   Based on an error between the position of the mark displayed by the region-of-interest display unit and the actual position of the reference point in response to designating the reference point on the radiographic image by the specifying unit as the region of interest. 5. The breast imaging apparatus according to claim 4, wherein the region of interest display means is calibrated.   6. The breast image pickup apparatus according to claim 5, wherein position information of the reference point on the radiation image is automatically performed based on shape recognition of the reference point.   7. The breast image pickup apparatus according to claim 5, further comprising a light detection unit that detects a position of the mark displayed by the region of interest display unit.

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