JP2017060559A - Mammography apparatus and mammography method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mammography apparatus that has improved visibility of calcification without changing a burden of a pain on a medical examinee during the compression of the breast.SOLUTION: A mammography apparatus 1 includes an X-ray tube 21a for irradiating an X-ray, an FPD 22c for detecting the X-ray, a movement mechanism for supporting the X-ray tube 21a and moving the X-ray tube 21a, and a tomosynthesis imaging function 31d for performing tomosynthesis imaging by controlling the X-ray tube and the X-ray detector so as to perform the imaging a plurality of times intermittently, and controlling the movement mechanism 24 so that a movement speed of the X-ray tube 21a changes during a period from the start of the initial imaging to the end of the last imaging of the plurality of times of imaging.SELECTED DRAWING: Figure 5

Description

  Embodiments as one aspect of the present invention relate to a mammography apparatus and mammography method for imaging a breast.

  Mammography, which provides a two-dimensional image of breast tissue and performs a breast examination, is widely used to diagnose cancer and other abnormalities. Since the breast has a three-dimensional and delicate structure, it is photographed by a dedicated X-ray apparatus (mammography apparatus).

  The breast X-ray imaging apparatus controls the X-ray tube and the X-ray detector so as to perform intermittent imaging for the compressed breast, and from the first imaging start to the final imaging among the multiple imaging. Until the end (image acquisition time), the X-ray source is moved at a constant speed to perform tomosynthesis imaging (see, for example, Patent Documents 1 and 2). The X-ray tube is rotated to irradiate X-rays from multiple directions, and the projection image is collected. In Patent Document 1, the X-ray source is linearly moved at a constant speed, and tomosynthesis imaging is performed. Tomosynthesis imaging is performed by rotating the radiation source at a constant speed.

JP 2011-62276 A JP 2014-166264 A

  According to the conventional tomosynthesis imaging, each imaging is performed by irradiating the breast with X-rays while the X-ray tube is moving. Therefore, there is a problem in that each photographing is in a so-called panning state, and the pixels are deteriorated due to the occurrence of blurring.

  If the movement of the X-ray tube is stopped for each imaging, the degradation of the image quality is eliminated, but the time required for the tomosynthesis imaging becomes longer accordingly. In that case, since the time for compressing the breast becomes longer, the time that the examinee is painful becomes longer.

  Moreover, in the X-ray transmission image based on each tomosynthesis imaging, the resolution of the tomosynthesis image obtained by imaging near the directly-facing position (angle 0 °) among the multiple tomosynthesis imaging is important. It is known that there is.

  In order to solve the above-described problem, the mammography apparatus of the present embodiment supports an X-ray source that irradiates X-rays, an X-ray detector that detects the X-rays, and the X-ray source, The moving mechanism for moving the X-ray source, and the X-ray source and the X-ray detector are controlled so as to perform a plurality of intermittent imaging, and the final imaging from the start of the first imaging among the plurality of imaging And tomosynthesis imaging means for executing tomosynthesis imaging by controlling the moving mechanism so that the moving speed of the X-ray source changes until the end of imaging.

  In order to solve the above-described problem, the mammography method of the present embodiment controls the X-ray source and the X-ray detector so as to perform intermittent multiple imaging, and among the multiple imaging Tomosynthesis imaging is performed by controlling the moving mechanism that supports the X-ray source and moves the X-ray source so that the moving speed of the X-ray source changes from the start of the first imaging to the end of the final imaging. To do.

1 is a perspective view showing an appearance of a mammography apparatus according to the present embodiment. 1 is a cross-sectional view illustrating a configuration of a mammography apparatus according to an embodiment. The figure for demonstrating tomosynthesis imaging | photography. 1 is a diagram showing a configuration of an image processing apparatus provided in a mammography apparatus according to the present embodiment. 1 is a block diagram showing functions of a mammography apparatus according to the present embodiment. The figure for demonstrating the example of a change of the rotational movement speed of a X-ray tube. The figure which shows the 1st example of the imaging | photography sequence of tomosynthesis imaging | photography which the mammography apparatus concerning this embodiment performs. The figure which shows the imaging | photography angle based on the imaging | photography sequence shown in FIG. The figure which shows the imaging | photography angle of equal intervals. The figure which shows the 2nd example of the imaging | photography sequence of tomosynthesis imaging | photography which the mammography apparatus concerning this embodiment performs. The figure for demonstrating the example of a change of the rotational movement speed of a X-ray tube. The figure which shows the 3rd example of the rotational movement speed of a X-ray tube. 6 is a flowchart showing the operation of the mammography apparatus according to the present embodiment.

  The mammography apparatus and mammography method of this embodiment will be described with reference to the accompanying drawings.

  FIG. 1 is a perspective view showing an appearance of a mammography apparatus 1 according to the present embodiment. FIG. 2 is a cross-sectional view showing a configuration of the mammography apparatus 1 according to the present embodiment.

  1 and 2 show a mammography apparatus (mammography apparatus) 1 according to this embodiment for imaging a breast (subject) B of a patient. The mammogram apparatus 1 includes an imaging table apparatus 11 and an image processing apparatus 12.

  The imaging stand device 11 includes a movable irradiation unit 21, a movable detection unit 22, a stand unit 23, a moving mechanism 24 (shown in FIG. 2), and an operation unit 25. The movable irradiation unit 21 is supported by the stand unit 23 so as to be rotatable via the moving mechanism 24.

  The movable irradiation unit 21 includes an X-ray tube (X-ray source) 21a and a face guard 21b.

  The X-ray tube 21a receives supply of high voltage power from a high voltage supply device 25d, which will be described later, and irradiates X-rays toward the imaging table 22b, which will be described later, via the breast B according to the high voltage power conditions. This is a vacuum tube.

  The face guard 21b is a protective device for protecting the examinee's head from X-ray exposure during imaging.

  In addition, although the movable irradiation part 21 is not shown in figure, adjustment tools, such as an X-ray aperture and a quality filter, for adjusting the quality of the X-rays generated by the X-ray tube 21a or limiting the irradiation field. It may be prepared.

  The movable detection unit 22 includes a compression plate 22a, an imaging table 22b, and an FPD (flat panel detector) 22c.

  The compression plate 22a is provided above the imaging table 22b in order to compress the breast B with the imaging table 22b. The compression plate 22a is formed of a transparent resin, and is supported so as to be able to come into contact with and separate from the imaging table 22b. Then, the breast B can be compressed by moving the compression plate 22a toward the imaging table 22b, and the thickness of the breast B can be made thin and substantially uniform. When a later-described compression foot pedal 25a is operated by a photographer such as an engineer, the compression plate 22a is electrically driven by driving a drive mechanism (not shown) including a motor for moving the compression plate 22a in the vertical direction. To move up and down. In addition, the structure which the compression board 22a moves to an up-down direction manually according to operation of the knob (not shown) by a photographer may be sufficient.

  The imaging table 22b includes an FPD 22c as an X-ray detector for detecting X-rays transmitted through the breast B and a grid (not shown) for removing the scattered radiation and improving the contrast of the captured image. It is a stand with. In the FPD 22c, a plurality of detection elements are two-dimensionally arranged, and scanning lines and signal lines are arranged between the detection elements so as to be orthogonal to each other. The time-series analog signal (video signal) projection data output from the FPD 22 c is converted into a digital signal and output to the image processing device 12.

  The stand unit 23 supports the movable irradiation unit 21 and the movable detection unit 22 via a moving mechanism 24 described later.

  As shown in FIG. 2, the moving mechanism 24 is connected to the movable irradiation unit 21. When the moving mechanism 24 rotates with respect to the stand unit 23, the moving mechanism 24 rotates the movable irradiation unit 21 in the left-right direction with respect to the stand unit 23.

  The moving mechanism 24 can be connected to the movable detection unit 22. When the movement mechanism 24 is connected to the movable detection unit 22, the movement mechanism 24 rotates with respect to the stand unit 23, so that the movement mechanism 24 moves with respect to the stand unit 23. The part 22 is integrally rotated in the left-right direction. On the other hand, when the moving mechanism 24 is not connected to the movable detection unit 22, the moving mechanism 24 rotates relative to the stand unit 23, so that the moving mechanism 24 is movable to the stand unit 23. Only the part 21 is rotated in the left-right direction.

  For example, the movement mechanism 24 and the movable detection unit 22 are both provided with a gear, and the movable detection unit 22 is connected to the movement mechanism 24 in a state where the gear is engaged, and is disconnected from the movement mechanism 24 in a state where the gear is not engaged. It is.

  As described above, when the movable detection unit 22 is separated from the movement mechanism 24, that is, in the case of tomosynthesis imaging, the movement mechanism 24 relative to the stand unit 23 remains fixed to the stand unit 23. Only the movable irradiator 21 rotates in accordance with the rotation. On the other hand, when the movable detection unit 22 is connected to the moving mechanism 24, that is, in CC imaging (head-to-tail imaging) and MLO imaging (inside / outside oblique imaging), the movement mechanism 24 with respect to the stand unit 23 According to the rotation, the movable irradiation unit 21 and the movable detection unit 22 rotate and move together.

  The mammography apparatus 1 can perform imaging in various imaging modes including CC imaging, MLO imaging, and tomosynthesis imaging by controlling connection or disconnection of the movable detection unit 22 with the moving mechanism 24. is there. With tomosynthesis imaging, X-ray imaging is performed at a plurality of imaging angles while rotating the X-ray tube 21a on a compressed breast, and a plurality of X-ray transmission images (projected images) at a plurality of imaging angles are collected. It is a shooting method. According to tomosynthesis imaging, it is also possible to generate a 3D (stereoscopic) tomographic image using a plurality of X-ray projection images acquired by irradiating the breast B with X-rays from a plurality of imaging directions.

  FIG. 3 is a diagram for explaining tomosynthesis imaging.

  FIG. 3 shows the X-ray tube 21a, the compression plate 22a, the imaging table 22b, and the FPD 22c. As the X-ray tube 21a rotates around the rotation axis R, the X-ray tube 21a rotates and moves to draw an arc above the FPD 22c as shown in FIG. For example, in the case of rotation in the positive direction, the X-ray tube 21a rotates in the clockwise direction (arrow in FIG. 3) from the angle −X ° to the angle + X ° through the directly-facing position (angle 0 °). . In general, the swing angle of the X-ray tube 21a in tomosynthesis imaging is approximately 9 ° (X = 4.5) to 50 ° (X = 25). Here, the directly facing position means the position of the X-ray tube 21a in CC imaging.

  Returning to the description of FIG. 1 and FIG. 2, the operation unit 25 includes a compression foot pedal 25a, a C-arm vertical / rotational fine adjustment switch 25b, an imaging condition setting panel 25c, and a high voltage supply device 25d.

  The compression foot pedal 25a is a pedal for an operator to step on to adjust the vertical position of the compression plate 22a.

  The C-arm vertical / rotation fine adjustment switch 25b moves the movable irradiation unit 21 and the movable detection unit 22 up and down, or rotates only the movable irradiation unit 21 or the movable irradiation unit 21 and the movable detection unit 22 as a unit. It is a switch to do.

  The imaging condition setting panel 25c is a panel for setting X-ray imaging conditions.

  The high voltage supply device 25 d is a device that supplies a voltage to the X-ray tube 21 a of the movable irradiation unit 21.

  When X-rays are generated by the X-ray tube 21a of the imaging table apparatus 11, the X-rays are applied to the breast B compressed between the compression plate 22a and the imaging table 22b. The X-rays that have passed through the breast B are detected by the FPD 22c of the imaging table 22b, converted into projection data, and output to the image processing device 12.

  The image processing device 12 controls the operation of the entire mammogram apparatus 1, generates an X-ray transmission image based on the projection data acquired by the imaging table apparatus 11, and performs image processing related to the X-ray transmission image. Device. The image processing apparatus 12 includes an input circuit 33, a display 34, and the like.

  FIG. 4 is a diagram illustrating a configuration of the image processing apparatus 12 provided in the mammography apparatus 1 according to the present embodiment.

  FIG. 4 shows an image processing apparatus 12 included in the mammography apparatus 1. The image processing apparatus 12 includes a processing circuit 31, a storage circuit (storage unit) 32, an input circuit (input unit) 33, a display (display unit) 34, and an IF (communication unit) 35.

  The processing circuit 31 reads various control programs stored in the storage circuit 32 and performs various calculations, and comprehensively controls processing operations in the storage circuit 32, the input circuit 33, the display 34, and the IF 35.

  The processing circuit 31 means a circuit such as an application specific integrated circuit (ASIC) and a programmable logic device, in addition to a dedicated or general-purpose CPU (central processing unit). Examples of the programmable logic device include a simple programmable logic device (SPLD), a complex programmable logic device (CPLD), and a field programmable gate array (FPGA). Circuit. The processing circuit 31 implements the function shown in FIG. 5 by reading and executing a program stored in the memory or directly incorporated in the processing circuit 31.

  The processing circuit 31 may be configured as a single circuit, or may be configured as one processing circuit 31 by combining a plurality of independent circuits. When the processing circuit 31 is configured by a plurality of circuits, a memory for storing a program may be provided for each circuit individually, or a storage circuit 32 described later stores a program corresponding to the function of each circuit. You may do.

  The storage circuit 32 includes a semiconductor memory device such as a RAM (Random Access Memory) and a flash memory, a hard disk, an optical disk, and the like. The memory circuit 32 may be configured by a portable medium such as a USB (universal serial bus) memory and a DVD (digital video disk). The storage circuit 32 stores various processing programs used in the processing circuit 31 (including an OS (operating system) in addition to an application program), data necessary for executing the program, and medical images. The OS can also include a GUI (Graphical User Interface) that can use graphics for displaying information on the display 34 for the operator and perform basic operations by the input circuit 33.

  The input circuit 33 is a circuit that inputs a signal from an input device such as a pointing device (such as a mouse) or a keyboard that can be operated by an operator. Here, the input device itself is also included in the input circuit 33. . When the input device is operated by the operator, the input circuit 33 generates an input signal corresponding to the operation and outputs it to the processing circuit 31. The mammography apparatus 1 may include a touch panel in which an input device is configured integrally with the display 34.

  The display 34 is configured by a display unit such as an LCD (liquid crystal display). The display 34 displays various operation screens and various display information such as data generated by the processing circuit 31 according to instructions from the processing circuit 31.

  The IF (interface) 35 includes a connector that conforms to a parallel connection specification or a serial connection specification. When the mammography apparatus 1 is provided on a network, the IF 35 transmits / receives information to / from an external apparatus on the network. For example, the IF 35 communicates with an external device by transmitting image data generated by the mammography apparatus 1 to an image management apparatus or an interpretation terminal (not shown).

  Subsequently, functions of the mammography apparatus 1 according to the present embodiment will be described.

  FIG. 5 is a block diagram showing functions of the mammography apparatus 1 according to the present embodiment.

  When the processing circuit 31 of the image processing apparatus 12 executes the program, as shown in FIG. 5, the processing circuit 31 has an operation support function (operation support means) 31a, a (mode setting means) 31b, and an imaging condition setting function ( A photographing condition setting means) 31c, a tomosynthesis photographing function (tomosynthesis photographing means) 31d, and a photographing sequence setting function (photographing sequence setting means) 31e.

  The operation support function 31a, the mode setting function 31b, the shooting condition setting function 31c, the tomosynthesis shooting function 31d, and the shooting sequence setting function 31e of the processing circuit 31 are each configured as a program, and one circuit is the operation support function 31a and the mode. A setting function 31b, an imaging condition setting function 31c, a tomosynthesis imaging function 31d, and an imaging sequence setting function 31e can be executed. Alternatively, the operation support function 31a, the mode setting function 31b, the shooting condition setting function 31c, the tomosynthesis shooting function 31d, and the shooting sequence setting function 31e may be implemented in a plurality of dedicated independent circuits.

  The operation support function 31 a functions as a user interface such as a GUI (graphical user interface) that can perform basic operations by the input circuit 33 to display information for the operator on the display unit 34.

  The mode setting function 31b is a function for setting shooting modes such as CC shooting, MLO shooting, and tomosynthesis shooting in accordance with instructions input from the input circuit 33 via the operation support function 31a.

  When the shooting mode is set to tomosynthesis shooting by the mode setting function 31b, the shooting condition setting function 31c is input from the input circuit 33 (or the shooting condition setting panel 25c shown in FIG. 1) via the operation support function 31a. This function sets shooting conditions for tomosynthesis shooting according to instructions. Here, the imaging conditions include a region of interest, a time per imaging (imaging time), a tomosynthesis imaging time, and the like.

  The tomosynthesis imaging function 31d is a state in which the breast B is compressed by the compression plate 22a of the imaging platform apparatus 11, and the X-ray tube 21a and the X-ray tube 21a A function that controls the FPD 22c and performs tomosynthesis imaging so that the rotational movement speed of the X-ray tube 21a changes during the period from the start of the first imaging to the end of the final imaging (image acquisition time). is there.

  FIG. 6 is a diagram for explaining an example of a change in the rotational movement speed of the X-ray tube 21a.

  FIG. 6 shows a rotational movement section W of the X-ray tube 21a that rotates clockwise from an angle −X ° to an angle + X ° through a directly-facing position (angle 0 °). FIG. 6 shows a rotational movement section W (first rotational movement section W1) including the directly-facing position in the rotational movement section W accompanying the rotational movement of the X-ray tube 21a, and other rotational movement sections (second rotational movement). Section W2). The rotational movement speed of the X-ray tube 21a in the first rotational movement section W1 is controlled to be lower than the movement speed in the second rotational movement section W2.

  The rotational movement speed of the X-ray tube 21a in the first rotational movement section W1 can be obtained based on the required resolution of the X-ray transmission image, the imaging time (irradiation time) of each imaging, and the like. The rotational movement speed of the X-ray tube 21a in the second rotational movement section W2 is the rotational movement speed of the X-ray tube 21a in the first rotational movement section W1 or the distance (angle − X ° to + X °) or the like. Here, the distance of the rotational movement section W of the X-ray tube 21a may be the same as that according to the prior art.

  Returning to the description of FIG. 5, the tomosynthesis imaging function 31 d includes an imaging control function (imaging control means) 311, a speed control function (speed control means) 312, and an image generation function (image generation means) 313.

  The imaging control function 311 is a function for controlling the X-ray tube 21a and the X-ray detector 22c so as to perform intermittent imaging.

  The speed control function 312 is a function that controls the moving mechanism 24 so that the rotational movement speed of the X-ray tube 21a changes from the start of the first imaging to the end of the final imaging among a plurality of intermittent imaging.

  The image generation function 313 is a function for generating an X-ray transmission image based on data obtained by each tomosynthesis imaging and digitized. The image generation function 313 can also include a function of generating a 3D tomographic image based on a plurality of X-ray transmission images corresponding to a plurality of projection angles.

  In this way, the tomosynthesis imaging function 31d controls the X-ray tube 21a and the FPD 22c so as to perform a plurality of intermittent imaging operations in a compressed state of the breast B by the compression plate 22a of the imaging platform apparatus 11, and performs a plurality of times. Tomosynthesis imaging is performed by controlling the moving mechanism 24 so that the rotational movement speed of the X-ray tube 21a changes from the start of the first imaging to the end of the final imaging.

  FIG. 7 is a diagram illustrating a first example of an imaging sequence of tomosynthesis imaging performed by the mammography apparatus 1 according to the present embodiment. FIG. 8 is a diagram showing a shooting angle based on the shooting sequence shown in FIG.

  The upper part of FIG. 7 is a time chart showing the timings of a plurality of intermittent shootings, for example, 11 shootings F1 to F11. Note that the number of times of shooting related to tomosynthesis shooting is not limited to 11, but may be two or more times.

  The lower part of FIG. 7 is a time chart showing the transition of the rotational movement speed of the X-ray tube 21a. As shown in the lower part of FIG. 7, the image acquisition time T of tomosynthesis imaging is constant in each of the 11 shootings F <b> 1 to F <b> 11 during the shooting, and changes in each of the shootings other than the shooting. Is set to the rotational movement speed of the X-ray tube 21a. The image collection time T for tomosynthesis imaging corresponds to the rotational movement time in the rotational movement section W shown in FIG.

  The image collection time T of tomosynthesis imaging shown in the lower part of FIG. 7 is the first rotational movement time T1 corresponding to the rotational movement time of the first rotational movement section W1 shown in FIG. 6 and the second rotational movement section W2 shown in FIG. And a second rotational movement time T2 corresponding to the rotational movement time. In the first rotational movement time T1, the fourth photographing F4 to the eighth photographing F8 shown in the upper part of FIG. 7 are performed. In the second rotational movement time T2, the first shooting F1 to the third shooting F3 and the ninth shooting F9 to the eleventh shooting F11 shown in the upper part of FIG. 7 are performed.

  According to the timing of 11 times of imaging F1 to F11 shown in FIG. 7 and the rotational movement speed of the X-ray tube 21a, as shown in FIG. Shooting F1-F11 is performed. Specifically, as shown in FIG. 8, in the first rotational movement section W1 (shown in FIG. 6) corresponding to the first rotational movement time T1 shown in FIG. 7, the second rotational movement time T2 corresponding to the second rotational movement time T2. Images are taken at a plurality of photographing angles that are denser than the rotational movement section W2 (shown in FIG. 6).

  According to the imaging sequence shown in FIG. 7, the resolution obtained by imaging within the first rotational movement section W1 (shown in FIG. 6) while the image acquisition time T of tomosynthesis imaging and the time interval of imaging are the same as in the prior art. The number of high X-ray transmission images can be increased.

  Note that tomosynthesis imaging includes an image acquisition time T, an acceleration time (running time) preceding the image acquisition time T, and a deceleration time subsequent to the image acquisition time T. During the acceleration time, the X-ray tube 21a can be accelerated from the stopped state to the rotational movement speed necessary for tomosynthesis imaging, and the imaging table device 11 (shown in FIGS. 1 and 2) is vibrated. Sufficient time is given that can be slowly accelerated so as not to let it go. Similarly, with respect to the deceleration time, the X-ray tube 21a can be decelerated from the rotational movement speed necessary for tomosynthesis imaging to the stop state, and the imaging table device 11 (shown in FIGS. 1 and 2). Sufficient time is given to allow slow deceleration so as not to vibrate.

  Returning to the description of FIG. 5, the mammography apparatus 1 may have an imaging sequence setting function 31e. A case where the mammography apparatus 1 has an imaging sequence setting function 31e will be described.

  The shooting sequence setting function 31e is a function for setting a shooting sequence for tomosynthesis shooting in accordance with the shooting conditions set by the shooting condition setting function 31c. The shooting sequence setting function 31e sets an equal time interval sequence S1 with a constant interval between a plurality of shootings or an equal angle interval sequence S2 with a constant interval between a plurality of shooting angles.

  In the case of the equi-time interval sequence S1, the imaging sequence setting function 31e is similar to the conventional technique in the speed transition (illustrated in the lower part of FIG. 7) in which the rotational movement speed of the X-ray tube 21a changes during the image acquisition time T of tomosynthesis imaging. A shooting sequence is set by combining equal time intervals of shooting (shown in the upper part of FIG. 7). On the other hand, in the case of the equiangular interval sequence S2, the imaging sequence setting function 31e changes the speed transition (illustrated in the lower part of FIG. 10 described later) in which the rotational movement speed of the X-ray tube 21a changes during the image acquisition time T of tomosynthesis imaging. As with the prior art, a shooting time interval (shown in the upper part of FIG. 10 described later) designed to be shot at equiangular intervals is set.

  Here, in the case of the equal time interval sequence S1, the imaging sequence setting function 31e executes imaging at a constant time interval (shown in the upper part of FIG. 7) regardless of a change in the rotational movement speed of the X-ray tube 21a. . As a result, the angular intervals at which multiple shootings are performed become unequal intervals (shown in FIG. 8).

  On the other hand, in the case of the equiangular interval sequence S2, the imaging sequence setting function 31e rotates the X-ray tube 21a in order to make the angular interval at which a plurality of imagings are performed equal intervals (shown in FIG. 9 described later). A plurality of shooting timings are set at unequal intervals (shown in the upper part of FIG. 10 to be described later) in accordance with the movement speed change.

  Since the equal time interval sequence S1 has been described with reference to FIGS. 7 and 8, the equal angle interval sequence S2 will be described next.

  FIG. 9 is a diagram showing equidistant shooting angles. FIG. 10 is a diagram illustrating a second example of an imaging sequence of tomosynthesis imaging performed by the mammography apparatus 1 according to the present embodiment.

  FIG. 9 shows shooting angles in a plurality of intermittent shootings, for example, 11 shootings F1 to F11 when the equiangular interval sequence S2 is set. Note that the number of times of shooting related to tomosynthesis shooting is not limited to 11, but may be two or more times.

  The upper part of FIG. 10 is a time chart showing the timings of the eleven shootings F1 to F11 that are intermittent when the equiangular interval sequence S2 is set. The lower part of FIG. 10 is the same time chart as the lower part of FIG. 7, showing the transition of the rotational movement speed of the X-ray tube 21 a. That is, FIG. 10 is different from the upper part of FIG. 7 in the timing of 11 times of imaging F1 to F11 in the transition of the rotational movement speed of the same X-ray tube 21a as in the lower part of FIG.

  As shown in FIG. 9, 11 times shown in the upper part of FIG. 10 according to the rotational movement speed of the X-ray tube 21a shown in the lower part of FIG. 10 so that eleven times of photographing F1 to F11 are performed at equidistant imaging angles. The time intervals of the photographing F1 to F11 are adjusted. That is, in the equiangular interval sequence S <b> 2, a part of the intermittent shootings 11 to 11 is unequal. Specifically, in the first rotational movement section W1 (shown in FIG. 6) corresponding to the first rotational movement time T1 shown in FIG. 10, the second rotational movement section W2 (FIG. 6) corresponding to the second rotational movement time T2. A plurality of shooting timings that are less sparse than those shown in FIG.

  According to the equiangular interval sequence S2 shown in FIG. 9, the image collection time T of tomosynthesis imaging and the intervals of a plurality of imaging angles are the same as those in the prior art, and within the first rotational movement section W1 (shown in FIG. 6). The resolution of the X-ray transmission image obtained by imaging can be improved.

  In the transition of the rotational movement speed of the X-ray tube 21a shown in FIGS. 7 to 10, the case where a two-stage constant speed section is set as the rotational movement speed of the X-ray tube 21a during imaging has been described. The present invention is not limited, and a case where a constant speed section of three or more stages is set may be used. Control by a three-stage constant speed section will be described with reference to FIGS.

  FIG. 11 is a diagram for explaining an example of a change in the rotational movement speed of the X-ray tube 21a.

  FIG. 11 shows a rotational movement section W of the X-ray tube 21a that rotates clockwise from an angle −X ° to an angle + X ° through a directly-facing position (angle 0 °). FIG. 11 shows a rotational movement section W (first rotational movement section W1) including the directly-facing position in the rotational movement section W accompanying the rotational movement of the X-ray tube 21a and other rotational movement sections (second rotational movement). Section W2 and second rotational movement section W3) are shown. The rotational movement speed of the X-ray tube 21a in the first rotational movement section W1 is controlled to be lower than the movement speeds in the second rotational movement section W2 and the third rotational movement section W3.

  Further, the second rotational movement section W2 and the third rotational movement section W3 are provided line-symmetrically with the directly facing position as an axis. The second rotational movement section W2 is closer to the directly-facing position than the third rotational movement section W3. Therefore, the rotational movement speed of the X-ray tube 21a in the second rotational movement section W2 is controlled to be lower than the movement speed in the third rotational movement section W3.

  The rotational movement speed of the X-ray tube 21a in the first rotational movement section W1 can be obtained based on the required resolution of the X-ray transmission image, the imaging time (irradiation time) of each imaging, and the like. The rotational movement speed of the X-ray tube 21a in the second rotational movement section W2 and the third rotational movement section W3 is the rotational movement speed of the X-ray tube 21a in the first rotational movement section W1 or the rotational movement of the X-ray tube 21a. It can be determined based on the distance (angle -X ° to + X °) of the section W. Here, the distance of the rotational movement section W of the X-ray tube 21a may be the same as that according to the prior art.

  FIG. 12 is a diagram showing a third example of the rotational movement speed of the X-ray tube 21a.

  FIG. 12 is a time chart showing the transition of the rotational movement speed of the X-ray tube 21a. As shown in FIG. 12, the X-ray tube 21a has a constant image acquisition time T for tomosynthesis imaging so as to be constant during each imaging period and to change in a period other than each imaging period. Is set. The image collection time T for tomosynthesis imaging corresponds to the rotational movement time in the rotational movement section W shown in FIG.

  The image collection time T for tomosynthesis imaging shown in FIG. 12 includes the first rotational movement time T1 corresponding to the rotational movement time of the first rotational movement section W1 shown in FIG. 11 and the rotation of the second rotational movement section W2 shown in FIG. A second rotational movement time T2 corresponding to the movement time and a third rotational movement time T3 corresponding to the rotational movement time of the third rotational movement section W3 shown in FIG. 11 are included.

  When the equal time interval sequence S1 is set, the transition of the rotational movement speed of the X-ray tube 21a shown in FIG. 12 can be combined with a plurality of imaging at equal time intervals as shown in the upper part of FIG. In that case, as shown in FIG. 8, a plurality of photographings F1 to F11 including many photographing angles are performed in the first rotational movement section W1 (shown in FIG. 6).

  On the other hand, in the case where the equiangular interval sequence S2 is set, the transition of the rotational movement speed of the X-ray tube 21a shown in FIG. 12 can be combined with a plurality of times of imaging with unequal time intervals. In that case, as shown in FIG. 9, 11 photographings F1 to F11 are performed at eleven photographing angles at equal intervals.

  Returning to the description of FIG. 5, when the imaging mode is set to CC imaging or MLO imaging by the mode setting function 31 b, the imaging platform device 11 is controlled in the compressed state of the breast B by the compression plate 22 a of the imaging platform device 11. Thus, CC imaging and MLO imaging are executed according to the conventional technology.

  Subsequently, the operation of the mammography apparatus 1 according to the present embodiment will be described with reference to FIGS. 1 and 13.

  FIG. 13 is a flowchart showing the operation of the mammography apparatus 1 according to the present embodiment.

  Mammography apparatus 1 sets tomosynthesis imaging from imaging modes such as CC imaging, MLO imaging, and tomosynthesis imaging (step ST1).

  When the imaging mode is set to tomosynthesis imaging in step ST1, mammography apparatus 1 sets imaging conditions for tomosynthesis imaging in accordance with an instruction input from input circuit 33 (step ST2). Here, the imaging conditions are a region of interest, a time per imaging, a tomosynthesis imaging time, and the like.

  Mammography apparatus 1 sets an imaging sequence for tomosynthesis imaging in accordance with the imaging conditions set in step ST2 (step ST3). In step ST3, an equal time interval sequence S1 (shown in FIG. 7) or an equal angle interval sequence S2 (shown in FIG. 10) is set.

  The mammography apparatus 1 determines whether or not the equal time interval sequence S1 is set in step ST3 (step ST4).

  If YES in step ST4, that is, if it is determined that the equal time interval sequence S1 has been set, the mammography apparatus 1 is in the compression state of the breast B by the compression plate 22a of the imaging table apparatus 11, and the imaging table The apparatus 11 is controlled to perform tomosynthesis imaging according to the imaging conditions set at step ST2 and the imaging sequence of the equal time interval sequence S1 set at step ST3 (step ST5). In step ST5, imaging (X-ray irradiation) is performed at the imaging timing shown in the upper part of FIG. 7, and the X-ray tube 21a is rotated in accordance with the transition of the rotational movement speed shown in the lower part of FIG. Is executed.

  On the other hand, if the determination in step ST4 is NO, that is, if it is determined that the equiangular interval sequence S2 has been set, the mammography apparatus 1 is in the compressed state of the breast B by the compression plate 22a of the imaging table apparatus 11. Then, the imaging platform 11 is controlled to perform tomosynthesis imaging according to the imaging conditions set at step ST2 and the imaging sequence of the equiangular interval sequence S2 set at step ST3 (step ST6). In step ST6, imaging (X-ray irradiation) is performed at the imaging timing shown in the upper part of FIG. 10, and tomosynthesis imaging is performed by rotating the X-ray tube 21a with the transition of the rotational movement speed shown in the lower part of FIG. Is executed.

  The mammogram apparatus 1 generates an X-ray transmission image based on the digitized data obtained by each tomosynthesis imaging performed in steps ST5 and ST6 (step ST7). The mammography apparatus 1 can also generate a 3D tomogram based on a plurality of X-ray transmission images corresponding to a plurality of projection angles generated in step ST7 (step ST8).

  In the mammography apparatus 1 according to the present embodiment, the X-ray tube 21a has been described as having a structure that rotates. However, the present invention is not limited to this case. For example, the present invention can be applied to a structure in which the X-ray tube 21a moves linearly (Japanese Patent Laid-Open No. 2011-62276).

  According to the equi-time interval sequence S1 (shown in FIGS. 7 and 8) of the mammography apparatus 1 and mammography method according to the present embodiment, the first time can be obtained without changing the imaging time of tomosynthesis imaging from the prior art. It is possible to increase the number of high-resolution X-ray transmission images obtained by imaging within the rotational movement section W1 (shown in FIG. 6). As a result, according to the mammography apparatus 1 according to the present embodiment, the visibility of calcification can be improved without changing the burden of pain on the examinee due to breast compression.

  Further, according to the equiangular interval sequence S2 (shown in FIGS. 9 and 10) of the mammography apparatus 1 and mammography method according to the present embodiment, without changing the imaging time of tomosynthesis imaging from the prior art, It is possible to improve the resolution of the X-ray transmission image obtained by imaging within the first rotational movement section W1 (shown in FIG. 6). As a result, according to the mammography apparatus 1 according to the present embodiment, the visibility of calcification can be improved without changing the burden of pain on the examinee due to breast compression.

  Although several embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 1 Mammography apparatus 11 Imaging stand apparatus 12 Image processing apparatus 31 Processing circuit 31a Operation support function 31b Mode setting function 31c Imaging condition setting function 31d Tomosynthesis imaging function 31e Imaging sequence setting function 311 Imaging control function 312 Speed control function 313 Image generation function

Claims (9)

An X-ray source that emits X-rays;
An X-ray detector for detecting the X-ray;
A moving mechanism that supports the X-ray source and moves the X-ray source;
The X-ray source and the X-ray detector are controlled so as to perform a plurality of intermittent imaging, and the X-ray source of the X-ray source between the start of the first imaging and the end of the last imaging among the plurality of imaging. Tomosynthesis imaging means for performing tomosynthesis imaging by controlling the moving mechanism so that the moving speed changes;
A mammography apparatus having:   In the tomosynthesis imaging unit, the moving speed of the X-ray source in the first moving section including the facing angle is lower than the moving speed in the other second moving sections among the moving sections accompanying the movement of the X-ray source. The mammography apparatus according to claim 1, wherein the moving mechanism is controlled so that   The tomosynthesis imaging means is configured such that, among the movement sections accompanying the movement of the X-ray source, the movement speed of the X-ray source is constant in the movement section during each of the plurality of imaging operations, and 3. The breast X according to claim 1, wherein the moving mechanism is controlled so that a moving speed of the X-ray source changes in a moving section other than during each imaging among the moving sections accompanying the movement of the X-ray source. X-ray equipment. The imaging sequence setting means further sets, as an imaging sequence, a relationship between a transition of the moving speed of the X-ray source in the movement section accompanying the movement of the X-ray source and a plurality of imaging timings in the plurality of imaging. ,
The mammography apparatus according to claim 1, wherein the tomosynthesis imaging unit performs the tomosynthesis imaging according to the imaging sequence.   The mammography apparatus according to claim 4, wherein the imaging sequence setting unit sets the plurality of imagings at equal time intervals.   5. The mammography apparatus according to claim 4, wherein the imaging sequence setting unit adjusts a time interval of the plurality of imaging so that the plurality of imaging is at an equiangular interval.   The mammography apparatus according to any one of claims 1 to 6, wherein the moving mechanism rotates or linearly moves the X-ray source.   The mammography apparatus according to any one of claims 1 to 7, wherein the tomosynthesis imaging unit generates a 3D tomogram based on a plurality of X-ray images obtained by the plurality of imaging operations. Controlling the X-ray source and the X-ray detector so as to perform intermittent multiple imaging,
A moving mechanism that supports the X-ray source and moves the X-ray source so that the moving speed of the X-ray source changes from the start of the first imaging to the end of the final imaging among the plurality of imaging. A mammography method for performing tomosynthesis imaging under control.

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