JP5065641B2 - Mammography equipment - Google Patents

Description

  The present invention relates to a mammography apparatus that compresses a breast in a slab shape with a compression plate and performs imaging with an X-ray tube and a flat detector.

  In the mammography apparatus, in order to automatically control the amount of X-ray exposure, an integral value of the output of the exposure control sensor is set to a predetermined value using an X-ray sensor for exposure control together with a film on which a breast image is projected. The X-ray exposure has been terminated at the point of time when the value is reached. This function is called AEC.

Nowadays, the film has been replaced by semiconductor detectors (hereinafter referred to as flat detectors)
The timing that the control sensor determines to be optimal due to the difference in energy characteristics between the exposure control sensor and the flat detector is not necessarily optimal for the flat detector,
Since the X-ray does not pass through the flat detector, the exposure control sensor must be placed in front of the flat detector, in which case the shadow of the exposure control sensor appears in the image,
-It is inefficient to have an exposure control sensor in addition to the flat panel detector,
・ The flat detector has a wide dose range to obtain a diagnosable image because its characteristics are linear unlike films.
As shown in FIG. 15, the pre-exposure is performed before the main exposure and the X-ray condition for the main exposure is determined from the result without using the automatic exposure control (AEC). A so-called pre-exposure method is employed.

  In the pre-exposure method, prior to the main exposure for obtaining a diagnostic image, a dose much smaller than the dose for the main exposure is exposed, the image is collected, and the X of the main exposure is collected from the image. This is a method for determining the line conditions (tube voltage, mAs, filter) and performing the main exposure. The advantages and problems of this pre-exposure method are as follows.

As an advantage of the pre-exposure method,
-X-ray conditions suitable for breast thickness and composition (ratio of mammary gland, fat) can be used,
Since the result of pre-exposure is obtained as an image, it is possible to set an optimum X-ray condition for the region of interest according to the distribution of mammary gland and fat. about,
Can be given.

On the other hand, as a problem of the pre-exposure method,
・ Because the image by pre-exposure contains a lot of detector noise, it can be used to determine the X-ray condition of this exposure, but it cannot be used as a diagnostic image, so the patient may be exposed. Regardless, you can't get the most out of it,
・ Because pre-exposure is not used for diagnostic images, we want to use weak X-rays to reduce exposure. However, if weak X-rays are used, SNR decreases due to X-ray quantum noise, and SNR decreases due to circuit noise. Occurs, the accuracy of the determination of the X-ray conditions decreases,
-SNR degradation due to circuit noise,
Can be given.

  An object of the present invention is to provide a mammography apparatus capable of expanding the range of utilization of signal charges accompanying X-ray exposure.

In the first aspect of the present invention, a mammography apparatus detects an X-ray tube that generates X-rays, a compression mechanism that compresses a breast of a subject, and X-rays that have passed through the compressed breast. A non-destructive flat panel detector that retains charge even after signal readout, and a detector control unit that controls operations related to charge accumulation, signal readout, and charge reset of the flat panel detector, the detector control unit Is characterized in that the charge reset is not performed between the pre-exposure for determining the imaging condition of the main exposure and the main exposure.
In the second aspect of the present invention, the mammography apparatus detects an X-ray tube that generates X-rays, a compression mechanism that compresses the breast of the subject, and X-rays that have passed through the compressed breast. A non-destructive flat panel detector that retains charge even after signal readout, and a detector control unit that controls operations related to charge accumulation, signal readout, and charge reset of the flat panel detector, the detector control unit After the pre-exposure for determining the imaging conditions for the main exposure and before the next exposure, the charge accumulation and signal readout are performed, and the charge reset is not performed, and the main exposure is performed. The charge accumulation, signal readout, and the charge reset are performed after the next exposure and before the next exposure.
In the third aspect of the present invention, the mammography apparatus detects an X-ray tube that generates X-rays, a compression mechanism that compresses the breast of the subject, and X-rays that have passed through the compressed breast. A non-destructive flat panel detector that retains charge even after signal readout, a first operation mode in which charge accumulation, signal readout, and charge reset are executed as one cycle in synchronization with the generation of the X-ray, and the X-ray And a detector control unit that selectively controls the operation of the flat panel detector in a second operation mode in which the charge accumulation and the signal reading are executed as one cycle in synchronization with the occurrence of the above-mentioned phenomenon.
In the fourth aspect of the present invention, the mammography apparatus detects an X-ray tube that generates X-rays, a compression mechanism that compresses the breast of the subject, and X-rays that have passed through the compressed breast, and is nearby. Non-destructive type flat detector that has a function of adding signals in pixels and retains charge even after signal reading, and operation related to charge accumulation, signal reading, charge reset, and neighboring pixel addition of the flat detector A detector control unit for controlling the charge accumulation, after the pre-exposure for determining the imaging conditions of the main exposure and before the next exposure, Perform the signal readout and the neighboring pixel addition, and do not perform the charge reset, perform the charge accumulation, the signal readout and the charge reset after the main exposure and before the next exposure, And the neighboring pixel addition is not performed. It is characterized in.
In the fifth aspect of the present invention, the mammography apparatus detects an X-ray tube that generates X-rays, a compression mechanism that compresses the breast of the subject, and X-rays that have passed through the compressed breast, and is nearby. The pixel has a function of adding signals, and is a non-destructive flat panel detector that retains charge even after signal readout, and charge accumulation, signal readout, and charge reset in synchronization with the generation of the X-ray. A first operation mode that is executed as a cycle, and a second operation mode that executes the charge accumulation, signal readout, and neighboring pixel addition as one cycle in synchronization with the generation of the X-rays. And a detector control unit for controlling the operation.
In a sixth aspect of the present invention, a mammography apparatus detects an X-ray tube that generates X-rays, a compression mechanism that compresses a breast of a subject, and X-rays that have passed through the compressed breast. A non-destructive flat panel detector that retains charge even after signal readout, and a detector control unit that controls operations related to charge accumulation, signal readout, and charge reset of the flat panel detector, the detector control unit After the pre-exposure for determining the imaging conditions of the main exposure, and before the next exposure, the charge accumulation and signal readout are performed and the charge reset is not performed. The charge reset is performed after the signal reading operation is repeated a plurality of times later and before the next exposure.
In the seventh aspect of the present invention, the mammography apparatus detects an X-ray tube that generates X-rays, a compression mechanism that compresses the breast of the subject, and X-rays that have passed through the compressed breast. A non-destructive flat panel detector that retains charge even after signal readout, and a detector control unit that controls operations related to charge accumulation, signal readout, and charge reset of the flat panel detector, the detector control unit Is after the pre-exposure for determining the imaging conditions of the main exposure and before the next exposure, the charge accumulation, repeating the signal reading a plurality of times, without performing the charge reset, The charge accumulation, the signal readout, and the charge reset are performed after the main exposure and before the next exposure.

  According to the present invention, in the mammography apparatus, it is possible to expand the utilization range of signal charges accompanying X-ray exposure.

Embodiments of a mammography apparatus according to the present invention will be described below with reference to the drawings.
FIG. 1 shows the configuration of a mammography apparatus according to this embodiment. The mammography apparatus has an imaging body 1. As shown in FIG. 2, the imaging main body 1 is equipped with an X-ray tube 2 at one end of a U-shaped arm 20 of the support mechanism 4. The X-ray tube 2 receives a high voltage (tube voltage) from the high voltage generator 3 and receives a filament current to generate X-rays. A radiation quality adjusting filter 21 is detachably provided on the front surface of the X-ray tube 2 together with an irradiation field limiting mask. The X-ray quality is determined by the combination of the quality control filter 21 and the tube voltage. The tube current (mA) is controlled by the filament current, and the dose is determined by the time product (mAs) of the tube current.

  A flat detector (flat panel detector; FPD) 5 is attached to the other end of the U-shaped arm 20 so as to face the X-ray tube 2. A grid 23 for removing scattered radiation and improving image contrast is disposed on the front surface of the flat detector 5.

  As shown in FIG. 3, the flat detector 5 has a plurality of pixels 20 arranged in a two-dimensional grid. As shown in FIG. 4, each pixel 20 includes a photodiode 11 that generates an electric charge upon incidence of light converted from X-rays by a scintillator (not shown). The electric charge generated in the photodiode 11 is accumulated in the capacitor 13 via the read switch (transistor) 12. An address line 16 is connected to the gate of the read switch 12. The gates of the plurality of read switches 12 arranged in the horizontal direction are commonly connected to the same address line 16. The address line 16 is connected to the gate of another read switch (transistor) A. The gates of the plurality of squeezing switches A arranged in the horizontal direction are connected to the same address line 16 in common. A plurality of (here, N) address lines 16 are sequentially activated by the vertical scanning circuit 22. The potential of the activated address line 16 becomes, for example, “H (high)”, and the gates of the plurality of read switches 12 connected thereto are simultaneously closed (become conductive). As a result, a voltage corresponding to the amount of charge accumulated in the capacitor 13 is applied to the gate of the amplification transistor 14, and a current corresponding thereto flows through the transistor A to the signal line 17. Instead of reading out the amount of charge accumulated in the capacitor 13 as a current signal, the voltage change corresponding to the amount of charge is observed, so that the charge is held in the capacitor 13 even after the signal is read out. Such a method is called a non-destructive type. In this embodiment, this non-destructive detector 5 is employed.

  In the nondestructive detector 5, the drain line 19 is connected to the capacitor 13 in order to discharge the accumulated charge of the capacitor 13 and reset the pixel 20. A reset switch (transistor) 15 is inserted into the drain line 19. A reset line 18 is commonly connected to the reset switch 15. When the potential of the reset line 18 is driven to, for example, high (H) by the vertical scanning circuit 22, a plurality of reset switches 15 connected thereto are closed simultaneously (become conductive) and accumulated in all capacitors 13. The charged charge is released in a very short time. Thereby, the reset of all the pixels 20 is completed.

  The gates of the plurality of amplification transistors 14 arranged in the vertical direction are commonly connected to the same signal line 17. The plurality of selection switches (transistors) 23 of the plurality of signal lines 17 are sequentially turned on by the horizontal scanning circuit 21 during the closed period of the gate of the readout switch 12.

  The data collection circuit 6 amplifies the voltage signal on the signal line 17 and converts it into a digital signal.

  A compression mechanism 11 is mounted on the column portion of the U-shaped arm 20. The compression mechanism 11 includes a compression plate 22, a movement mechanism thereof, and a movement drive unit. The compression plate 22 moves in a direction approaching / separating from the grid 23 while maintaining a parallel state with the grid 23. The movement of the compression plate 22 is typically performed by foot operation of the foot pedal 24. The breast of the subject is compressed in a slab shape between the grid 23 and the compression plate 22.

  The mammography apparatus according to the present embodiment includes a system control unit 7, an imaging control unit 8, an operation unit 9, an image recording unit 10, a signal processing unit 12, an X-ray condition determination unit 14, along with structures such as the support mechanism 4. An image display unit 15 and an image processing unit 16 are provided. The imaging control unit 8 controls the high voltage generation unit 3 and the flat detector 5 in accordance with imaging conditions set in advance, thereby executing imaging for the breast of the subject pressed into a slab shape. The imaging control unit 8 selectively controls the flat detector 5 in two types of operation modes. The two types of operation modes are essentially distinguished by the presence or absence of a reset operation.

  FIG. 5 shows the movement in the first operation mode. The first operation mode is a general mode with a reset operation after signal reading. During the X-ray exposure period, the address line 16 and the reset line 17 are held at the “L (low)” level by the vertical scanning circuit 22. As a result, the readout switch 12 and the switch A are opened together with the reset switch 15 (blocking state), and the electric charge generated in the photodiode 11 is held. After the exposure, the address lines 16-1, 16-2,... 16-N are sequentially displaced to the “H” level by the vertical scanning circuit 22. When the address line 16 is at the “H” level, the plurality of read switches 12 and the gates of the switches A are closed (conductive state). As a result, charges are accumulated in the capacitor 13, and a voltage corresponding to the accumulated charge amount is applied to the gate of the amplification transistor 14. During the period when each address line 16 is at the “H” level, the horizontal scanning circuit 21 sequentially closes the selection switches 23 (conductive state). As a result, a current corresponding to the gate voltage of the amplification transistor 14 flows through the signal line 17 and is supplied to a sense amplifier (not shown). During the signal readout period, the reset line 17 is held at the “L” level by the vertical scanning circuit 22. Thereby, the open state (non-conducting state) of the reset switch 15 is maintained, and the charge of the capacitor 13 is held.

  After the signal reading is completed, all the reset lines 17 are displaced to the “H” level by the vertical scanning circuit 22. As a result, the reset switches 15 are simultaneously closed (conductive state), and the charges of all the capacitors 13 are released.

  FIG. 6 shows the movement in the second operation mode. The second operation mode is a mode in which the charge of the capacitor 13 is held without performing the reset operation after reading the signal. The operation up to the completion of the signal reading is equivalent to the first operation mode. That is, during the X-ray exposure period, the address line 16 is held at the “L” level by the vertical scanning circuit 22 together with the reset line 17. The charge generated at 11 is retained. After the exposure is completed, the plurality of address lines 16 are sequentially displaced to the “H” level by the vertical scanning circuit 22, and the selection switch 23 is sequentially closed (conducted) by the horizontal scanning circuit 21 in synchronization therewith. . A current corresponding to the gate voltage of the amplification transistor 14 flows through the signal line 17 and is supplied to a sense amplifier (not shown).

  During the signal readout period, the reset line 17 is held at the “L” level by the vertical scanning circuit 22. Thereby, the open state (non-conducting state) of the reset switch 15 is maintained, and the charge of the capacitor 13 is held. This state is maintained even after the signal reading is completed, that is, the “L” level of all the reset lines 17 is maintained by the vertical scanning circuit 22, the open state (non-conducting state) of the reset switch 15 is maintained, and all capacitors 13 charges are retained.

  In the present embodiment, the first operation mode and the second operation mode can be applied in any combination.

  As a typical example, as shown in FIG. 7 and FIG. 8, pre-exposure is performed before the main exposure, and the X-ray condition (mainly tube voltage, tube current time integration (mainly tube voltage, tube current time integration ( mAs), the so-called pre-exposure method for determining the exposure duration (irradiation time)), the second operation mode is applied in the pre-exposure by the control of the imaging control unit 8, and the main exposure is performed. In shooting, the second mode of operation is applied. Thereby, the charge generated by the pre-exposure is held in the capacitor 13 even after the signal is read out, and is reflected in the signal read after the main exposure as the total charge amount generated in the main exposure.

  That is, in the present embodiment using the non-destructive readout detector 5, after pre-exposure, the electric charge accumulated on the detector 5 is read out to obtain the image information. The charge is stored as it is. Based on the image information obtained by the pre-exposure, the X-ray condition determining unit 14 determines the X-ray condition for the main exposure. The electric charge generated by the main exposure is added to the electric charge generated by the pre-exposure on the pixel 20, and is read out after the main exposure is completed, converted into a charge voltage, and used as image data.

  According to this method, information obtained by pre-exposure can be used as a diagnostic image together with information on the main exposure, so that unnecessary exposure of the patient can be reduced. Moreover, since it does not become useless exposure, it is possible to increase the pre-exposure dose, thereby improving the SNR of the pre-exposure image and improving the accuracy of X-ray condition determination.

  Although the detector 5 is a non-destructive type, when the non-destructive type and a pixel addition type detector are used as the detector 5, the second operation mode is not reset and pixel addition is performed. Can be deformed. As shown in FIG. 9, as a typical structure of the pixel addition type detector 5, 101 is a pixel, and the pixel 101 includes a photodiode D1 and MOS transistors MS0, MS1, MS2, MS3. The MOS transistor MS0 is a transistor for sending charges from the photodiode D1 to the gate part of the output transistor MS2 and its stray capacitance (FD), MS1 is a switch transistor for resetting the FD part, and MS3 is obtained by the output transistor MS2. This is a switch transistor for outputting the received signal at a desired timing. Reference numeral 102 denotes an adder circuit, and capacitors CA1, CA2, and CA3 in the adder circuit 102 are capacitors for clamping pixel signals on the common output lines Pix-out1, Pix-out2, and Pix-out3, respectively. One terminal of the clamp capacitors CA1, CA2, CA3 is connected to the common output lines Pix-out1, Pix-out2, Pix-out3 via the switch transistors MA1, MA2, MA3, and the clamp capacitors CA1, CA2, CA3 The other terminal is connected in common and connected to a switch transistor MR0 of the readout circuit 103 described later, and is connected to a voltage source (potential VCL) through the switch transistor MA0. A readout circuit 103 temporarily stores the output of the adder circuit 102 and / or the non-addition output in the capacitors C0, C1, C2, and C3 via the switch transistors MR0 to MR3. The switch transistors MR4 to MR7 are selected and sequentially output via the output amplifier 105.

  When the charge accumulated on the detector 5 is read after the pre-exposure, the information of each pixel is added and read without reading all the information of each pixel independently. The addition is performed by, for example, the addition circuit 102 as shown in FIG. The charge accumulated in the pixel capacitor generates a voltage, and a current corresponding to the voltage is generated by MS2 and flows through the signal line (pix-outN) for a certain time, and is accumulated in the capacitor inside the adder circuit 102. In the adder circuit 102, capacitors of the number of columns to be added are provided in parallel, and the total charge amount accumulated in these capacitors is accumulated and read out in the capacitor C0 in the read circuit 103. Since the charge accumulated in the pixel capacitor is not lost, the charge generated by this exposure is added on the pixel.

  In the addition type detector 5, as shown in FIG. 10, in the modified second operation mode, the X-ray exposure period retains electric charge, and after the exposure ends, when reading the signal, Addition is performed between two or three pixels adjacent in the horizontal direction. That is, when the charge accumulated on the detector 5 is read after pre-exposure, the information of each pixel is added and read without reading all the information of each pixel independently. Thereby, the reading time can be shortened. The image obtained by pre-exposure is usually used to determine the X-ray condition for the main exposure by calculating the average of the pixel values in the region of interest (ROI) including a plurality of pixels. Even if the resolution is lowered, no problem occurs. As described above, the charge of each pixel is stored as it is even after pixel addition reading. The charge generated by the main exposure is added to the charge generated by the pre-exposure on the pixel, and after completion of the main exposure, reading, charge voltage conversion, and AD conversion are performed to obtain image data. As another effect, since charge-voltage conversion and analog / digital conversion are performed after adding charges of a plurality of pixels, the ratio of circuit noise mixed in these processes to the signal (pixel charge) decreases, Data with good SNR is obtained, and the accuracy of determining the X-ray condition is improved.

  The first operation mode with reset described above can be modified as shown in FIG. As described above, since the charge on the pixel after the signal readout is stored unless the reset operation is performed, the readout operation after the main exposure can be repeated a plurality of times in the modified first operation mode. As shown in FIG. 12, the signal processor 12 averages a plurality of pixel values having different readout times for each pixel, thereby reducing the influence of the circuit noise and improving the SNR of the image. After the readout after the main exposure is repeated a predetermined number of times, the pixel charge is reset. In addition, an image is displayed to allow the operator to check the shooting result after the main exposure is completed, but the image displayed here should be used without adding and averaging the data read at the first time out of multiple readings. Thus, the display for confirmation can be performed in a short time.

  The second operation mode described above can be modified as shown in FIG. As described above, the charge on the pixel after the signal readout is stored unless the reset operation is performed. Therefore, in the modified second operation mode, the readout operation after exposure, for example, after pre-exposure is repeated a plurality of times. It can be carried out. It has been shown that the X-ray condition determination accuracy can be improved by increasing the dose of pre-exposure when the subject is stationary between pre-exposure and main exposure. By using the second operation mode for pre-exposure, an effect can be obtained even when the subject is not stationary between the pre-exposure and the main exposure.

  In the application example of FIG. 13, since it is assumed that the subject moves between pre-exposure and main exposure, the images of pre-exposure and main exposure cannot be summed up. It is desirable to use the irradiation data only for determining the X-ray condition, and it is preferable to perform the reset operation after the completion of the pre-exposure reading and before the main exposure. Therefore, it is desirable that the pre-exposure dose be as small as possible. In such a case, in the conventional method, the charge generated in the detector is small, and the influence of SNR deterioration due to circuit noise of the charge-voltage conversion circuit and the analog / digital conversion circuit itself is large. Since the charges on the pixels are stored after the readout after the pre-exposure, in this example, as shown in FIGS. 13 and 14, the readout operation after the pre-exposure is repeated a plurality of times, and a plurality of obtained results are obtained. By averaging the pixel values, the influence of the circuit noise is reduced and the accuracy of X-ray condition determination is improved. After the readout after the pre-exposure is completed a plurality of times, the charge of the pixel is erased by reset and the main exposure is performed.

  As described above, in this embodiment, by selectively using two types of operation modes that are distinguished by the presence or absence of the reset operation with respect to the detector, the range of utilization of signal charges accompanying X-ray exposure is expanded. In this case, the pre-exposure data is not used for determining the X-ray condition of the main exposure, but the pre-exposure data can be contributed to the image together with the main exposure data.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

The figure which shows the structure of the mammography apparatus which concerns on embodiment of this invention. FIG. 2 is an external view of the photographing main body of FIG. 1. 2 is a schematic plan view of the flat detector of FIG. FIG. 4 is an equivalent circuit diagram of one pixel in FIG. 3. The timing diagram of the 1st operation mode by the imaging | photography control part of FIG. The timing diagram of the 2nd operation mode by the imaging control part of FIG. The figure which shows the operation example which applied the 2nd operation mode to the pre-exposure by the imaging | photography control part of FIG. 1, and applied the 1st operation mode to this exposure. FIG. 8 is a detailed view of FIG. 7. FIG. 6 is a schematic plan view showing another configuration example of the flat detector of FIG. 1. FIG. 10 is a diagram illustrating an operation example in which the modified second operation mode is applied to the pre-exposure by the imaging control unit in FIG. 1 and the first operation mode is applied to the main exposure in the configuration of FIG. The figure which shows the operation example which applied the 2nd operation mode to the pre-exposure by the imaging | photography control part of FIG. 1, and applied the 1st operation mode transformed into this exposure. The figure which shows the operation | movement procedure corresponding to the operation | movement of FIG. The figure which shows the operation example which applied the 2nd operation mode transformed into the pre-exposure by the imaging | photography control part of FIG. 1, and applied the 1st operation mode to this exposure. The figure which shows the operation | movement procedure corresponding to the operation | movement of FIG. The figure which shows the operation | movement procedure which concerns on this exposure from the pre-exposure of the conventional detector.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Imaging | photography main body, 2 ... X-ray tube, 3 ... High voltage generator, 4 ... Supporting mechanism, 5 ... Planar detector, 6 ... Data collection part, 7 ... System control part, 8 ... Imaging control part, 9 ... Operation , 10 ... an image storage unit, 12 ... a signal processing unit, 14 ... an X-ray condition determination unit, 15 ... an image display unit, 16 ... an image processing unit.

Claims (7)

An X-ray tube that generates X-rays;
A compression mechanism that compresses the breast of the subject;
A non-destructive flat panel detector for detecting X-rays transmitted through the compressed breast, which retains electric charge after signal readout;
A detector control unit for controlling operations related to charge accumulation, signal readout, and charge reset of the flat panel detector,
The mammography apparatus, wherein the detector control unit does not perform the charge reset between pre-exposure for determining an imaging condition for main exposure and main exposure. An X-ray tube that generates X-rays;
A compression mechanism that compresses the breast of the subject;
A non-destructive flat panel detector for detecting X-rays transmitted through the compressed breast, which retains electric charge after signal readout;
A detector control unit for controlling operations related to charge accumulation, signal readout, and charge reset of the flat panel detector,
The detector control unit performs the charge accumulation and signal readout after the pre-exposure for determining the imaging condition of the main exposure and before the next exposure, and does not perform the charge reset. A mammography apparatus which performs the charge accumulation, signal readout, and the charge reset after the main exposure and before the next exposure. An X-ray tube that generates X-rays;
A compression mechanism that compresses the breast of the subject;
A non-destructive flat panel detector for detecting X-rays transmitted through the compressed breast, which retains electric charge after signal readout;
A first operation mode in which signal readout and charge reset are executed as one cycle after completion of the X-ray exposure , and second operation in which signal readout is performed as one cycle after the X-ray exposure ends and no charge reset is performed . A mammography apparatus comprising: a detector control unit that selectively controls the operation of the flat panel detector according to a mode. An X-ray tube that generates X-rays;
A compression mechanism that compresses the breast of the subject;
A non-destructive flat panel detector that detects X-rays transmitted through the compressed breast and has a function of adding a signal in a neighboring pixel, and holds a charge even after signal readout;
A detector control unit that controls operations related to charge accumulation, signal readout, charge reset, and neighboring pixel addition of the flat panel detector,
The detector control unit performs the charge accumulation, the signal readout, and the neighboring pixel addition after the pre-exposure for determining the imaging condition of the main exposure and before the next exposure, and The charge reset is not performed, the charge accumulation, the signal readout, and the charge reset are performed after the main exposure and before the next exposure, and the neighboring pixel addition is not performed. Mammography device to do. An X-ray tube that generates X-rays;
A compression mechanism that compresses the breast of the subject;
A non-destructive flat panel detector that detects X-rays transmitted through the compressed breast and has a function of adding a signal in a neighboring pixel, and holds a charge even after signal readout;
A first operation mode in which signal readout and charge reset are executed as one cycle after completion of the X-ray exposure , and second operation in which signal readout is performed as one cycle after the X-ray exposure ends and no charge reset is performed . A mammography apparatus comprising: a detector control unit that selectively controls the operation of the flat panel detector according to a mode. An X-ray tube that generates X-rays;
A compression mechanism that compresses the breast of the subject;
A non-destructive flat panel detector for detecting X-rays transmitted through the compressed breast, which retains electric charge after signal readout;
A detector control unit for controlling operations related to charge accumulation, signal readout, and charge reset of the flat panel detector,
The detector control unit performs the charge accumulation and signal readout and does not perform the charge reset after the pre-exposure for determining the imaging condition of the main exposure and before the next exposure. A mammography apparatus that performs the charge reset after repeating the signal reading operation a plurality of times after the main exposure and before the next exposure. An X-ray tube that generates X-rays;
A compression mechanism that compresses the breast of the subject;
A non-destructive flat panel detector for detecting X-rays transmitted through the compressed breast, which retains electric charge after signal readout;
A detector control unit for controlling operations related to charge accumulation, signal readout, and charge reset of the flat panel detector,
The detector control unit performs the charge accumulation after the pre-exposure for determining the imaging condition of the main exposure and before the next exposure, and repeats the signal reading a plurality of times, A mammography apparatus that performs the charge accumulation, the signal readout, and the charge reset after the main exposure but before the next exposure without resetting.

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