JP4760266B2 - Mammography system - Google Patents

Description

The present invention relates to a mammography system .

  A breast image obtained by performing mammography using radiation is widely used as a medical image for diagnosis. Appropriate control of the radiation dose to be exposed in mammography is important for preventing an excessive exposure dose to the subject. In addition, radiation dose and image quality are very closely related, and if the dose is not appropriate, the granularity of the image will increase, so the imaging performance of the subject will deteriorate and the diagnostic performance will deteriorate, so the radiation dose to be exposed will be controlled appropriately. It is also important to ensure diagnostic performance of images. Therefore, an imaging device that performs mammography is equipped with an automatic exposure control device (AEC) and is controlled so that the radiation dose is appropriate.

  The automatic exposure control has a sensor that detects a radiation amount that has passed through the subject on the opposite side between the radiation source and the subject, and controls the radiation exposure time according to the radiation amount detected by the sensor. Since most breast cancers arise from mammary tissue, it is important to expose the mammary tissue to an optimal dose of radiation. Therefore, the radiographer needs to position the sensor so that the position of the sensor for detecting the radiation dose corresponds to the highest density part of the mammary gland in order to expose the optimal dose of radiation to the mammary tissue region. is there.

As an aid to this automatic exposure control, for example, in Patent Document 1, the position of the sensor is indicated on the breast before the X-ray is exposed by projecting the sensor position on the breast. The technology is described.
JP-A-8-80295

  However, the location and density distribution of the mammary gland vary depending on the patient, and it is difficult to judge from the appearance. For this reason, the position of the sensor for detecting the radiation dose may deviate from the portion having the highest breast density, and imaging with an appropriate radiation dose may not be performed. In such a case, re-imaging has been performed conventionally, but re-imaging is not preferable because the patient will be exposed again.

An object of the present invention is to reduce if not performed is taken in the proper radiation dose during shooting of a radiographic image of the breast, the exposure times of the patient with recaptured.

To solve the above problems, the inventions of claim 1,
Breast radiography apparatus provided with a plurality of sensors for detecting the amount of radiation transmitted through the breast and performing automatic exposure control, a display unit for displaying a breast image obtained by the mammography apparatus, and a control apparatus A mammography system comprising:
Sensor selection means for selecting any one of the plurality of sensors by a user operation;
The mammography apparatus performs the automatic exposure control based on the sensor selected by the sensor selection unit to generate the breast image,
The control device is characterized in that an image processing condition for performing image processing is set in accordance with a coincidence ratio between the position area of the sensor selected by the sensor selection means and the mammary gland area of the breast image .

The invention according to claim 2 is the invention according to claim 1,
The image processing includes frequency enhancement processing,
The control device sets an image processing condition for frequency enhancement processing with a lower enhancement degree as the matching ratio is lower .

The invention according to claim 3 is the invention according to claim 1 or 2 ,
The image processing includes noise suppression processing,
The control device sets a frequency enhancement process when the matching ratio is higher than a preset threshold value, and sets a noise suppression process when the matching ratio is lower than the threshold value. Yes.

According to the present invention, it is possible to perform image processing on a breast image under image processing conditions according to the positional relationship between the sensor that detects radiation and the breast image. When the position is not appropriate and imaging with an appropriate radiation dose cannot be performed, it is possible to reduce the number of exposures of the patient caused by re-imaging.

[First Embodiment]
First, the configuration of the first exemplary embodiment of the present invention will be described.
FIG. 1 is a conceptual diagram showing an overall configuration of a medical image photographing system 100 in the present embodiment. As shown in FIG. 1, the medical image photographing system 100 includes an imaging device 10, a reading device 20, a control device 30, and an image output device 40. The control device 30 includes the imaging device 10, the reading device 20, and an image. The output device 40 is configured to be connected so that data can be transmitted and received.

Hereinafter, each device constituting the medical image photographing system 100 will be described.
The imaging device 10 exposes radiation to a patient's breast as a subject and captures a radiation image of the breast. In the present embodiment, an example in which a photographing apparatus of a type that performs photographing using the cassette C is applied will be described.

  In FIG. 2, the example of an external appearance structure of the imaging device 10 is shown. FIG. 3 shows a functional configuration of the photographing apparatus 10. As shown in FIG. 3, the photographing apparatus 10 includes a control unit 11, an operation unit 12, a display unit 13, a photographing unit 14, a barcode reader 15, a sensor unit 16, and an I / F 17. Connected by.

  The control unit 11 includes a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), and the like, and reads various processing programs stored in the ROM, In cooperation with each other, various processes including a process on the imaging apparatus side in a breast image imaging process to be described later are executed, and imaging of each part of the imaging apparatus 10 such as automatic exposure control in the radiation source 145 and rotation control of the imaging unit 14 is performed. Radiation imaging of the subject is performed by comprehensively controlling the operation, and imaging information (information on the sensor used to detect the amount of radiation transmitted through the subject at the time of imaging (sensors 1 to 7 of the sensor unit 16 (see FIG. 5)) Among them, the cassette used to shoot the sensor position information, size information, etc.) and shooting conditions (sensor sensitivity, tube voltage value, filter type, etc.)) Outputs with the cassette ID to the controller 30.

  The operation unit 12 includes a key for inputting various setting conditions, and outputs an operation signal corresponding to the operated key to the control unit 11. For example, the position and size of each sensor in the sensor unit 16 used to detect the amount of radiation that passes through the subject during imaging, sensor sensitivity, tube voltage value, filter type, radiation exposure timing, and rotation angle of the imaging unit 14 Various keys such as numeric keys and function keys for inputting values and the like are provided.

  As shown in FIG. 2, the display unit 13 includes a display display 131 such as an LCD (Liquid Crystal Display), and displays various display information such as input information from the operation unit 12 and processing results by the control unit 11. This is displayed on the display 131.

  The imaging unit 14 performs imaging by exposing a subject to radiation, and as shown in FIG. 2, the imaging unit 14 can be moved up and down along a column 142 so that the height can be adjusted according to the position of the patient's breast. It is configured to be movable up and down in the direction indicated by the arrow α, and is configured to be rotatable about the support shaft 144 (to be rotatable in the direction indicated by the arrow β) in order to change the shooting direction. The rotation can be manually rotated by a photographing engineer as an operator, or the operation unit 12 can be operated to instruct rotation.

  In the imaging unit 14, a radiation source 145 that generates radiation and an imaging table 146 for mounting the breast are arranged to face each other, and the breast placed on the imaging table 146 is pressed to compress the breast. A compression plate 147 is provided. FIG. 4 shows a side view of the photographing unit 14. As shown in FIG. 4, the photographing unit 14 is configured so that the cassette C can be attached to the cassette holder 146 a of the photographing stand 146. The cassette C incorporates a photostimulable phosphor plate, absorbs radiation transmitted through the subject, and records the radiation image. The cassette C is provided with a bar code B indicating identification information for uniquely identifying the cassette C (hereinafter referred to as a cassette ID). On the other hand, the imaging table 146 is provided with a barcode reader 15 for reading the barcode B displayed on the cassette C. The barcode B of the cassette C is provided at the center of one side of the back side of the recording surface of the radiation image. Further, the barcode reader 15 in the photographing stand 146 is provided at the center of one side of the back side of the cassette C in the cassette insertion direction.

  When the photographic engineer attaches the cassette C to the photographic stand 146, for example, by inserting the side with the barcode B affixed to face the insertion opening of the cassette holder 146a, The direction can always be specified in one direction.

  The barcode reader 15 outputs the cassette ID obtained by reading the barcode B of the attached cassette C to the control unit 11.

  The barcode reader 15 is installed at the position shown in FIG. 4 as long as the cassette C is attached to the imaging table 146 and coincides with the barcode B and does not affect the shooting of the subject. Not exclusively.

  As shown in FIG. 4, the sensor unit 16 is a sensor that is provided below the cassette C mounted on the cassette holder 146a and detects radiation that has passed through the breast and the cassette C. For example, a photomultiplier, an ion It is comprised by a chamber or a semiconductor.

FIG. 5 shows an arrangement example of the sensor unit 16. FIG. 5A shows a small sensor arrangement example, and FIG. 5B shows a large sensor arrangement example. The sensor unit 16 is arranged so that the plurality of sensors 1 to 7 shown in FIG. 5 are fixed to be parallel to the lower surface of the cassette C attached to the cassette holder 146a. It can be used selectively. In FIG. 6, the internal structural example of each sensor 1-7 is shown. As shown in FIG. 6, each of the sensors 1 to 7 has six detection units a to f, and is large from the control unit 11.
), Six detection units a to f are used, and three detection units a to c are used when detection by the control unit 11 is performed in a small size. Then, radiation is detected and a detection signal is output to the control unit 11. In the control unit 11, when the detection signal from the selected sensor exceeds a preset threshold value, automatic exposure control is performed to control the radiation source 145 to stop radiation exposure. In the present embodiment, the sensor to be used is selected from a plurality of sensors 1 to 7 that are fixedly arranged. One or more sensors may be provided, and the photographing engineer may move the sensor to an arbitrary position to position the sensor.

  The I / F 17 is an interface for performing data input / output between the imaging device 10 and the control device 30.

  A reading device 20 shown in FIG. 1 is a device that reads a medical image recorded in a cassette C and obtains digital image data. The reading device 20 irradiates the photostimulable phosphor sheet of the cassette C with excitation light, photoelectrically converts the photostimulated light emitted from the sheet, and A / D-converts the obtained image signal for medical use. Get the image data of the image. The reading device 20 includes a barcode reader (not shown), reads the cassette ID from the barcode B attached to the cassette C, and controls the image data of the medical image and the cassette ID in association with each other via an interface (not shown). Output to device 30. When the cassette 20 is mounted, the reading device 20 detects the mounting error in the top and bottom (upper and lower) direction and the vertical direction by not being able to read the cassette barcode by a bar code reader (not shown). The mounting direction is always constant (same direction).

  The control device 30 is a medical image photographing support device for supporting radiography of a subject by a photographing engineer. A cassette ID and photographing information are input from the photographing device 10, and a cassette ID and medical image data are read from the reading device 20. Is input, image processing conditions corresponding to automatic exposure control conditions at the time of shooting are set based on sensor information and medical image data included in the shooting information, and an image is displayed on the medical image according to the set image processing conditions. The image is processed and output to the image output device 40.

  FIG. 7 shows a functional configuration example of the control device 30. As shown in FIG. 7, the control device 30 includes a control unit 31, an operation unit 32, a display unit 33, an image processing unit 34, an I / F 35, and the like, and each unit is connected by a bus 36.

  The control unit 31 includes a CPU, a RAM, a ROM, and the like, reads out a system program and various processing programs stored in the ROM, and controls mammography processing described later in cooperation with the read program. Various processes including apparatus side processes are executed.

  The operation unit 32 is an input unit that receives input from an operator, and includes a keyboard having cursor keys, numeric input keys, various function keys, and the like, and a pointing device such as a mouse. Or an instruction signal input by a mouse operation is output to the control unit 31. The operation unit 32 may include a touch panel on the display screen of the display unit 33, and in this case, an instruction signal input via the touch panel is output to the control unit 31.

  The display unit 33 is a display unit, and is configured by a monitor such as an LCD or a CRT. The display unit 33 displays an input instruction, data, or the like from the operation unit 32 in accordance with a display signal instruction input from the control unit 31.

  The image processing unit 34 is an image processing unit, and in accordance with an instruction from the control unit 31, frequency enhancement processing for adjusting the sharpness of an image and gradation correction processing for adjusting density and contrast, Various image processes such as a dynamic range compression process and a graininess suppression process are performed in order to fit an image with a wide dynamic range within an easy-to-view density range without reducing the contrast of details of the subject.

  The I / F 35 is an interface for performing data input / output between the control device 30 and each of the imaging device 10, the reading device 20, and the image output device 40.

  The image output device 40 is a device that records and outputs an image on a film based on an image signal input from the control device 30.

Next, the operation in this embodiment will be described.
FIG. 8 is a flowchart showing a breast image photographing process executed in the medical image photographing system 100.

  First, the cassette C is mounted on the imaging table 146 of the imaging apparatus 10 by the imaging engineer (step S1). In the photographing apparatus 10, when the cassette C is mounted in the correct direction, that is, with the barcode reader 15 and the barcode B facing each other, the barcode B is read by the barcode reader 15 and the cassette ID is acquired. Is called. If the cassette C is not mounted in the correct direction and the barcode cannot be read, an error message notifying the mounting error is displayed on the display unit 13.

  Next, the imaging engineer positions the imaging, and arranges the breast as the subject on the imaging table 146, compression of the breast by the upper and lower sides of the compression plate 147, rotation of the imaging unit 14, input of imaging conditions, and the like ( Step S2). At the same time, the size of the sensor unit 16 used for radiation dose detection and any one of the sensors 1 to 7 are selected by the operation of the operation unit 12 by the imaging technician, thereby positioning the sensor unit (step S3). .

  In radiography, granularity (roughness) occurs in an image obtained when the radiation dose is not sufficient, and a good image suitable for diagnosis cannot be obtained. On the other hand, if the radiation dose is too large, the exposure amount of the subject increases, which is not preferable. In view of this, the imaging apparatus 10 performs automatic exposure control for controlling the radiation dose to be exposed according to the detection signal from the sensor unit 16. Here, the breast is mainly composed of mammary gland tissue and other adipose tissue that spreads from the nipple toward the chest wall, and the mammary gland tissue has a characteristic that it easily absorbs radiation, and the adipose tissue easily transmits radiation. Yes. Breast tissue is susceptible to lesions such as cancer, and because radiation is most easily absorbed in the high density area of the mammary gland, a sufficient dose of radiation must be exposed to the highest breast density area. In this case, an image suitable for diagnosis cannot be obtained, which affects the diagnosis. Therefore, it is suitable for diagnosis to perform radiography by selecting a sensor at a position corresponding to the portion of the arranged subject having the highest breast density (position facing the radiation source 145 across the breast high density region). It is important to get an image. The location and density distribution of the mammary gland vary depending on the patient and cannot be determined from the appearance. Therefore, the radiographer determines from the age of the patient and the hardness of the breast based on experience and selects the sensor to be used.

  After positioning and selection of a sensor to be used, radiation is exposed from the radiation source 145 and imaging is performed. That is, when radiation exposure from the radiation source 145 is started in response to an imaging instruction from the operation unit 12, and the detection signal input from the selected sensor exceeds a preset threshold value in the control unit 11. In addition, the radiation source 145 is controlled to stop radiation exposure (step S4). Here, as described above, each of the sensors 1 to 7 of the sensor unit 16 has the detection units a to f, and the control unit 11 includes a detection unit (sensor size is within the selected sensor). In the case of a small size, a detection signal is output from each of the detection units a to c, and in the case of a large sensor size, the detection units a to f). In the control unit 11, for example, the average of the detection signals to be detected is calculated, and when the average value exceeds a preset threshold, the radiation exposure from the radiation source 145 is stopped. The radiation exposure from the radiation source 145 may be performed when the detection signal of the detection sensor having the smallest amount of radiation transmission among the detection units to be detected, that is, the detection signal having the small detection signal exceeds a preset threshold value. May be stopped.

  After shooting, in the shooting device 10, shooting information including sensor information and other shooting conditions is associated with the cassette ID and output to the control device 30 (step S5). Here, the sensor information includes the position information of the sensors 1 to 7 selected in the sensor unit 16, and when the sensor has two or more sizes as in the present embodiment, the size information also includes Including. For the position information, the sensor number (numbers 1 to 7) may be used as the position information, or the XY coordinate position of the medical image may be used as the position information. When the sensor position information is used as the sensor number, it is assumed that the control device 30 holds XY coordinate information corresponding to the sensor number. Moreover, you may include information, such as the magnitude | size of each detection part af existing inside the selected sensor, a position, and the radiation dose which reached | attained each detection part.

  When the photographing is completed, the photographed technician attaches the cassette C that has been photographed to the reading device 20 to the reading device 20 (step S6). In the reading device 20, when the cassette C is mounted in the correct direction, the cassette ID is read by the barcode reader. When the cassette C is mounted in the correct direction, the reading device 20 reads an image recorded on the mounted cassette C (step S7), and the obtained medical image data and the cassette read. The ID is associated and output to the control device 30 (step S8).

  In the control device 30, when imaging information including sensor information and imaging conditions is input from the imaging device 10, and medical image data is input from the reading device 20, imaging information with a matching cassette ID, medical image data, and Are associated (step S9), and an image processing condition setting process is executed (step S10).

  In the control device 30, the image processing unit 34 performs frequency enhancement processing for adjusting the sharpness of the image, gradation processing for adjusting the density and contrast, and the like on the image data of the medical image that has been input. As the frequency enhancement processing, for example, a non-sharp image obtained by extracting only the low-frequency component of the image signal of the original image is created, and the non-sharp image is subtracted from the image signal of the original image to set a pre-set enhancement coefficient (hereinafter referred to as the frequency enhancement process). Are added to the original image signal to enhance a predetermined spatial frequency component (for example, Japanese Patent Laid-Open Nos. 55-164374 and 10-75395). . However, if the frequency enhancement processing is performed, the degree of granularity (graininess) of the image also increases (granularity). Therefore, for an image with insufficient radiation dose, the enhancement degree is suppressed according to the radiation dose. Alternatively, it is necessary to perform noise suppression processing for suppressing the granularity of the image. As described above, in order to irradiate a subject with a sufficient amount of radiation, it is necessary to perform automatic exposure control using a sensor at a position corresponding to a portion of the subject where the breast density is high. As the mammary gland density shifts, sufficient radiation dose cannot be obtained and the granularity increases. Therefore, in the image processing condition setting processing in step S10, the region indicated by the positional information of the sensor used for radiation at the time of imaging is compared with the mammary gland region in the input medical image, and frequency enhancement processing is performed according to the matching ratio K. Further, by setting image processing conditions related to noise suppression processing, it is possible to adjust the granularity according to the automatic exposure control conditions.

FIG. 9 shows the image processing condition setting process (image processing condition setting process A) executed in step S10 of FIG. By executing this processing, an image processing condition setting unit is realized.
In the control device 30 according to the present embodiment, the reference enhancement degree β0 is set in advance as an image processing condition for the frequency enhancement process. Further, it is assumed that the image processing condition of the noise suppression process is set to ON or OFF, and the noise suppression process is set to OFF by default. The threshold values used in steps S103, S105, and S107 of FIG. 9 are 1 ≧ K0>K1> K2 ≧ 0, and K0, K1, and K2 can be set by the operator via the operation unit 32.

In the image processing condition setting process A, first, a mammary gland region is extracted from the input medical image (step S101).
As described above, the breast is mainly composed of a mammary gland tissue and other adipose tissue, and the mammary gland tissue has a characteristic that it easily absorbs radiation and the adipose tissue easily transmits radiation. Therefore, in the breast region on the medical image, the signal value of the mammary gland region is lower than that of other regions. Based on this characteristic, a mammary gland region is extracted from the medical image. For example, in the present embodiment, the signal value of a medical image is binarized using an appropriate threshold, the boundary between “0” and “1” is tracked, and the breast region and other regions (radiation reaches directly) The breast region is extracted by dividing the image into regions, and a histogram of signal values is obtained for each of the sensor size regions used for imaging in the extracted breast region, and the region having the highest frequency of the lowest signal value is obtained. Extracted as a mammary gland region (high density mammary gland region). Also, as described in Japanese Patent Laid-Open No. 2001-238868, a local region is set in a medical image, and a threshold is set based on a signal value (pixel value) in the local region to binarize the region. The mammary gland region may be extracted by repeating the process for the entire image.

  Next, the area indicated by the sensor position information (sensor position area) and the extracted mammary gland area are collated, and the coincidence ratio K between the sensor position area and the mammary gland area is calculated (step S102). The coincidence ratio K can be obtained, for example, as the ratio of the area overlapping the mammary gland area to the entire sensor position area. When the coincidence ratio K is calculated, the calculated coincidence ratio K is compared with a preset threshold value K0. When K> K0 (step S103; YES), the enhancement degree β0 serving as a reference is the frequency enhancement process. The image processing condition is set (step S104), and the process proceeds to step S11 in FIG. When K> K0 is not satisfied (step S103; NO), the coincidence ratio K is compared with a preset threshold value K1, and when K> K1 (step S105; YES), the enhancement degree β1 (β0> lower than the enhancement degree β0). β1) is set as the image processing condition for the frequency enhancement process (step S106), and the process proceeds to step S11 in FIG. When K> K1 is not satisfied (step S105; NO), the coincidence ratio K is compared with a preset threshold value K2, and when K> K2 (step S107; YES), noise suppression for suppressing the granularity of the image. Execution (ON) of the process is set as an image processing condition (step S108), and the process proceeds to step S11 in FIG. As noise suppression processing, for example, there is a method using multi-resolution decomposition (see Japanese Patent Laid-Open No. 2000-306089). In this case, the noise suppression process may be performed without performing the frequency enhancement process, or the frequency enhancement process may be performed with an enhancement degree lower than the reference and the noise suppression process may be performed. If K> K2 is not satisfied (step S107; NO), a message indicating that re-shooting is necessary is displayed on the display unit 33 (step S109), and the process returns to step S1 in FIG.

  In step S11 of FIG. 8, the image processing unit 34 performs image processing on the medical image based on the set image processing conditions, and outputs the processed medical image to the image output device 40 (step S12). This process ends. In the image output device 40, a medical image is recorded on a recording medium such as a film and is output as a hard copy.

  As described above, according to the control device 30, the imaging information including the input sensor information is associated with the medical image, the mammary gland region is extracted from the input medical image, and the sensor information included in the sensor information is extracted. The region indicated by the position information and the extracted mammary gland region are collated to calculate a matching ratio K between them, and based on the matching ratio K, an image processing condition to be applied to the input medical image is set and set. Based on the image processing conditions, the medical image is subjected to image processing and output from the image output device 40.

  Therefore, if the sensor position is shifted from the mammary gland region at the time of radiography, and imaging with an appropriate exposure dose cannot be performed, the granularity of the image can be reduced by reducing the frequency enhancement processing than usual or performing image processing such as noise suppression processing. Therefore, it is possible to output an image with reduced granularity without performing re-imaging unless it is impossible to diagnose, and it is possible to reduce the number of patient exposures due to re-imaging. Become.

[Second Embodiment]
In the second embodiment, the image processing condition setting process executed in step S10 of FIG. 8 is different from that of the first embodiment. Since the configuration of the medical image capturing system 100 and the breast image capturing process in the medical image capturing system 100 are the same as those described in the first embodiment, description thereof will be omitted.

FIG. 10 shows the image processing condition setting process (image processing condition setting process B) executed in step S10 of FIG. By executing this processing, an image processing condition setting unit is realized.
In the control device 30 in the second embodiment as well, as in the first embodiment, the reference enhancement degree β0 is set in advance as an image processing condition for frequency enhancement processing.

  First, based on the position information and size information included in the sensor information, an annotation indicating the position and size of the sensor used at the time of photographing is superimposed on the medical image (step S201), the medical image on which the annotation is superimposed, and the photographing A shooting pass / fail input screen including an OK button and an NG button for the imaging engineer to selectively input the pass / fail judgment result is displayed on the display unit 33 (step S202).

  FIG. 11 shows an example of a shooting pass / fail input screen. As shown in FIG. 11, since an annotation (indicated by P in the figure) indicating the position and size of the sensor used at the time of photographing is superimposed on the medical image and displayed on the photographing quality input screen, as an operator The photographer visually recognizes an area where the mammary gland is dense (an area where the density is relatively low in the breast area; indicated by M in the figure) and visually confirms the mammary gland high density area and the sensor position indicated by the annotation. As a result of the comparison, for example, whether or not the imaging is good (OK or NG) can be determined based on whether or not all the sensor position regions are included in the high-density mammary gland region. If the result of determination is OK, shooting can be terminated by pressing the OK button via the operation unit 32. If it is NG, it is possible to shift to an image processing condition setting screen for selecting an image processing condition or re-photographing by pressing the NG button via the operation unit 12.

  When the OK button is pressed through the operation unit 32 (step S203; YES), a reference enhancement degree β0 that is set in advance is set as an image processing condition for frequency enhancement processing (step S204). 8 moves to step S11. When the NG button is pressed via the operation unit 32 (step S203; NO), an image processing condition setting screen for selecting and inputting image processing conditions or re-photographing is displayed on the display unit 33 (step S205).

  FIG. 12 shows an example of the image processing condition setting screen. As shown in FIG. 12, the image processing condition setting screen displays buttons for selecting “decrease enhancement processing”, “noise suppression”, and “re-photographing”. Here, as described in the first embodiment, when the radiation dose is insufficient, the granularity of the output image is increased. A frequency enhancement process is performed on the medical image obtained by photographing so as to improve the sharpness of the output image. However, if the frequency enhancement processing is performed, the granularity of the image also increases. Therefore, for an image with insufficient radiation dose, the enhancement level is reduced or the granularity of the image is suppressed depending on the radiation dose. Therefore, it is necessary to perform noise suppression processing. As described above, a sufficient amount of radiation cannot be obtained and the granularity increases as the position of the sensor used for radiation detection at the time of radiographing deviates from a portion having a high breast density. Therefore, buttons for adjusting image processing conditions relating to granularity and sharpness are displayed on the image processing condition setting screen. The radiographer compares the breast density area with the sensor position area. For example, if the sensor position area is within the breast area but not at the highest breast density, the photographer selects the “Weakening enhancement” button and Select the “Noise suppression” button when there is a part that protrudes from the mammary gland region, and select the “Re-shoot” button when the sensor position is out of the mammary gland region. The granularity can be adjusted according to the conditions.

  When the “weaken enhancement process” button is pressed via the operation unit 32 (step S206; YES), the enhancement degree β1 (β0> β1) lower than the reference enhancement degree β0 is set as the image processing condition of the frequency enhancement process. After setting (step S207), the process proceeds to step S11 in FIG. When the “noise suppression” button is pressed through the operation unit 32 (step S206; NO, step S208; YES), execution (ON) of noise suppression processing for suppressing granularity is set as an image processing condition. Then (step S209), the process proceeds to step S11 in FIG. As noise suppression processing, for example, there is a method using multi-resolution decomposition (see Japanese Patent Laid-Open No. 2000-306089). In this case, the noise suppression process may be performed without performing the frequency enhancement process, or the frequency enhancement process may be performed with an enhancement degree lower than the reference and the noise suppression process may be performed. When the “re-photograph” button is pressed via the operation unit 32 (step S206; NO, step S208; NO, step S210; YES), the process returns to step S1 in FIG.

  In step S11 of FIG. 8, the image processing unit 34 performs image processing on the medical image based on the set image processing conditions, and outputs the processed medical image to the image output device 40 (step S12). This process ends. In the image output device 40, a medical image is recorded on a recording medium such as a film and is output as a hard copy.

  In the image processing condition setting process B, a button for selecting whether the shooting is OK or NG is displayed on the shooting pass / fail input screen, and when the NG button is pressed, the enhancement process is performed on the image processing condition setting screen. The button for selecting whether to weaken, suppress noise, or perform re-shooting is displayed, but the OK button and enhancement processing are weakened on one screen, whether to suppress noise, or perform re-shooting The selection button may be displayed to reduce the number of operations by the operator.

  As described above, according to the control device 30, the imaging information including the input sensor information and imaging conditions is associated with the medical image, and the input medical information is based on the input sensor information and the medical image. An annotation indicating the position and size of the sensor that detects the amount of radiation used for radiographing used for imaging is superimposed on the image, and an OK button for the imaging engineer to select a medical image on which the annotation is superimposed and a judgment result of the imaging quality And a shooting pass / fail input screen including the NG button and the NG button. When the NG button is pressed from the shooting pass / fail input screen, an image processing condition setting screen including a “weaken enhancement process” button, a “noise suppression process” button, and a “reshoot” button is displayed. Based on the comparison between the sensor position and the mammary gland high-density area in the medical image, the radiographer presses the “Weaken enhancement process” button, and the enhancement level in the frequency enhancement process is set to a condition that is weaker than the standard. Emphasis processing is executed. When the “noise suppression button” is pressed, noise suppression processing is executed, and processing for suppressing granularity is executed. When the “re-photograph” button is pressed, re-photographing is executed.

  Therefore, if the sensor position deviates from the high density region of the mammary gland during radiography, and imaging with an appropriate exposure dose cannot be performed, the granularity of the image can be reduced by weakening frequency enhancement processing or performing image processing such as noise suppression processing. Therefore, it is possible to output an image with reduced granularity without performing re-imaging unless it is impossible to diagnose, and it is possible to reduce the number of patient exposures due to re-imaging. Become.

In addition, the description content in the said embodiment is a suitable example of the medical image imaging system 100 which concerns on this invention, and is not limited to this.
For example, in the first and second embodiments, the photographing device 10, the reading device 20, and the control device 30 have been described as separate bodies, but a device that combines the functions of these devices may be used.

  Moreover, in the said embodiment, although it was set as the structure by which the control apparatus 30 and each apparatus were directly connected, it is good also as a structure connected via the communication network.

  In the above-described embodiment, the cassette C with the built-in photostimulable phosphor plate is used, the radiographed cassette C is read by the reading device 20, and the obtained medical image data is output to the control device 30. In the above description, a medical image capturing system is described as an example. A radiation detector such as an FPD (flat panel detector) is used to convert a radiation image transmitted through a subject in the imaging apparatus 10 into visible light, and the visible light is photoelectrically converted. It is also possible to adopt a configuration in which the electric signal is detected and A / D converted and output to the control device 30 together with the photographing information.

  In the above-described embodiment, imaging at the time of mammography has been described as an example. However, the present invention can also be applied to imaging of other parts.

  In addition, the detailed configuration and detailed operation of each device constituting the medical image photographing system 100 can be changed as appropriate without departing from the spirit of the present invention.

1 is a diagram showing an overall configuration of a medical image photographing system 100 according to the present invention. 1 is an external view of a photographing apparatus 10. FIG. 2 is a block diagram illustrating a functional configuration of the imaging apparatus 10. FIG. FIG. 3 is a diagram schematically illustrating a side surface of a photographing unit. It is a figure which shows the example of arrangement | positioning of the sensors 1-7 of the sensor part 16, (a) is a figure which shows the example of small sensor arrangement, (b) is a figure which shows the example of large sensor arrangement. It is a figure which shows the detection parts af of each sensor 1-7 of the sensor part 16. FIG. 2 is a block diagram showing a functional configuration of a control device 30. FIG. 4 is a flowchart showing breast image capturing processing executed in the medical image capturing system 100. 4 is a flowchart showing an image processing condition setting process A executed by a control unit 31 of the control device 30. 3 is a flowchart showing an image processing condition setting process B executed by a control unit 31 of the control device 30. It is a figure which shows an example of a photographing quality input screen. It is a figure which shows an example of an image processing condition setting screen.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Medical imaging system 10 Imaging device 11 Control part 12 Operation part 13 Display part 14 Imaging part 142 Support | pillar 144 Support shaft 145 Radiation source 146 Imaging stand 146a Cassette holder 147 Compression plate 16 Sensor part 1-7 Sensor af Detection part 17 I / F
18 Bus 20 Image reading device 30 Control device 31 Control unit 32 Operation unit 33 Display unit 34 Image processing unit 35 I / F
36 Bus 40 Image output device B Barcode C Cassette

Claims (3)

Breast radiography apparatus provided with a plurality of sensors for detecting the amount of radiation transmitted through the breast and performing automatic exposure control, a display unit for displaying a breast image obtained by the mammography apparatus, and a control apparatus A mammography system comprising:
Sensor selection means for selecting any one of the plurality of sensors by a user operation;
The mammography apparatus performs the automatic exposure control based on the sensor selected by the sensor selection unit to generate the breast image,
The control apparatus sets an image processing condition for performing image processing according to a matching ratio between a position region of a sensor selected by the sensor selection unit and a mammary gland region of the breast image. Radiography system. The image processing includes frequency enhancement processing,
The mammography system according to claim 1, wherein the control device sets an image processing condition of frequency enhancement processing with a lower enhancement degree as the matching ratio is lower. The image processing includes noise suppression processing,
The control device sets frequency enhancement processing when the matching ratio is higher than a preset threshold value, and sets noise suppression processing when the matching ratio is lower than the threshold value. The mammography system according to 2.

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