JP4904898B2 - Medical image photographing support device, medical image photographing support method, and program - Google Patents

Description

  The present invention relates to a medical image capturing support apparatus, a medical image capturing support method, and a program thereof that support the capturing of medical images using radiation.

  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.

  In addition, as described in Non-Patent Document 1, in recent years, there are a plurality of sensors that detect the amount of radiation that has passed through the subject, on the opposite side between the radiation source and the subject, and from the detection values of the plurality of sensors. There has also been proposed an imaging apparatus having a function of calculating the mammary gland content of the entire subject and controlling the radiation dose to be exposed to the subject based on the mammary gland content.

The technique described in Non-Patent Document 1 does not require an operation for aligning the sensor position with the portion having the highest mammary gland density by the imaging technician, and can improve imaging efficiency.
JP-A-8-80295 Rad Fan Vol. 3 NO. 5 (2005) (pp. 63-64)

  However, even in the technique of Non-Patent Document 1, automatic exposure control may not function well depending on the type of breast of the subject or a sensor failure. Since it was not possible to immediately check whether automatic exposure control was performed after shooting, a medical image with an image quality not suitable for diagnosis was output, or after checking the image after outputting the medical image, There is a possibility that the inconvenience arises that the patient must be called again to perform imaging.

  An object of the present invention is to enable an imaging engineer to check whether or not imaging has been performed with an appropriate exposure dose.

In order to solve the above-mentioned problem, the invention described in claim 1
A sensor that detects the amount of radiation that has passed through the subject at the time of radiography, and a mammary gland content rate of the subject is calculated based on a detection value by the sensor, and the subject is exposed to the subject based on the calculated first mammary gland content rate. A medical imaging support apparatus connected to an imaging apparatus having a control means for controlling the radiation dose to be emitted,
A calculating means for calculating a first second mammary gland content rate from the medical image obtained by radiographing the subject with a radiation amount corresponding to the mammary gland content rate calculated on the basis of the value detected by the sensor,
A determination unit that compares the first mammary gland content rate with the second mammary gland content rate, and determines the quality of the radiography based on the comparison result;
An output means for outputting a determination result by the determination means;
It is characterized by having.

The invention according to claim 2 is the invention according to claim 1,
Image processing condition setting means for setting image processing conditions to be applied to the medical image based on the first mammary gland content rate and the second mammary gland content rate;
Image processing means for performing image processing on the medical image based on the image processing conditions set by the image processing condition setting means;
It is characterized by having.

The invention according to claim 3 is the invention according to claim 1 or 2,
The image processing condition is a condition for adjusting the granularity and / or sharpness of the medical image.

The invention according to claim 4
A sensor that detects the amount of radiation that has passed through the subject at the time of radiography, and a mammary gland content rate of the subject is calculated based on a detection value by the sensor, and the subject is exposed to the subject based on the calculated first mammary gland content rate. A medical image photographing support method in a medical image photographing support device connected to an imaging device provided with a control means for controlling the radiation dose to be emitted,
Calculating a first second mammary gland content rate from the medical image obtained by radiographing the subject with a radiation amount corresponding to the mammary gland content rate calculated based on a value detected by said sensor,
Comparing the first mammary gland content rate and the second mammary gland content rate, and determining the quality of the radiography based on the comparison result;
Outputting the determination result by an output means;
It is characterized by including.

The invention according to claim 5 is the invention according to claim 4,
Setting image processing conditions to be applied to the medical image based on the first mammary gland content rate and the second mammary gland content rate;
Applying image processing to the medical image based on the set image processing conditions;
It is characterized by including.

The invention according to claim 6 is the invention according to claim 4 or 5,
The image processing condition is a condition for adjusting the granularity and / or sharpness of the medical image.

The invention described in claim 7
A sensor that detects the amount of radiation that has passed through the subject at the time of radiography, and a mammary gland content rate of the subject is calculated based on a detection value by the sensor, and the subject is exposed to the subject based on the calculated first mammary gland content rate. A computer used for a medical image photographing support apparatus connected to an imaging apparatus having a control means for controlling the radiation dose to be emitted;
Calculating means for calculating a first second mammary gland content rate from the medical image obtained by radiographing the subject with a radiation amount corresponding to the mammary gland content rate calculated on the basis of the value detected by the sensor,
A determination unit that compares the first mammary gland content rate with the second mammary gland content rate, and determines the quality of the radiography based on the comparison result,
Output means for outputting a determination result by the determination means;
It is a program for making it function as.

  According to the first, fourth, and seventh aspects of the present invention, it is possible to immediately confirm whether or not the photographing engineer has performed photographing with an appropriate exposure dose, and the photographing efficiency can be improved.

  According to the second and fifth aspects of the present invention, even when it is determined that imaging with an appropriate exposure dose could not be performed, good image quality that is acceptable for diagnosis by changing the image processing conditions Medical images can be provided, and the number of patient exposures due to re-imaging can be reduced.

  According to the third and sixth aspects of the present invention, even when it is determined that imaging with an appropriate exposure dose has not been performed, the image quality is acceptable for diagnosis by adjusting the granularity of the image. A medical image can be provided, and the number of exposures of the patient due to re-imaging can be reduced.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS. However, the present invention is not limited to the illustrated example.

First, the configuration of the present embodiment 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 of 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 (the mammary gland content rate (first mammary gland content rate) calculated based on the detection values detected by each sensor of the sensor unit 16 at the time of imaging) The imaging conditions (sensor sensitivity, tube voltage value, filter type, etc.) are output to the control device 30 together with the cassette ID of the cassette C used for imaging.

  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, various keys such as numeric keys and function keys for inputting sensor sensitivity of the sensor unit 16, tube voltage value, filter type, radiation exposure timing, rotation angle value of the imaging unit 14, 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 the imaging engineer, or can be instructed to rotate by operating the operation unit 12.

  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 imaging technician attaches the cassette C to the imaging table 146, for example, by inserting the side on which the barcode B is pasted to face the insertion port of the cassette holder 146a, the imaging engineer records the subject to be recorded on the cassette C. 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.

  Note that the barcode B and the barcode reader 15 are installed at the same positions when the cassette C is mounted on the imaging table 146, and the installation positions shown in FIG. Not limited to.

  As shown in FIG. 4, the sensor unit 16 is a sensor that is provided on the lower side of the cassette C attached to the cassette holder 146a and detects a radiation amount that has passed through the breast and the cassette C. For example, a photomultiplier, An ion chamber or a semiconductor is used.

  FIG. 5 shows a sensor arrangement example of the sensor unit 16. As shown in FIG. 5, the sensor unit 16 is fixed and arranged so that a plurality of sensors 1 to 48 are parallel to the lower surface of the cassette C attached to the cassette holder 146a. The control unit 11 calculates the mammary gland content rate of the entire subject breast based on the detection values detected by the sensors 1 to 48, and calculates the mammary gland content rate (hereinafter referred to as the first mammary gland content rate). Based on the above, automatic exposure control of radiation exposure of the radiation source 145 is performed.

  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 stimulable phosphor plate of the cassette C with excitation light, photoelectrically converts the stimulated light emitted from the plate, and A / D converts the obtained image signal to obtain a 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, the imaging information is associated with the medical image data by the cassette ID, the quality of imaging is determined based on the first mammary gland content rate included in the imaging information and the medical image data, and the determination result Is displayed on the display screen.

  FIG. 6 shows a functional configuration example of the control device 30. As shown in FIG. 6, 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 processing, determination processing, and image processing condition determination processing are executed.

  The operation unit 32 includes a keyboard having a cursor key, numeric input keys, various function keys, and the like, and a pointing device such as a mouse, and controls an instruction signal input by key operation or mouse operation on the keyboard. To 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 configured by a monitor such as an LCD or a CRT, and displays an input instruction, data, or the like from the operation unit 32 in accordance with an instruction of a display signal input from the control unit 31. In this Embodiment, the display part 33 displays and outputs the determination result notification screens 331-333 (refer FIG. 9 (a)-(c)) as an output means.

  The image processing unit 34 performs various types of image processing such as frequency enhancement processing for adjusting the sharpness of an image and gradation processing for adjusting density and contrast on the input image data in accordance with an instruction from the control unit 31.

  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. 7 is a flowchart showing breast image photographing processing executed in the medical image photographing system 100.

  First, the cassette C is mounted on the imaging table 146 of the imaging apparatus 10 in accordance with the cassette insertion operation to the cassette insertion port 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).

  When an imaging instruction is input from the operation unit 12 after positioning, radiation exposure from the radiation source 145 is started under the control of the control unit 11. That is, shooting is started (step S4). When imaging starts, each sensor of the sensor unit 16 detects the amount of radiation that has passed through the subject, the detection value of each sensor is output to the control unit 11, and the control unit 11 detects from each sensor. Based on the value, the first mammary gland content rate that is the mammary gland content rate of the entire subject is calculated (step S5). Then, automatic exposure control is performed based on the calculated first mammary gland content rate, and when a dose of radiation corresponding to the calculated first mammary gland content rate is exposed, the radiation exposure by the radiation source 145 is performed. Shooting is stopped (step S6).

  In radiography, the image obtained when the radiation dose to the subject is not sufficient is grainy (roughness), 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. 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. Since mammary gland tissue is susceptible to lesions such as cancer, an image suitable for diagnosis cannot be obtained unless radiation of a dose corresponding to the mammary gland content of the subject is exposed, which affects the diagnosis. Therefore, the control unit 11 of the photographing apparatus 10 calculates the first mammary gland content rate that is the mammary gland content rate of the entire subject based on the detection value from each sensor of the sensor unit 16, and the calculated first mammary gland. Automatic exposure control is performed to control the radiation dose to be exposed based on the content rate.

  In the present embodiment, in the RAM of the control unit 11, the transmitted dose when each dose (each dose in the range to be exposed in mammography) is exposed to the breast of each mammary gland content rate in advance. Is stored as data. This is data obtained by measuring in advance using an experimental phantom of a breast of each mammary gland content rate. In step S5, based on the detection value for n microseconds after the start of exposure from each sensor of the sensor unit 16, the transmitted dose of the subject that has reached each sensor in n microseconds after the start of exposure is measured. Based on the radiation dose exposed from the radiation source 145 and the pre-measurement data of each breast gland content previously stored in the RAM, the breast gland content of the breast portion on each sensor is obtained. Then, by calculating the average of the mammary gland content of the breast portion on each sensor, the first mammary gland content that is the mammary gland content of the entire breast region of the subject is calculated.

  The RAM of the control unit 11 stores in advance, for each mammary gland content rate, the radiation dose necessary for obtaining an image suitable for diagnosis in mammography of the mammary gland content rate as data. 11 reads out the radiation dose according to the calculated first mammary gland content from the RAM, and performs automatic exposure control. Note that the radiation dose necessary for obtaining an image suitable for diagnosis in mammography of each mammary gland content is determined experimentally or empirically.

  After imaging, in the imaging apparatus 10, the control unit 11 calculates the first mammary gland content rate and other imaging conditions (for example, sensor sensitivity (AECsens), breast thickness (Thickness), tube voltage (kVp)), filter Imaging information including imaging information including seed (filter) and exposure dose (mAs) is associated with the cassette ID and output to the control device 30 (step S7).

  When the photographing is completed, the cassette C that has been photographed is attached to the reading device 20 in accordance with the cassette insertion operation of the photographing engineer (step S8). 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 attached in the correct direction, the reading device 20 reads an image recorded on the attached cassette C (step S9), and the image data of the obtained medical image is read. The cassette ID is associated and output to the control device 30 (step S10).

  In the control device 30, when the cassette ID and the imaging information from the imaging device 10 are input by the I / F 35, and further the image data of the medical image from the reading device 20 is input, the control unit 31 matches the cassette ID. The imaging information to be performed is associated with the image data of the medical image, and the imaging information is written as supplementary information of the medical image data, for example, in the header portion of the medical image data (step S11). Next, the image analysis program is read from the ROM of the control unit 31, the image data input according to the image analysis program is analyzed, and the mammary gland content rate is calculated (step S12). Hereinafter, the calculated mammary gland content is referred to as a second mammary gland content. A calculation means is realized by executing step S12.

The second mammary gland content rate can be calculated by recognizing the breast region and the mammary gland region from the input image data and calculating the ratio of the mammary gland region to the breast region (the following [Equation 1]).
Mammary gland content (%): X
Mammary gland area: N
Breast area: M
[Equation 1]
X = (N / M) × 100

  The breast region can be recognized by, for example, obtaining a histogram of signal values of all pixels of the image data, determining a threshold value by a discriminant analysis method, and binarizing the entire image data using the determined threshold value. . The mammary gland region is recognized by, for example, setting a local region in an image, determining a threshold value based on a signal value of a pixel in the local region, and binarizing the breast region using the determined threshold value. (JP 2001-238868 A).

  When the second mammary gland content rate is calculated from the medical image data, the control unit 31 determines whether or not the imaging is good based on the first breast content rate and the second mammary gland content rate input from the imaging device 10. The determination process is performed (step S13).

FIG. 8 shows the determination process executed in step S13 of FIG. The determination means is realized by executing the processing.
First, the first mammary gland content rate input from the imaging device 10 is compared with the second mammary gland content rate calculated in step S12 (step S101). As a result of the comparison, “first mammary gland content rate ≧ When it is determined that the second mammary gland content ”is satisfied (step S102; YES), it is determined that sufficient radiation has been exposed to the mammary gland content of the subject and appropriate imaging has been performed (OK). A determination result notification screen 331 for notifying the determination result (OK) is displayed on the display unit 33 (see step S104, FIG. 9A).

  As a result of the comparison, when it is determined that “first mammary gland content rate <second mammary gland content rate” (step S102; NO), “second mammary gland content rate−first mammary gland content rate (difference K) ) ≦ set value K0 ”is determined, and when it is determined that“ second mammary gland content rate−first mammary gland content rate ≦ set value K0 ”, that is, breast content calculated from a medical image. When it is determined that the difference K obtained by subtracting the mammary gland content used for the automatic exposure control from the rate is equal to or less than the preset set value K0 (step S103; YES), appropriate imaging has been performed (OK). The determination result notification screen 331 for notifying the determination result (OK) is displayed on the display unit 33 (step S104). The set value K0 is a value experimentally or empirically determined in advance as the maximum value of the difference K in a range that does not affect the captured image quality.

  When the OK button or the re-shooting button is pressed from the determination result notification screen 331 (step S105; YES), the process proceeds to step S14 in FIG. On the other hand, when it is determined that “the second mammary gland content rate−the first mammary gland content rate (difference K) ≦ the set value K0”, that is, it is used for automatic exposure control from the breast content rate calculated from the medical image. When it is determined that the difference K obtained by subtracting the obtained mammary gland content exceeds a preset value K0 (step S103; NO), sufficient radiation has not been exposed to the mammary gland content of the subject. Therefore, it is determined that proper photographing has not been performed (NG), and a determination result notification screen 332 or 333 that prompts the notification of the determination result (NG) and the re-shooting or the change of the image processing conditions is displayed on the display unit 33. (See step S106, FIGS. 9B and 9C). When a button (a re-shooting button or a processing condition change button) is pressed from the determination result notification screen 332 or 333 (step S107; YES), the process proceeds to step S14 in FIG. In step S103, when it is determined that “second mammary gland content rate−first mammary gland content rate ≦ set value K0”, it is displayed in step S107 according to the difference K between the mammary gland content rates of the two. The screen is different.

  FIG. 9A shows an example of a determination result notification screen 331 for notifying the determination result (OK). As shown in FIG. 9A, on the screen, a display for notifying that the determination result is OK, a captured medical image, an OK button for instructing transition to the next step, and re-imaging are displayed. A re-shoot button for instructing is displayed. The radiographer confirms the medical image on the determination result notification screen 331, and if the positioning is OK, operates the operation unit 32 and presses the OK button. If the positioning is poor and re-imaging is necessary, re-imaging is performed. Press the button.

  FIG. 9B shows an example of a determination result notification screen 332 that notifies the determination result (NG). This screen is a screen displayed when the difference K obtained by subtracting the first mammary gland content rate from the second mammary gland content rate does not exceed the set value K2. The setting value K2 is experimentally set as the minimum value of the difference K that cannot obtain an image quality that can be diagnosed by the doctor even if the processing condition of the frequency enhancement processing applied to the medical image is changed or the noise suppression processing is applied to the medical image. Or, it is a value determined in advance by experience. That is, the determination result notification screen 332 is displayed when a medical image having a quality that can be diagnosed by image processing can be obtained without performing re-imaging. On the screen, a display indicating that the determination is NG, a message for suggesting re-imaging by changing the image processing condition or by manual operation (that is, without performing automatic exposure control), a captured medical image, A processing condition change button for instructing an image processing condition change and a re-imaging button for instructing re-imaging are displayed. The radiographer confirms the medical image, and if the positioning and image quality are OK, operate the operation unit 32 and press the processing condition change button. If the imaging engineer determines that the positioning is poor or the image quality is undiagnosable, Press the shooting button.

  FIG. 9C illustrates an example of a determination result notification screen 333 that notifies the determination result (NG). This screen is a screen that is displayed when the difference K is equal to or greater than the set value K2. That is, the determination result notification screen 333 is displayed when a medical image having a diagnosable image quality cannot be obtained unless re-imaging is performed. On the screen, a display indicating that the determination is NG, a message for suggesting re-imaging by manual operation, a medical image that has been captured, and a re-imaging button for instructing re-imaging are displayed. Yes. After confirming that re-shooting is necessary, the imaging engineer operates the operation unit 32 and presses the re-shoot button.

  Here, depending on the type of breast of the subject, automatic exposure control by the imaging device 10 may not function normally, and imaging with an appropriate radiation dose may not be performed. In that case, even if re-photographing is performed many times using automatic exposure control, it is not possible to obtain a diagnosable image quality. Therefore, on the determination result notification screens 332 and 333, a display for suggesting re-shooting by manual operation to the imaging engineer is performed.

  In step S14 of FIG. 7, the control unit 31 determines whether or not the re-shooting button is pressed by the operation unit 32 from the determination result notification screen (any of the determination result notification screens 331 to 333), and re-shooting is performed. If it is determined that the button has been pressed (step S14; YES), the process returns to step S1, and the processes after step S1 are executed again.

  If it is determined by the control unit 31 that a button other than the re-photographing button has been pressed by the operation unit 32 from the determination result notification screen (step S14; NO), an image processing condition setting process is performed (step S15).

Here, 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 input medical image image data. The 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). And the like, which enhance the predetermined spatial frequency component by adding the product multiplied by the degree of enhancement) to the original image signal (for example, Japanese Patent Laid-Open Nos. 55-163472 and 10-75395). . However, if the frequency enhancement processing is performed, the degree of granularity (granularity) of the image also increases. Therefore, for an image whose radiation dose is not sufficient, the enhancement level is determined based on the radiation dose. It is necessary to perform noise suppression processing to further suppress or suppress the granularity of the image. Therefore, in the image processing condition setting process of step S15, the first mammary gland content rate used for automatic exposure control at the time of photographing is compared with the second mammary gland content rate calculated from the medical image, and the difference K is set as the difference K. Accordingly, by setting (changing) image processing conditions related to frequency enhancement processing and noise suppression processing, it is possible to adjust the granularity according to the automatic exposure control conditions.

FIG. 10 shows the image processing condition setting process executed in step S15 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. Further, the setting value K1 used in step S203 of FIG. 10 is experimental or empirical on the assumption that an image quality acceptable for diagnosis can be obtained without performing noise suppression processing if the processing conditions of the frequency enhancement processing are adjusted. Is the maximum value of the difference K, and 100 ≧ K2>K1>K0> 0.

  In the image processing condition setting process, it is first determined whether or not “second mammary gland content rate−first mammary gland content rate (difference K) ≦ set value K0”, and “second mammary gland content rate− If it is determined that the first mammary gland content rate (difference K) ≦ the set value K0 ”(step S201; YES), the reference enhancement degree β0 is set as an image processing condition for the frequency enhancement process (step S202). The processing moves to step S16 in FIG. When it is determined that “second mammary gland content rate−first mammary gland content rate (difference K) ≦ set value K0” is not satisfied (step S201; NO), the difference K is compared with the set value K1, and K ≦ K1. (Step S203; YES), the enhancement degree β1 (β0> β1) lower than the reference enhancement degree β0 is set as the image processing condition for the frequency enhancement process (step S204), and the process proceeds to step S16 in FIG. Transition. When K ≦ K1 is not satisfied (step S203; NO), execution (ON) of noise suppression processing for suppressing the granularity of the image is set as an image processing condition (step S205), and the processing is performed in step S16 of FIG. Transition. 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.

  After setting the image processing conditions, the image processing unit 34 performs image processing such as gradation processing, frequency enhancement processing based on the set image processing conditions, and noise suppression processing (step S16). Then, the image data of the medical image that has been subjected to image processing is output to the image output device 40 (step S17), and this processing ends. In the image output device 40, a medical image is recorded and output on a recording medium such as a film.

  As described above, according to the control device 30, the imaging information including the first mammary gland content rate used for the automatic exposure control input from the imaging device 10, and the medical image input from the reading device 20 Is determined based on the comparison result between the first mammary gland content rate used in the automatic exposure control and the second mammary gland content rate calculated from the medical image, and the determination result is Display on the display. Further, when the determination result is NG, a message suggesting re-photographing by manual operation or a change of the image processing condition is displayed together with the determination result, and when the operation unit 32 is instructed to change the image processing condition, automatic exposure control is performed. Based on the comparison result between the first mammary gland content rate used in the above and the second mammary gland content rate calculated from the medical image, an image processing condition to be applied to the input medical image is set, and the image processing unit 34 Thus, the medical image is subjected to image processing based on the set image processing conditions and output from the image output device 40.

  Therefore, the imaging engineer can immediately confirm whether or not the imaging apparatus 10 has performed imaging with an appropriate exposure dose, and can improve imaging efficiency. In addition, when the determination result of the imaging quality is NG, if the difference between the mammary gland content ratios is within a range that can be diagnosed by changing the image processing condition, the image processing condition can be changed and the manual operation can be performed. If diagnosis is impossible even if re-photographing is proposed and image processing conditions are changed, re-photographing by manual operation is proposed, so that a diagnostic image with always good image quality can be provided. In addition, unless the image processing conditions can be changed and the diagnosis is impossible, the image processing conditions can be changed to suppress the granularity of the image, so the granularity is suppressed without performing re-shooting. Images can be output, and the number of exposures of the patient due to re-imaging can be reduced.

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 above-described embodiment, the imaging device 10, the reading device 20, and the control device 30 have been described as separate units.

  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.

  Moreover, in the said embodiment, the cassette C which incorporated the photostimulable phosphor plate was used, the radiographic cassette C was read by the reading device 20, and the image data of the obtained medical image was transferred to the control device 30. The medical image capturing system to output is described as an example, but using a radiation detector such as an FPD (flat panel detector), the radiation image transmitted through the subject is converted into visible light in the imaging apparatus 10, and the visible light is photoelectrically converted. Then, it may be detected as an electrical signal, and the detected electrical signal may be A / D converted and output to the control device 30 together with shooting information.

  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. FIG. 4 is a diagram illustrating an arrangement example of sensors 1 to 48 of the sensor unit 16. 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. 3 is a flowchart showing a determination process executed by a control unit 31 of the control device 30. It is a figure which shows an example of the determination result notification screens 331-333 displayed on the display part. 4 is a flowchart illustrating image processing condition setting processing executed by a control unit 31 of the control device 30.

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 1-48 Sensor 17 I / F
18 Bus 20 Reading Device 30 Control Device 31 Control Unit 32 Operation Unit 33 Display Unit 331 Judgment Result Notification Screen 332 Judgment Result Notification Screen 333 Judgment Result Notification Screen 34 Image Processing Unit 35 I / F
36 Bus 40 Image output device B Barcode C Cassette

Claims (7)

A sensor that detects the amount of radiation that has passed through the subject at the time of radiography, and a mammary gland content rate of the subject is calculated based on a detection value by the sensor, and the subject is exposed to the subject based on the calculated first mammary gland content rate. A medical imaging support apparatus connected to an imaging apparatus having a control means for controlling the radiation dose to be emitted,
Calculating means for calculating a second mammary gland content rate from a medical image obtained by radiographing the subject with a radiation dose corresponding to the first mammary gland content rate calculated based on a detection value by the sensor;
A determination unit that compares the first mammary gland content rate with the second mammary gland content rate, and determines the quality of the radiography based on the comparison result;
An output means for outputting a determination result by the determination means;
A medical image photographing support device comprising: Image processing condition setting means for setting image processing conditions to be applied to the medical image based on the first mammary gland content rate and the second mammary gland content rate;
Image processing means for performing image processing on the medical image based on the image processing conditions set by the image processing condition setting means;
The medical image photographing support apparatus according to claim 1, further comprising: The medical image photographing support apparatus according to claim 2 , wherein the image processing condition is a condition for adjusting granularity and / or sharpness of the medical image. A sensor that detects the amount of radiation that has passed through the subject at the time of radiography, and a mammary gland content rate of the subject is calculated based on a detection value by the sensor, and the subject is exposed to the subject based on the calculated first mammary gland content rate. A medical image photographing support method in a medical image photographing support device connected to an imaging device provided with a control means for controlling the radiation dose to be emitted,
Calculating a second mammary gland content rate from a medical image obtained by radiographing the subject with a radiation dose corresponding to the first mammary gland content rate calculated based on a detection value by the sensor;
Comparing the first mammary gland content rate and the second mammary gland content rate, and determining the quality of the radiography based on the comparison result;
Outputting the determination result by an output means;
A medical image photographing support method comprising: Setting image processing conditions to be applied to the medical image based on the first mammary gland content rate and the second mammary gland content rate;
Applying image processing to the medical image based on the set image processing conditions;
The medical image photographing support method according to claim 4, further comprising: 6. The medical image photographing support method according to claim 5 , wherein the image processing condition is a condition for adjusting the granularity and / or sharpness of the medical image. A sensor that detects the amount of radiation that has passed through the subject at the time of radiography, and a mammary gland content rate of the subject is calculated based on a detection value by the sensor, and exposure to the subject is performed based on the calculated first mammary gland content rate. A computer used for a medical image photographing support apparatus connected to an imaging apparatus having a control means for controlling the radiation dose to be emitted;
Calculating means for calculating a second mammary gland content rate from a medical image obtained by radiographing the subject with a radiation dose corresponding to the first mammary gland content rate calculated based on a detection value by the sensor;
A determination unit that compares the first mammary gland content rate with the second mammary gland content rate, and determines the quality of the radiography based on the comparison result,
Output means for outputting a determination result by the determination means;
Program to function as.

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