JP6662428B2 - Dynamic analysis system - Google Patents

Description

  The present invention relates to a dynamic analysis system.

  In recent years, with the advent of flat panel detectors (FPDs) that support moving images, a technique that performs continuous X-ray imaging of the part of the human body to be diagnosed, captures the dynamics of that part, and analyzes the function of that part (For example, see Patent Document 1).

  It has also been proposed to generate a function related to the dynamics, for example, a feature amount related to the ventilation or blood flow function based on a series of frame images obtained by the dynamic imaging, and use the generated amount as diagnostic support information (for example, And Patent Document 2).

JP 2004-324434 A International Publication No. 2009/090894

  An object of the present invention is to make it possible to quantitatively estimate a state after a pulmonary resection before a pulmonary resection based on a dynamic image analysis result.

In order to solve the above problems, a dynamic analysis system according to the first aspect of the present invention includes:
Recognizing means for recognizing a region of an artifact from a plurality of frame images generated by photographing dynamics of a subject;
Attenuation processing means for attenuating the image signal component due to the artifact by attenuating the image signal component of the region of the plurality of frame images recognized by the recognition means,
Analysis means for analyzing a plurality of frame images after the attenuation processing by the attenuation processing means, the dynamics of the chest of the subject from a plurality of frame images showing the dynamics of the chest of the subject ,
Area selection means for selecting a partial area in the lung field of the subject ,
With
The analysis means,
Based on a plurality of frame images showing the dynamics of the chest of the subject, a feature amount indicating a local movement in the lung field of the subject is calculated, and based on the calculated feature amount indicating a local movement in the lung field. , characterized in calculating the feature quantity in the entire lung field, wherein the amount of excluding the selected region selected by the region selecting means from the entire lung region and from the entire calculated the lung field excluding the selection area area The ratio of the amount to the calculated feature amount in the entire lung field is calculated.

The invention according to claim 2 is the invention according to claim 1,
The feature quantity indicating a local movement in the lung field of the subject is a feature quantity related to a ventilation function or a blood flow function in the lung field.

The invention according to claim 3 is the invention according to claim 1 or 2,
Input means for inputting a measurement result of another inspection of the subject,
The analysis unit calculates a value obtained by multiplying a measurement result of another test input by the input unit by a ratio of a feature amount in a region obtained by removing the selected region from the entire lung field to a feature amount in the entire lung field. It is characterized by doing.

The dynamic analysis system according to the invention described in claim 4 is
Recognizing means for recognizing a region of an artifact from a plurality of frame images generated by photographing dynamics of a subject;
Attenuation processing means for attenuating the image signal component due to the artifact by attenuating the image signal component of the region of the plurality of frame images recognized by the recognition means,
A plurality of frame images of the attenuated processing by the attenuation processing means, analyzing means from a plurality of frame images showing the kinetics of the chest of lung resection before the subject to analyze the dynamics of chest of the subject,
With
Said analyzing means, based on the lung resection before the subject's chest plurality of frame images showing the kinetics of ventilation or blood flow of the lung resection becomes the extent to which in comparison with prior lung resection The ratio is calculated.

  According to the present invention, it is possible to quantitatively estimate a state after a pulmonary resection before a pulmonary resection based on an analysis result of a dynamic image.

It is a figure showing the whole dynamic analysis system composition concerning this embodiment. FIG. 2 is a block diagram illustrating a functional configuration of a console in FIG. 1. 3 is a flowchart illustrating a shooting control process performed by a control unit in FIG. 2. 3 is a flowchart illustrating a dynamic analysis process performed by the control unit in FIG. 2. It is a flowchart which shows the artifact attenuation process performed in step S11 of FIG. It is a figure which shows typically the density profile of the cross section direction of an artifact area, and its correction. FIG. 3A is a top view illustrating a state in which a laser beam is applied to a position corresponding to an isocenter of a subject and a range in which images of a plurality of tomographic planes are generated by reconstruction processing of the subject, using a radiation generator. is there. (B) is a figure when (a) is seen from the opposite side surface of the radiation generator. FIG. 3C is a diagram illustrating a side surface of the subject as viewed from FIG. It is a figure which shows an example of the image of the chest to which the artifact was attached.

  Hereinafter, preferred embodiments according to the present invention will be described with reference to the drawings. The present invention is not limited to the illustrated example.

<First embodiment>
(Configuration of dynamic analysis system 100)
First, the configuration of the first embodiment according to the present invention will be described.
FIG. 1 shows an example of the overall configuration of a dynamic analysis system 100 according to the present embodiment.
The dynamic analysis system 100 is, for example, a round-turning system for imaging a patient who is difficult to move during or after surgery, and includes a radiation generator 1, a console 2, an access point 3, and an FPD (Flat). Panel Detector) cassette 4. The radiation generator 1 has wheels and is configured as a movable round car with a console 2 and an access point 3 installed. In the dynamic analysis system 100, the console 2 can be communicatively connected to the radiation generator 1 and the FPD cassette 4 via the access point 3.

As shown in FIG. 1, the dynamic analysis system 100 is brought into an operating room, an intensive care unit, a hospital room Rc, or the like, and moves the FPD cassette 4 between, for example, a subject H and a bed B lying on the bed B, or as shown in FIG. This is a system that irradiates radiation from the portable radiation source 11 of the radiation generating apparatus 1 in a state where it is inserted into an insertion port provided on the opposite side of the bed B from the subject H, and performs dynamic imaging of the subject H. .
Dynamic imaging refers to irradiating the subject H with pulsed radiation such as X-rays repeatedly at predetermined time intervals (pulse irradiation) or irradiating the subject H continuously at a low dose rate (continuous irradiation). ) Means obtaining a plurality of images. In the dynamic imaging, for example, the dynamics of the subject H having a periodicity (cycle) such as a morphological change in the expansion and contraction of the lung due to respiratory movement, a heartbeat, and the like are captured. A series of images obtained by the continuous shooting is called a dynamic image. Each of the plurality of images constituting the dynamic image is called a frame image.
In the present embodiment, the dynamic analysis system 100 is described as imaging the chest of the subject H and imaging the dynamics, but the imaging region is not limited to this.

Hereinafter, each device constituting the dynamic analysis system 100 will be described.
The radiation generator 1 is a radiation generator capable of at least one of pulse irradiation and continuous irradiation. The radiation generator 1 includes a radiation source 11 for irradiating radiation, a radiation irradiation controller 12, an exposure switch 13, and the like.

The radiation source 11 irradiates the subject H with radiation (X-rays) under the control of the radiation irradiation control unit 12.
The radiation irradiation control unit 12 performs radiation imaging by controlling the radiation source 11 based on the radiation irradiation conditions transmitted from the console 2. The radiation irradiation conditions input from the console 2 include, for example, a tube current, a tube voltage, a frame rate (the number of frame images photographed per unit time (1 second)), a total photographing time per photographing, or a total photographed frame image. The number, the type of additional filter, and the irradiation time per frame image in the case of pulse irradiation.
The exposure switch 13 inputs a radiation irradiation instruction signal to the console 2 when pressed.

  The console 2 outputs radiation irradiation conditions to the radiation generator 1, outputs image reading conditions to the FPD cassette 4, controls radiation photographing and radiation image reading operations, and outputs image data transmitted from the FPD cassette 4. Is displayed as a preview, or the image data is analyzed to calculate the feature amounts related to the ventilation function and blood flow function of the lung.

  FIG. 2 shows a functional configuration example of the console 2. As illustrated in FIG. 2, the console 2 includes a control unit 21, a storage unit 22, an operation unit 23, a display unit 24, a communication unit 25, a connector 26, and the like, and each unit is connected by a bus 27.

  The control unit 21 includes a CPU (Central Processing Unit), a RAM (Random Access Memory), and the like. The CPU of the control unit 21 reads the system programs and various processing programs stored in the storage unit 22 according to the operation of the operation unit 23 and develops them in the RAM. Various processes including a dynamic analysis process are executed to centrally control the operation of each unit of the console 2 and the operations of the radiation generator 1 and the FPD cassette 4. The control unit 21 functions as attenuation processing means, analysis means, and recognition means.

The storage unit 22 is configured by a nonvolatile semiconductor memory, a hard disk, or the like. The storage unit 22 stores various programs executed by the control unit 21 and data such as parameters necessary for execution of processing by the programs or processing results. For example, the storage unit 22 stores a program for executing the imaging control process illustrated in FIG. 3 and a program for executing the dynamic analysis process illustrated in FIG. Various programs are stored in the form of readable program codes, and the control unit 21 sequentially executes operations according to the program codes.
The storage unit 22 stores radiation irradiation conditions and image reading conditions during dynamic imaging. The user can set the radiation irradiation condition and the image reading condition by operating the operation unit 23.
The storage unit 22 stores the image data transmitted from the FPD cassette 4 in association with the patient information of the subject H, an analysis result calculated based on the image data, and the like.

  The operation unit 23 includes a keyboard having cursor keys, numeric input keys, various function keys, and the like, and a pointing device such as a mouse, and controls an instruction signal input by a key operation or a mouse operation on the keyboard. 21. The operation unit 23 may include a touch panel on the display screen of the display unit 24. In this case, the operation unit 23 outputs an instruction signal input via the touch panel to the control unit 21.

  The display unit 24 includes a monitor such as an LCD (Liquid Crystal Display) or a CRT (Cathode Ray Tube), and displays an input instruction from the operation unit 23, data, and the like in accordance with an instruction of a display signal input from the control unit 21. I do.

  The communication unit 25 includes a wireless LAN adapter or the like, and controls data transmission / reception with the radiation generator 1 or an external device such as the FPD cassette 4 connected to a communication network such as a wireless LAN via the access point 3. I do.

  The connector 26 is a connector for communication connection with the FPD cassette 4 via a cable (not shown).

  Returning to FIG. 1, the access point 3 relays communication between the radiation generator 1 and the console 2, communication between the console 2 and the FPD cassette 4, and the like.

  The FPD cassette 4 is a portable radiation detector for dynamic imaging. The FPD cassette 4 detects, at a predetermined position on a substrate such as a glass substrate, radiation irradiated from the radiation source 11 and transmitted through at least the subject H in accordance with the intensity thereof, converts the detected radiation into an electric signal, and stores the electric signal. Are arranged in a matrix (two-dimensional). A switching unit such as a TFT (Thin Film Transistor) is connected to each radiation detecting element, and the switching unit controls accumulation and reading of an electric signal to each radiation detecting element to acquire image data (frame image). You. The FPD includes an indirect conversion type in which radiation is converted into an electric signal by a photoelectric conversion element via a scintillator, and a direct conversion type in which radiation is directly converted into an electric signal, and any of them may be used.

  The FPD cassette 4 includes a reading control unit that controls accumulation and reading of an electric signal by a switching unit, and a communication unit that communicates with the console 2 via the access point 3 (neither is shown). . Image reading conditions such as a frame rate, the number of captured frame images per image, and image size (matrix size) are set by the console 2 via the communication unit. The reading control unit controls accumulation and reading of electric signals to each radiation detection element by the switching unit based on the set image reading conditions. The FPD cassette 4 has a connector, and can be connected to the console 2 via a cable (not shown).

  Note that the FPD cassette 4 may be brought by a radiographer or other radiographer, but the FPD cassette 4 is provided in a round-trip car because the FPD cassette 4 is relatively heavy and may fall or break down if dropped. It can be inserted into a cassette pocket 61a and transported.

(Operation of dynamic analysis system 100)
Next, the operation of the dynamic analysis system 100 will be described.
First, the photographing operation will be described.
FIG. 3 shows a flow of a photographing control process executed by the console 2 in response to an operation of the photographer. The photographing control processing is executed in cooperation with the photographing control processing program stored in the control unit 21 and the storage unit 22.

  First, the operation unit 23 of the console 2 is operated by the photographing technician, and the patient information (name, height, weight, physique, age, sex, etc. of the patient) of the imaging target (subject H), the inspection target site, and the analysis target (calculation) The photographing order information including the characteristic amount) is input (step S1).

  Next, the radiation irradiation condition is read out from the storage unit 22 and set in the radiation irradiation control unit 12 via the communication unit 25, and the image reading condition is read out from the storage unit 22 and the FPD is read out via the communication unit 25. This is set in the reading control unit of the cassette 4 (step S2).

  Next, a radiation irradiation instruction from the exposure switch 13 is awaited (step S3). During this time, the technician positions the patient. Specifically, the subject H is arranged such that the front (or back or side) of the chest of the subject H faces the radiation source 11. Further, the FPD cassette 4 is disposed on the surface of the subject H opposite to the radiation source 11 so as to face the radiation source 11. When the positioning is completed, the imaging technician operates the exposure switch 13 to instruct radiation irradiation.

  When a radiation irradiation instruction is input by the exposure switch 13 (Step S3; YES), an imaging start instruction is output to the radiation irradiation control unit 12 and the FPD cassette 4, and dynamic imaging is started (Step S4). That is, in the case of pulse irradiation, radiation is irradiated by the radiation source 11 at a pulse interval set in the radiation irradiation control unit 12, and in the case of continuous irradiation, the radiation is interrupted by the radiation source 11 at the dose rate set in the radiation irradiation control unit 12. Irradiation is continuously performed without radiation, and a frame image is acquired by the FPD cassette 4. The number of frame images to be photographed is preferably at least one cycle of breathing.

  The frame images acquired by the photographing are sequentially input from the FPD cassette 4 to the console 2 via the communication unit 25, are stored in the storage unit 22 in association with the numbers indicating the photographing order (step S5), and are displayed on the display unit. 24 (step S6). The photographing technician confirms the positioning or the like based on the displayed dynamic image, and determines whether an image suitable for diagnosis has been obtained by photographing (imaging OK) or whether reimaging is necessary (imaging NG). Alternatively, after the photographing is completed, a series of photographed frame images are read from the storage unit 22 automatically or by operating the operation unit 23, and are sequentially switched and displayed on the display unit 24 (moving image display). Alternatively, by checking the dynamic images displayed side by side on the display unit 24, it is determined whether an image suitable for diagnosis has been obtained by imaging (imaging OK) or re-imaging is required (imaging NG). Then, the user operates the operation unit 23 to input the determination result.

  When a determination result indicating shooting OK is input by a predetermined operation of the operation unit 23 (step S7; YES), a dynamic image is added to each of a series of frame images acquired by dynamic imaging and stored in the storage unit 22. Ancillary information such as an identification ID for identification, patient information, a part to be examined, an analysis target, a radiation irradiation condition, an image reading condition, and a number indicating an imaging order is attached (for example, in a header area of the image data in DICOM format). (Written) (step S8). Then, this processing ends. On the other hand, when the determination result indicating the photographing NG is input by a predetermined operation of the operation unit 23 (step S7; NO), a series of frame images stored in the storage unit 22 is deleted (step S9), and the present processing is performed. finish.

Next, a dynamic analysis process performed on a dynamic image stored in the storage unit 22 by the photographing control process will be described.
Here, during and after the operation, a medical tube such as a central venous catheter or a drainage tube is often connected to the patient. Conventionally, when chest X-ray dynamic imaging was performed with these patients as subjects, and dynamic analysis was performed on the obtained dynamic images, medical tubes associated with the patient's body motion, heart beat, respiratory motion, etc. Movement was an artifact of the analysis results.
Therefore, in the dynamic analysis processing of the present embodiment, before the analysis, an artificial object attenuation process for attenuating an image signal component due to an artificial object such as a medical tube is performed from the dynamic image, and dynamic analysis is performed on the obtained dynamic image.

  FIG. 4 shows a flow of the dynamic analysis processing executed by the console 2. The dynamic analysis processing is executed in cooperation with the control unit 21 and a program stored in the storage unit 22.

First, an artifact attenuation process is performed on each frame image (step S11).
FIG. 5 shows the flow of the artifact attenuation process executed in step S11. The artifact attenuation process is executed in cooperation with the control unit 21 and a program stored in the storage unit 22.

In the artifact attenuation processing, first, a lung field region is extracted from each frame image (step S111).
Any method may be used to extract the lung field region. For example, a threshold value is determined by a discriminant analysis from a histogram of signal values (density values) of each pixel of the frame image, and a region having a signal higher than the threshold value is primarily extracted as a lung field region candidate. Next, by performing edge detection near the boundary of the primary extracted lung field area candidate and extracting a point having the maximum edge along the boundary in a small area near the boundary, the boundary of the lung field area can be extracted. it can.

Next, an artifact recognition process is performed on the extracted lung field region of each frame image, and the region of the artifact is recognized (step S112).
Medical tubes are typical examples of the artifacts contained in the patient's body, so in the following description, a case where a thin tubular object region is recognized as an artificial region region will be described as an example. It is not limited.

In step S112, first, an edge-enhanced image of a thin tubular artifact is generated, and an edge is detected from the edge-enhanced image to recognize the region of the artifact.
Specifically, first, a sharpening process such as a spatial frequency emphasizing process is applied to a lung field region extracted from each frame image to generate an image in which the edge of the artifact is enhanced.
At this time, a GUI (Graphical User Interface) for the user to input the size (thickness / diameter) of the used artificial object from the operation unit 23 is displayed on the display unit 24, and is input by the operation of the operation unit 23. The edge of the structure having the input size (thickness / diameter) may be emphasized using a filter that emphasizes the spatial frequency corresponding to the size (thickness / diameter) of the artifact. Thereby, the recognition accuracy of the artifact can be improved.
Alternatively, a GUI for inputting the type of the artifact inserted into the patient from the operation unit 23 may be displayed on the display unit 24, and the edge of the artifact may be emphasized according to the type of the input artifact. Good. For example, if the artificial product is a central venous catheter, for adults, it is common to use a catheter having a thickness (diameter) of about 1 to 3 mm, and for a tube for thoracic drainage, for an adult, the thickness ( It is common to use a tube with a diameter of about 4 to 15 mm, and the tracheal tube rarely appears in the lung field, but for adults, a tube with a thickness (diameter) of about 6 to 9 mm is used. General. Therefore, for example, if the type of the input artifact is an adult central venous catheter, edge enhancement is performed using a filter that enhances the spatial frequency of about 1 to 3 mm. More specifically, in order to emphasize two edges formed on the tube side surface (both ends in the radial direction), a size D * c (here, c Is preferably set as a spatial frequency at which 0 <c <1) is emphasized by a filter.
Thereby, the recognition accuracy of the artifact can be improved. Edge enhancement may be performed using a Sobel filter or a Canny filter.
Alternatively, the edge of the artifact may be emphasized by using the movement of the artifact between the frame images caused by the movement of the subject H by subtracting the adjacent frame images of the dynamic image.

  After the generation of the edge-enhanced image, the edge-enhanced image is binarized with a predetermined threshold, and for example, an edge detection image in which 1 is assigned to an edge candidate point (pixel) of an artifact and 0 is assigned to other points (pixels) Generate The edge detection image is preferably subjected to an expansion process for connecting nearby edge candidate points as one lump. In addition, in this expansion processing, it is preferable to perform processing using a parameter corresponding to the size of the artificial object. For example, when the target artificial object is a tube, a predetermined distance range according to the thickness and diameter of the tube is used. By connecting the edge candidate points located inside the two, the two edge candidate points formed on the tube side surface side (both ends in the radial direction) can be collectively represented as one line. Further, in order to make it easier to detect the line shape formed by the connected edge candidate points in the line detection processing described later, the thinning processing is performed on the edge detection image in which the edge candidate points are connected by the expansion processing, It is preferable to express as a line of an edge candidate point having a width of one point (pixel). Next, edge candidate points are detected as straight lines and curves in the edge detection image by a generalized Hough transform using a straight line / arc / missing ellipse as a model, a polynomial approximation by a spline interpolation method, or an active contour method. Is performed. Before performing the contour detection processing, in order to simplify the shape of the line to be detected and reduce the degree of the curve, the edge detection image is divided into several to several tens of equally sized blocks. It is preferable to perform contour line detection processing and then combine the divided blocks to return to the original image size. Then, an area surrounded by the contour lines (straight lines and curves) detected by the contour line detection processing is recognized as an artificial area (artificial object area). If the target artificial object is a tube, apply an expansion process to the image after the outline detection process so that the width of the detected outline becomes a width corresponding to the thickness and diameter of the tube, and perform the expansion process after the expansion process. It is preferable that the contour line be a region of an artifact (artificial region). In addition, when the target artificial object is a tube, the above-described contour detection processing is not performed, and the thinned edge candidate point is compared with the thickness of the tube with respect to the edge detection image after the thinning processing. The expansion process may be performed so as to have a width corresponding to the diameter, and the edge candidate point after the expansion process may be recognized as an artificial region (artificial region). By omitting the contour detection processing, the processing time required for recognizing the artifact region can be reduced.

In addition, since bone regions such as ribs and collarbones in the frame image are confusing in recognition of the artifact region, bone regions such as ribs and collarbones are separately separated from each frame image before the above-described recognition of the artifact region. Recognition processing may be performed, for example, by attenuating the image signal component of the recognized bone region, or by recognizing the region of the artifact from a region other than the bone region of each frame image.
For example, as described in US Patent Application Publication No. 2014/0079309, the bone region is recognized by, for example, template matching with a prepared rib template or collarbone template, or fitting a curve fitting function after edge detection. And the like. In addition, based on the prior knowledge of the bone structure such as ribs and collarbones, based on the features such as position, shape, size, density gradient, direction, etc., the recognized bone area is carefully inspected for errors and excessive The extracted portion may be determined and removed from the bone region.
Attenuation of the image signal component of the bone is performed by generating a density profile of the bone region and subtracting the value of the density profile from which noise or the like has been removed from the original frame image, as in steps S113 and S114 described below. It can be carried out.

  Alternatively, after recognizing the region of the artifact from the frame image, the bone region is recognized, and the region other than the region recognized as the bone region among the regions recognized as the region of the artifact is finally converted to the region of the artifact. It may be recognized as an area.

  Next, a density profile of the recognized artifact region is generated (step S113). Specifically, a density profile in the cross-sectional direction is created for each recognized artificial object region for each original frame image. For example, in the case of a tubular artifact, the concentration profile in a line perpendicular to the travel of the tube is defined as the concentration profile in the cross-sectional direction. As shown in FIG. 6, the concentration profile in the cross-sectional direction of the artificial region is obtained by plotting the change in concentration in the cross-sectional direction of the artificial region, with the horizontal axis representing the position in the cross-sectional direction and the vertical axis representing the signal value (pixel value). It is.

  Note that the density profile in the cross-sectional direction of the artifact region of each frame image is compared with the density profile created for the preceding and succeeding frame images, and the value to be subtracted is substantially matched in the preceding and following frame images. It is preferable to correct it.

  For example, at each pixel of the frame image of interest, the value of the density profile in the cross-sectional direction of the artifact region, and a representative value (e.g., a median value or an average value) obtained from the density profiles of the pixels of the preceding and following frame images, Alternatively, the value of the density profile of an adjacent frame image (the immediately preceding or immediately following frame image) is compared, and if there is a difference equal to or larger than a predetermined threshold value, the difference is replaced with the compared value (representative value). Modify the density profile. Alternatively, as shown in FIG. 6, at the same position as the waveform of the cross-sectional density profile of the artifact region at a certain position of the frame image of interest, a waveform obtained from the representative values of the density profiles of a plurality of preceding and succeeding frame images (For example, a waveform created from the median value of each density profile) or a density profile waveform of an adjacent frame image (the immediately preceding or immediately following frame image) and a correlation (for example, a cross-correlation coefficient) are obtained. The degree of coincidence of the waveforms is evaluated, and if the degree of coincidence (correlation value) is lower than a predetermined threshold, the entire density profile at each position in the cross-sectional direction of the frame image of interest may be corrected by replacing with a compared waveform.

  Accordingly, since the value of the density profile to be subtracted from the original frame image in step S114 substantially matches the plurality of frames before and after, the image after the artifact attenuation processing is extremely different from the plurality of frame images before and after. For example, when calculating a difference value for each corresponding pixel or each region between different frame images such as adjacent frame images, the variation in the artifact attenuation processing for each frame image can be suppressed. It is possible to eliminate the influence of the airway and extract only changes in the lung field due to respiration and blood flow.

  Then, a low-pass filter is applied to the created density profile to remove spatial high-frequency components such as noise, and the value of the density profile from which the noise and the like have been removed is subtracted from the original frame image, so that an image signal due to an artifact is generated. An image with the components attenuated is obtained (step S114).

  When only a thin artificial object having a thickness (diameter) of less than 1 mm is attached to a patient such as a pediatric central venous catheter, the processing of steps S112 to S114 is not performed because the artificial object has little effect on the analysis result. Instead, the image signal component due to the artifact may be attenuated by performing smoothing with a smoothing filter having a block size whose one side is several times the diameter of the artifact.

When the artifact attenuation process ends, the process proceeds to step S12 in FIG. 4, and the dynamic image after the artifact attenuation process is displayed on the display unit 24 (step S12). The dynamic image may be displayed by sequentially switching a series of frame images after the artifact attenuation processing and displaying the moving image on the display unit 24 (moving image display), or displaying the series of frame images side by side on the display unit 24. You may do it.
By displaying the dynamic image after the artifact attenuation processing, the user can confirm what image is input to the dynamic analysis. In step S <b> 12, it is preferable that the dynamic image after the artifact attenuation processing and the dynamic image before the artifact attenuation processing are switched by the operation of the operation unit 23 or displayed in parallel. By displaying the dynamic image after the artifact attenuation process and the dynamic image before the artifact attenuation process so that they can be compared, the dynamic image changed by the artifact attenuation process, the image after the artifact attenuation process The user can confirm and judge whether or not is appropriate as a dynamic image used for dynamic analysis.

Next, dynamic analysis of the chest is performed on the dynamic image after the artifact attenuation processing (step S13).
The dynamic analysis of the chest includes an analysis for calculating a feature amount indicating a local movement of the lung field and an analysis for calculating a feature amount indicating the movement of the entire lung field. In addition, there is an analysis for the ventilation function and an analysis for the blood flow function.

There are several analyzes for calculating a feature amount indicating a local signal change due to a ventilation function of a lung field. For example, there is an inter-frame difference image calculation. The ventilation inter-frame difference image is calculated by performing the following processing on a series of frame images.
Binning processing → Low-pass filter processing in the time axis direction → Difference processing between frames → Noise removal processing

In the binning process, in each frame image, an image region is divided into small regions in units of pixel blocks of a predetermined size, and a representative value, for example, an average value of signal values of pixels in the region is calculated for each small region (averaging is performed). ) Processing. Note that the representative value is not limited to the average value, and may be a median value, an average value, or a mode value. It is preferable to set the size of the pixel block in accordance with the part to be analyzed and / or the feature amount calculated by the analysis from the viewpoint of improving the analysis accuracy. In addition, by setting the size of the pixel block to an integral multiple of the rib interval, even if the ribs move due to breathing, the ratio of the ribs present in the pixel block becomes substantially constant. It is possible to reduce the change in density caused by the movement of the ribs due to the respiration in the block, and it is possible to improve the analysis accuracy.
The low-pass filter process in the time axis direction is a process for extracting a temporal change of a signal value due to ventilation, and performs filtering at a cutoff frequency of 0.5 Hz, for example.
The inter-frame difference processing associates small regions at the same pixel position in a series of frame images (regions output from the detection elements at the same position of the FPD cassette 4) with each other, and, for each small region, between adjacent frame images. This is a process of calculating a difference value between signal values and creating an inter-frame difference image.
When a still image of the inter-frame difference image is created, the inhalation period and the expiration period in a series of frame images are calculated by analyzing the change in the density of the entire lung field or the change in the position of the diaphragm, and for each small region. For the inspiration period, an image is created by integrating the absolute value of the positive inter-frame difference value, and for the expiration period, an image is obtained by integrating the absolute value of the negative inter-frame difference value.
Since the inter-frame difference value is small at the location of abnormal ventilation, by outputting this inter-frame difference image, it is possible to identify a local abnormal location of ventilation.

There are several analyzes for calculating a feature amount indicating a local signal change due to a blood flow in a lung field. For example, there is an inter-frame difference image calculation. The blood flow inter-frame difference image is calculated by performing the following processing on a series of frame images.
Binning processing → High-pass filter processing in the time axis direction → Difference processing between frames → Noise removal

The high-pass filter process in the time axis direction is a process for extracting a temporal change of a signal value due to a blood flow, and performs filtering at a cutoff frequency of 0.7 Hz, for example. The other steps are the same as the processing described in the above-described ventilation inter-frame difference image.
Since an inter-frame difference value becomes small at an abnormal portion of the blood flow, it is possible to specify a local abnormal portion of the blood flow by outputting the inter-frame difference image.

  The dynamic analysis result is stored in the storage unit 22 in association with the patient information and a series of frame images of the dynamic image of the analysis source.

Next, the analysis result in step S13 is displayed on the display unit 24 (step S14), and the dynamic analysis processing ends.
For example, when an inter-frame difference image is obtained as an analysis result, each small area of each image is indicated by brightness or color corresponding to the inter-frame difference value, and a series of images is displayed on the display unit 24 as a moving image or displayed side by side. indicate. Alternatively, a still image of the inter-frame difference image may be generated, and each small area may be displayed on the display unit 24 with the brightness or color corresponding to the inter-frame difference value.

In addition, an analysis result such as an image in which an inter-frame difference value is indicated by a color and a dynamic image before the analysis are displayed in parallel, or displayed at the same position on the display unit 24 so as to be switchable at an arbitrary timing, or transmitted. It is good also as changing and superimposing and displaying it. This display makes it easy to compare the analysis result with the dynamic image before analysis. For example, the local value in the analysis result such as an inter-frame difference image is determined by any structure on the dynamic image before analysis. It is easy to determine whether the condition is caused by the movement of an object, and the state of the diseased part can be more accurately determined.
Further, the above-described ventilation inter-frame difference image and the blood flow inter-frame difference image are displayed in parallel, or displayed at the same position on the display unit 24 so as to be switchable at an arbitrary timing, or the transmittance is changed. May be superimposed and displayed. By performing such display, it becomes easier to compare the local abnormal part of the ventilation and the blood flow, and the state of the diseased part can be grasped more accurately.

In addition, for example, a result of CAD (Computer-Aided Diagnosis) used for diagnosis support of cancer and the like and an analysis result of an image or the like in which an inter-frame difference value is displayed in color are displayed in parallel or at the same position on the display unit 24. The display may be switchable at an arbitrary timing, or may be superimposed and displayed while changing the transmittance.
By performing such display, for example, it is easy to compare the result of CAD in which a region similar to a nodule or a tumor shadow in the lung field is marked with the analysis result of an image or the like in which an inter-frame difference value is shown in color. In other words, the state of the diseased part can be more accurately grasped by grasping whether or not the marked area in the CAD result matches the local value in the analysis result of the inter-frame difference image or the like.

As an analysis for calculating a characteristic amount indicating a local signal change due to ventilation or blood flow in a lung field, Japanese Patent Application Laid-Open No. 2010-268979 discloses a technique for ventilation, such as breathing at the vertical position of the diaphragm. The lung field region is divided into a plurality of regions on the basis of the time change of the index value indicating the pulsation of the heart such as the index value indicating the movement, if the blood flow, the time change of the signal value on the heart wall position or the heart region, etc. It is also possible to calculate the phase delay time of the pixel signal value time change for each region, calculate how much the time change of the pixel signal value in which region in the lung field is delayed and display it on the display unit 24.
Alternatively, as described above, in the case of ventilation, an index value indicating the respiratory movement such as the vertical position of the diaphragm, and in the case of blood flow, the heart beat such as the time change of the signal value on the heart wall position or heart region. Using the time change of the index value shown as a reference waveform, a cross-correlation coefficient with the pixel signal value time change is calculated for each region obtained by dividing the lung field region into a plurality of regions, and the pixel signal value of any region in the lung field is calculated. It is also possible to calculate an index indicating whether the time change is correlated with the reference waveform and display the index on the display unit 24.
Further, based on the phase lag time and the cross-correlation coefficient of the time change of the pixel signal value local in the lung field with respect to the time change indicating the reference respiratory motion or heart beat, for example, the phase lag time is determined based on the respiratory motion. Alternatively, the signal value change is caused by the movement of a structure such as a rib in an area where the phase is substantially inverted or an area where the cross-correlation coefficient is smaller than a predetermined value, which corresponds to about half the time of the beat cycle. It is recognized as a region that has occurred, that is, a bone region, and as described above, a density profile is generated for the recognized bone region, and the value of the density profile from which noise or the like has been removed is subtracted from the original frame image. May be applied to the image signal component of the bone part.

In addition, in the analysis result of an image or the like in which an inter-frame difference value is shown in color for a subject under consideration of an operation such as a pulmonary resection, the analysis displayed on the display unit 24 by the user operating the operation unit 23 or the like. For the result, for example, a part of the lung field such as a region corresponding to the lung resection range can be selected, and as a feature amount of ventilation or blood flow in a region excluding the selected region from the entire lung field, for example, The integrated value of the local inter-frame difference value in the region excluding the selected region from the entire field is calculated. Next, as a feature amount of ventilation or blood flow in the entire lung field, for example, a local frame in the entire lung field is calculated. The integrated value of the inter-difference value is calculated, and further, the characteristic amount of ventilation or blood flow in a region excluding the selected region from the calculated entire lung field is calculated. Calculated by dividing the value symptoms amount as a ratio of the two, it may be displayed on the display unit 24 the result as analysis result. For example, by selecting a pulmonary resection region as the above-described selection region, the ventilation or blood flow characteristic amount in a region excluding the selected region from the entire lung field calculated is calculated as the ventilation or blood flow after pulmonary resection. And the calculated feature value of ventilation or blood flow in the entire lung field was calculated as described above by assuming that it corresponds to ventilation or blood flow before lung resection. The ratio of both features is the ratio of ventilation or blood flow after pulmonary resection to that before pulmonary resection, that is, how much ventilation or blood flow is obtained by performing pulmonary resection compared to before pulmonary resection Therefore, it is possible to quantitatively estimate the state after the pulmonary resection before the pulmonary resection.
Further, the measurement result of another inspection for the subject H can be input to the console 2 via the operation unit 23 or the communication unit 25, and the measurement result of another inspection for the input subject H is calculated as described above. A value obtained by multiplying the ratio of the two feature amounts may be calculated, and the result may be displayed on the display unit 24 as an analysis result. For example, similarly, a lung resection area is similarly selected as the above-mentioned selection area, and the result of the spirometry test before the lung resection is input as the measurement result of the separate test for the subject H, whereby the measurement of another test for the subject H is performed. The value obtained by multiplying the result by the ratio of the two feature values calculated as described above can be regarded as an estimated value of the spirometry test before and after the pulmonary resection. As a postoperative condition, it is possible to estimate the result of spirometry examination after pulmonary resection, and based on this result, it is appropriate to perform pulmonary resection in which the subject removes the selected area It is possible to make an appropriate determination.

  In step S13, similar dynamic analysis is performed not only on the dynamic image to which the artifact attenuation processing is applied, but also on the original dynamic image to which the artifact attenuation processing is not applied. It is preferable that the analysis result for the dynamic image to which the attenuation processing is applied and the analysis result for the original dynamic image before the artificial object attenuation processing are applied are displayed in a switchable or parallel manner by operating the operation unit 23. By displaying the analysis result for the dynamic image after the artifact attenuation processing and the analysis result for the dynamic image before the artifact attenuation processing in a comparable manner, how the analysis result of the dynamic image changed by the artifact attenuation processing The user can confirm and determine whether the analysis result after the artifact attenuation processing is appropriate.

  Although the imaging order information is input to the console 2 by the imaging technician, the imaging order information may be input to the console 2 from a terminal such as an RIS (Radiology Information System) connected via a wired / wireless network. Good.

  Further, when the imaging order information is input to the console 2, all or a part of the frame images of the dynamic image previously captured by the patient to be imaged, radiation irradiation conditions and image reading conditions attached to the dynamic image, It is preferable that the data is read from the console 2 or an image storage server such as a PACS (Picture Archiving and Communication System) connected to the console 2 via a wired / wireless network and displayed on the display unit 24. By displaying all or a part of the frame images of the dynamic images captured by the patient to be imaged in the past on the console 2, radiation irradiation conditions, and image reading conditions, the same positioning, patient operation, and radiation irradiation as in the past imaging are performed. It becomes easy to photograph the patient under the conditions and image reading conditions, and it is possible to obtain dynamics that can be more easily compared with past images. For this reason, the console 2 stores a specific frame image of the dynamic image or an image obtained by reversibly or irreversibly compressing all or part of the dynamic image for a long time so that the dynamic image captured in the past can be immediately referred to. It is preferable to keep it.

  When the dynamic image is captured without the scattered radiation removal grid, the scattered radiation component is estimated for each frame image before applying the artifact attenuation processing to each frame image, and the original frame image is calculated. It is preferable to apply a scattered radiation removal process for removing scattered radiation components from the light. Thereby, the contrast of the image is improved, and the recognition accuracy of the artifact recognition process in the artifact attenuation process can be improved.

  Further, the amount of radiation irradiated per frame from the radiation generator 1 may change during imaging, and a temporal change in the amount of radiation may cause an error in the analysis result. Therefore, before applying the artifact attenuation processing, it is preferable to perform a radiation dose time change correction process for canceling a change in the radiation dose applied per frame to each frame image. In this correction process, the console 2 obtains information on the radiation dose for each frame image from the radiation generator 1 and, for example, converts the pixel value of each frame to the radiation dose of each frame according to the information on the radiation dose. Correction may be performed by a method such as dividing by a proportional value, or a region where there is no movement such as a radiation irradiation region or a region where the subject is substantially stationary on the subject is directly recognized from each frame image, and the recognized motion is The correction may be made according to the pixel value of the region where there is no. This makes it possible to remove the influence of the time change of the radiation irradiation amount from the feature amounts relating to the ventilation function and the blood flow function, and to improve the diagnosis accuracy based on the analysis result of the dynamic image.

  In addition, the control unit 21 of the console 2 executes the above-described direct operation every time each frame image is sequentially acquired during the capturing of the dynamic image, or immediately after a series of dynamic image capturing is completed, so that the correction process can operate normally. A determination process is performed to determine whether or not a region where there is no movement such as a radiation irradiation region or a region where the subject is substantially stationary on the subject is included in each frame image. It is preferable to display a warning to that effect so as to prompt the user to take a picture again.

  Also, the console 2 can capture the FPD cassette 4 and the radiation source 11 by capturing a still image for positioning confirmation (scout photography) immediately before moving image capturing or by analyzing one to several frame images immediately after starting dynamic image capturing. May be determined, whether the positioning of the subject H is appropriate or not, and the image processing parameters at the time of displaying the dynamic image before analysis may be determined. When these analyzes are performed on a frame image immediately after the start of dynamic image capturing, it is preferable to analyze the image almost in real time whenever each frame image is sequentially acquired during capturing of the dynamic image. The alignment between the FPD cassette 4 and the radiation source 11 and the determination of whether or not the positioning of the subject H is appropriate include, for example, in the case of radiographing of the chest, image radiation performed first by the control unit 21 directly Recognize the exposed area and the subject area to be irradiated, then recognize the lung field area and the mediastinum area from the subject area, and further from the mediastinum area, the spinous processes of the vertebrae in the vertically aligned vertebrae, Recognize pedicles sandwiching spinous processes. Then, by automatically measuring whether or not the spinous process is located at the center of the recognized both pedicles, it is determined whether or not the spinous process is in the middle of the pedicle. If the spinous process is not at the midpoint of the pedicle, it is determined that the irradiation is performed not obliquely but perpendicularly to the surface of the FPD cassette 4 and the display unit 24 displays that the alignment of the radiation source 11 should be changed. . At this time, if the vertebrae having recognized the spinous process and the pedicle are enlarged and displayed on the display unit 24, the user can easily understand how much the radiation source 11 should be moved, which is more preferable.

  In addition, the console 2 or the FPD cassette 4 analyzes a still image for scouting for positioning confirmation immediately before moving image capturing (scout image capturing), or one to several frame images immediately after the start of dynamic image capturing to obtain the frame. Recognize the lung field area in the image, determine the area of the circumscribed rectangle × α (α> 1) as the target area, and read only the determined target area in the subsequent frame image collection in the FPD cassette 4. Alternatively, the reading by the FPD cassette 4 is performed on the entire area, but the area to be transferred from the FPD cassette 4 to the console 2 in the entire area of the read frame image may be limited to the determined target area. Here, in the determination of the target area, it may be set so that the area irradiated directly from the radiation source 11 to the FPD cassette 4 includes a predetermined area. In this way, by limiting the area read by the FPD cassette 4 or the area transferred from the FPD cassette 4 to the console 2 to a part of the area, the amount of power consumed in reading or transferring can be suppressed. Further, the storage capacity of the storage unit in the FPD cassette 4 and the storage unit 22 for storing the image data can be reduced.

  In addition, in order to suppress blurring (motion artifact) due to movement of the radiation source 11 and the subject H, it is preferable that the radiation generator 1 emits radiation from the radiation source 11 by pulse irradiation. Even when only the function of continuously and continuously irradiating the radiation with continuous irradiation from 11 is provided, the radiation generator 1 sets the irradiation port of the radiation source 11 to a stop portion for narrowing the irradiation field of the radiation (not shown). The diaphragm unit has a shutter that completely shuts off the output of radiation, and the diaphragm unit changes the continuous irradiation to pulse irradiation by driving the opening and closing of the shutter at a desired timing. The configuration may be such that radiation is irradiated by pulse irradiation. At this time, it is preferable that the aperture unit and the FPD cassette 4 be synchronized so that the timing at which the aperture unit opens the shutter and emits pulsed radiation falls within the accumulation time of the FPD cassette 4. Further, the aperture unit having a shutter opening / closing mechanism is configured so as to be detachably attached to the radiation source 11 so that the existing radiation generator for photographing still images in the facility can emit only a single radiation, Even in the case where continuous irradiation is realized by irradiating the single-shot radiation for a long time, by attaching the detachable aperture portion to the radiation source 11 externally, it is possible to reduce the cost without replacing the entire radiation generator 1. Thus, pulse irradiation can be realized. In general, most radiation generators for photographing still images have a minimum tube current that can be set at 10 [mA] or 20 [mA]. In order to reduce the total exposure dose to the subject, it is necessary to reduce the dose rate of the radiation applied to the subject to the dose rate applied to the subject when the tube current is set to, for example, about 0.5 to 3 [mA]. is there. Therefore, the diaphragm unit is externally attached to the radiation source 11 of the radiation generating apparatus for photographing a still image, and the single-shot radiation radiated from the radiation source 11 is periodically closed and shut by the diaphragm unit. However, by using pulse irradiation, the dose rate applied to the subject can be reduced to a dose rate suitable for dynamic imaging, and the total exposure dose to the subject can be suppressed. At this time, in order to further reduce the dose rate, the aperture section may be configured to have a mechanism for loading an additional filter into the irradiation port of the aperture section.

  In addition, since the radiation generator 1 for round-trip or portable use is of a movable and compact form, the rise time at which the tube voltage rises to near a set value immediately after the start of radiation irradiation, and the start-up time immediately after the end of radiation irradiation. In many cases, the fall time when the voltage falls to almost 0 is long. At this time, until the tube voltage rises to around the set value, and until the tube voltage falls to almost 0, radiation of a low tube voltage is irradiated, and a frame image satisfying a desired image quality suitable for analysis. Is not generated, and wasteful exposure to the subject is increased. Therefore, when the tube voltage is lower than a desired value, such as immediately after the start of radiation irradiation or immediately after the end of radiation irradiation, the diaphragm unit has a function of shutting off radiation by closing the shutter with the shutter opening / closing mechanism. Is preferred. Accordingly, since only the radiation of the tube voltage that generates a frame image suitable for analysis is applied to the subject, it is possible to reduce unnecessary exposure of the subject. Alternatively, immediately after the start of radiation irradiation, the first predetermined number of frames or a predetermined time, the reading operation of the FPD cassette 4 or / and the storage of the image data in the storage unit in the FPD cassette 4 or / and Transmission of image data from the FPD cassette 4 to the console 2 via the communication unit 25 may be controlled so as not to be performed. As a result, the power consumption of the FPD cassette 4 can be reduced during irradiation with low tube voltage radiation that generates a frame image unsuitable for analysis. Wear can be reduced. In addition, since a frame image inappropriate for analysis is not stored in the storage unit in the FPD cassette 4, the storage capacity of the storage unit in the FPD cassette 4 can be effectively used.

  In addition, as described above, immediately after the start of radiation irradiation or immediately after the end of radiation irradiation, the tube voltage is lower than a desired value, and radiation suitable for analysis is not irradiated from the radiation source 11, and the diaphragm unit is By closing the shutter by the shutter opening / closing mechanism, the FPD cassette 4 acquires one to a plurality of frame images during a part of the period while the radiation emitted from the radiation source 11 is blocked, An offset value caused by a dark current superimposed on a frame image collected while the FPD cassette 4 is not irradiated with radiation is removed from a frame image collected while the FPD cassette 4 is not irradiated with radiation. May be used as image data for offset correction. By doing so, it is possible to collect image data for offset correction at a time closer to the period during which the FPD cassette 4 is irradiated with radiation, and to obtain the accuracy of offset correction for removing the offset value. And an image more suitable for analysis and diagnosis can be obtained.

  Further, when the captured image is a dynamic image of the respiratory state of the chest, for example, by using a non-contact sensor such as a microwave radio wave sensor, by transmitting radio waves and receiving reflected waves from the subject surface, The respiratory dynamics of the subject H may be measured, and the respiratory dynamics information of the subject H may be displayed on the display unit 24 of the console 2 in real time. As described above, by extracting the respiratory dynamic information of the subject using a sensor different from the FPD cassette 4, the user can monitor the respiratory dynamics of the subject even during irradiation. The user can determine the radiation irradiation start timing in accordance with the respiratory dynamics of the subject H. In addition, it is preferable that the respiratory kinetic information such as the phase of the respiratory motion acquired by such a separate sensor or the like is attached to a dynamic image or an analysis result of the dynamic image and held, but when added to image data. In order to transfer the data to a terminal such as a server or viewer such as a PACS, and to separate and display the data on a terminal such as a server or a viewer such as a PACS, the data is separated from the PACS or the like. Terminals such as servers and viewers need to hold the configuration in the data in advance, and the types of servers and terminals that can separately display image data and respiratory information are extremely limited. . Therefore, the respiratory kinetic information such as the phase of the respiratory motion described above may be embedded in the corresponding frame image in the image data, for example, as text information as an annotation, or as a graphical diagram as waveform data. . As a result, the type of the server or terminal is not limited, and, more generally, the image data and the respiratory kinetic information such as the phase of the respiratory motion are separated and displayed on the server or the terminal that has read the data. It is possible to do.

In addition, since the radiation generator 1 for round-trip or portable is a movable and compact form, the maximum radiation irradiation time is short, and in one dynamic imaging, one cycle of respiratory dynamics cannot be captured. There is. In such a case, for example, as described above, the respiratory dynamics of the subject H are monitored by a sensor other than the FPD cassette 4 even during radiation irradiation, and the phase at the end of the radiation irradiation of the first dynamic imaging is held. In the meantime, at the time of the second imaging, even if the user instructs the start of radiation irradiation, the respiratory motion of the subject H becomes the above-mentioned held phase based on the output of the above-mentioned sensor, even if the user instructs the start of radiation irradiation. The irradiation may be stopped until the irradiation reaches the held phase, and the irradiation may be started. Further, if necessary, the phase at the end of the radiation irradiation of the second dynamic imaging is held, and the same control is performed after the next third imaging. This makes it possible to match the phase of the last frame image of the previously captured dynamic image with the first frame image of the next captured dynamic image. By generating a dynamic image, even if the maximum radiation irradiation time is short as described above and one dynamic imaging cannot capture one cycle of respiratory dynamics, the subject H is not exposed to unnecessary exposure, It is possible to generate and analyze a dynamic image equivalent to a case where one or more dynamic cycles are continuously captured.

<Second embodiment>
Next, a second embodiment of the present invention will be described.
The configuration of the dynamic analysis system 100 according to the second embodiment is substantially the same as that described with reference to FIGS. 1 and 2 in the first embodiment, but in the second embodiment, the radiation generator 1 At the beginning or end of dynamic imaging, imaging can be performed by sequentially switching and irradiating a plurality of radiations of different energies (tube voltages) to obtain k frame images for energy subtraction processing. In the console 2, as the radiation irradiation conditions, in addition to the radiation irradiation conditions for dynamic imaging, the type (j; j ≧ 2) of energy (tube voltage) to be switched at the time of imaging for acquiring an image for energy subtraction processing, and the energy. The number of times (k) of imaging while switching and the order of switching the energy can be set by the operation unit 23. In order to perform imaging while switching the energy, it is preferable that the radiation generator 1 emits radiation from the radiation source 11 by pulse irradiation.

Here, the energy subtraction process is a process of extracting or attenuating a structure having a predetermined linear attenuation coefficient by calculating j frame images captured by switching j types of energy continuously in time. . The number k of times of imaging while switching the energy type for the energy subtraction process is equal to or more than the number j of the energy types.
For example, when acquiring a frame image for energy subtraction processing at the beginning of a dynamic image, assuming that there are three types of energy (energy A, B, C), k = j as in the following (1): And k で き る j as in (2). (1) As shown in A, B, C, C, C, etc., in the first three imagings, three types of energy are switched to irradiate radiation to obtain a frame image for energy subtraction processing, Subsequently, imaging is performed by irradiating a plurality of times with radiation of the same energy type as the energy type C that was last switched, and acquiring as a frame image for dynamic analysis by imaging with the last continuous energy type C (k = J)
(2) Frame images for energy subtraction processing by irradiating radiation by switching three energy types in the first five imagings, such as A, B, C, A, B, B, B. Then, the radiation of the same energy type as the energy type B that was last switched is performed a plurality of times to perform imaging, and the imaging with the last continuous energy type B is acquired as a frame image for dynamic analysis. Case (k ≠ j)

  That is, in the second embodiment, in step S2 of the imaging control process of FIG. 3, the radiation irradiation conditions including the type of radiation energy to be switched for the energy subtraction process, the number of times of imaging while switching the energy, and the order are the radiation generation conditions. It is set in the device 1. In step S4, the radiation generator 1 switches the radiation of the set j types of energy at the beginning or end of the dynamic imaging, and performs k times of imaging, and obtains k (k ≧ j) energy subtractions. A dynamic image including a frame image for processing is acquired.

  In the console 2, dynamic analysis processing is performed on the dynamic images acquired by the imaging control processing in the same manner as in the first embodiment, but in the present embodiment, the dynamic analysis processing in the artificial object attenuation processing in step S2 is performed. An object recognition process (step S112) is different from the first embodiment. Hereinafter, an artifact recognition process performed by the control unit 21 in the second embodiment will be described.

  First, using the first or last k frame images of a dynamic image acquired by dynamic imaging, an artificial object recognition process by energy subtraction processing is performed, and k-j + 1 artificial object enhanced images (artifacts are recognized). Image). The artificial object recognition processing by the energy subtraction processing performed here is performed, for example, among the first or last k frame images of the dynamic image, j temporally consecutive frames captured with radiation of j kinds of different energies. This is a process of performing an operation for each image to attenuate the image signal components of the bones and soft tissues of the subject reflected in the dynamic image, thereby obtaining an image that recognizes the artifact.

  Here, in order to attenuate the image signal components of both the bone part and the soft tissue of the subject reflected in the dynamic image, it is preferable that the above-mentioned different energy types j are three or more. When i kinds of artifacts having different linear attenuation coefficient energy characteristics are captured in the dynamic image, the above-mentioned different energy type j is set to i + 2 or more, and the image is taken with the j kinds of radiation having different energies. Attenuating image signal components of the bones and soft tissues of the subject and other artifacts having energy characteristics of the linear attenuation coefficient by the calculation according to the following [Equation] for each of j frame images that are temporally continuous. Accordingly, it is preferable to obtain i artifact-enhanced images in which only artifacts having energy characteristics of a specific linear attenuation coefficient are respectively enhanced.

In a case where the signal values of arbitrary pixels corresponding to each of the frames in the temporally continuous j frame images captured by the j types of radiation having different energies are p1 to _j , for example, the following [ [Mathematical formula-see original document], pixel values Pe1 to Pei in which only artifacts having energy characteristics of linear attenuation coefficients _{e1 to ei} are emphasized (extracted) can be obtained.
[formula]
P _e1 = α ₁₁ * P ₁ + α ₁₂ * P ₂ + α ₁₃ * P ₃ + ... + α _1j P _j
P _e2 = α ₂₁ * P ₁ + α ₂₂ * P ₂ + α ₂₃ * P ₃ + ... + α _2j P _j
...
P _ei = α _i1 * P ₁ + α _i2 * P2 + α _i3 * P ₃ + ... + α _ij P _j
(α _{11 to} α _ij represent real coefficients)
At this time, the calculation method applied to the j frame images is changed according to the type of the artifact, more specifically, according to the artifact having the energy characteristics of the i kinds of linear attenuation coefficients (α ₁₁ to α ₁₁ ). It is preferable to change the coefficient of α _ij ). Here, a GUI for inputting the type or material of the artifact inserted into the patient from the operation unit 23 is displayed on the display unit 24, and the linear attenuation of the artifact is performed according to the type or material of the input artifact. The energy characteristics of the coefficients may be specified, and the coefficients α _{11 to} α _ij may be set based on the energy characteristics of the specified linear attenuation coefficient of the artifact.

  An artifact-enhanced image obtained by adding corresponding pixel values of the i artifact-enhanced images obtained by the above [Expression] is output as an artifact recognition processing result. Alternatively, each of the i number of artifact-enhanced images obtained by the above [Equation] is subjected to a binarization process with a predetermined threshold value, and a region indicating one of the values is obtained as an artifact region image. For example, if at least one of the i pixels corresponds to an artificial region, the corresponding pixel is regarded as an artificial region with respect to the artificial object region images. It may be output as a result. Such an artifact recognition process is performed using j temporally consecutive frame images captured with radiations of j kinds of different energies while shifting the frame images one by one, whereby temporally continuous It is possible to obtain k-j + 1 pieces of artifact recognition processing results. For example, as shown in the above (2), when the images A, B, C, A, B, B, B,. Using k = 5 frame images of B, C, A, and B, each of three temporally continuous frame images captured with radiation of three different energies, that is, ABC, BCA, and CAB By performing the artifact recognition process by the energy subtraction process for each group, k-j + 1 = 3 artifact-enhanced images are obtained.

  In the case of k−j + 1> 1, it is preferable that the first or last k−j + 1 pieces of artifact recognition processing results are collated, and the k−j + 1 pieces of artifact recognition results are corrected. Further, the artifact-enhanced image obtained by the above-described processing is further subjected to, for example, the artifact-recognition processing described in the processing of step S112 in FIG. 5 of the first embodiment. It may be possible to recognize an artifact by doing so. Thereby, the recognition accuracy of the artifact can be improved.

  After acquiring the k-j + 1 frame images in which the artifact is recognized by the artifact recognition process by the energy subtraction process, the control unit 21 determines the k-j + 1 frame image based on the artifact recognition result. For each of the remaining frame images that have not been subjected to the artifact recognition processing, the artifact recognition processing is performed by simple image processing.

As a simple artifact recognition process, for example, referring to the artifact region recognized in the immediately preceding frame image, only a few pixels around the boundary of the artifact region, the spatial edge of the artifact (gradient) To find the artifact region by extracting the edge of the artifact. As a result, the amount of calculation can be reduced and processing can be performed at high speed as compared with the case where complete artifact recognition processing is performed on all frame images. As an example of a method of accurately extracting a spatial edge of an artifact, there is a method using an active contour extraction method. This is a method of performing contour extraction a plurality of times using the coordinates of the artifact region extracted in the immediately preceding frame image as the initial position, and using the shape of the artifact and the edge features on the image as evaluation functions. It is possible to accurately grasp the outline of an object. Further, by using this active contour extraction method, it is possible to flexibly cope with a change in the shape or position of the target artificial object, so that it can be used even between images having a large change between frame images.
For further simplification, for example, if the captured image is a dynamic image of the respiratory state of the chest, the artifact usually moves in a specific direction during inspiration and expiration, depending on the type of the artifact, In each frame image, it is determined whether the timing is inspiration or expiration, and for the artificial region extracted in the immediately preceding frame image, for example, in the case of inspiration, an edge is searched only in the downward direction, In the case of, the edge of the artifact may be searched for in a specific direction at the time of inhalation or expiration according to the type of the artifact, such as searching for an edge only in the upward direction. Also, as described above, when a plurality of types of artifacts are reflected, the direction of edge search is changed during inspiration and expiration according to each artifact, and extraction is individually performed for each artifact. You may go.

  The timing of inspiration or expiration can be determined by detecting the direction in which the diaphragm moves relative to the immediately preceding frame image, or whether the density change in the lung field region has increased or decreased. In the direction in which the diaphragm moves, it can be determined that the diaphragm moves in the downward direction as inhalation and that the diaphragm moves in the upward direction as expiration. In the density change of the lung field area, it can be determined that the inhalation occurs when the density increases, and that the expiration occurs when the density decreases. Since the diaphragm has a large concentration gradient, it is possible to easily recognize whether the frame image is inhaled or expired by detecting the edge of the diaphragm. Further, the lung field area can be recognized by detecting the edge of the rib cage as in the process of step S111. However, even if the lung field area is not recognized, for example, the density of the fixed area at the center of the image increases. The timing of inhalation and expiration can be determined depending on whether it is on or off.

  In this way, by sequentially processing each frame image with reference to the artifact recognition result of the immediately preceding frame image, the artifact recognition processing of each frame image can be simplified, and the It is possible to increase the processing speed of the artifact recognition processing.

  In addition, during the shooting of j frame images used for one energy subtraction process, the body motion, the breathing motion, and the pulsation of the subject H occur, and the shading of the same structure reflected in each frame image is the position. To cause a displacement, it is preferable to perform a positioning process for correcting the displacement. In addition, in each frame image of a dynamic image captured with low-energy radiation, since the amount of noise is large in a region corresponding to a structure having a low X-ray transmittance of the subject, noise suppression processing is performed to make the noise inconspicuous. Is preferred. However, these alignment processing and noise suppression processing require a long processing time. In addition, there is a limitation on a switching time interval for switching radiation of different energy between frames, and a frame rate is limited (upper limit).

  Therefore, by limiting the number of frame images used for the energy subtraction process to k, the processing speed of the artifact recognition processing for the entire dynamic image can be increased. Applying object attenuation processing, it is possible to shorten the time interval until the dynamic image after application is displayed or input to the dynamic analysis processing, and to switch the radiation energy only for the first or last k dynamic images. It is possible to shoot at a lower frame rate than the desired frame rate, and to shoot the remaining frames at the desired frame rate. If the processing time and the frame rate are sufficient, the artifact recognition processing using the energy subtraction processing may be applied to all the frame images of the dynamic image.

  Since the processing after step S113 is the same as that of the first embodiment, the description is referred to.

  As described above, according to the second embodiment, complete artifact recognition processing is performed only on some frame images, and simple artifact recognition processing is performed on other frame images. Thus, it is possible to reduce the amount of processing calculations and perform high-speed processing.

  In the second embodiment, the artificial object recognition processing using the energy subtraction processing is performed using a part of a series of frame images, and the already-performed artificial object recognition processing is performed on the remaining frame images. Refers to the artifact region recognized by, and searches for the spatial edge (gradient) of the artifact and extracts the edge of the artifact only in a few pixels around the boundary of the artifact region. A simple artificial object extraction process for recognizing is performed, but instead of the artificial object recognition process using the energy subtraction process, another artificial object recognition process, for example, the artificial object recognition process described in the first embodiment is used. Processing may be performed.

  Further, an image obtained by extracting only the soft tissue by the above-described energy subtraction processing may be used as the input image for the dynamic analysis in step S13 in FIG. In the image in which only the soft tissue is extracted by the energy subtraction processing, the dynamics analysis can be performed with high accuracy because the image signal component of the artificial object is attenuated. However, depending on the artificial object, there are many cases where there is no significant difference in the energy characteristics of the linear attenuation coefficient with the soft tissue. At this time, the image obtained by extracting only the soft tissue by the energy subtraction processing includes the image signal of the artificial object. In some cases, the components cannot be attenuated and remain. In this case, in the complete artifact recognition process performed only on some frame images, first, as described above, an artifact-enhanced image is obtained for each artifact to be attenuated by the energy subtraction process, and then For the artifact-enhanced image of each artifact, processes such as generation of edge enhancement and detection of straight lines and curves are performed by the artifact recognition process described in the process of step S112 in FIG. 5 of the first embodiment. Then, an artifact region is recognized for each artifact. For other frame images, a simple artifact recognition process is performed for each artifact based on the artifact region for each artifact recognized in the complete artifact recognition process. Recognize the artifact region for each artifact. Then, for each of the original frame images, the density profile of the artifact region described in the processing of steps S113 and S114 of FIG. 5 of the first embodiment is generated, and the process of attenuating the image signal component of the artifact region is performed. Is performed for each artifact, and an image is obtained in which the image signal components of all target artifacts are attenuated. In this manner, an image in which the image signal component of the target artificial object is accurately attenuated can be generated, and the diagnosis accuracy based on the analysis result of the dynamic image can be improved.

<Third embodiment>
Next, a third embodiment of the present invention will be described.
The configuration of the dynamic analysis system 100 in the third embodiment is substantially the same as that described with reference to FIGS. 1 and 2 in the first embodiment, but in the third embodiment, the dynamic analysis system 100 Furthermore, it has a tomosynthesis photographing function.
That is, the radiation generating apparatus 1 includes a moving mechanism for moving the radiation source 11 in the body axis direction of the subject H. At the time of tomosynthesis imaging, the radiation generating apparatus 1 moves the radiation source 11 with respect to the FPD cassette 4 a predetermined number of times. The FPD cassette 4 acquires a predetermined number of images, and transmits the acquired images to the console 2. In addition, in order to suppress blurring (motion artifact) due to the movement of the radiation source 11 and the subject H, the radiation generation device 1 preferably radiates radiation from the radiation source 11 by pulse irradiation. It is also possible to configure so that the FPD cassette 4 performs a predetermined number of image acquisition processes during the continuous irradiation of the radiation.

  In the console 2, as radiation irradiation conditions, it is possible to set radiation irradiation conditions during tomosynthesis imaging in addition to dynamic imaging conditions. The dynamic imaging of the chest is performed under a respiratory condition, whereas the tomosynthesis imaging of the chest is performed a plurality of times by changing the imaging angle in a breath-hold state. Therefore, before or after the dynamic imaging, the operator sets conditions for tomosynthesis imaging on the console 2 using the operation unit 23 and performs imaging.

  The projection image group obtained by the tomosynthesis imaging is reconstructed by the console 2 in cooperation with the control unit 21 and the program stored in the storage unit 22, and the images (tomographic images) of a plurality of tomographic planes (slice planes) are obtained. ) Is generated. Then, the tomographic images of the plurality of slice planes are used when recognizing an artifact region in each frame image obtained by dynamic imaging in step S112 of the artifact recognition process. Here, the tomographic images obtained by the tomosynthesis imaging are cross-sectional images of the subject H at a plurality of different positions in the radiation irradiation direction (z direction) on a plane (slice) orthogonal to the z direction.

  In the artifact recognition processing using the tomographic image obtained by tomosynthesis imaging, for example, first, the tomographic image of the slice plane of the region located on the body surface of the subject H, including the front rib, the rear rib, the collarbone, and the vertebra, is omitted. By adding (integrating) the pixel values of the corresponding pixels in all the remaining slices, a chest image from which bones have been removed is obtained. The chest image from which the bone part has been removed can correspond to a frame image having the same respiratory phase as the respiratory phase in the breath-hold state obtained by tomosynthesis with respect to a series of frame images of the dynamic image captured before and after that. . The artifact recognition described in the first embodiment is performed on the chest image from which the bones have been removed. That is, an edge region is recognized by performing edge enhancement, edge detection, and detection of a straight line and a curve by a frequency enhancement process corresponding to the artifact. Since the ribs have been removed from the chest image generated from the tomographic image, the recognition accuracy of the artifact is higher than in the first embodiment.

  Next, the simple artificial object recognition process described in the second embodiment is performed on each frame image obtained by dynamic imaging based on the chest image created based on the above-described tomographic image, so that each frame image is obtained. Recognize the artifact region in the frame image. Here, the size of the lung field in the chest image obtained from the tomographic image matches one of the frame images of the dynamic image. Therefore, first, a frame image in which the size of the lung image matches the size of the chest image obtained from the tomographic image is selected, and a simple artifact recognition process based on the artifact region recognized in the chest image is performed on this frame image. Do. Then, by sequentially performing the simple artifact recognition processing on the adjacent frame images, the artifact recognition processing is performed on each frame image. As a result, it is possible to reduce the amount of processing calculations and perform high-speed processing.

  Since the processing after step S113 is the same as that of the first embodiment, the description is referred to.

  According to the third embodiment, the artifact recognition processing is performed based on the image from which the bones have been removed, and the image signal component due to the artifact in the recognized artifact region is attenuated. It can be carried out. In addition, complete artifact recognition processing is performed only on one chest image, and simple artifact recognition processing is performed on the other frame images. Become. In the present embodiment, both dynamic imaging and tomosynthesis imaging are performed on the same subject to be inspected of the same subject. Therefore, the dynamic image before analysis, the image of the analysis result for the dynamic image, and the tomosynthesis captured image are reproduced. Images of a plurality of tomographic planes obtained by the configuration processing are displayed in parallel, or two of these images are displayed at the same position on the display unit 24 so as to be switchable at an arbitrary timing, or the transmittance is displayed. It is preferable to change and display them. With such a display, it is possible to make a diagnosis while simultaneously comparing functional information and morphological information based on movement, so that the state of the diseased part can be grasped more accurately and the diagnostic accuracy can be improved. In the parallel display and the switching display, for example, an analysis result such as an inter-frame difference image may be displayed as a moving image, and images of a plurality of tomographic planes by tomosynthesis may be displayed in a moving image. Further, in the display in which the transmittance is changed and superimposed, for example, an image of a plurality of tomographic planes by tomosynthesis is displayed on one image that remarkably reflects the most local motion extracted from an analysis result of an inter-frame difference image or the like. The image may be superimposed and displayed as a moving image, or conversely, an analysis result such as an inter-frame difference image may be superimposed on one image showing the most morphological features extracted from images of a plurality of tomographic planes by tomosynthesis. It may be displayed together as a moving image. This makes it easy to compare the functional information and the morphological information at the same position in the inspection target site, and can more accurately grasp the state of the diseased part. Furthermore, the results of applying CAD processing used to assist diagnosis of cancer and the like to images of a plurality of cross-sectional images by tomosynthesis and the analysis results of dynamic images such as images in which the inter-frame difference values are shown in color are shown. The display may be performed in parallel, may be switched at the same position on the display unit 24 at an arbitrary timing, or may be superimposed and displayed with different transmittance.

In both dynamic imaging and tomosynthesis imaging, the irradiation direction of the radiation at the center point of the radiation radiated from the radiation source 11 and the normal line of the FPD cassette 4 extended from the center point of the imaging area of the FPD cassette 4 are described. It is preferable to perform the alignment so that However, in the round-trip system, since the FPD cassette 4 and the radiation generator 1 are separated from each other, it is difficult for a user to accurately perform such an alignment, and it takes time to perform an accurate alignment. Therefore, for example, by installing at least three or more three-dimensional magnetic sensors in the inside of the FPD cassette 4 and in the vicinity of the irradiation port of the radiation source 11, the round-trip system uses the position of the FPD cassette 4 and the horizontal plane. , And the position of the irradiation port of the radiation source 11 and the radiation irradiation direction can be detected, and the radiation irradiation direction at the center point of the radiation radiated from the radiation source 11 and the imaging area of the FPD cassette 4 can be detected. The position and orientation of the radiation generator 1 and the position and orientation of the radiation source 11 are adjusted by a drive mechanism (not shown) mounted on the radiation generator 1 so that the normal to the FPD cassette 4 extending from the center point coincides with the normal line. Preferably, it is moved and changed. Further, the radiation generating apparatus 1 includes an aperture unit for narrowing the radiation field (not shown) at the irradiation port of the radiation source 11, further includes a driving mechanism for changing the radiation field, and an image of the FPD cassette 4. It is good also as a structure which changes the irradiation field of a radiation so that it may substantially correspond to an activation area. Alternatively, the detected position of the FPD cassette 4, the angle with respect to the horizontal plane, the position of the irradiation port of the radiation source 11, and the irradiation direction of the radiation are displayed on the display unit 24 of the console 2. The user may be able to identify whether the position and orientation of the radiation source 11 should be moved or changed. Furthermore, it is determined whether or not the irradiation direction of the radiation at the center point of the radiation radiated from the radiation source 11 substantially coincides with the normal line of the FPD cassette 4 extending from the center point of the imaging area of the FPD cassette 4. Alternatively, it may be determined that the information is displayed on the display unit 24 of the console 2.
By doing so, the time required for the user to accurately align the FPD cassette 4 with the radiation source 11 can be shortened, and the accurate alignment can prevent unnecessary exposure to the subject H and deterioration of the image data image quality. be able to.

  Also, when performing tomosynthesis imaging of the subject H in the lying position, generally, when the FPD cassette 4 is not placed horizontally, in order to move the radiation source 11 with accurate alignment with respect to the FPD cassette 4, The radiation generator 1 requires a complicated drive mechanism. Therefore, in order to simplify the driving mechanism of the radiation source 11 in tomosynthesis imaging of the radiation generating apparatus 1, the FPD cassette 4 is detected by the aforementioned three-dimensional magnetic sensor or the like to detect how much the FPD cassette 4 is inclined with respect to the horizontal plane. It may be determined whether or not 4 is placed substantially horizontally and displayed on the display unit 24 of the console 2. In addition, since the angle of how much the FPD cassette 4 is tilted with respect to the horizontal plane is also an index indicating the body position of the subject H, the angle depends on how much the detected FPD cassette 4 is tilted with respect to the horizontal plane. Alternatively, parameters for analysis processing for dynamic images and reconstruction processing for tomosynthesis captured images may be changed.

  Further, in the tomosynthesis imaging, in the z direction, the image of the tomographic plane with respect to the isocenter C, that is, the vicinity of the rotation center (see FIG. 7B) at the time of movement of the radiation source 11 in the tomosynthesis imaging has the least artifact. . Therefore, at the time of tomosynthesis imaging, as shown in FIG. 7A, the subject H is moved from the radiation generating apparatus 1 so that the user can position the subject H to be most viewed in the inspection target portion at the isocenter C. In contrast, the position of the isocenter C is preferably identifiable to the user as shown by CP in FIG. 7C by, for example, irradiating the LED laser beam LB and projecting light. Accordingly, the user can easily perform positioning such that the most desired portion of the inspection target portion of the subject H is located near the isocenter C at the time of imaging.

  Further, if the range in which the tomosynthesis photographed image is reconstructed and the images of the plurality of tomographic planes are generated is different from the range desired by the user, an image of the tomographic plane of a desired part cannot be obtained, or An unnecessary image of the tomographic plane is generated, the reconstruction processing time is required without permission, the data capacity is increased, and the storage capacity is consumed without permission. Therefore, in the tomosynthesis imaging, the user can change the positioning or reconstruction processing parameters so that the range in which the images of the plurality of tomographic planes are generated by the reconstruction processing in advance is the desired range of the user. As shown in FIG. 7A, for example, an LED laser beam LB is irradiated on a range in which images of a plurality of tomographic planes are generated by the reconstruction processing of the subject H from the radiation generator 1 to project light, or the like. As shown in FIG. 7 (c), it is preferable that the user be able to identify the user. Accordingly, the user can change the positioning or reconstruction processing parameters so that an image of the tomographic plane only in a desired range of the inspection target portion of the subject H is generated at the time of imaging, and the efficiency of the inspection is improved. Can be raised.

  Here, FIG. 7A shows the position of the radiation generating apparatus 1 corresponding to the isocenter C of the subject H and the laser beam LB in a range R in which images of a plurality of tomographic planes are generated by the reconstruction processing of the subject H. FIG. 3 is a diagram of a state of irradiating the light as viewed from above. FIG. 7B is a diagram when FIG. 7A is viewed from the side opposite to the radiation generator 1, and also shows the relationship between the subject H, the radiation generator 1, and the FPD. FIG. 7C is a diagram illustrating a side surface of the subject H when (a) is viewed from the radiation generating apparatus 1 side.

  In addition, in the vicinity of the irradiation port of the radiation source 11, the distance from the irradiation port to the surface of the subject H is measured in a non-contact manner. For example, an ultrasonic ranging sensor, an infrared light emitting element, and a light receiving element are provided. An infrared sensor or the like that converts the reflected light into a distance by detecting the reflected light of the reflected light with a light receiving element, and evaluates and calculates the same is provided. The console 2 measures the distance (FSD) : Focal spot to Skin Distance) and a function of estimating the dose rate or incident dose on the surface of the subject H based on the radiation irradiation conditions to be transmitted to the radiation irradiation controller 12. By storing these dose rates or incident doses in association with the captured image data, it becomes possible to manage the dose to which the subject H has been exposed. Further, when the calculated dose rate or the estimated value of the incident dose on the surface of the subject H is equal to or greater than a predetermined threshold, the console 2 controls the radiation generation device 1 to prohibit the irradiation of the radiation from the radiation generating apparatus 1, for example, by controlling the subject H It is possible to prevent the subject H from being irradiated with radiation having a dose rate or an incident dose that is equal to or greater than a predetermined value due to the radiation irradiation opening being too close.

  In addition, the console 2 performs radiation irradiation based on the position of the irradiation port of the radiation source 11 and the position of the FPD cassette 4 detected by a three-dimensional magnetic sensor or the like mounted on the FPD cassette 4 and the position of the irradiation port of the radiation source 11. The distance (SID: Source to Image Distance) from the mouth to the FPD cassette 4 is measured, and further, the irradiation field size is reduced from an aperture unit provided at the irradiation port of the radiation source 11 to narrow the irradiation field of the radiation (not shown). A function of estimating the incident surface dose from the above-mentioned FSD, the radiation irradiation conditions to be transmitted to the radiation irradiation control unit 12, and the measured SID and the detected irradiation field size using a calculation formula such as the NDD method. It is preferable to mount it. Further, the console 2 calculates the body thickness information of the subject H by subtracting the FSD from the SID measured as described above, and the console 2 transmits the information to the radiation irradiation control unit 12 based on the calculated body thickness information. The radiation irradiation condition to be performed may be calculated. This makes it possible to irradiate radiation under radiation irradiation conditions suitable for the body thickness of the subject H, and it is possible to suppress deterioration in image quality due to insufficient dose or increase in unnecessary exposure to the subject H due to excessive dose. Become.

  In addition, the console 2 is configured to store the SID, FSD, and radiation irradiation conditions measured by the above-mentioned sensors and the like in association with the captured image data. If the captured image data on the console 2 is held, the SID, the FSD, and the irradiation condition attached to the image data captured in the past are read, and the read irradiation condition is transmitted to the irradiation control unit 12. At the same time, the position and orientation of the radiation generator 1 and the position and orientation of the radiation source 11 are moved and changed by a drive mechanism (not shown) mounted on the radiation generator 1 so as to match the read SID and FSD. Is preferred. This allows the user to accurately reproduce the alignment and radiation irradiation conditions taken in the past, making it easier to compare with images taken in the past, and obtaining dynamic images that are easier to compare with past images. Becomes

<Fourth embodiment>
In the first to third embodiments, from the viewpoint of improving the diagnostic accuracy of the dynamic image, in the dynamic image, the image signal component of the artifact that hinders the diagnosis of the dynamic image is attenuated, and the image signal component of the artificial object is attenuated. The example in which the displayed dynamic image is displayed and used for the dynamic analysis has been described. However, on the other hand, there is also a desire to confirm that the artificial object has been properly inserted. However, for example, an artificial object such as a lead or a catheter of a cardiac pacemaker has low contrast on an X-ray image, and it is difficult to confirm the dynamic image without performing the artificial object attenuation processing as it is. Therefore, in the fourth embodiment, an example will be described in which, when displaying dynamic images in the first to third embodiments, an image in which an artificial object is emphasized is created and displayed together.

  The dynamic analysis system of the fourth embodiment is substantially the same as the configuration of the dynamic analysis system 100 described in the first to third embodiments, but can also perform still image shooting (simple X-ray imaging). .

  In the console 2, it is possible to set, as the radiation irradiation condition, the radiation irradiation condition at the time of still image photographing in addition to the condition at the time of dynamic photographing. In still image shooting, before or after dynamic image shooting, an operator sets still image shooting conditions on the console 2 using the operation unit 23 and performs image shooting.

  The chest simple X-ray image obtained by the still image photographing is subjected to an artifact enhancement process by the console 2 in cooperation with the control unit 21 and the program stored in the storage unit 22, and the artifact enhancement is performed. An image is generated. A known image processing technique can be used as the technique of the artifact enhancement processing. For example, a method of performing smoothing by a median filter and sharpening by a blur mask process on a chest simple X-ray image, and performing a binarization process on the obtained image by threshold setting using a moving average method ( “Improvement of visualization of cardiac pacemaker lead in chest X-ray image”, Journal of the Japanese Society of Radiological Technology, Vol. 63, No. 4, p.

  The artifact-emphasized image is stored in the storage unit 22 by the control unit 21 in association with the dynamic image taken together with the imaging of the chest simple X-ray image, and is displayed on the display unit 24. For example, in step S12 in the first to third embodiments, the dynamic image after the artifact attenuation (or before and after the artifact attenuation) may be displayed together with the dynamic image, or the artificial image may be displayed on the display unit 24. An operation button or the like for instructing the display of the object emphasized image may be displayed, and the artificial object emphasized image may be displayed according to the operation of the operation button by the operation unit 23.

As described above, in the fourth embodiment, by displaying the dynamic image in which the artifact is attenuated, it becomes possible for the user to observe the ventilation state during and after the operation without being affected by the artifact. By displaying the artifact-emphasized image together, the user can easily confirm whether the artifact has been properly inserted.
Also, during pulse irradiation for dynamic imaging, continuous irradiation may be used for patients who use a pacemaker or the like, since a malfunction may be caused to a pacemaker or an implantable defibrillator (hereinafter, referred to as a pacemaker or the like in the present application). Need to shoot. Therefore, when the presence is set in the pacemaker or the like in the patient information, or by analyzing a still image photographing (scout photographing) immediately before dynamic photographing or one to several frame images immediately after the start of dynamic photographing by pulse irradiation, It is preferable that the console 2 recognizes a pacemaker or the like in the lung field area and, when it is recognized that there is a pacemaker or the like, displays on the console 2 that the dynamic imaging by pulse irradiation is prohibited or stopped. Thereby, it is possible to avoid a malfunction of the pacemaker or the like at the time of photographing a patient using the pacemaker or the like. When a pacemaker or the like is recognized by analyzing one to several frame images immediately after the start of dynamic imaging by pulse irradiation, a signal for stopping irradiation is transmitted from the console 2 to the radiation generator 1 and radiation irradiation is performed. May be stopped, or a signal for switching to continuous irradiation may be transmitted to automatically switch to continuous irradiation with the same exposure dose.

  In addition, when the radiation generating apparatus 1 can perform both pulse irradiation and continuous irradiation, the movement of the target part of the subject is relatively slow, and dynamic imaging is performed at a low frame rate. When analyzing an image, it is preferable that pulse irradiation with less blur due to motion in each frame be automatically selected. By doing so, even in the case of a low frame rate, blurring due to motion is suppressed in each frame, and a fine object can be drawn more clearly. In addition, when the subject moves relatively quickly at a high frame rate and the subject moves relatively quickly, the FPD cassette 4 eliminates the accumulation time and controls to repeat only reading. The radiation irradiation method may be configured to be continuous irradiation. By eliminating the accumulation time from the control of the FPD cassette 4 in this manner, a higher frame rate can be realized as compared with the pulse irradiation in which the accumulation time is secured.

  As described in the first to fourth embodiments, according to the dynamic analysis system 100, the control unit 21 of the console 2 determines the dynamic of the subject generated by the cooperation of the radiation generator 1 and the FPD cassette 4. An image signal component due to an artifact is attenuated from the plurality of frame images shown, and dynamics of the subject are analyzed based on the plurality of frame images after the attenuating process.

  Therefore, it is not difficult to judge whether the difference in the analysis result of the dynamic image indicates a change in the state of the patient or the difference due to the presence or absence of the artifact, and based on the analysis result of the dynamic image. Diagnosis accuracy can be improved.

  Note that the description contents in the above embodiments and modified examples are a suitable example of the dynamic analysis system according to the present invention, and the present invention is not limited thereto.

  For example, in the above embodiment, the case where the dynamic analysis system is a system for a round examination has been described as an example. However, the present invention relates to a dynamic analysis system that performs imaging on an obtained dynamic image by performing imaging in an imaging room. Is also applicable.

  Further, in the above embodiment, the radiation irradiation conditions for still image photographing and dynamic image photographing are set on the console 2. However, the radiation irradiation control unit 12 of the radiation generation apparatus 1 irradiates the radiation irradiation for still image photographing. Conditions and radiation irradiation conditions for dynamic imaging can be set in advance. Further, the exposure switch 13 is provided with separate switches for still image capturing and dynamic imaging, and the switch for still image capturing is depressed. In this case, it is preferable that the irradiation is performed under the radiation irradiation condition for still image photographing, and that the irradiation is performed under the radiation irradiation condition for dynamic photographing when the dynamic photographing switch is pressed. With such a configuration, it is possible to quickly switch between the still image and the dynamic imaging, and to reduce the occurrence of mistakes in erroneous exposure by setting the radiation irradiation conditions for the still image and the dynamic imaging incorrectly. it can.

Further, in the above embodiment, the radiation irradiation conditions are read from the storage unit 22 and set in the radiation irradiation control unit 12 via the communication unit 25. After having a display unit and an operation unit, the radiation irradiation conditions stored in the storage unit of the radiation generation device 1 are displayed on the display unit of the radiation generation device 1 and selected / corrected by the operation unit of the radiation generation device 1 , May be set in the radiation irradiation control unit 12. At this time, the set radiation irradiation conditions may be transmitted from the radiation generator 1 to the console 2 via the communication unit 25.
Alternatively, the set radiation irradiation conditions are not exchanged via the communication unit 25, and the FPD cassette 4 starts radiation irradiation by determining whether the radiation irradiated from the radiation generator 1 is still image photographing or dynamic photographing. Detection is performed based on the dose rate immediately after or the pixel value of the frame image, and the FPD cassette 4 automatically sets the frame rate and one per image immediately after the start of radiation irradiation in accordance with the detected information of whether the still image or the dynamic image is detected. The image reading conditions such as the number of captured frame images, the image size (matrix size), the sensitivity (gain), the number of binning, the radiation irradiation standby time, and the like may be changed, and the frame image may be acquired under the changed image reading conditions. At this time, for example, when it is detected that a still image has been captured, the image reading conditions are set so that reading is performed only once with a small gain, no binning, and a radiation irradiation standby time of 0.5 to several seconds. If dynamic imaging is detected, a large gain is used to set the binning of several pixels to several tens of pixels, and a radiation irradiation standby time of 0 to 50 milliseconds is set. The process shifts to the irradiation standby time, and the image reading condition is changed so that the radiation irradiation standby and reading are repeatedly performed. Alternatively, when the information of whether the FPD cassette 4 detects the still image shooting or the dynamic shooting is mismatched with the currently set image reading condition, the fact is notified to the console 2 and the radiation irradiation condition is displayed on the console 2. It may be displayed immediately after the start of radiation irradiation that imaging is to be stopped due to mismatch of the image reading conditions.
Normally, the dose rate differs between still image shooting and dynamic shooting, and the dose rate for dynamic shooting is sufficiently smaller than the dose rate for still image shooting. Therefore, the FPD cassette 4 is irradiated immediately after radiation irradiation is started. It is possible to distinguish between still image shooting and dynamic shooting based on the radiation dose rate or the pixel value of the frame image. Further, the FPD cassette 4 can detect the rising characteristic of the dose rate of the irradiated radiation immediately after the start of the radiation irradiation (the rate of change of the dose rate), and can discriminate between the still image photographing and the dynamic photographing. As the dose rate detecting means, for example, an exposure sensor that outputs an output value proportional to the irradiated radiation amount is provided on the back surface of the glass substrate inside the FPD cassette 4, and is provided at predetermined time intervals, for example, several μsec to several The sensor output value is read out at intervals of 100 μsec. Then, a dose rate is calculated from a change amount of the sensor output value at a predetermined time interval. It is also possible to calculate the rate of change of the dose rate from the dose rate calculated at predetermined time intervals. First, by detecting that the obtained sensor output value exceeds a predetermined threshold value, it is detected that a predetermined radiation dose has been applied. Next, based on the calculated dose rate or the rate of change of the dose rate, for example, it is determined whether the image is still image capturing or dynamic image capturing by determining whether or not the value is equal to or more than a predetermined threshold value.
In addition, the FPD cassette 4 is configured to generate a still image based on the value of the dose rate and a time interval in which the dose rate continuously exceeds the predetermined threshold or a time interval in which the dose rate becomes substantially zero from the predetermined threshold. It is also possible to discriminate between radiography and dynamic radiography, and to determine whether dynamic radiography is pulse irradiation or continuous radiation, and set an image reading condition according to the discrimination. For example, if the dose rate is equal to or less than a predetermined threshold, it is determined that continuous irradiation of dynamic imaging is performed. Alternatively, if the product of the dose rate and the time interval at which the dose rate is continuously equal to or greater than the predetermined threshold is equal to or greater than the predetermined threshold, it is determined that the still image is to be captured, and the other is determined to be pulse irradiation for dynamic imaging. Further, it is preferable that the predetermined threshold here is changed according to patient information such as physique, age, and gender. For example, in a case where the physique is a thin type or a child, if the dose rate irradiated (output) from the radiation generator 1 does not change, the threshold is set to a large value. Further, it is also possible to detect the timing at which the dose rate becomes substantially 0 from the predetermined threshold value, and detect the irradiation end timing of one pulse of radiation in the pulse irradiation of the still image photographing and the dynamic photographing. In the case of detecting from the pixel value of the frame image, for example, the FPD cassette 4 continuously collects the frame image at a predetermined frame rate before irradiation, and the representative value of all or a part of the obtained frame image is a predetermined threshold value. Is detected, it is detected that the predetermined radiation dose has been applied, and further, the dose rate is estimated from the representative value, and it is determined whether still image shooting or dynamic shooting is performed.
Here, it is determined whether the FPD cassette 4 is a still image photographing or a dynamic photographing, but the dose rate or the rate of change of the dose rate or the frame rate is transmitted from the FPD cassette 4 to the console 2 via the communication unit 25 immediately after the start of irradiation. The representative value of the pixel value of the image or the frame image is transmitted, the console 2 identifies the still image shooting or the dynamic shooting, and the image reading condition according to the identified still image shooting or the dynamic shooting information is determined by the console 2. May be transmitted to the FPD cassette 4 via the communication unit 25 and set. With such a configuration, even if the radiation irradiation condition is not communicated between the radiation generator 1 and the console 2 or the FPD cassette 4, the console 2 is started immediately after the start of the radiation irradiation based on the radiation irradiated by the radiation generator 1. Alternatively, the FPD cassette 4 identifies the still image shooting or the dynamic shooting, sets an appropriate image reading condition in the FPD cassette 4 and collects a frame image, so that the radiation generating apparatus 1 and the console 2 or the FPD cassette 4 Even when communication cannot be performed due to a different manufacturer or the like, the FPD cassette 4 can quickly and easily switch between a still image photographing and a dynamic photographing simply by changing the radiation irradiation condition in the radiation generator 1. . Alternatively, it is displayed on the console 2 that the imaging is stopped due to a mismatch between the radiation irradiation condition and the image reading condition, and it is possible to prevent the patient from being unnecessarily exposed.

  The access point 3 has a function of connecting to, for example, a 3G line, a 4G line, a satellite communication line, and connecting to a mobile phone network and the Internet via these wireless communication lines. 22, encrypting and / or compressing the image data, the analysis result calculated based on the image data, the patient information of the subject H, and the like, stored in the server 22, directly from the round-trip system, Alternatively, a transfer function may be provided to a server or terminal such as a PACS in a hospital located at a distant place. At this time, vital information of the subject H such as respiratory rate, heart rate, blood pressure, etc., or measurement of another test for the subject H such as oxygen saturation, respiratory flow, electrocardiogram, etc. is provided to the console 2 via the operation unit 23 or the communication unit 25 A result may also be input, and a function of transferring vital information or a measurement result of another inspection input to the console 2 with image data may be provided. In this way, the patient information, vital information, measurement results of another test, and image data accompanying the analysis results are transmitted from the round-trip system so that the data can be directly viewed from facilities such as hospitals located at a distant place. With this configuration, the round-trip system is used in disaster and emergency situations, and images are taken with the round-trip system, analysis results are calculated based on the captured image data, and vital information or measurement results from another test are performed. If there is no appropriate physician at the site who can make a diagnosis based on these data and information even after acquiring and inputting the data, a physician at a distant place can view these data and information and quickly diagnose Remote diagnosis can be performed, and treatment such as treatment can be quickly performed on the subject H on the spot based on an appropriate doctor's diagnosis result. When quickness is prioritized, depending on the communication capacity that can be communicated per unit time of the wireless communication line, for example, when the communication capacity is small, the compression rate is increased to reduce the data capacity, It is preferable to change the compression method such as reversible compression.

  In the above-described embodiment, the access point 3 is configured to be movable in the round-trip system. However, a plurality of access points 3 may be provided. All access points may be configured to be fixedly installed in the hospital.

  In the above-described embodiment, the communication unit 25 includes a wireless LAN adapter and the like, and external devices such as the radiation generator 1 and the FPD cassette 4 connected to a communication network such as a wireless LAN via the access point 3. However, the console 2 does not use the access point 3 with some or all of the external devices, and uses, for example, an ad hoc mode of a wireless LAN or Bluetooth (registered trademark). The communication unit 25 and the external device may directly transmit and receive data. Thus, a configuration in which part or all of the access point 3 is omitted can be achieved, and a lighter and lower-cost system can be realized.

  Further, when transmitting the frame images collected by the FPD cassette 4 to the console 2 via a communication unit 25 via a wireless or wired network, the FPD cassette 4 Each time a frame image is sequentially acquired during capturing of a dynamic image, each frame image is temporarily stored in a storage unit in the FPD cassette 4, and each frame image is thinned out for at least one of spatial and temporal data. The processing may be performed, and the frame image data after the thinning may be transmitted to the console 2 almost in real time, and the console 2 may display the frame image data received from the FPD cassette 4 on the display unit 24 almost in real time. At this time, after the end of a series of dynamic image capturing, the FPD cassette 4 outputs each frame image data before thinning stored in the storage unit in the FPD cassette 4 or an untransmitted frame image data to the console 2. Only the data may be transmitted to the console 2. In this way, even when the communication capacity that can be communicated per unit time is small, such as when using a wireless network, the frame image collected by the FPD cassette 4 during the capturing of the dynamic image can be displayed almost in real time on the display unit. 24 can be controlled so that the user such as a technician can quickly grasp the abnormal state of the photographing from the frame image displayed on the display unit 24 and determine the interruption of the photographing. It is possible to avoid unnecessary exposure to the patient at the time of abnormal imaging.

  Also, during reading of the FPD cassette 4, electromagnetic waves (environmental noise) emitted from a medical device such as a roundabout or portable radiation generator placed around the FPD cassette 4 or a high-frequency treatment device are exposed to the FPD cassette. 4 may cause artifacts in the image data read from the FPD cassette 4. Therefore, the FPD cassette 4 or the console 2 detects an electromagnetic wave around the FPD cassette 4 and a frequency characteristic of the electromagnetic wave before or during imaging, and generates an artifact such as a streak generated on image data based on the detected frequency characteristic. It is preferable to estimate the spatial pattern (spatial frequency) and perform image correction processing on the FPD cassette 4 or the console 2 to attenuate artifacts of the estimated spatial pattern on the collected frame images. By mounting such an artifact estimation and correction process, it is possible to improve diagnostic accuracy based on the analysis result of the dynamic image.

  In the above description, an example in which a hard disk, a semiconductor nonvolatile memory, or the like is used as a computer-readable medium of the program according to the present invention is disclosed, but the present invention is not limited to this example. As another computer-readable medium, a portable recording medium such as a CD-ROM can be applied. In addition, a carrier wave (carrier wave) is also applied as a medium for providing the data of the program according to the present invention via a communication line.

  In addition, the detailed configuration and detailed operation of each device constituting the dynamic analysis system can be appropriately changed without departing from the spirit of the invention.

Reference Signs List 100 Dynamic analysis system 1 Radiation generator 11 Radiation source 12 Radiation irradiation control unit 13 Exposure switch 2 Console 21 Control unit 22 Storage unit 23 Operation unit 24 Display unit 25 Communication unit 26 Connector 27 Bus 3 Access point 4 FPD cassette

Claims (4)

Recognizing means for recognizing a region of an artifact from a plurality of frame images generated by photographing dynamics of a subject;
Attenuation processing means for attenuating the image signal component due to the artifact by attenuating the image signal component of the region of the plurality of frame images recognized by the recognition means,
Analysis means for analyzing a plurality of frame images after the attenuation processing by the attenuation processing means, the dynamics of the chest of the subject from a plurality of frame images showing the dynamics of the chest of the subject ,
Area selection means for selecting a partial area in the lung field of the subject ,
With
The analysis means,
Based on a plurality of frame images showing the dynamics of the chest of the subject, a feature amount indicating a local movement in the lung field of the subject is calculated, and based on the calculated feature amount indicating a local movement in the lung field. , characterized in calculating the feature quantity in the entire lung field, wherein the amount of excluding the selected region selected by the region selecting means from the entire lung region and from the entire calculated the lung field excluding the selection area area A dynamic analysis system, wherein a ratio between the amount and the calculated feature amount in the entire lung field is calculated.   2. The dynamic analysis system according to claim 1, wherein the feature indicating the local movement of the subject in the lung field is a feature related to a ventilation function or a blood flow function in the lung field. 3. Input means for inputting a measurement result of another inspection of the subject,
The analysis unit calculates a value obtained by multiplying a measurement result of another test input by the input unit by a ratio of a feature amount in a region obtained by removing the selected region from the entire lung field to a feature amount in the entire lung field. The dynamic analysis system according to claim 1 or 2, wherein the dynamic analysis is performed. Recognizing means for recognizing a region of an artifact from a plurality of frame images generated by photographing dynamics of a subject;
Attenuation processing means for attenuating the image signal component due to the artifact by attenuating the image signal component of the region of the plurality of frame images recognized by the recognition means,
A plurality of frame images of the attenuated processing by the attenuation processing means, analyzing means from a plurality of frame images showing the kinetics of the chest of lung resection before the subject to analyze the dynamics of chest of the subject,
With
Said analyzing means, based on the lung resection before the subject's chest plurality of frame images showing the kinetics of ventilation or blood flow of the lung resection becomes the extent to which in comparison with prior lung resection Kinetic analysis system, characterized by calculating the ratio of kin.