Patent Description:
As radiographic apparatuses for use in medical image diagnosis and nondestructive inspection using radiation, such as X-rays, radiographic apparatuses that include a matrix substrate including a pixel array formed by combining switches, like thin-film transistors (TFTs), with conversion elements, like photoelectric conversion elements, have been put to practical use.

Several studies have been conducted to make radiographic apparatuses multifunctional. One of the approaches is to implement a built-in function for monitoring radiation irradiation. Such a function enables, for example, detection of a timing of starting radiation irradiation from a radiation source, detection of a timing of stopping the radiation irradiation, and detection of a radiation dosage or a cumulative dosage.

<CIT> discusses a radiographic system including a radiographic apparatus, a radiation source, and an image control apparatus. The radiographic apparatus includes pixels for monitoring radiation irradiation. In a case where the radiographic system detects a timing of stopping irradiation, the radiographic apparatus transmits an irradiation stop signal to a radiation generation apparatus. While <CIT> does not discuss specific control signals, the conventional radiation exposure control is performed by inputting an analog signal from a radiation receiving portion of an ion chamber or a photo timer into an exposure control unit inside the radiation generation apparatus. In response to detection of an integrated value of the analog signal and the like exceeding a predetermined threshold, the radiations are stopped, whereby automatic exposure control (AEC) is performed for dose control. A further prior art example is disclosed in the document <CIT>.

There is a technique for calculating a dose index value by analyzing a captured radiographic image, to display the dose index value on a graphical user interface (GUI). The dose index value is a numerical representation of the radiation dose received by the radiographic image detection apparatus.

An example of a dose index is an exposure index (EI). The dose index is a value for evaluating a dose used in radiographic imaging. EI is an index standardized by the International Electric Conference (IEC) as IEC <NUM>-<NUM>. Specifically, an area to calculate an EI value in a radiographic image is determined, and a representative value is extracted from among pixel values of pixels in the calculation area. A predetermined conversion is then performed on the extracted representative value, and the resulting dose index value is displayed. In each medical facility, EI information is managed and an EI value determined to be an optimum dose for radiographic images (for example, a minimum dose with satisfactory image quality) is set as a target value (Target Exposure Index) EIt. Determination of whether a dose is excessive or insufficient is then performed using a deviation (Deviation Index) DI between a calculated EI value and EIt to facilitate optimum imaging.

According to a first aspect of the present invention, there is provided a radiographic system as specified in claims <NUM> to <NUM>. According to a second aspect of the present invention, there is provided a radiographic method as specified in claim <NUM>. According to a third aspect of the present invention, there is provided a program as specified in claim <NUM>.

For example, in a case where automatic exposure control (AEC) is used when lung fields are imaged, radiographic imaging is typically performed on measuring fields set at both lungs. In such a case, by stopping radiation irradiation at a timing of when an irradiation dose for both lungs reaches an optimum dose, an irradiation dose in the radiation irradiation can be reduced. Consequently, it is desirable that an exposure index (EI) value and a target value EIt are displayed or set based on the measuring fields.

However, since conventional apparatuses display the EI value and set the target value EIt as a dose index of the entire radiographic image, whether a sufficient amount of radiation is incident on the AEC measuring fields is unable to be determined based on the numerical values.

Exemplary embodiments of the present invention have been achieved in view of the foregoing issue, and are directed to providing a radiographic system where an operator can appropriately determine whether a desirable amount of radiation is incident on measuring fields during radiographic imaging using AEC.

The present exemplary embodiments can also be directed to providing operations and effects that are derived from configurations described below and not obtainable by the conventional art.

A radiographic system according to a first exemplary embodiment will be described below with reference to the drawings. <FIG> is a diagram illustrating a radiographic system according to the present exemplary embodiment.

As illustrated in <FIG>, a radiographic system <NUM> is disposed in a radiation chamber <NUM> where radiographic imaging using radiation irradiation is performed and a control chamber <NUM> in the vicinity of the radiation chamber <NUM>.

The radiation chamber <NUM> includes, as the radiographic system <NUM>, a radiographic apparatus <NUM>, an upright stand <NUM>, a first communication cable <NUM>, an access point (AP) <NUM>, a communication control apparatus <NUM>, a radiation generation apparatus <NUM>, a radiation source <NUM>, a second communication cable <NUM>, and a third communication cable <NUM>.

The control chamber <NUM> includes, as the radiographic system <NUM>, a control apparatus <NUM>, an irradiation switch <NUM>, an input apparatus <NUM>, a display apparatus <NUM>, an in-hospital local area network (LAN) <NUM>, and a fourth communication cable <NUM>.

The configuration of the apparatuses installed in the radiation chamber <NUM> and the control chamber <NUM> is not limited to the foregoing. Any configuration that functions as the radiographic system <NUM> may be employed.

The radiographic apparatus <NUM> includes a power supply control unit <NUM> including a battery, a wired communication unit <NUM>, and a wireless communication unit <NUM>. The radiographic apparatus <NUM> detects radiation transmitted through a subject <NUM> and generates a radiographic image. An image according to the present exemplary embodiment refers not only to an image being displayed on a display unit but also to an image being stored in a database or storage unit as image data.

The wired communication unit <NUM> performs information exchange by cable connection using a communication standard of predetermined agreement or a standard, such as the Ethernet (registered trademark), for example.

The wireless communication unit <NUM> includes a circuit substrate equipped with an antenna and a communication integrated circuit (IC), for example. The circuit substrate equipped with the communication IC performs communication processing using a wireless LAN-based protocol via the antenna. The frequency band, standard, and method of the wireless communication are not limited in particular. A proximity wireless communication method, such as near field communication (NFC) and Bluetooth®, or a method such as ultra-wideband (UWB) may be used. The wireless communication unit <NUM> may support a plurality of wireless communication methods and perform communication by selecting one from among the supported wireless communication methods as appropriate.

The upright stand <NUM> is a pedestal to which the radiographic apparatus <NUM> can be attached, to perform radiographic imaging in an upright position. The radiographic apparatus <NUM> can be detachably attached to the upright stand <NUM>, and can capture images both in an attached state and a detached state.

The first communication cable <NUM> is a cable for connecting the radiographic apparatus <NUM> and the communication control apparatus <NUM>.

The AP <NUM> performs wireless communication with the radiographic apparatus <NUM>. For example, the AP <NUM> is used to relay communication between the radiographic apparatus <NUM> and the control apparatus <NUM> and between the radiographic apparatus <NUM> and the radiation generation apparatus <NUM> in using the radiographic apparatus <NUM> detached from the upright stand <NUM>.

While <FIG> illustrates a case where the communication is performed via the AP <NUM>, either the radiographic apparatus <NUM> or the communication control apparatus <NUM> may serve as an AP to perform direct communication without the intermediary of the AP <NUM>.

The communication control apparatus <NUM> controls communication between the AP <NUM>, the radiation generation apparatus <NUM>, and the control apparatus <NUM>.

The radiation generation apparatus <NUM> controls the radiation source <NUM> to emit radiation based on a predetermined irradiation condition.

The radiation source <NUM> irradiates the subject <NUM> with radiation based on control by the radiation generation apparatus <NUM>.

The second communication cable <NUM> is a cable for connecting the AP <NUM> and the communication control apparatus <NUM>.

The third communication cable <NUM> is a cable for connecting the radiation generation apparatus <NUM> and the communication control apparatus <NUM>.

The control apparatus <NUM> communicates with the radiation generation apparatus <NUM> and the radiographic apparatus <NUM> via the communication control apparatus <NUM>, and controls the radiographic system <NUM> in a centralized manner.

The irradiation switch <NUM> inputs a radiation irradiation timing based on an operation by an operator <NUM>.

The input apparatus <NUM> is an apparatus for inputting instructions from the operator <NUM>. Various input devices, such as a keyboard and a touch panel, are used as the input apparatus <NUM>.

The display apparatus <NUM> is an apparatus for displaying an image-processed radiographic image and a graphical user interface (GUI). An example of the display apparatus <NUM> is a display.

The in-hospital LAN <NUM> is a backbone network in the hospital.

The fourth communication cable <NUM> is a cable for connecting the control apparatus <NUM> and the communication control apparatus <NUM> in the radiation chamber <NUM>.

<FIG> is a diagram illustrating the radiographic apparatus <NUM>. As illustrated in <FIG>, the radiographic apparatus <NUM> includes a radiation detector <NUM>. The radiation detector <NUM> has a function of detecting irradiating radiation. The radiation detector <NUM> includes a plurality of pixels arranged to form a plurality of rows and a plurality of columns. In the following description, an area of the radiation detector <NUM> where the plurality of pixels is arranged will be referred to as a radiation detection area. The plurality of pixels includes imaging pixels <NUM> for obtaining a radiographic image or irradiation information, and correction pixels <NUM> for removing dark current components and crosstalk components.

In the present exemplary embodiment, the use of the imaging pixels <NUM> for obtaining irradiation information will be described. The imaging pixels <NUM> will therefore be hereinafter referred to as detection pixels <NUM>. The detection pixels <NUM> may be used for a purpose of obtaining radiographic images or for a purpose of obtaining irradiation information. Alternatively, the detection pixels <NUM> may obtain both radiographic images and irradiation information. In other words, the detection pixels <NUM> may be configured to obtain at least either radiographic images or irradiation information.

The detection pixels <NUM> each include a first conversion element <NUM> for converting radiation into an electrical signal, and a first switch <NUM> disposed between a column signal line <NUM> and the first conversion element <NUM>.

The first conversion element <NUM> includes a scintillator, which is for converting radiation into light, and a photoelectric conversion element, which is for converting the light into an electrical signal. The scintillator is typically formed in a sheet shape to cover the radiation detection area, and shared by the plurality of pixels. Alternatively, the first conversion element <NUM> includes a conversion element that directly converts radiation into light.

The first switch <NUM> includes a thin-film transistor (TFT) having an active region formed of a semiconductor, such as amorphous silicon and polycrystalline silicon (desirably polycrystalline silicon), for example.

The correction pixels <NUM> each include a second conversion element <NUM> for converting radiation into an electrical signal, and a second switch <NUM> disposed between a column signal line <NUM> and the second conversion element <NUM>.

Since the second conversion element <NUM> and the second switch <NUM> are similar to the first conversion element <NUM> and the first switch <NUM>, respectively, the redundant descriptions will be omitted.

An area where both detection pixels <NUM> and correction pixels <NUM> for obtaining irradiation information are arranged is laid out at any position within the radiation detection area of the radiographic apparatus <NUM>. For example, similar to a conventional separate AEC sensor, such an area may be laid out at a plurality of positions like areas A to C in <FIG>, or areas K to O in <FIG>.

The radiographic apparatus <NUM> includes a plurality of column signal lines <NUM> and a plurality of drive lines <NUM>.

Each of the column signal lines <NUM> corresponds to different one of the columns in the radiation detection area. Each of the drive lines <NUM> corresponds to different one of the rows in the radiation detection area.

The drive lines <NUM> are driven by a driving circuit <NUM>.

A first electrode of the first conversion element <NUM> and a first electrode of the second conversion element <NUM> are connected to a first main electrode of the first switch <NUM> and a first main electrode of the second switch <NUM>, respectively. A second electrode of the first conversion element <NUM> and a second electrode of the second conversion element <NUM> are each connected to a bias line <NUM>. Each of the bias lines <NUM> extends in the column direction and is connected to the second electrodes of a plurality of the conversion elements <NUM> and <NUM> arranged in a column direction in common.

The bias lines <NUM> receive a bias voltage Vs from an element power supply circuit <NUM>. The bias voltage Vs is supplied from the element power supply circuit <NUM>.

The power supply control unit <NUM> includes the battery and a direct-current-to-direct-current (DCDC) converter. The power supply control unit <NUM> includes the element power supply circuit <NUM>, and generates an analog circuit power supply voltage and a digital circuit power supply voltage. The digital circuit power supply voltage is for use in driving control and communication.

A second main electrode of the first switch <NUM> each in a plurality of the detection pixels <NUM> and a second main electrode of the second switch <NUM> each in a plurality of the correction pixels <NUM>, in a single column, are connected to a column signal line <NUM>. A control electrode of the first switch <NUM> each in the plurality of the detection pixels <NUM> and a control electrode of the second switch <NUM> each in the plurality of the correction pixels <NUM>, in a single row, are connected to a drive line <NUM>. The plurality of the column signal lines <NUM> is connected to a reading circuit <NUM>. Here, the reading circuit <NUM> includes a plurality of detection units <NUM>, a multiplexer <NUM>, and an analog-to-digital (AD) converter <NUM>.

The column signal lines <NUM> are each connected to corresponding one of the detection units <NUM> in the reading circuit <NUM>. Here, one column signal line <NUM> corresponds to one detection unit <NUM>.

The detection units <NUM> each include a differential amplifier, for example. The multiplexer <NUM> selects the detection units <NUM> in predetermined order and supplies a signal from the selected one of the detection units <NUM> to the AD converter <NUM>.

The AD converter <NUM> converts the supplied signal into a digital signal and outputs the digital signal.

A signal processing unit <NUM> outputs information indicating irradiation of the radiographic apparatus <NUM> with radiation, based on the output of the reading circuit <NUM> (AD converter <NUM>). Specifically, for example, the signal processing unit <NUM> performs characteristic correction processing, detects irradiation with radiation, and calculates a radiation dosage and a cumulative dosage. The characteristic correction processing includes removing dark current components and crosstalk components of the radiographic apparatus <NUM> by using the correction pixels <NUM>.

An imaging apparatus control unit <NUM> controls, for example, the driving circuit <NUM> and the reading circuit <NUM>, based on information from the signal processing unit <NUM> and control commands from the control apparatus <NUM>.

<FIG> is a diagram illustrating the imaging apparatus control unit <NUM> of the radiographic apparatus <NUM>. As illustrated in <FIG>, the imaging apparatus control unit <NUM> includes a driving control unit <NUM>, a central processing unit (CPU) <NUM>, a memory <NUM>, a generation apparatus control unit <NUM>, an image control unit <NUM>, and a communication switching unit <NUM>.

The driving control unit <NUM> controls the driving circuit <NUM> and the reading circuit <NUM>, based on information from the signal processing unit <NUM> and control commands from the control apparatus <NUM>. The driving control unit <NUM> communicates with the radiographic apparatus <NUM> to receive a radiographic image and to control operation.

The CPU <NUM> controls the entire radiographic apparatus <NUM> using programs and various types of data stored in the memory <NUM>.

The memory <NUM> stores programs and various types of data that the CPU <NUM> uses in executing processing, for example. The various types of data include various types of data obtained by the processing of the CPU <NUM> and radiographic images.

The generation apparatus control unit <NUM> controls communication with the radiation generation apparatus <NUM>, based on information from the signal processing unit <NUM> and information from the driving control unit <NUM>.

The generation apparatus control unit <NUM> and the radiation generation apparatus <NUM> exchange information about control of the radiation generation apparatus <NUM> (such as notifications to start and stop radiation irradiation, a radiation dosage, and a cumulative dosage).

In a case where a radiation dosage in a radiation detection area (measuring field) as a monitoring target of a radiation dosage reaches a reference threshold (target cumulative dosage), the generation apparatus control unit <NUM> notifies the radiation generation apparatus <NUM> of a stop notification among pieces of information about the control of the radiation generation apparatus <NUM>. Examples of the measuring field include the areas A to C in <FIG> and the areas K to O in <FIG>. The detection pixels <NUM> included in the radiation detection area (measuring field) correspond to an example of a dose detection unit for detecting a dose reached to the dose detection unit during radiation irradiation. The generation apparatus control unit <NUM> detects radiation incident on the measuring field by using the detection pixels <NUM>, and calculates a cumulative dosage that is a cumulative value of doses (reached doses) detected by the signal processing unit <NUM> during a predetermined period.

The generation apparatus control unit <NUM> issues a stop notification at a timing of when a radiation dosage in a measuring field selected as a monitoring target reaches the reference threshold (hereinafter, this procedure is referred to as a reached dose monitoring function). In a case where a plurality of measuring fields is selected as a monitoring target, the following three control methods can be employed, for example. In an OR control method, the generation apparatus control unit <NUM> issues a stop notification at a timing of when a cumulative value of any one of the selected measuring fields reaches the target cumulative dosage. In an average control method, the generation apparatus control unit <NUM> issues a stop notification at a timing of when an average of cumulative values of a plurality of selected measuring fields reaches a value set as the target cumulative dosage. In an AND control method, the generation apparatus control unit <NUM> issues a stop notification at a timing of when all cumulative values of a plurality of selected measuring fields reach a value set as the target cumulative dosage. Control methods other than the foregoing methods may be used. Two or more of the foregoing methods may be used in combination.

If, for example, four measuring fields R1, R2, R4, and R5 in <FIG> are selected, it can be determined that irradiation of two juxtaposed measuring fields with as much radiation as the target cumulative dosage is sufficient since the radiographic apparatus <NUM> is used in more than one orientation. In such a case, the generation apparatus control unit <NUM> may specify a combination of operators like (R1 AND R2) OR (R2 AND R5) OR (R5 AND R4) OR (R4 AND R1), and issue a stop notification in response to two measuring fields reaching the target cumulative dosage first. While, the OR, average, and control methods are described as examples, other control methods and operators (such as NAND, NOR, and XOR) may also be combined. Specifically, the control method for AEC may be one using at least any one of the AND, OR, average, NAND, NOR, and XOR methods.

The mode in which the generation apparatus control unit <NUM> issues a stop notification is set based on any one of the radiographic apparatus <NUM>, the radiation generation apparatus <NUM>, and the control apparatus <NUM>, for example. The radiographic system <NUM> may have a mode in which radiation irradiation is not stopped in accordance with a reached radiation dosage. The radiographic system <NUM> may include a not-illustrated general exposure control sensor (such as an ion chamber and a photo timer) attached outside the radiographic apparatus <NUM> and stop radiation irradiation in accordance with a radiation dosage. While, in the present exemplary embodiment, the radiographic apparatus <NUM> includes the generation apparatus control unit <NUM>, the radiographic apparatus <NUM> may be configured to detect radiation irradiation by using the signal processing unit <NUM> and perform radiographic imaging without communicating with the radiation generation apparatus <NUM>.

The image control unit <NUM> stores an image from the reading circuit <NUM> into the memory <NUM>, and controls communication with the control apparatus <NUM>. The image control unit <NUM> and the control apparatus <NUM> exchange radiographic images and control-related information (such as control commands).

The communication switching unit <NUM> switches the wired communication unit <NUM> and the wireless communication unit <NUM> to enable communication by the wired communication unit <NUM> when the first communication cable <NUM> is connected to the radiographic apparatus <NUM>, and enable communication by the wireless communication unit <NUM> when the first communication cable <NUM> is disconnected from the radiographic apparatus <NUM>.

<FIG> is a diagram illustrating the control apparatus <NUM>. As illustrated in <FIG>, the control apparatus <NUM> includes a determination unit <NUM>, a calculation unit <NUM>, and a display control unit <NUM>.

The determination unit <NUM> determines an area (region of interest) to calculate a dose index value in a radiographic image generated by the radiographic apparatus <NUM>. As employed herein, an area to calculate a dose index value is broadly classified into the following two types: a measuring field like the areas A to C in <FIG> and the areas K to O in <FIG>, and a predetermined area like an area P in <FIG> and an area Q in <FIG>. Examples of the latter area is an optional area which includes the entire area of the radiographic image, is specified by the operator <NUM>, or corresponds to an imaging site. Such areas are exemplary and not restrictive.

In the present exemplary embodiment, areas to calculate the dose index value are represented by rectangles as illustrated in <FIG>, for example. However, this is not restrictive. The areas may be represented by figures of any shape, such as a circular shape and a trapezoidal shape.

Examples of a dose index value to be calculated in an area determined by the determination unit <NUM> include an EI value. While, in the present exemplary embodiment, an EI value is used as a dose index value, similar techniques can be applied to dose indices in general. A dose index value may be a value proportional or inversely proportional to a pixel value of a radiographic image.

The calculation unit <NUM> calculates a dose index value of an area determined by the determination unit <NUM>. A dose index target value (for example, target exposure index EIt) which is used to determine that an optimum dose is applied may be set area by area, and the calculation unit <NUM> may calculate a deviation index (for example, deviation index DI). The target exposure index EIt and the deviation index DI are indices standardized as International Electric Conference (IEC) <NUM>-<NUM>. Specifically, the deviation index DI is calculated by the following equation:<MAT>.

In general, if a deviation index DI is greater than <NUM>, it is determined that the dose is higher than normal. If the deviation index DI is less than <NUM>, it is determined that the dose is lower than normal.

The dose index target value does not necessarily need to be set area by area. For example, in a case where dose index target values are set for a first area, a second area, and a third area, a first dose index target value may be set for the first and second areas in common, and a second dose index target value may be set for the third area.

The display control unit <NUM> displays at least one of the indices calculated by the calculation unit <NUM>, namely, the dose index values, dose index target values, and deviation indices, on the display apparatus <NUM>. A method for displaying the at least one of the indices on the display apparatus <NUM> may be changed in accordance with an imaging condition.

In the present exemplary embodiment, the determination unit <NUM>, the calculation unit <NUM>, and the display control unit <NUM> are described as functions of the control apparatus <NUM>. However, the radiographic apparatus <NUM> may be configured to include the functions of the determination unit <NUM>, the calculation unit <NUM>, and the display control unit <NUM>. In other words, at least either the control apparatus <NUM> or the radiographic apparatus <NUM> may have functions corresponding to the determination unit <NUM>, the calculation unit <NUM>, and the display control unit <NUM>.

A procedure for calculating an EI value from a radiographic image will be described with reference to a flowchart of <FIG>.

In step S701, the determination unit <NUM> initially excludes an area that has not been irradiated with radiation and is outside the region of interest of a diagnostic image, from an EI value calculation area of a radiographic image. Examples of the exclusion method include a method for performing calculations based on collimator information or tube-to-flat panel detector (FPD) distance (FDD) information, a method for extracting an irradiated field from the image using various types of imaging site information determined in advance, and a method for performing determination using machine learning.

In step S702, the determination unit <NUM> identifies a direct radiation equivalent area and excludes an area outside the region of interest from the EI value calculation area. Examples of the exclusion method include an empirical fixed threshold method, a mode method, a differential histogram method, a percentile method, and discriminant analysis.

In step S703, the determination unit <NUM> excludes, from the EI value calculation area, a low dose area which is in the region of interest but is not to be used as a normal diagnostic image for calculation of a dose index of the region of interest. Examples of the exclusion method include region growing and snakes.

The EI value calculation area is determined by applying the processing so far to the area determined to calculate a dose index value by the determination unit <NUM> in advance, or by applying the processing to the entire radiographic image and then extracting the area determined to calculate a dose index value by the determination unit <NUM>.

The foregoing processing of steps S701 to S703 may or may not be performed in a selective manner. The processing order is not limited to the foregoing procedure. For example, the exclusion processing of step S703 may be performed before the exclusion processing of step S702.

In step S704, the calculation unit <NUM> calculates a representative value of the region of interest in the radiographic image determined by the processing of steps S701 to S703. Examples of a representative value include a pixel value of, for example, an average, a median, and a mode. In a case where there is a plurality of regions of interest like when a plurality of measuring fields is set, a representative value of each of the regions of interest is calculated. The operator <NUM> can thus identify a dose value in each of the regions of interest.

In step S705, the calculation unit <NUM> converts the representative value into a dose, based on a known relationship between an incident dose and a pixel value. The calculation unit <NUM> then calculates a dose index value by multiplying the converted dose by a constant. More specifically, the calculation unit <NUM> calculates the dose index value (EI value) by converting the representative value in such a manner that <NUM> = <NUM>µGy. At the same time, the calculation unit <NUM> calculates a deviation index DI from the dose index target value EIt. The operator <NUM> checks whether radiographic imaging with an expected radiation dose has been performed.

Next, display examples of dose index values on the display apparatus <NUM> will be described with reference to <FIG> and <FIG>.

The display control unit <NUM> displays the dose index values calculated by the calculation unit <NUM> on the display apparatus <NUM>.

As illustrated in <FIG>, the dose index values may be displayed as annotations at corners of a radiographic image. As illustrated in <FIG>, each of the dose index values may be superimposed on an image area where the corresponding dose index value has been calculated. Alternatively, the dose index values may be displayed separately from the radiographic image. For example, as illustrated in <FIG>, the dose index values may be displayed next to the radiographic image. As illustrated in <FIG>, the dose index values may be displayed without the radiographic image. Moreover, as illustrated in <FIG>, each of the dose index values may be rendered in a gray scale (or color scale) and displayed on the radiographic image. As illustrated in <FIG>, only the gray scale (or color scale) may be separately displayed. As illustrated in <FIG>, the radiographic image and the gray scale (or color scale) may be displayed in combination. In other words, at least two or more pieces of information about the values calculated by the calculation unit <NUM> may be displayed by changing at least either color or tone level.

While <FIG> and <FIG> illustrate examples of displaying the dose index values using text or color, the display method may be defined by any combination of recognizable expressions, such as text, symbols, figures, sizes, color, and shapes. Moreover, the display control unit <NUM> may display dose index target values and deviation index values along with the dose index values. The dose index target values and the deviation index values may be displayed by the same display method as that of the dose index values or by any other display method. Instead of displaying the dose index values or deviation index values, a warning dialog may be displayed in a case where the dose index values and deviation index reach or exceed a predetermined threshold, for example. Only one such threshold may be set. Thresholds may be set for respective areas where the dose index values are calculated.

In a case where a notification to stop the radiation irradiation is performed, the display control unit <NUM> may identifiably display, on the display apparatus <NUM>, a measuring field that has been used for determination of stopping the radiation irradiation, among the one or more measuring fields. In a case where the control method is the AND method, one or more measuring fields lastly reached the target dose are identifiably displayed. In a case where the control method is the OR method, the measuring field first reached the threshold is identifiably displayed. In a case where the control method is the average method, all the measuring fields are identifiably displayed. Examples of the method for identifiable display include identifiably displaying text information, and highlighting the measuring field(s) on the radiographic image. The dose index value(s) of the measuring field(s) ultimately used for determination of stopping the radiation irradiation may be displayed. The dose index values of all the measuring fields may be displayed, and the measuring field(s) ultimately used for determination of stopping the radiation irradiation may be marked up.

Next, an operation of the radiographic system <NUM> during imaging will be described with reference to <FIG>.

When the radiographic system <NUM> is powered up and the radiographic apparatus <NUM> is powered on, the radiographic apparatus <NUM> performs initialization to enable communication with the control apparatus <NUM>.

In step S101, the radiographic system <NUM> sets subject information, such as an identifier (ID), name, and date of birth of the subject <NUM>, into the control apparatus <NUM>. The radiographic system <NUM> also sets imaging information, such as an imaging site, a measuring field, and a dose index target value for the subject <NUM>. For example, the subject information and the imaging information may be automatically set by selecting a test order received via the in-hospital LAN <NUM>. The operator <NUM> may set the imaging information by selecting a predetermined imaging protocol. Yet alternatively, the operator <NUM> may directly input and set the subject information and the imaging information. The radiographic system <NUM> sets the measuring field(s) of the radiographic apparatus <NUM>, based on the input information. After the information about the subject <NUM> and the information about the imaging site are set into the control apparatus <NUM>, the operator <NUM> fixes the posture of the subject <NUM> and the radiographic apparatus <NUM>. The operator <NUM> further inputs a dose, maximum irradiation time, a tube current, a tube voltage, site information, the measuring field(s), and the dose index target value(s) into the control apparatus <NUM>. The control apparatus <NUM> transmits the input irradiation condition of radiation, site information, measuring field(s), and dose index target value(s) to the radiographic apparatus <NUM> and the radiation generation apparatus <NUM>. The radiographic system <NUM> may be configured so that the information is input into the radiation generation apparatus <NUM> and notified to the control apparatus <NUM> and the radiographic apparatus <NUM>. Here, the control apparatus <NUM> may obtain information managed in association with at least either the subject information or the imaging information. For example, information managed in association with the site information may include AEC measuring field selection information, the AEC method for a case where a plurality of measuring fields is selected (such as the AND method), and target cumulative dosage serving as the threshold to stop radiation irradiation. In other words, the control apparatus <NUM> can obtain information about the AEC control method associated with at least either the subject information or the imaging information. Specifically, for example, in a case where the site information indicates a front chest, the information managed in association with the site information includes selection information for selecting a right measuring field and a left measuring field (areas K and L in <FIG>) corresponding to both lung fields and the AND method that is an AEC method. In a case where the site information indicates a side chest, the information managed in association with the site information includes selection information for selecting the center measuring field (area M in <FIG>). In the present exemplary embodiment, the control apparatus <NUM> is described to obtain the information managed in associated with the input or notified site information in step S101. However, such information may be managed in association with subject information or imaging information different from the site information. For example, the information may be managed in association with an imaging technique, an imaging orientation, an imaging direction, the presence or absence of a grid, or the type of radiographic apparatus.

After the completion of the imaging preparations, in step S102, the operator <NUM> presses the irradiation switch <NUM>. In response to the irradiation switch <NUM> being pressed, the radiation source <NUM> emits radiation toward the subject <NUM>. Here, the radiographic apparatus <NUM> communicates with the radiation generation apparatus <NUM> to control start of radiation irradiation. The radiation irradiating the subject <NUM> are transmitted through the subject <NUM> and incident on the radiographic apparatus <NUM>. In a case where the radiographic apparatus <NUM> is set to use the reached dose monitoring function, the radiographic apparatus <NUM> detects radiation incident on the measuring field(s) by using the detection pixels <NUM>, and the signal processing unit <NUM> calculates a cumulative dosage that is a cumulative value of a dose (reached dose) detected in a predetermined period. The imaging apparatus control unit <NUM> calculates a reference threshold, based on cumulative dosage information from the signal processing unit <NUM> and the site information and imaging condition input by the operator <NUM>, and determines radiation irradiation stop timing, based on a mode set by the generation apparatus control unit <NUM>. The radiographic apparatus <NUM> notifies the radiation generation apparatus <NUM> to stop the radiation irradiation via the first communication cable <NUM>, the communication control apparatus <NUM>, and the third communication cable <NUM>, based on the determined radiation irradiation stop timing. The radiation generation apparatus <NUM> stops the radiation irradiation based on the notified radiation irradiation stop timing. While the radiographic apparatus <NUM> issues the notification to stop the radiation irradiation as a result of detection of the radiation, this is not restrictive. The radiographic apparatus <NUM> may be configured to transmit the reached dose at predetermined time intervals as a result of detection, and the radiation generation apparatus <NUM> may calculate a cumulative value of the reached dose. After the radiation irradiation is stopped, the radiographic apparatus <NUM> converts the incident radiation into visible light and then detects the visible light as radiographic image signals by using the photoelectric conversion elements. The radiographic apparatus <NUM> reads the radiographic image signals by driving the photoelectric conversion elements, and converts the analog signals into digital signals through the AD converter <NUM> to obtain a radiographic image.

In step S103, the radiographic system <NUM> transfers the obtained radiographic image from the radiographic apparatus <NUM> to the control apparatus <NUM> via the first communication cable <NUM>, the communication control apparatus <NUM>, and the third communication cable <NUM>. The control apparatus <NUM> applies image processing to the received digital radiographic image. The control apparatus <NUM> displays the image-processed radiographic image on the display apparatus <NUM>. The control apparatus <NUM> thus functions also as an image processing apparatus and a display control apparatus.

In step S104, the control apparatus <NUM> determines whether the reached dose monitoring function is enabled. In a case where the reached dose monitoring function is enabled (YES in step S104), the processing proceeds to step S105. On the other hand, in a case where the reached dose monitoring function is not enabled (NO in step S104), the processing proceeds to step S106.

In step S105, the determination unit <NUM> determines the measuring field(s) set in step S101 as a calculation area or areas (EI value calculation area(s)) to calculate radiation dosage. For example, in the case of imaging the lung field, radiographic imaging is often performed on measuring fields set to both lungs. In such a case, the calculation areas to calculate the radiation dosage are the measuring fields set to both lungs. The calculation area(s) determined by the determination unit <NUM> in step S105 does not necessarily need to be the same as the measuring field(s). For example, a measuring field-based area obtained by the processing illustrated in <FIG> may be determined as a calculation area.

In step S106, the determination unit <NUM> determines a predetermined area as a calculation area to calculate radiation dosage. For example, the predetermined area is set by the operator <NUM> in step S101. In a case where an area that can be determined regardless of the imaging information or the setting by the operator <NUM>, like the entire area of the radiographic image, is set as the predetermined area, the operator <NUM> does not necessarily need to perform the setting. The radiographic system <NUM> may be configured so that the calculation area can be changed by the operator <NUM> after imaging.

While, in the present exemplary embodiment, the calculation area(s) is/are determined based on whether the reached dose monitoring function is enabled, this is not restrictive.

In step S107, the control apparatus <NUM> transmits the received digital radiographic image to the calculation unit <NUM>. The calculation unit <NUM> calculates the dose index value of each calculation area determined as described above based on the received radiographic image. For example, the calculation unit <NUM> calculates the dose index value of each of the measuring fields set to both lungs.

In step S108, the calculation unit <NUM> calculates the deviation index value(s). While, in the present exemplary embodiment, the control apparatus <NUM> calculates the dose index values and the deviation index values, these values may be calculated by the radiographic apparatus <NUM> or by another not-illustrated calculation apparatus.

In step S109, the control apparatus <NUM> transfers the dose index values and the deviation index values calculated by the calculation unit <NUM> to the display control unit <NUM>. The display control unit <NUM> provides display illustrated in <FIG>, for example. <FIG> illustrate an example where the reached dose monitoring function is enabled, the lung field is imaged while measuring fields at both lung areas R1 and R2 illustrated in <FIG> are set, and dose index values and deviation index values of the corresponding areas are displayed as illustrated <FIG>.

Whether to display the calculated values on the display apparatus <NUM> may be set before imaging or set by the operator <NUM> after imaging. The display setting may be changed in accordance with the setting of the reached dose monitoring function. Alternatively, a not-illustrated icon or dialog may be controlled to be displayed in a case where the received dose index values and the received deviation index values satisfy a specific condition. Examples of the specific condition include that the dose index values and the deviation index values are greater than predetermined values.

While, in the present exemplary embodiment, an image just captured is taken as an example, images captured in the past may be displayed in a similar manner. The measuring field(s) actually used by the reached dose monitoring function may be obtained from the radiographic apparatus <NUM> and reflected on the display content. For example, when radiation irradiation is stopped, displaying of which a measuring field or measuring fields are ultimately used for the determination of stopping the radiation irradiation can be performed on the display apparatus <NUM>. In other words, the control apparatus <NUM> can explicitly display the one or more measuring fields used for the determination of stopping the radiation irradiation based on the control method. In a case where the control method is the AND method, the one or more measuring fields lastly reached the target dose can be explicitly displayed. In a case where the control method is the OR method, the one or more measuring fields first reached the threshold can be explicitly displayed. In a case where the control method is the average method, all the measuring fields can be explicitly displayed. The measuring field(s) may be explicitly displayed using text information. The measuring field(s) may be explicitly displayed at their positions on the radiographic image. The operator <NUM> can thus easily recognize which one or more of the measuring field(s) has been used for the determination of stopping the radiation irradiation. The operator <NUM> can also easily recognize which one or more of the measuring field(s) has been used for the determination of stopping the radiation irradiation and the dose index value(s) in the measuring field(s).

In the above-described manner, a series of processes by the radiographic system <NUM> is performed.

As a result of the foregoing, the operator <NUM> can appropriately determine whether a desirable amount of radiation is incident on an AEC measuring field during radiographic imaging.

In a case of imaging in which a plurality of regions of interest is set, like when a plurality of measuring fields is set, the operator <NUM> can determine whether the regions of interest are irradiated with an appropriate amount of radiation by checking the respective dose index values and the deviation index values displayed on the display apparatus <NUM>. For example, in a case where an imaging dose can be reduced by using the reached dose monitoring function and an appropriate amount of radiation is confirmed to be incident on each region of interest, it can be easily determined that the imaging has been appropriately conducted.

In a second exemplary embodiment, a description will be provided of a configuration of a radiographic system <NUM> that calculates dose index values for a predetermined area and respective AEC measuring fields and displays the dose index values. This enables an operator to appropriately determine whether desirable amounts of radiation are incident on the predetermined area and the respective AEC measuring fields.

Processing by the radiographic system <NUM> according to the present exemplary embodiment will be described below with reference to <FIG> to <FIG>. A functional configuration of the radiographic system <NUM> is similar to the radiographic system <NUM> in the first exemplary embodiment, and the redundant description will thus be omitted.

Display examples of dose index values on the display apparatus <NUM> will initially be described with reference to <FIG> and <FIG>.

The display control unit <NUM> displays a first dose index value (in the diagrams, V1) and second dose index values (in the diagrams, V2 and V3) calculated by the calculation unit <NUM> on the display apparatus <NUM>. As illustrated in <FIG>, the first dose index value and the second dose index values may be displayed as annotations at corners of the radiographic image. As illustrated in <FIG>, the first dose index value may be displayed at a given position on the radiation image, and the second dose index values may be superimposed at the respective positions of the measuring fields where the respective dose index values are calculated on the radiographic image. As illustrated in <FIG>, the dose index values may be displayed separately from the radiographic image. As illustrated in <FIG>, the dose index values may be displayed without the radiographic image. Alternatively, as illustrated in <FIG>, the dose index values may be rendered in a gray scale (or color scale) and displayed to express relative positions between the radiographic image and the measuring fields on the radiographic image. As illustrated in <FIG>, only the gray scale (or color scale) may be separately displayed. As illustrated in <FIG>, the radiographic image and the gray scale (or color scale) may be displayed in combination. In other words, at least two or more pieces of information about the values calculated by the calculation unit <NUM> may be displayed by changing at least either color or tone level.

While <FIG> and <FIG> illustrate examples of displaying the dose index values using text or color, the display method may be defined by any combination of recognizable expressions, such as text, symbols, figures, sizes, color, and shapes. Moreover, the display control unit <NUM> may also display a first dose index target value, a first deviation index value, second dose index target values, and second deviation index values along with the first dose index value and the second dose index values. The first dose index target value and the first deviation index value may be displayed by a display method similar to or different from that of the first dose index value. The second dose index target values and the second deviation index values may be displayed by a display method similar to or different from that of the second dose index values. Instead of displaying the first dose index target value, the first deviation index value, the second dose index target values, and the second deviation index values, a warning dialog may be displayed in a case where a predetermined threshold is reached or exceeded, for example.

Next, an operation of the radiographic system <NUM> during imaging according to the second exemplary embodiment will be described with reference to <FIG>.

In step S1401, the radiographic system <NUM> sets subject information, such as an identifier (ID), name, and date of birth of the subject <NUM> into the control apparatus <NUM>. The radiographic system <NUM> also sets imaging information, such as an imaging site, the measuring field(s), and dose index target value(s) of the subject <NUM>.

For example, the subject information and the imaging information may be automatically set by selecting a test order received via the in-hospital LAN <NUM>. The operator <NUM> may set the imaging information by selecting a predetermined imaging protocol. Alternatively, the operator <NUM> may directly input and set the subject information and the imaging information. The radiographic system <NUM> sets the measuring field(s) of the radiographic apparatus <NUM> in accordance with the input information. After the information about the subject <NUM> and the information about the imaging site are set into the control apparatus <NUM>, the operator <NUM> fixes the posture of the subject <NUM> and the radiographic apparatus <NUM>. The operator <NUM> further inputs a dose, maximum irradiation time, a tube current, a tube voltage, site information, the measuring field(s), and the dose index target value(s) into the control apparatus <NUM>. The control apparatus <NUM> transmits the input irradiation condition of radiation, site information, a measuring field(s), and a dose index target value(s) to the radiographic apparatus <NUM> and the radiation generation apparatus <NUM>. The radiographic system <NUM> may be configured so that the information is input into the radiation generation apparatus <NUM> and notified to the control apparatus <NUM> and the radiographic apparatus <NUM>.

After the completion of the imaging preparations, in step S1402, the operator <NUM> presses the irradiation switch <NUM>. In response to the irradiation switch <NUM> being pressed, the radiation source <NUM> emits radiation toward the subject <NUM>. Here, the radiographic apparatus <NUM> communicates with the radiation generation apparatus <NUM> to control start of radiation irradiation. The radiation irradiating the subject <NUM> are transmitted through the subject <NUM> and incident on the radiographic apparatus <NUM>. In a case where the radiographic apparatus <NUM> is set to use the reached dose monitoring function, the radiographic apparatus <NUM> detects radiation incident on the measuring field(s) by using the detection pixels <NUM>, and the signal processing unit <NUM> calculates a cumulative dosage that is a cumulative value of a dose (reached dose) detected in a predetermined period. The imaging apparatus control unit <NUM> calculates a reference threshold based on cumulative dosage information from the signal processing unit <NUM> and the site information and imaging condition input by the operator <NUM>, and determines radiation irradiation stop timing based on a mode set by the generation apparatus control unit <NUM>. The radiographic apparatus <NUM> notifies the radiation generation apparatus <NUM> to stop the radiation irradiation via the first communication cable <NUM>, the communication control apparatus <NUM>, and the third communication cable <NUM> based on the determined radiation irradiation stop timing. The radiation generation apparatus <NUM> stops the radiation irradiation based on the notified radiation irradiation stop timing. While the radiographic apparatus <NUM> issues the notification to stop the radiation irradiation as a result of detection of the radiation, this is not restrictive. The radiographic apparatus <NUM> may be configured to transmit the reached dose at predetermined time intervals as a result of detection, and the radiation generation apparatus <NUM> may calculate a cumulative value of the reached dose. After the radiation irradiation is stopped, the radiographic apparatus <NUM> converts the incident radiation into visible light and then detects the visible light as radiographic image signals by using the photoelectric conversion elements. The radiographic apparatus <NUM> reads the radiographic image signals by driving the photoelectric conversion elements, and converts the analog signals into digital signals through the AD converter <NUM> to obtain a radiographic image.

In step S1403, the radiographic system <NUM> transfers the obtained radiographic image from the radiographic apparatus <NUM> to the control apparatus <NUM> via the first communication cable <NUM>, the communication control apparatus <NUM>, and the third communication cable <NUM>. The control apparatus <NUM> applies image processing to the received digital radiographic image. The control apparatus <NUM> displays the image-processed radiographic image on the display apparatus <NUM>. The control apparatus <NUM> thus functions also as an image processing apparatus and a display control apparatus.

In step S1404, the control apparatus <NUM> transfers the received digital radiographic image data (digital radiographic image) to the calculation unit <NUM>. The calculation unit <NUM> calculates dose index values of a plurality of regions of interest, based on the received radiographic image data. More specifically, the calculation unit <NUM> calculates a first dose index value from a predetermined area of the radiographic image generated based on the received radiation image data. In the following description, the predetermined area refers to the entire radiographic image. However, this is not restrictive. The calculation unit <NUM> also calculates a second dose index value or values based on the measuring field(s) in the radiographic image generated based on the received radiographic image data.

In step S1405, the calculation unit <NUM> calculates deviation index values. While in the present exemplary embodiment the control apparatus <NUM> calculates the dose index values and the deviation index values, the dose index values and deviation index values may be calculated by the radiographic apparatus <NUM> or by another not-illustrated calculation apparatus.

In step S1406, the calculation unit <NUM> transfers the first dose index value, the second dose index value(s), the first dose index target value, the second dose index target value(s), the first deviation index value, and the second deviation index value(s) to the display control unit <NUM>. The display control unit <NUM> provides display such as illustrated in <FIG>. In other words, the display control unit <NUM> displays information about the values calculated by the calculation unit <NUM> on the display apparatus <NUM>.

<FIG> illustrate examples of a case where the reached dose monitoring function is enabled, both lung areas K and L illustrated in <FIG> are set as measuring fields, and the lung field is imaged. Dose index values (first dose index value and second dose index values) and deviation index values (first deviation index value and second deviation index values) of the entire radiographic image and the areas of the respective measuring fields to be monitored are displayed as illustrated in <FIG>.

Displaying the dose index values (first dose index value and second dose index values) and the deviation index values (first deviation index value and second deviation index values) of the entire radiographic image and the areas of the respective measuring fields to be monitored enables the operator <NUM> to check whether the doses to the region of interest of the radiographic image and the measuring fields set to be monitored are appropriate. Whether to display the calculated values on the display apparatus <NUM> may be set before imaging or set by the operator <NUM> after imaging. The display setting may be changed in accordance with the setting of the reached dose monitoring function. Alternatively, a not-illustrate icon or dialog may be controlled to be displayed in a case where the first dose index value and the second dose index value and the first deviation index value and the second deviation index value satisfy a specific condition. Examples of the specific condition include that any one of the first dose index value and the second dose index value and the first deviation index value and the second deviation index value is greater than a predetermined value.

While, in the present exemplary embodiment, an image just captured is taken as an example, images captured in the past may be displayed in a similar manner. To calculate the second dose index value(s), the calculation unit <NUM> may obtain the measuring field(s) used by the reached dose monitoring function from the radiographic apparatus <NUM> or the image control unit <NUM>, and reflect the measuring field(s) on the display content.

In such a manner, a series of processes by the radiographic system <NUM> according to the second exemplary embodiment is performed.

As a result of the foregoing, the operator <NUM> can appropriately determine whether desirable amounts of radiation are incident on the predetermined area and the respective AEC measuring fields by checking the first dose index value and the second dose index value displayed on the display apparatus <NUM>. For example, in a case where the predetermined area is the entire area of the radiographic image, the operator <NUM> can check both the dose index value of the radiation irradiating the entire area and the dose index values of the radiation irradiating the measuring fields in a subsequent step.

For example, in a case where an imaging dose can be reduced by using the reached dose monitoring function and appropriate amounts of radiation are confirmed to be incident on the region of interest of the radiographic image and the respective measuring fields, the operator <NUM> can easily determine that the imaging has been appropriately conducted.

An exemplary embodiment of the present invention can also be implemented by processing for supplying a program for implementing one or more functions of the foregoing exemplary embodiments to a system or an apparatus via a network or a storage medium, and reading and executing the program by one or more processors in a computer of the system or apparatus. Circuits for implementing one or more of the functions may be used for implementation.

The processors and circuits may include a CPU, a micro processing unit (MPU), a graphics processing unit (GPU), an application-specific integrated circuit (ASIC), and a field-programmable gate array (FPGA). The processors and circuits may also include a digital signal processor (DSP), a data flow processor (DFP), and a neural processing unit (NPU).

The radiographic system according to each of the foregoing exemplary embodiments may be implemented as a single apparatus. A plurality of apparatuses may be communicably combined to execute the foregoing processing. Both cases are covered by the exemplary embodiments of the present invention. A common server apparatus or a group of servers may be configured to execute the foregoing processing. A plurality of apparatuses constituting the radiographic system may be capable of communication at a predetermined communication rate, and does not need to be located in the same facility or in the same country.

An exemplary embodiment of the present invention may cover a mode in which a software program for implementing the functions of the foregoing exemplary embodiments is supplied to a system or an apparatus, and a computer of the system or apparatus reads and executes the supplied program code.

The program code installed on the computer to implement the processing of the exemplary embodiment by the computer is therefore also an exemplary embodiment of the present invention. An operating system (OS) running on the computer may perform part or all of the actual processing based on instructions included in the program read by the computer, in which case the functions of the foregoing exemplary embodiments are implemented by the processing.

The present invention is not limited to the foregoing exemplary embodiments. Various modifications (including organic combinations of the exemplary embodiments) can be made, and such modifications are not excluded from the scope of the present invention. Examples of the modifications may include making the exemplary embodiments adaptable to capturing of moving images as well as still images.

In other words, all configurations obtained by combining the foregoing exemplary embodiments are also intended to be covered by the exemplary embodiments of the present invention.

Claim 1:
A radiographic system that includes a radiation generation apparatus configured to emit radiation, a radiographic apparatus configured to generate a radiographic image based on the radiation, a control apparatus configured to communicate with the radiographic apparatus to receive the radiographic image and control operation, the radiographic system comprising:
obtaining means configured to obtain a plurality of dose index values using the radiation image generated based on the radiation,
the radiographic system further comprising setting means for setting a dose index target value corresponding to the plurality of dose index values, and
characterized in that:
the obtaining means is further configured to obtain a plurality of deviation index values using the plurality of dose index values and the dose index target value.