JP2011147615A - X-ray fluoroscopic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately set conditions for fluoroscopy and conditions for radiography suitable for X-ray examination. <P>SOLUTION: An F-kV-F-mAs line computing part 65 computes an F-kV-F-mAs line representing the correlations between fluoroscopic tube voltage and fluoroscopic mAs based on prior registered data including the fluoroscopic dose, radiographic dose and fluoroscopic tube voltage suitable for various thickness of subjects and basic data including the relational expression between the fluoroscopic tube voltage and fluoroscopic mAs (fluoroscopic tube current irradiation time product) with the previously stored thickness of subjects as parameters. A fluoroscopy condition setting part 66 sets the fluoroscopic tube voltage and fluoroscopic mAs suitable for a fluoroscopic mode by comparing the average pixel value and a prescribed threshold of fluoroscopic image data sequentially generated as the fluoroscopic tube voltage and fluoroscopic mAs are updated along the F-kV-F-mAs line. A radiography condition setting part 67 sets the radiographic tube voltage and radiographic mAs suitable for a radiographic mode based on the fluoroscopic tube voltage and fluoroscopic mAs and the prior registered data. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an X-ray fluoroscopic apparatus, and more particularly to an X-ray fluoroscopic apparatus that sets an imaging condition based on a fluoroscopic condition set in a fluoroscopic mode preceding an imaging mode.

  Medical image diagnostic technology using an X-ray diagnostic apparatus, an MRI apparatus, or an X-ray CT apparatus has made rapid progress with the development of computer technology and has become indispensable in today's medical care.

  In the X-ray diagnosis, prior to an imaging mode for the purpose of generating image data used for diagnosis, the imaging direction and imaging area of this imaging mode, as well as imaging conditions (for example, imaging tube voltage, imaging tube current and irradiation) X-ray irradiation in a fluoroscopic mode for the purpose of setting (time) is performed on the subject. In such an X-ray fluoroscopic apparatus capable of continuously performing X-ray irradiation in the fluoroscopic mode and the imaging mode, an image in the fluoroscopic mode is obtained by irradiating the subject with pulsed X-rays at predetermined time intervals. Data (perspective image data) can be observed in real time, and an automatic brightness adjustment method (ABC method) is usually applied to optimize the brightness of the perspective image data (see, for example, Patent Document 1). .

  In this automatic brightness adjustment method, for example, an average pixel in a predetermined region of interest of projection data or image data obtained by X-ray irradiation in a fluoroscopic mode is compared with a preset brightness value (threshold value), and the comparison result is Based on this, control of the fluoroscopic conditions (fluoroscopic tube voltage, fluoroscopic tube current and irradiation time) is performed. Specifically, the correspondence between fluoroscopic mAs (F-mAs) indicating the product of fluoroscopic tube current and irradiation time stored in advance in the storage circuit of the X-ray fluoroscopic apparatus and fluoroscopic tube voltage (F-kV) is shown. A suitable fluoroscopic tube voltage (F-kVx) and fluoroscopic mAs (F-mAsx) in the fluoroscopic mode of the subject are set along the F-kV / F-mAs line shown in FIG. Based on (F-kVx) and fluoroscopic mAs (F-mAsx), a suitable shooting tube voltage (R-kVx) and shooting mAs (R-mAsx) have been set for the shooting mode following the fluoroscopic mode.

JP 2003-115399 A

  As described above, in the X-ray fluoroscopic imaging apparatus, the average pixel value in a predetermined region of interest of the two-dimensional projection data or the fluoroscopic image data obtained in the fluoroscopic mode of the subject is compared with a threshold value. If there is a difference, the fluoroscopic tube voltage and fluoroscopic mAs are updated along the above-mentioned FkV / F-mAs line, and the average pixel value of the projection data or fluoroscopic image data newly obtained at this time is compared with the threshold value. Is repeated to set the above-described fluoroscopic tube voltage (F-kVx) and fluoroscopic mAs (F-mAsx). Then, a suitable photographing tube voltage (R-kVx) and photographing mAs (R-mAsx) corresponding to the obtained fluoroscopic conditions are set based on the fluoroscopic condition-imaging condition correspondence table.

  However, the above method has the following problems. That is, in the setting of the conventional fluoroscopic conditions and imaging conditions performed by such a procedure, the fluoroscopic tube voltage (F-kVz) and fluoroscopic mAs (obtained by the F-kV / F-mAs line irrespective of the subject thickness) F-mAsz), the tube voltage, which is the main factor of contrast in the image data, cannot be controlled to a value corresponding to the subject thickness.

  If the tube voltage (R-kVx) and the shooting mAs (R-mAsx) are set based on the fluoroscopy condition-imaging condition correspondence table, the fluoroscopy using these fluoroscopy conditions and the imaging conditions is performed. Since it is necessary to verify the validity by generating and displaying image data and photographed image data, it takes a lot of time and labor to finally determine the desired fluoroscopic conditions and photographing conditions.

  The present invention has been made in view of such a problem, and an object of the present invention is to arbitrarily set an imaging condition based on a fluoroscopic condition set in a fluoroscopic mode preceding the imaging mode. By setting the fluoroscopic conditions using the F-kV / F-mAs line calculated in advance based on pre-registered data or the like input to the camera, it is possible to accurately and accurately collect photographed image data having good image quality and sensitivity. An object of the present invention is to provide an X-ray fluoroscopic apparatus capable of performing in a short time.

  In order to solve the above-described problem, an X-ray fluoroscopic imaging apparatus according to a first aspect of the present invention is an X-ray fluoroscopic imaging apparatus that sets an imaging condition in an imaging mode based on a fluoroscopic condition set in a fluoroscopic mode. Perspective control means for controlling the tube current and tube voltage of the X-ray tube in the fluoroscopic mode so that the fluoroscopic image data collected in the fluoroscopic mode has a predetermined luminance, and the tube voltage substantially equal to the tube voltage in the fluoroscopic mode And a shooting control means for controlling shooting conditions in the shooting mode so that shooting in shooting mode is performed.

  According to a second aspect of the present invention, there is provided an X-ray fluoroscopic imaging apparatus for setting an imaging condition in an imaging mode based on a fluoroscopic condition set in a fluoroscopic mode preceding an imaging mode. A storage means for storing data indicating the relationship between the specimen thickness and the fluoroscopic tube voltage, a calculation means for calculating a correspondence relationship between the fluoroscopic tube voltage and the fluoroscopic mAs based on the data, and a fluoroscopic mode. A fluoroscopy condition voltage setting unit for setting a fluoroscopic tube voltage in a fluoroscopic mode and a parameter related to the fluoroscopic mAs based on a pixel value of image data and a calculation result of the calculating unit; and a parameter relating to the fluoroscopic tube voltage or the fluoroscopic mAs. And an imaging condition setting means for setting parameters related to the imaging tube voltage and imaging mAs in the imaging mode based on at least one of the parameters. It is set to.

  According to the present invention, when setting the photographing condition based on the fluoroscopic condition set in the fluoroscopic mode preceding the photographing mode, F− calculated based on pre-registered data or the like arbitrarily input by the operator. By setting the fluoroscopy conditions using the kV · F-mAs line, it is possible to collect photographed image data having good image quality and sensitivity accurately and in a short time. For this reason, diagnostic accuracy and diagnostic efficiency can be improved.

1 is a block diagram showing the overall configuration of an X-ray fluoroscopic apparatus in an embodiment of the present invention. The block diagram which shows the specific structure of the X-ray generation part, X-ray detection part, and high voltage generation part with which the X-ray fluoroscope of the Example is provided. The figure which shows the structure of the flat detector with which the X-ray fluoroscope of the Example is provided. The figure which shows the relationship between the object thickness t in the prior registration data of the Example, and fluoroscopic tube voltage (F-kV). The figure which shows the specific example of the F-kV * F-mAs line calculated in the Example. The figure for demonstrating the update of fluoroscopy conditions performed along the F-kV * F-mAs line of the Example. The flowchart which shows the setting procedure of fluoroscopy conditions and imaging | photography conditions in the Example.

  Embodiments of the present invention will be described below with reference to the drawings.

  The X-ray fluoroscopic apparatus according to the present embodiment described below includes the fluoroscopic mode and the X-ray dose (fluoroscopic dose and radiographic dose) input in the initial setting performed prior to the X-ray examination of the subject and the subject. Pre-registration data such as fluoroscopic tube voltage specified for each thickness, fluoroscopic mode tube voltage (fluoroscopic tube voltage) and tube current / irradiation time using the object thickness stored in advance in the X-ray fluoroscopic apparatus as parameters. F-kV / F-mAs line indicating the correspondence between fluoroscopic tube voltage and fluoroscopic mAs, or the relationship between fluoroscopic tube voltage and parameters affecting fluoroscopic mAs, based on the basic data including the relational expression with the product (fluoroscopic mAs) Is calculated. Then, by comparing the fluoroscopic tube voltage along the F-kV / F-mAs line and the pixels of the fluoroscopic image data sequentially generated along with the update of the fluoroscopic mAs, the pixel value = α is obtained. The fluoroscopic tube voltage (F-kVx) and the fluoroscopic mAs (F-mAsx) to be obtained are set, and the photographing tube voltage (R-kVx) and the photographing mAs suitable for the photographing mode are set based on these irradiation conditions and the above pre-registered data. (R-mAsx) is set.

(Device configuration)
The configuration of the X-ray fluoroscopic apparatus according to the present embodiment will be described with reference to FIGS. FIG. 1 is a block diagram showing the overall configuration of the X-ray fluoroscopic apparatus, and FIG. 2 is a specific example of an X-ray generator, an X-ray detector, and a high voltage generator included in the X-ray fluoroscopic apparatus. It is a block diagram which shows a structure.

  An X-ray fluoroscopic apparatus 100 shown in FIG. 1 two-dimensionally detects an X-ray generation unit 1 that performs X-ray irradiation in a fluoroscopic mode and an imaging mode on a subject 150, and X-rays that have passed through the subject 150. An X-ray detector 2 that generates projection data based on the detection data, and a high-voltage generator 3 that supplies the X-ray generator 1 with a high voltage necessary for X-ray irradiation in the fluoroscopic mode and the imaging mode. The image data generation unit 4 that generates image data in the perspective mode (perspective image data) and image data in the imaging mode (captured image data) based on the projection data generated in the X-ray detection unit 2, and the obtained above-described image data The display unit 5 for displaying the image data is provided.

  Further, the X-ray fluoroscopic imaging apparatus 100 includes fluoroscopic image data sequentially generated by the image data generation unit 4 using the fluoroscopic conditions in accordance with the update of the fluoroscopic conditions in the fluoroscopic mode (that is, fluoroscopic tube voltage and fluoroscopic mAs), and later described. Based on pre-registration data input from the input unit 7 and device basic data stored in advance in a basic data storage unit 63 to be described later, a fluoroscopic tube voltage (F−) suitable for the fluoroscopic mode of the subject 150. kVx) and fluoroscopic mAs (F-mAsx) are set, and the irradiation condition setting unit 6 sets the imaging tube voltage (R-kVx) and imaging mAs (R-mAsx) based on these fluoroscopic conditions and pre-registered data. And an input unit 7 for inputting pre-registration data and various command signals, and a system control unit 8 for comprehensively controlling the above-described units.

  Next, specific configurations of the X-ray generator 1, the X-ray detector 2, and the high voltage generator 3 will be described with reference to the block diagram of FIG.

  The X-ray generator 1 shown in FIG. 2 includes an X-ray tube 11 that generates X-rays to the subject 150 by a high voltage supplied from a high-voltage generator 3 described later, and an X-ray generated by the X-ray tube 11. An X-ray restrictor 12 that forms an X-ray weight (cone beam) with respect to the line is provided. The X-ray tube 11 is a vacuum tube that generates X-rays, and accelerates electrons emitted from a cathode (filament) by a high voltage to collide with a tungsten anode to generate X-rays. The X-ray diaphragm 12 is located between the X-ray tube 11 and the subject 150 and has a function of narrowing the X-ray beam generated from the X-ray tube 11 to a predetermined irradiation field.

  On the other hand, the X-ray detector 2 includes I.I. I. (Image intensifier) and X-ray TV method and flat detector method. Furthermore, there are two types of flat detectors: one that converts X-rays directly into electric charge, and one that converts light into light after being converted into light. There is something to convert. Here, although the X-ray detection unit 2 provided with a flat panel detector capable of directly converting X-rays into electric charges will be described, the present invention is not limited to this.

  That is, the flat detector 21 of the X-ray detector 2 is configured by two-dimensionally arranging minute detection elements in the column direction and the line direction, and each of the detection elements senses X-rays and corresponds to the incident X-ray dose. A photoelectric film that generates charge, a charge storage capacitor that stores the charge generated in the photoelectric film, and a TFT (thin film transistor) that reads the charge stored in the charge storage capacitor at a predetermined timing are provided. In the following, for the sake of simplicity, the planar detector 21 in which two detection elements are arranged in the column direction and the line direction will be described.

  In the flat detector 21 shown in FIG. 3, the first terminals of the photoelectric films 212-11, 212-12, 212-21 and 212-22, the charge storage capacitors 213-11, 213-12, 213-21 and 213-22 is connected to the first terminal, and the connection point is connected to the source terminals of TFTs 214-11, 214-12, 214-21, and 214-22. On the other hand, the second terminals of the photoelectric films 212-11, 212-12, 212-21, and 212-22 are connected to a bias power source (not shown), and charge storage capacitors 213-11, 213-12, 213-21, and 213 are connected. The second terminal of -22 is grounded. Furthermore, the gates of the TFTs 214-11 and 214-21 arranged in the line direction (horizontal direction in FIG. 3) are commonly connected to the output terminal 22-1 of the gate driver 22, and the gates of the TFTs 214-12 and 214-21 are gates. The driver 22 is commonly connected to the output terminal 22-2.

  On the other hand, the drain terminals of the TFTs 214-11 and 214-12 arranged in the column direction (vertical direction in FIG. 3) are commonly connected to the signal output line 219-1, and the drain terminals of the TFTs 214-21 and 214-22 are signal output. Commonly connected to line 219-2. The signal output lines 219-1 and 219-2 are connected to the projection data generation unit 23. On the other hand, the gate driver 22 supplies a driving pulse for reading to the gate terminal of the TFT 214 in order to read out signal charges generated in the photoelectric film 212 of the detection element 211 and accumulated in the charge storage capacitor 213 by X-ray irradiation. .

  Returning to FIG. 2, the projection data generator 23 includes a charge / voltage converter 231 that converts charges read in parallel from the flat detector 21 in units of rows or columns into voltages, and the charge / voltage converter. An A / D converter 232 that converts the output of 231 into a digital signal and a parallel / serial converter 233 that converts the digitally converted parallel signal into a time-series serial signal (projection data) are provided.

  On the other hand, the high voltage generator 3 includes a high voltage generator 32 that generates a high voltage applied between the anode and the cathode in order to accelerate the thermoelectrons generated from the cathode of the X-ray tube 11, and the irradiation conditions of FIG. An X-ray controller that controls tube current, tube voltage, irradiation time, irradiation timing, etc. in the high voltage generator 32 based on the irradiation conditions of the fluoroscopic mode and the imaging mode supplied from the setting unit 6 via the system control unit 8 31 is provided.

  Returning to FIG. 1, the image data generation unit 4 includes, for example, a projection data storage unit and an image processing unit (not shown). The projection data storage unit sequentially stores the projection data supplied in time series from the projection data generation unit 23 of the X-ray detection unit 2 to generate two-dimensional projection data. On the other hand, the image processing unit includes an arithmetic circuit and a storage circuit, and the arithmetic circuit performs image processing such as interpolation processing and filtering processing on the two-dimensional projection data read from the projection data storage unit to perform two-dimensional processing. Perspective image data and captured image data are generated. Further, the fluoroscopic image data read from the projection data storage unit is supplied to a pixel value calculation unit 61 described later provided in the irradiation condition setting unit 6 of FIG.

  The display unit 5 includes a display data generation unit, a data conversion unit, and a monitor (not shown), and the display data generation unit generates the fluoroscopic image data and the radiography generated by the image processing unit of the image data generation unit 4 in the fluoroscopy mode and the imaging mode. Image data is converted into a predetermined display format, and additional information such as subject information and projection data collection conditions is added as necessary to generate display data. The data conversion unit performs a conversion process such as D / A conversion or television format conversion on the display data obtained by the display data generation unit and displays the display data on the monitor.

  Next, the irradiation condition setting unit 6 includes a fluoroscopic tube voltage (F-kVx) and fluoroscopic mAs (F-mAsx) suitable for the fluoroscopic mode of the subject 150, a radiographic tube voltage (R-kVx) suitable for the radiographic mode, and It has a function of setting imaging mAs (R-mAsx), and includes a pixel value calculation unit 61, a pixel value comparison unit 62, a basic data storage unit 63, a registered data storage unit 64, and an F-kV / F-mAs line calculation unit 65. A fluoroscopy condition setting unit 66 and an imaging condition setting unit 67.

  The pixel value calculation unit 61 receives the positional information of the region of interest set by the input unit 7 for the fluoroscopic image data generated by X-ray irradiation and displayed on the display unit 5 via the system control unit 8, and the image data The region of interest is set for the fluoroscopic image data supplied from the projection data storage unit of the generation unit 4. Then, the average pixel value of the fluoroscopic image data in this region of interest is calculated. Further, the fluoroscopic image data newly generated with the update of the fluoroscopic conditions (the fluoroscopic tube voltage (F-kV) and the fluoroscopic mAs (F-mAs)) by the fluoroscopic condition setting unit 66 is also performed by the same procedure. A region of interest is set, and an average pixel value in this region of interest is calculated.

  On the other hand, the pixel value comparison unit 62 compares the threshold value α set in the initial setting with the average pixel value of the region of interest supplied from the pixel value calculation unit 61 and supplies the comparison result to the fluoroscopy condition setting unit 66. To do.

On the other hand, in the basic data storage unit 63, for example, a fluoroscopic tube voltage (F-kV) that is set in advance for the X-ray fluoroscopic apparatus 100 and has a subject thickness or the like as shown in the following equation (1) as a parameter. ) And fluoroscopic mAs (F-mAs) are stored as device basic data.

  However, F-dose in Equation (1) is the X-ray dose (fluoroscopic dose) in the fluoroscopic mode, and SID (Source Image Distance) is from the X-ray source of the X-ray tube 11 to the image receiving surface of the flat detector 21. Indicates distance. Further, t represents the body thickness of the subject 150, and a to d represent coefficients set based on prior measurement using the X-ray fluoroscopic apparatus 100.

  Next, in the registration data storage unit 64, values of fluoroscopic dose (F-dose) and radiographic dose (R-dose) arbitrarily registered by an operator or the like in the initial setting of the X-ray fluoroscopic apparatus 100 are stored. Similarly, various data specifying the fluoroscopic tube voltage (F-kV) for each subject thickness t is stored in the form of a mathematical formula, a graph, a lookup table, or the like. FIG. 4 is a specific example of pre-registration data in which the relationship (F-kV = f (t)) between the subject thickness t and the fluoroscopic tube voltage (F-kV) is shown in a graph format. A suitable fluoroscopic tube voltage (F-kV) is registered for each of these before the X-ray examination of the subject 150. Note that the pre-registration data such as F-dose, R-dose, and F-kV = f (t) described above is usually arbitrarily registered based on the operator's preference, inspection contents, etc. When 100 is used by a plurality of operators, these pre-registration data are registered for each operator, and when used for a plurality of tests, they are registered for each test.

  Next, the F-kV / F-mAs line calculation unit 65 for calculating the correspondence between the fluoroscopic tube voltage and the fluoroscopic mAs or the correspondence between the fluoroscopic tube voltage and the parameter affecting the fluoroscopic mAs is read from the basic data storage unit 63. The relationship between the fluoroscopic tube voltage (F-kV) and the fluoroscopic mAs (F-mAs) using the subject thickness t as a parameter (see equation (1)), and the subject thickness t read from the registered data storage unit 64 F-kV / F-mAs line indicating the correspondence between fluoroscopic tube voltage (F-kV) and fluoroscopic-mAs (F-mAs) using the relationship with fluoroscopic tube voltage (F-kV) (see FIG. 4) Is calculated.

  FIG. 5 shows a specific example of the F-kV / F-mAs line calculated by the F-kV / F-mAs line calculator 65, and the horizontal axis represents the fluoroscopic tube voltage (F-kV). The vertical axis represents fluoroscopic mAs (F-mAs). Each point on the F-kV / F-mAs line Q1 simultaneously satisfies the relational expression (1) and the relation shown in FIG.

  Referring back to FIG. 1 again, the fluoroscopy condition setting unit 66 receives the information on the F-kV / F-mAs line calculated by the F-kV / F-mAs line calculation unit 65 and receives the F-kV / F-mAs line information. Initial fluoroscopic conditions (initial fluoroscopic tube voltage (F-kVo) and initial fluoroscopic mAs (F-mAso)) are set for the mAs line. When fluoroscopy is started, a comparison result between the average pixel value of the fluoroscopic image data generated under the initial fluoroscopic condition and the threshold value α is received from the pixel value comparison unit 62, and the initial fluoroscopic condition is updated based on the comparison result Thus, a fluoroscopic condition suitable for the fluoroscopic mode is set. At this time, for example, the new fluoroscopic tube voltage and fluoroscopic mVs are uniquely determined by updating the initial fluoroscopic tube voltage (F-kVo) along the F-kV / F-mAs line.

Next, the comparison of the average pixel value of the fluoroscopic image data generated by the updated fluoroscopic condition and the threshold value α and the update of the fluoroscopic condition based on the comparison result are sequentially repeated,
Even if the body thickness changes due to body posture change or the like of the subject 150, it is updated to fluoroscopic conditions (fluoroscopic tube voltage (F-kVx) and fluoroscopic mAs (F-mAsx)) that can obtain an average pixel value almost equal to the threshold value α. to continue. Then, the updated information on the fluoroscopic tube voltage (F-kVx) and the fluoroscopic mAs (F-mAsx) is supplied to the X-ray control unit 31 of the high voltage generation unit 3 via the system control unit 8.

  FIG. 6 schematically shows the update of the fluoroscopic condition using the F-kV / F-mAs line. For example, when the fluoroscopic tube voltage F-kVo is initially set at the start of fluoroscopy, F− The initial perspective mAs (F-mAso) is determined by the intersection Po between the vertical line So indicating kV = F-kVo and the F-kV · F-mAs line Q1. When the average pixel value of the fluoroscopic image data obtained by this initial fluoroscopic condition is smaller than the threshold value α, the fluoroscopic tube voltage (F-kVa) larger than the initial fluoroscopic tube voltage F-kVo is updated, and F-kV = F A new perspective mAs (F-mAsa) is determined by the intersection Pa between the vertical line Sa of −kVa and the F-kV · F-mAs line Q1. On the other hand, when the average pixel value of the fluoroscopic image data obtained by the initial fluoroscopic condition is larger than the threshold value α, the fluoroscopic tube voltage (F-kVb) is updated to be smaller than the initial fluoroscopic tube voltage F-kVo, and F-kV · F- A new perspective mAs (F-mAsb) is determined by the intersection Pb between the vertical line Sb of kVb and the F-kV · F-mAs line Q1.

Next, the imaging condition setting unit 67 in FIG. 1 sets imaging conditions suitable for the imaging mode based on the latest fluoroscopic conditions set by the fluoroscopy condition setting unit 66 and the pre-registered data read from the registration data storage unit 64. . Specifically, as shown in the following formula (2), a photographing tube voltage (R-kVx) in the photographing mode having a magnitude equal to the fluoroscopic tube voltage (F-kVx) in the fluoroscopic mode is set, and the fluoroscopy in the fluoroscopic mode is performed. Imaging mAs (R-mAsx) in the imaging mode is set by multiplying mAs (F-mAsx) by the ratio of the imaging dose (R-dose) and the transmitted dose (F-dose) of the pre-registered data. Then, information on the set imaging tube voltage (R-kVx) and imaging mAs (R-mAsx) is supplied to the X-ray control unit 31 of the high voltage generation unit 3 via the system control unit 8.

  Next, the input unit 7 is an interactive interface including an input device such as a display panel, a keyboard, a trackball, a joystick, a mouse, and a selection button on the console, and inputs subject information, pre-registered data, The threshold α is set, the region of interest is set, the projection data collection condition is set, the image data generation condition is set, the image data display condition is set, and various command signals are input.

  The system control unit 8 includes a CPU and a storage circuit (not shown), and various input information and setting information supplied from the input unit 7 are stored in the storage circuit. On the other hand, the X-ray fluoroscopic imaging apparatus 100 includes controls for performing generation and display of fluoroscopic image data, setting of fluoroscopic conditions and imaging conditions, generation and display of captured image data, and the like based on such information. For each unit described above.

(Setting procedure for fluoroscopy and shooting conditions)
Next, the procedure for setting the fluoroscopic conditions and the imaging conditions in this embodiment will be described with reference to the flowchart shown in FIG.

  Prior to the X-ray examination of the subject 150, the operator of the X-ray fluoroscopic imaging apparatus 100 inputs subject information at the input unit 7, then inputs pre-registered data, sets a threshold value α and a region of interest, and collects projection data. Conditions, image data generation conditions, image data display conditions, etc. are set. The input or set information is stored in the storage circuit of the system control unit 8, and further, the above-described pre-registered data (ie, fluoroscopic dose (F-dose), imaging dose (R-dose), and subject) Data indicating the relationship between the thickness t and the fluoroscopic tube voltage (F-kV)) is stored in the registered data storage unit 64 (step S1 in FIG. 7).

  Next, the F-kV / F-mAs line calculation unit 65 includes a fluoroscopy tube voltage (F-kV) and a fluoroscopy mAs (F-mAs) using the object thickness t stored in advance in the basic data storage unit 63 as a parameter. And the data (see FIG. 4) indicating the relationship between the above-described subject thickness t and fluoroscopic tube voltage (F-kV) stored in the registered data storage unit 64. The F-kV / F-mAs line indicating the correspondence between the fluoroscopic tube voltage (F-kV) and the fluoroscopic mAs (F-mAs) is calculated using these data (see FIG. 5) (step of FIG. 7). S2).

  When the calculation of the F-kV / F-mAs line is completed, the operator moves the subject 150 placed on the top (not shown) to a predetermined position, and then sees through the input unit 7. A mode start command is input (step S3 in FIG. 7), and this command signal is supplied to the system control unit 8 to start generation and display of fluoroscopic image data.

  That is, the system control unit 8 that has received the command signal generates initial fluoroscopic conditions (initial fluoroscopic tube voltage (F-kVo) and initial fluoroscopic mAs (F-mAso)) read from its memory circuit and X-ray generation. Is supplied to the X-ray control unit 31 of the high-voltage generating unit 3, and the X-ray control unit 31 that has received this instruction signal controls the high-voltage generator 32 based on the initial fluoroscopic condition to generate X-rays. A high voltage is applied to the X-ray tube 11 of the unit 1. Then, the X-ray tube 11 to which a high voltage is applied starts X-ray irradiation in the fluoroscopic mode with respect to the subject 150 via the movable aperture 12, and the X-ray that has passed through the subject 150 is provided behind the X-ray tube 11. Detected by the flat detector 21 of the X-ray detector 2.

  At this time, the photoelectric film 212 of the detection elements 211 arranged two-dimensionally in the flat detector 21 receives the X-ray transmitted through the subject 150 and supplies a signal charge proportional to the X-ray transmission amount to the charge storage capacitor 213. accumulate. When the X-ray irradiation is finished, the gate driver 22 to which the clock pulse is supplied from the system control unit 8 supplies the drive pulse to the TFT 214 of the flat detector 21 and sequentially reads out the signal charges stored in the charge storage capacitor 213. .

  The read signal charge is converted into a voltage by the charge / voltage converter 231 of the projection data generator 23, and further converted into a digital signal by the A / D converter 232, and then the parallel / serial converter 233. Are temporarily stored as projection data for one line in the buffer memory. Then, the parallel / serial converter 233 reads the projection data stored in its own buffer memory serially in line units and sequentially stores them in the projection data storage unit of the image data generation unit 4 to generate two-dimensional projection data. .

  Next, the image processing unit of the image data generation unit 4 performs image processing such as interpolation processing and filtering processing on the two-dimensional projection data generated in the projection data storage unit to perform two-dimensional image data (initial Fluoroscopic image data) is generated and displayed on the monitor of the display unit 5 (step S4 in FIG. 7).

  On the other hand, the pixel value calculation unit 61 of the irradiation condition setting unit 6 receives the position information of the region of interest set by the input unit 7 for the above-described initial fluoroscopic image data via the system control unit 8, and receives the image data generation unit. The region of interest described above is set for the initial fluoroscopic image data supplied from the projection data storage unit 4 (step S5 in FIG. 7). Then, the average pixel value of the initial fluoroscopic image data included in the region of interest is calculated (step S6 in FIG. 7).

  Next, the pixel value comparison unit 62 compares the threshold value α set in step S1 described above with the average pixel value of the region of interest supplied from the pixel value calculation unit 61, and the comparison result is a perspective condition setting unit. 66 (step S7 in FIG. 7).

  On the other hand, the fluoroscopy condition setting unit 66 receives the information on the F-kV / F-mAs line calculated by the F-kV / F-mAs line calculation unit 65 and outputs the F-kV / F-mAs line to the F-kV / F-mAs line. Initial fluoroscopic conditions (initial fluoroscopic tube voltage (F-kVo) and initial fluoroscopic mAs (F-mAso)) are set (see FIG. 6). Next, a comparison result between the average pixel value of the fluoroscopic image data generated under the initial fluoroscopic condition and the threshold value α is received from the pixel value comparing unit 62, and the update of the initial fluoroscopic condition based on the comparison result is F-kV · F. A new fluoroscopic condition is set by performing along the -mAs line (step S8 in FIG. 7).

  Then, generation of fluoroscopic image data based on the updated fluoroscopic conditions, setting of a region of interest for the obtained fluoroscopic image data, calculation of an average pixel value in the region of interest, comparison of the calculated average pixel value and a threshold value α, F − The fluoroscopy conditions based on the kV · F-mAs line are repeatedly updated so that the average pixel value and the threshold α are always equal during fluoroscopy (steps S4 to S8 in FIG. 7).

  On the other hand, the imaging condition setting unit 67 sets an imaging tube voltage (R-kVx) having a value equal to the latest fluoroscopic tube voltage (F-kVx) updated by the fluoroscopy condition setting unit 66, and the fluoroscopic mAs (F-mAsx). ) Is multiplied by the ratio of the imaging dose (R-dose) and the transmitted dose (F-dose) in the pre-registration data to set the imaging mAs (R-mAsx) suitable for the imaging mode (see Equation (2)). ). The updated latest tube voltage (R-kVx) and imaging mAs (R-mAsx) information are temporarily stored in the storage circuit of the system control unit 8 (step S9 in FIG. 7).

  Next, if the operator confirms that the position, body position, and contrast medium of the subject are in a state suitable for imaging with the fluoroscopic image data, the operator inputs an imaging mode start command at the input unit 7 (FIG. 7). Step S10). Upon receiving this command signal, the system control unit 8 increases the latest imaging tube voltage (R-kVx) and imaging mAs (R-mAsx) read from its storage circuit and an instruction signal for X-ray generation. The image data is supplied to the X-ray control unit 31 of the voltage generation unit 3 and the captured image data is generated and displayed in the same procedure as in step S4 described above (step S11 in FIG. 7).

  According to the embodiment of the present invention described above, when setting the imaging condition based on the fluoroscopic condition set in the X-ray inspection in the fluoroscopic mode performed prior to the imaging mode, it is arbitrarily input by the operator. By setting the fluoroscopic condition using the FkV-FmAs line calculated based on pre-registered data, it is possible to collect captured image data having good image quality and sensitivity in a short time. Become. For this reason, diagnostic accuracy and diagnostic efficiency can be improved.

  In particular, the above-described F-kV / F-mAs line is set based on the relationship between the subject thickness of the pre-registration data arbitrarily registered according to the operator's preference and examination content, and the fluoroscopic tube voltage. Therefore, the tube voltage, which is the main factor of image contrast, can be realized as required. That is, it differs from the conventional fluoroscopic tube voltage (F-kVz) and fluoroscopic mAs (F-mAsz) controlled based on the F-kV / F-mAs line unrelated to the subject thickness.

  In addition, the photographing tube voltage (R-kVx) and the photographing mAs (R-mAsx) suitable for the photographing mode are set in advance with the fluoroscopic tube voltage (F-kVx) and the fluoroscopic mAs (F-mAsx) set in the fluoroscopic mode. Since the photographing tube voltage (R-kVx) which is uniquely determined by the fluoroscopic dose and the photographing dose of the registered data and which is equal to the fluoroscopic tube voltage (F-kVx) is set, photographed image data having a desired image quality Can be collected stably. That is, the fluoroscopic image data having the same contrast as the captured image data can be easily observed on the display unit, so that the X-ray examination of the subject can be performed while confirming the contrast of the captured image data.

  For this reason, according to the present embodiment, not only the diagnostic efficiency is improved, but also the burden on the subject and the operator can be reduced. In particular, the frequency of redoing X-ray examinations associated with poor image quality of captured image data is greatly reduced, so that unnecessary exposure to the subject can be prevented.

  The tube voltage (R-Kvx) and the imaging mAs (R-mAsx) are the fluoroscopic tube voltage (F-Kvx) and the fluoroscopic mAs (F-mAsx), the fluoroscopic dose of the pre-registered data and the imaging as described above. Since it is easily determined based on the dose, it is not necessary to use a conventional automatic exposure control method (ACE method) that requires a dedicated X-ray sensor, and in particular, a flat detector in which the installation of the X-ray sensor is difficult. This can be a suitable method for an X-ray fluoroscopic imaging apparatus using the. In addition, the image quality and sensitivity of the fluoroscopic image data and the captured image data can be easily controlled by updating the above-described pre-registration data.

  As mentioned above, although the Example of this invention has been described, this invention is not limited to the above-mentioned Example, It can change and implement. For example, in the above-described embodiment, the case where the fluoroscopic tube voltage (F-Kvx) and the fluoroscopic mAs (F-mAsx) are set based on the comparison result between the average pixel value of the two-dimensional projection data in the fluoroscopic mode and the threshold value α. As described above, the above-described fluoroscopic conditions may be set based on a comparison result between an average pixel value of fluoroscopic image data generated using two-dimensional projection data and a predetermined threshold value.

  Moreover, although the case where the average value of the pixel value in the region of interest set in the fluoroscopic image data is compared with the threshold value α is described, the present invention is not limited to this. For example, the maximum value or the median value ( Median).

  Further, in the basic data storage unit 63 in the above-described embodiment, the relational expression between the fluoroscopic tube voltage (F-kV) and the fluoroscopic mAs (F-mAs) using the subject thickness t shown in the equation (1) as a parameter. However, when the image quality and sensitivity of the fluoroscopic image data are significantly different depending on the presence or absence of a grid, the basic data storage unit 63 identifies a plurality of mathematical expressions corresponding to these projection data collection conditions. Information may be stored as incidental information, and a mathematical formula suitable for calculating the F-kV / F-mAs line may be automatically selected from these mathematical formulas by automatically determining the collection conditions.

  In the above-described embodiment, F-kV · F for calculating the F-kV · F-mAs line indicating the correspondence between the fluoroscopic tube voltage and the fluoroscopic mAs or the correspondence between the fluoroscopic tube voltage and the parameter affecting the fluoroscopic mAs. Although the -mAs line calculation unit 65 has described the case of calculating the F-kV / F-mAs line in the graph format as shown in FIG. 5, the present invention is not limited to this, and formulas, lookup tables, etc. The F-kV / F-mAs line according to the format may be calculated.

  Further, the parameter affecting the above-described fluoroscopic mAs may be any of fluoroscopic mAs, fluoroscopic tube current, and irradiation time (fluoroscopic pulse width). The imaging condition setting unit 67 sets the imaging tube voltage and imaging mAs in the imaging mode or the parameters related to imaging tube voltage and imaging mAs based on at least one of the parameters related to the imaging tube voltage or the imaging mAs. May be.

DESCRIPTION OF SYMBOLS 1 ... X-ray generation part 11 ... X-ray tube 12 ... X-ray aperture 2 ... X-ray detection part 21 ... Planar detector 22 ... Gate driver 23 ... Projection data generation part 231 ... Charge-voltage converter 232 ... A / D Converter 233 ... Parallel / serial converter 3 ... High voltage generator 31 ... X-ray controller 32 ... High voltage generator 4 ... Image data generator 5 ... Display unit 6 ... Irradiation condition setting unit 61 ... Pixel value calculator 62 ... Pixel value comparison unit 63 ... Basic data storage unit 64 ... Registered data storage unit 65 ... F-kV / F-mAs line calculation unit 66 ... Perspective condition setting unit 67 ... Imaging condition setting unit 7 ... Input unit 8 ... System control unit 100 ... X-ray fluoroscopic apparatus

Claims (6)

In the X-ray fluoroscopic imaging apparatus that sets the imaging conditions in the imaging mode based on the fluoroscopic conditions set in the fluoroscopic mode,
Fluoroscopy control means for controlling the tube current and the tube voltage of the X-ray tube in the fluoroscopic mode so that the fluoroscopic image data collected in the fluoroscopic mode has a predetermined luminance;
An X-ray fluoroscopic imaging apparatus comprising: an imaging control unit that controls imaging conditions in an imaging mode so that imaging in an imaging mode is performed at a tube voltage substantially equal to a tube voltage in the fluoroscopic mode. In the X-ray fluoroscopic imaging apparatus that sets the imaging condition of the imaging mode based on the fluoroscopic condition set in the fluoroscopic mode preceding the imaging mode,
Storage means for storing data indicating the relationship between the subject thickness and the fluoroscopic tube voltage;
Calculating means for calculating a correspondence relationship between the fluoroscopic tube voltage and the parameters affecting the fluoroscopic mAs based on the data;
Fluoroscopy condition setting means for setting parameters related to the fluoroscopic tube voltage and fluoroscopic mAs in the fluoroscopic mode based on the pixel value of the image data generated in the fluoroscopic mode and the calculation result of the calculation means;
X-ray comprising: an imaging condition setting means for setting an imaging tube voltage in an imaging mode and a parameter related to imaging mAs based on at least one of the fluoroscopic tube voltage and parameters related to the fluoroscopic mAs. Perspective imaging device.   A pixel value calculation unit that calculates a pixel value of image data generated in the perspective mode; and a pixel value comparison unit that compares the calculated pixel value with a predetermined threshold value, and the perspective condition setting unit includes: 3. The X-ray fluoroscopic imaging according to claim 2, wherein parameters relating to the fluoroscopic tube voltage and the fluoroscopic mAs in the fluoroscopic mode are set based on a comparison result between a pixel value and the threshold value and a calculation result of the calculation means. apparatus.   The pixel value calculation means calculates one of an average pixel value, a maximum pixel value, and a central pixel value of a region of interest set for image data generated in the perspective mode. The X-ray fluoroscopic apparatus according to 3.   The X-ray fluoroscopic imaging apparatus according to claim 2, wherein the imaging condition setting unit sets an imaging tube voltage substantially equal to the fluoroscopic tube voltage.   The X-ray fluoroscopic imaging apparatus according to claim 2, wherein the imaging condition setting unit sets the imaging mAs by multiplying a ratio of an imaging dose and a transmission dose registered in advance to the fluoroscopic mAs.

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