JP2008048817A - X-ray imaging diagnostic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an X-ray imaging diagnostic apparatus capable of detecting an X-ray aperture insertion position in a saturation range. <P>SOLUTION: The X-ray imaging diagnostic apparatus is equipped with a detecting part 6 of the X-ray aperture insertion position for detecting the X-ray aperture insertion position from image data output from an X-ray flat panel detector 3, a saturation range detecting part 7 for detecting the saturation range in the image data output from the detector 3, and an afterimage read-out control part 8 for controlling the detector 3 in a manner to output afterimage data under no X-ray irradiation when the saturation range is found in the image data by the detecting part 7. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an X-ray diagnostic imaging apparatus capable of detecting an X-ray stop insertion position in a saturation region.

  A conventional X-ray diagnostic imaging apparatus outputs an X-ray source that irradiates a subject with X-rays, an X-ray plane detector that outputs X-ray information transmitted through the subject as image data, and an X-ray plane detector. And a monitor for displaying image data. The image data output from the X-ray flat panel detector is displayed on a monitor after image processing such as display gradation conversion and edge enhancement filtering is performed so as to provide an image display suitable for diagnosis. Here, the processing is performed on the X-ray irradiation field region excluding the region not related to the diagnosis, such as an X-ray diaphragm, as the target region to be subjected to image processing for display on the monitor. Therefore, in order to perform optimal image processing, it is necessary to accurately grasp the X-ray aperture position inserted in the image.

As a technique for obtaining the insertion position of the X-ray diaphragm from the image data obtained from the X-ray flat panel detector, for example, in Patent Document 1, a two-dimensional detection unit that converts the intensity distribution of radiation transmitted through the subject into image data, Irradiation field area recognition means for recognizing a radiation field area from the image data obtained by the two-dimensional detection unit, and radiation exposure control from the radiation field area image data obtained by the irradiation field recognition means A region-of-interest recognition unit that recognizes a region of interest, a parameter determination unit that determines a parameter for radiation exposure control from image data of the region of interest obtained by the region-of-interest recognition unit, and a parameter determination unit Radiographic imaging, comprising: parameter transmission means for transmitting the measured parameters to a control unit that controls the X-ray generator Location is disclosed.
JP 2003-250789 A

  However, in the conventional technique described above, in an inspection target part with a large subject thickness, such as lumbar lateral imaging, for example, an irradiation X-ray higher than other inspection target parts in order to obtain an optimal density for the subject region in the captured image data. As a result, the X-ray dose directly incident on the X-ray flat panel detector in the area other than the subject becomes excessive, and the edge portion of the X-ray diaphragm to be detected is saturated with the output signal (saturation). This makes it impossible to detect the X-ray irradiation field area for optimal image processing.

  An object of the present invention is to provide an X-ray diagnostic imaging apparatus capable of detecting an X-ray stop insertion position in a saturation region.

  In order to achieve the above-mentioned target, an X-ray diagnostic imaging apparatus according to the present invention uses an X-ray source that irradiates a subject with X-rays and an X-ray information that is disposed opposite to the X-ray source and transmits the subject as image data. An X-ray plane detector for outputting, an image processing means for performing image processing on the image data output from the X-ray plane detector, and a display means for displaying the image data output from the image processing means In the X-ray diagnostic imaging apparatus, the X-ray diaphragm insertion position detecting means for detecting the X-ray diaphragm insertion position from the image data output from the X-ray flat panel detector, and the output from the X-ray flat panel detector Saturation region detection means for detecting a saturation region in image data, and afterimage data that does not irradiate X-rays to the X-ray flat panel detector based on the saturation region detected by the saturation region detection means In further comprising a residual image read control means for so that control.

  The present invention has an effect of providing an X-ray diagnostic imaging apparatus capable of detecting an X-ray diaphragm insertion position in a saturation region.

Embodiments of the X-ray image diagnostic apparatus of the present invention will be described below with reference to the drawings.
FIG. 1 is a schematic diagram showing a configuration example of an embodiment of an X-ray image diagnostic apparatus of the present invention.

  An X-ray image diagnostic apparatus according to an embodiment of the present invention includes an X-ray source 2 that irradiates a subject 1 with X-rays, an X-ray flat panel detector 3 that outputs X-ray information transmitted through the subject 1 as image data, and An image processing unit 4 that performs image processing on the image data output from the X-ray plane detector 3, a display unit 5 that displays image data output from the image processing unit 4, and the X-ray plane detection An X-ray diaphragm insertion position detector 6 for detecting an X-ray diaphragm insertion position from the image data output from the detector 3, and a saturation for detecting a saturation region in the image data output from the X-ray flat panel detector 3 Area detection unit 7 and afterimage reading that controls the saturation area detection unit 7 to output afterimage data that does not irradiate X-rays to the X-ray flat panel detector 3 when a saturation region exists in the image data Control unit 8 and afterimage read control unit 8 Thus, an afterimage data storage unit 9 for storing the read afterimage data, and an afterimage image X-ray aperture insertion position detection for detecting the X-ray aperture insertion position from the afterimage data stored in the afterimage data storage unit 9 Unit 10 and the X-ray aperture insertion position detected by the X-ray aperture insertion position detection unit 6 and the afterimage X-ray aperture insertion position detection unit 10 are combined and output from the X-ray plane detector 3 An X-ray diaphragm insertion position storage unit 11 that stores the X-ray diaphragm insertion position information of the image data.

Next, the operation of the X-ray image diagnostic apparatus of the present invention will be described.
X-rays irradiated from the X-ray source 2 pass through the subject 1 and are then output as image data by the X-ray flat panel detector 3. From the image data output from the X-ray plane detector 3, the X-ray diaphragm insertion position detection unit 6 detects the insertion position of the X-ray diaphragm in the image data. The detection of the insertion position of the X-ray diaphragm in the X-ray diaphragm insertion position detection unit 6 is performed by a generally known edge detection method in an image, for example, an edge detection filter using a secondary differential coefficient.

  FIG. 2 is a schematic diagram for detecting the X-ray aperture insertion position in the X-ray aperture insertion position detection unit 6. It is possible to detect the insertion position of each blade of the X-ray diaphragm indicated by a broken line in the figure by sequentially repeating the secondary differential calculation in accordance with the arrow directions 20 to 23 shown in FIG.

  At this time, the saturation region detection unit 7 detects the saturation region of the image data output from the X-ray flat panel detector 3 based on a preset threshold value, and is detected by the X-ray aperture insertion position detection unit 6. Compare with X-ray aperture insertion position. Note that the threshold for detecting the saturation region is set in advance based on the bit length of the output image data of the X-ray flat panel detector 3. For example, when the bit length of the image data output from the X-ray flat panel detector 3 is 14-bit data, 16,384 counts are set as a threshold value.

FIG. 3 is a schematic diagram showing a state of comparison between the saturation region and the X-ray aperture insertion position detected by the X-ray aperture insertion position detection unit 6 in the saturation region detection unit 7.
For example, the insertion position of the X-ray diaphragm having four blades detected by the X-ray diaphragm insertion position detection unit 6 is detected at 30 to 32 in FIG. 3, and only the X-ray diaphragm insertion position where the saturation region exists is detected. When not detected, the saturation region detection unit 7 controls the afterimage read control unit 8 to acquire afterimage data. The afterimage read control unit 8 controls afterimage data reading in a state where the X-ray flat panel detector 3 is not irradiated with X-rays, and the read afterimage data is stored in the afterimage data storage unit 9.

  It is known that when the X-ray flat panel detector 3 is irradiated with very intense X-rays, an afterimage component depending on the irradiated X-ray dose is superimposed on the next readout image data.

  Fig. 4 shows the measurement data (R. Weisfield et al., High performance amorphous silicon image sensor for x-ray diagnostic medical imaging application, Proc. SPIE Medical Imaging 1999) showing the afterimage component of the X-ray flat panel detector 3. is there. As shown in FIG. 4, since the afterimage component decreases with time, the signal level of the saturation region also decreases when the afterimage data is read out by being controlled by the afterimage read control unit 8. An afterimage X-ray aperture insertion position detection unit 10 detects an X-ray aperture insertion position from the afterimage data stored in the data storage unit 9. Regarding the detection method, the X-ray aperture insertion position is detected by the same method as the detection method by the X-ray aperture insertion position detection unit 6.

  The X-ray aperture insertion position storage unit 11 combines the detected X-ray aperture insertion positions in the X-ray aperture insertion position detection unit 6 and the afterimage X-ray aperture insertion position detection unit 10 to insert one X-ray aperture. Store as position information. In the image processing unit 4, an area obtained by removing the X-ray diaphragm insertion position from the image data output from the X-ray plane detector 3 based on the X-ray diaphragm insertion position information stored in the X-ray diaphragm insertion position storage unit 11. Are subjected to various image processing and displayed on the display unit 5.

  In the above description, the afterimage data read by the afterimage read control unit 8 has been described by taking the image dose area as an example. However, the X-ray flat panel detector 3 may be controlled so as to read only the saturation area.

  FIG. 5 is a schematic diagram for explaining the control for reading out only a part of the afterimage data from the X-ray flat panel detector 3 by the afterimage read control unit 8. When the saturation region S is determined by the saturation region detection unit 7, the afterimage detection region reading control unit 8 controls the X-ray flat panel detector 3 so as to read only the rectangular region surrounding the saturation region S as image data. As a result, afterimage data can be read from the X-ray flat panel detector 3 only for the saturation region, so that the time for reading afterimage data can be shortened. Here, as a rectangular area surrounding the saturation area S, in FIG. 5, for example, a circumscribed rectangular area of the saturation area S is set as an area for reading afterimage data, but the present invention is not limited to this and becomes a necessary rectangular area. It may be set in advance as follows.

  FIG. 6 is a schematic diagram showing afterimage data read from the X-ray flat panel detector 3 by the afterimage detection area reading control unit 8. The image profile in FIG. 6 shows a profile between afterimage data bb ′. According to the afterimage characteristics shown in FIG. 4, the value of each area of afterimage data read from the X-ray flat panel detector 3 depends on the X-ray dose incident on the X-ray flat panel detector 3, so A luminance difference is generated in the incident X-ray region, and the after-image X-ray stop position detection unit 10 can easily detect the X-ray stop.

  FIG. 7 is a schematic diagram showing an image profile of an X-ray diaphragm edge portion in lumbar lateral imaging. The image profile in FIG. 7 indicates a profile between the image data aa ′. As shown in Fig. 7, because the X-ray dose directly incident on the X-ray flat detector is excessive, saturation of the output signal may affect the edge part of the X-ray diaphragm, and sufficient detection cannot be performed. It was. This technical problem can be solved.

  In the above description, the X-ray aperture insertion position detection unit 6 that detects the X-ray aperture insertion position from the image data and the afterimage X-ray aperture insertion position detection unit 10 that detects the X-ray aperture insertion position from the afterimage data are separately provided. However, the X-ray aperture insertion position may be detected by the same means.

The schematic diagram which shows the structural example of this invention X-ray image diagnostic apparatus. 4 is a schematic diagram for detecting an X-ray aperture insertion position in an X-ray aperture insertion position detection unit 6. FIG. 6 is a schematic diagram showing a state of comparison between a saturation region and an X-ray aperture detection position detected by an X-ray aperture insertion position detection unit 6 in a saturation region detection unit 7. FIG. Measurement data indicating the afterimage component of the X-ray flat panel detector 3. FIG. 6 is a schematic diagram for explaining control for reading out only a part of afterimage data from the X-ray flat panel detector 3 by the afterimage read control unit 8. FIG. 4 is a schematic diagram showing afterimage data read from the X-ray flat panel detector 3 by the afterimage detection area reading control unit 8. The schematic diagram which shows the image profile of the X-ray aperture edge part in the lumbar side surface imaging | photography.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Subject, 2 X-ray source, 3 X-ray plane detector, 4 Image processing part, 5 Display part, 6 X-ray aperture insertion position detection part, 7 Saturation area detection part, 8 Afterimage reading control part, 9 Afterimage data storage 10, afterimage image X-ray aperture position detection unit, 11 X-ray aperture insertion position storage unit

Claims (4)

An X-ray source that irradiates the subject with X-rays;
An X-ray flat panel detector disposed opposite to the X-ray source and outputting X-ray information transmitted through the subject as image data;
An X-ray diagnostic imaging apparatus comprising: an image processing unit that performs image processing on the image data output from the X-ray flat panel detector; and a display unit that displays image data output from the image processing unit.
X-ray diaphragm insertion position detection means for detecting an X-ray diaphragm insertion position from the image data output from the X-ray flat panel detector;
Saturation region detecting means for detecting a saturation region in the image data output from the X-ray flat panel detector;
Afterimage image reading control means for controlling the X-ray flat panel detector to output afterimage data not irradiated with X-rays based on the saturation area detected by the saturation area detection means;
An X-ray diagnostic imaging apparatus comprising: Afterimage data storage means for storing the afterimage data read by the afterimage read control means;
An afterimage image X-ray stop insertion position detecting means for detecting the X-ray stop insertion position from the afterimage data stored in the afterimage data storage means;
The X-ray aperture of the image data output from the X-ray plane detector by combining the X-ray aperture insertion positions detected by the X-ray aperture insertion position detecting means and the afterimage image X-ray aperture insertion position detecting means, respectively. X-ray aperture insertion position storage means stored as insertion position information;
The X-ray diagnostic imaging apparatus according to claim 1, further comprising:   The afterimage read-out control means does not read out the afterimage data from the X-ray flat panel detector when the saturation area detection means determines that there is no saturation area in the image data. The X-ray image diagnostic apparatus according to claim 1, wherein the X-ray image diagnosis apparatus controls a line plane detector.   The said afterimage image read-out control means controls the said X-ray flat panel detector so that only the saturation area | region of the said image data output from the said X-ray flat panel detector may be read. X-ray diagnostic imaging equipment.

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