JP2005287984A - X-ray ct apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the efficiency in the photography and diagnosis by reorganizing a tomographic image at an appropriate slicing position. <P>SOLUTION: First, in the cone-beam CT, simple photography is executed (e.g. in the front of the chest region). The CAD such as for extracting a tumor is executed for the image (the image may be a projection image at a specific projection angle) and a candidate region for the tumor, etc. is determined. Then, the total reorganization slicing positions are determined so that the slice pitch in the determined candidate region is finer. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a cone beam X-ray CT apparatus, and particularly to a cone beam X-ray CT apparatus that obtains a tomographic image efficiently.

  In a conventional X-ray CT apparatus, in order to determine which position tomographic image is reconstructed, for example, as disclosed in Japanese Patent No. 2829122, a slice region and a slice pitch are input and displayed on a scanogram. The method of confirming is performed.

  If the entire slice region is reconstructed by determining the slice position at a constant slice pitch as in the past, the number of tomographic images in the vicinity such as a tumor important for diagnosis will be insufficient.

  The slice position to be reconstructed should be reconstructed with a fine slice pitch for the region to be diagnosed in detail. However, if the entire slice region is reconstructed with the same fine slice pitch, the reconstruction time will be enormous, and the work required for the diagnosis by the diagnosing doctor will be increased.

  In the cone beam CT, first, simple imaging (for example, the front of the chest) is performed (a projection image at a specific projection angle may be used).

  CAD such as tumor extraction is performed on this image to determine a candidate area such as a tumor.

  The entire reconstructed slice position is determined so that the determined candidate area has a finer slice pitch.

  A tomographic image can be obtained efficiently by reconstructing at the reconstructed slice position determined in this way.

  The total number of slices is set to an appropriate number, and the tomographic image is reconstructed with a fine slice pitch in the region most desired to be diagnosed, so that highly accurate diagnosis can be performed efficiently.

[Example]
FIG. 1 is a schematic diagram showing the overall configuration of an example of an X-ray CT system according to the present invention.

  104. Controlled by the X-ray generator control unit 103. X-rays generated from the X-ray source are the subject. Through the patient 101. It is detected by an X-ray detector. The detected X-ray is used as a projection image. Input to the image input unit. This 103. An X-ray source and 101. X-ray detector is 102. Projection images are collected at every predetermined rotation angle while rotating around the patient as the center of rotation. Or 103. An X-ray source and 101. 102. A subject fixed to a rotary table while maintaining the positional relationship of the X-ray detector. The patient may be rotated.

  The input projection image at each rotation angle is 107. The image processing unit performs image processing such as pre-processing and reconstruction processing including correction of the X-ray detector and log conversion, and a tomographic image group is created. The generated tomographic image group is 109. Displayed on the diagnostic monitor 108. Stored in the image storage unit; 112. via the network Printer, 113. Diagnostic workstation, 114. Or output to an image database. Various operations such as a display window operation, a tomographic image switching display operation in a body axis direction, a cross-sectional conversion operation, and a three-dimensional surface display operation are performed in 110. Performed by the operation unit.

  FIG. 2 shows a flowchart of the processing flow of the embodiment that operates in such a system.

  In this embodiment, first, simple photographing is performed (201). This is because a plane sensor is used in the cone beam CT, and it is only necessary to take one still image with the plane sensor. Here, high speed is required for CT imaging, but this is not necessary for still images. Therefore, a more preferable still image can be obtained if the readout mode is taken as a high-definition image.

  In addition, a simple captured image may be used as a simple captured image without using a simple captured image.

  Next, candidate regions such as tumors are determined by CAD (Computer Aided Diagnosis) (202.). For example, a method disclosed in Japanese Patent Application Laid-Open No. 2003-000577 may be used as a method for determining a candidate region such as a tumor.

  When a candidate region such as a tumor is determined, a slice position to be reconstructed is determined based on the determined candidate region such as a tumor (203.).

  For this purpose, as shown in FIG. 3, the slice plane is set so that the candidate region such as a tumor has a fine slice pitch and the other regions have a coarse slice pitch. For this purpose, for example, the total number of slices to be reconstructed is determined in advance, and the overall reconstructed slice position is determined by determining the fine slice pitch and coarse slice pitch according to the ratio between the candidate region such as a tumor and other regions. You can do that.

  When the position of the slice plane to be reconstructed is determined in this way, the tomographic images at the respective slice positions are sequentially reconstructed (204.).

  The reconstructed tomographic image is provided to a doctor via a network or the like for diagnosis.

  As described above, efficient X-ray CT imaging and diagnosis can be realized.

Diagram showing an example system configuration Flow chart showing the flow of processing Conceptual diagram illustrating a method of determining a reconstructed slice position based on a CAD result

Claims (3)

First, a simple image is taken, a candidate area for diagnosis is determined for the captured simple image,
A cone beam X-ray CT apparatus that determines an entire reconstructed slice position so that the determined candidate area has a finer slice pitch than other areas, and reconstructs a tomographic image at that slice position.   The cone beam X-ray CT apparatus according to claim 1, wherein a projection image having a specific projection angle is used as a simple captured image.   The cone beam X-ray according to claim 1, wherein the total number of slices is determined in advance, and a fine slice pitch and a coarse slice pitch are determined according to a ratio between a candidate region to be diagnosed and other regions, and an entire reconstructed slice position is determined. CT device.

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