JP2005058309A5 - - Google Patents

Claims (3)

An X-ray source that irradiates the subject with X-rays, a two-dimensional X-ray detector that is disposed opposite to the X-ray source and obtains an X-ray fluoroscopic image of the subject, and these two-dimensional X-ray detectors and X-rays While rotating the radiation source on the circular orbital plane having the same rotation center, an X-ray fluoroscopic image of the subject arranged on the rotation center axis is obtained by the two-dimensional detector, and the obtained X-ray fluoroscopic image is used as a basis. to by the three-dimensional X-ray CT images performing image reconstruction operation, the cone beam X-ray CT apparatus having a display means for displaying the three-dimensional X-ray CT images are an image reconstruction image reconstruction means , the rotation center axis of the rotational movement, the error including the rotation start angle and the rotational speed of the rotary movement is calculated using the reconstructed image of the phantom including a plurality of wires which substantially arranged in parallel to said rotation axis an error calculation unit, wherein using the computed error three-dimensional X-ray Cone-beam X-ray CT apparatus characterized by comprising a correction means for correcting the T image. The error calculation means calculates an error corresponding to the first rotation angle range and an error corresponding to the second rotation angle range,
  The correction means corrects the three-dimensional CT image in the first rotation angle range using the corresponding error,
  Correcting the three-dimensional CT image of the second rotation angle range using the corresponding error;
  A misregistration calculating means for calculating a misregistration between the corrected three-dimensional CT images of the first and second rotation angle ranges;
  Superimposition correction means for correcting the three-dimensional CT images in the first and second rotation angle ranges so as to overlap each other based on the calculated displacement;
The cone beam X-ray CT apparatus according to claim 1, comprising: A hole chart phantom is set in advance on the front surface of the two-dimensional X-ray detector, an X-ray fluoroscopic image of the hole chart phantom installed is photographed by the two-dimensional detector, and the subject of the photographed hole chart is taken. A coordinate torsion angle calculating means for calculating a coordinate torsion angle of a projection image of the secondary detector on an axis along the opposite axis direction of the rotation center axis,
  The cone beam X-ray CT apparatus according to claim 1, wherein the correction unit corrects the three-dimensional X-ray CT image using the calculated coordinate twist angle.