Image reconstruction using multiple X-ray projections
First Claim
1. A method for reconstructing the image of an object using at least 2 single plane X-ray projections, the method comprising the steps of;
- a) substantially uniformly filling the object with an X-ray contrast agent;
b) irradiating said contrast agent-filled object with X-rays from at least two directions;
c) detecting said X-rays transmitted through said contrast agent-filled object to define at least two live X-ray projection absorbance profiles;
d) providing a first image to be corrected;
e) updating the image provided in step d) by setting the absorbance value to 0 for all picture elements having an absorbance below a preselected threshold value and by setting all other picture elements to the absorbance value corresponding to the concentration of the X-ray contrast agent within the object;
f) forward projecting the image obtained in step e) into said at least 2 planes of projection along said at least two directions to obtain X-ray absorbance profiles of said image to be corrected;
g) calculating the difference between the absorbance profiles of the object and of the image to be corrected;
h) correcting the image obtained in step e) using iterative reconstruction techniques;
i) repeating steps e) to h) until the difference between the current absorbance profiles and the object absorbance profiles is less than a selected value;
j) displaying the image.
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Abstract
A method for reconstructing two and three dimensional images of objects using X-ray image projections and iterative reconstruction techniques is provided. More specifically, the method provides an image of the object to be corrected. Two or more X-ray absorbance profiles of the image are obtained along two or more different projection directions. These profiles are compared with the corresponding absorbance profiles of the object substantially filled with an X-ray contrast agent and, based on this comparison, the image is corrected using the iterative reconstruction techniques. Before each iteration the pixels of the image are updated so that if the absorbance value of the pixel is below a preselected value then the pixel is set to 0, otherwise the pixel is set to the absorbance value corresponding to the concentration of the X-ray contrast agent within the object. The iteration stops when the difference between the absorbance profiles of the image and the object falls below a preselected value.
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Citations
19 Claims
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1. A method for reconstructing the image of an object using at least 2 single plane X-ray projections, the method comprising the steps of;
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a) substantially uniformly filling the object with an X-ray contrast agent;
b) irradiating said contrast agent-filled object with X-rays from at least two directions;
c) detecting said X-rays transmitted through said contrast agent-filled object to define at least two live X-ray projection absorbance profiles;
d) providing a first image to be corrected;
e) updating the image provided in step d) by setting the absorbance value to 0 for all picture elements having an absorbance below a preselected threshold value and by setting all other picture elements to the absorbance value corresponding to the concentration of the X-ray contrast agent within the object;
f) forward projecting the image obtained in step e) into said at least 2 planes of projection along said at least two directions to obtain X-ray absorbance profiles of said image to be corrected;
g) calculating the difference between the absorbance profiles of the object and of the image to be corrected;
h) correcting the image obtained in step e) using iterative reconstruction techniques;
i) repeating steps e) to h) until the difference between the current absorbance profiles and the object absorbance profiles is less than a selected value;
j) displaying the image. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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Specification