Computerized tomographic image exposure and reconstruction method
View Patent ↗A computerized tomographic image exposure and reconstruction method wherein an object is subjected to irradiation during a relative movement of a source of radiation, the object, and a radiation detector and wherein a digital representation of the radiation image of the object is computed by applying a tomographic reconstruction algorithm to image data read out of the irradiated radiation detector. A number of projection images are generated, each of the projection images being generated by integrating X-ray beams continuously emitted during the relative movement through a predefined movement path, and the created projection images are modeled in a tomographic reconstruction algorithm.
1. A computerized tomographic image exposure and reconstruction method, the method comprising the steps of:
subjecting an object to irradiation during a relative movement of a source of radiation, the object, and a radiation detector to obtain a radiation image;
computing a digital representation of the radiation image of the object by applying a tomographic reconstruction algorithm to image data detected by the radiation detector; and
generating a plurality of projection images by integrating X-ray beams continuously emitted during the relative movement through a predefined movement path; wherein
the plurality of projection images are modeled in a tomographic reconstruction algorithm.
2. The method according to claim 1 , wherein the radiation detector is a 2-dimensional flat panel detector arranged to capture the plurality of projection images.
3. The method according to claim 2 , wherein lines of the 2-dimensional flat panel detector are read out consecutively; and
a start position and an end position of the predefined movement path are taken into account when projections acquired in a line are reconstructed by the reconstruction algorithm.
4. The method according to claim 1 , wherein the modeling of the plurality of projection images in the tomographic reconstruction algorithm is performed by:
creating a projection geometry consisting of a set of intermediate projection positions for a continuous projection distributed over the predefined movement path; and
duplicating a value of the continuous projection for each intermediate projection position in the set of intermediate projection positions in the reconstruction algorithm.
5. The method according to claim 4 , wherein the reconstruction algorithm is an FBP algorithm implemented by applying the reconstruction algorithm to the duplicated continuous projections.
6. The method according to claim 1 , wherein the reconstruction algorithm is an iterative reconstruction algorithm including:
a forward tomographic projection obtained by combining the intermediate projection positions in the set of intermediate projection positions to create a forward continuous projection; and
a back projection obtained by distributing a projection difference image along the predefined movement path of each intermediate projection position in the set of intermediate projection positions.
7. The method according to claim 1 , wherein the relative movement is obtained by continuously rotating the source of radiation and the radiation detector around a fixed rotation center and the object is stationary.
8. The method according to claim 1 , wherein the relative movement is obtained by continuously rotating the source of radiation and the radiation detector around a moving rotation center and the object is stationary.
9. The method according to claim 1 , wherein the relative movement is obtained by continuously rotating the source of radiation relative to the radiation detector, and the radiation detector is stationary.
10. The method according to claim 1 , wherein the relative movement is obtained by a continuously rotating the source of radiation and moving the radiation detector.
11. The method according to claim 1 , wherein the relative movement of the radiation source and the radiation detector is non-linear.
12. The method according to claim 1 , wherein the relative movement of the radiation source and the radiation detector is non-circular.
13. The method according to claim 1 , wherein the object is rotating and a combination of the radiation source and the radiation detector is stationary.