Method and computer system for scattered beam correction in a multi-source CT

Abstract

A method and a computer system (10) are disclosed for scattered beam correction in a CT examination of an object in a multi source CT. In at least one embodiment, the method includes generating original projection data records; reconstruction of the object (P) with the original projection data records of at least one detector (3,5); determining the scattered radiation generated by each emitter (2,4) exclusively in the direction of the original beams of the at least one other emitter relative to its opposing detector (3,5); generating corrected projection data records by removing the calculated scattered radiation from the original projection data records; reconstruction of the object (P) with the corrected projection data records, and implementing a further iteration of the method when determining the scattered radiation or issuing the reconstruction result if at least one predetermined abort criterion applies.

Description

technical field [0001] The invention relates to a method and a computer system for scattered beam correction during a CT examination of an object in multi-source CT, wherein the scattered beam correction is carried out iteratively on projection data. Background technique [0002] In dual-source CT, by using two radiator-detector systems simultaneously, the x-ray quanta are scattered at the object to be measured from the x-ray radiator of the first radiator-detector system to an angularly offset ground on the same gantry The detectors of the second radiator-detector system are arranged, and vice versa. These so-called lateral scatter must be corrected by suitable methods in order to avoid artifacts. For this, it is necessary to identify the profile of the scattered beam intensity in each projection. [0003] The following three methods are basically known for this purpose: [0004] (i) Model-based estimation of the scatter from the sinogram data on the basis of the tempora...

AI Technical Summary

Problems solved by technology

This leads to a gradual loss of agreement between the measured scattered beam profile and the necessary data corrections as the z-coverage of the detector increases

[0010] A third method (iii) that alternately blanks the corresponding raw radiance and directly measures the lateral scatter during the blanking phase (iii) While there may be no lack of agreement in the data in the z direction, the data here cannot be arbitrarily finely tuned in the angular direction scanning, which leads to corresponding aliasing errors in the scatter data as well as in the starting data

Additionally, image noise is increased by blanking the raw radiation

Also, the dose efficiency becomes lower, since in practice the ON and OFF phases of the radiator cannot be arbitrarily short

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