Back to results
US 7,623,617 B2Granted
Method for scattered radiation correction of a CT system having at least two focus/detector systems arranged with an angular offset, and a CT system
AssigneeSiemens Aktiengesellschaft
InventorStefan Popescu
Life of this patent
Estimating the term…
Abstract
A method is disclosed for scattered radiation detection and/or for scattered radiation correction. In at least one embodiment, each radiation produced is provided with an individual temporal marker/variation of known magnitude, the change in the measured radiation being investigated for these typical temporal variations, and the fraction of the scattered radiation is inferred from the temporal variation found and, if appropriate, a corresponding correction is carried out. Furthermore, a CT system is disclosed, including a computer program that carries out at least one embodiment of the method.
Claims22
A method for scattered radiation correction of a CT system including at least two simultaneously operated focus/detector systems arranged with an angular offset from one another on a rotatable gantry, each including one focus and one assigned detector to receive direct radiation of the focus, the method comprising:
- producing X-radiation in each of the at least two focus/detector systems in an X-ray tube by a tube current with a tube voltage;
- arranging the focus/detector systems to be angularly offset from one another, in order to scan an object with the aid of the X-radiation produced by virtue of the fact that the focus/detector systems rotate about a system axis of the CT system;
- determining absorption values, for a multiplicity of individual rays in space, from a measured ratio of measured radiation intensity to nonattenuated radiation intensity of the individual rays;
- subjecting the measured values to scattered radiation correction;
- and
- reconstructing at least one of CT pictures and CT volume data of the object, with the aid of the determined absorption values, radiation intensity of the emitted radiation of each focus/detector system being varied individually as a function of time by a mean value of greater than 50% of the maximum radiation intensity, and, in the respectively assigned detector, the scattered radiation fraction of other nonassigned focus/detector systems being determined by virtue of the fact that at least one of their individual temporal variation of the radiation intensity does not correspond to the assigned focus/detector system, their individual temporal variation of the radiation intensity corresponds to a nonassigned focus/detector system.
3 more elements
An X-ray CT system comprising:
- at least two focus/detector systems to produce X-radiation in each of the at least two focus/detector systems in an X-ray tube by a tube current with a tube voltage, the focus/detector systems being angularly offset from one another to scan an object with the aid of the X-radiation produced by virtue of the fact that the focus/detector systems rotate about a system axis of the CT system;
- and
- a control and arithmetic logic unit for producing tomographic pictures, the control and arithmetic logic unit containing program code, that when executed, carries out a method comprising:
- determining absorption values, for a multiplicity of individual rays in space, from a measured ratio of measured radiation intensity to nonattenuated radiation intensity of the individual rays,
- subjecting the measured values to scattered radiation correction, and
- reconstructing at least one of CT pictures and CT volume data of the object, with the aid of the determined absorption values, radiation intensity of the emitted radiation of each focus/detector system being varied individually as a function of time by a mean value of greater than 50% of the maximum radiation intensity, and, in the respectively assigned detector, the scattered radiation fraction of other nonassigned focus/detector systems being determined by virtue of the fact that at least one of their individual temporal variation of the radiation intensity does not correspond to the assigned focus/detector system, their individual temporal variation of the radiation intensity corresponds to a nonassigned focus/detector system.
3 more elements
An X-ray CT system comprising:
- at least two focus/detector systems to produce X-radiation in each of the at least two focus/detector systems in an X-ray tube by a tube current with a tube voltage, the focus/detector systems being angularly offset from one another to scan an object with the aid of the X-radiation produced by virtue of the fact that the focus/detector systems rotate about a system axis of the CT system;
- means for determining absorption values, for a multiplicity of individual rays in space, from a measured ratio of measured radiation intensity to nonattenuated radiation intensity of the individual rays;
- means for subjecting the measured values to scattered radiation correction;
- and
- means for reconstructing at least one of CT pictures and CT volume data of the object, with the aid of the determined absorption values, radiation intensity of the emitted radiation of each focus/detector system being varied individually as a function of time by a mean value of greater than 50% of the maximum radiation intensity, and, in the respectively assigned detector, the scattered radiation fraction of other nonassigned focus/detector systems being determined by virtue of the fact that at least one of their individual temporal variation of the radiation intensity does not correspond to the assigned focus/detector system, their individual temporal variation of the radiation intensity corresponds to a nonassigned focus/detector system.
2 more elements
Dependencies are inferred from the claim text.