Method and x-ray system for dual-energy spectra ct scanning and image reconstruction

Abstract

A method for dual-energy spectra CT scanning and image reconstruction of two tomographic image datasets from a higher-energy and a lower-energy x-ray energy spectrum is disclosed. In at least one embodiment, readings are taken with the different x-ray energy spectra during the scanning; the different x-ray energy spectra are also created at least by different acceleration voltages of the x-ray source; and the spatial distribution of the scanning x-rays per x-ray energy spectrum is undertaken randomly or pseudo-randomly (in the absence of a regular pattern). With the attenuation datasets thus obtained, reconstructions of two tomographic image datasets in accordance with a least one iterative CS reconstruction method are carried out and subsequently the reconstructed tomographic image datasets are stored and / or output and / or further processed.

Description

technical field [0001] The present invention relates to a method and X-ray system for dual energy spectral CT scanning and reconstruction of two tomographic image data sets from higher energy and lower energy X-ray spectral images. Background technique [0002] Various methods are known in the prior art for scanning an examination object with two or more different X-ray power spectra. [0003] In a first simple variant a single source X-ray system is used which performs successive scans of two objects in succession with different energy spectra, where each scan comprises at least half a cycle and in X-ray Set the respective additional accelerating voltages on the tubes. However, this method has proven to be problematic, especially when scanning patients, since spatial object movements can occur between scans and therefore a strict spatial correlation between the individually determined object data is no longer guaranteed. [0004] Dual-source X-ray systems are usually used...

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Problems solved by technology

The problem here is that, when the current of the x-ray tube is kept constant independently of the accelerating voltage, a distinctly different photon flow is formed depending on the accelerating voltage, so that correspondingly distinct signals are also produced in the image data calculated from it. noise ratio

[0014] In addition, for the professional concept "compressed sensing" in English, which currently does not have a well-established professional concept, the concept of direct translation "compressed scanning" is used, where it is noted that this is a literal translation, but does not correspond to English in a literal sense The professional concept of "compressed sensing"

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