Method and system for spectral characterization in computed tomography x-ray microscopy system
AssigneeCarl Zeiss X-ray Microscopy, Inc.
InventorsZhifeng Huang, Thomas A. Case, Lourens B. Steger
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Abstract
A spectrum measurement and estimation method for tomographic reconstruction, beam hardening correction, dual-energy CT and system diagnosis, etc., comprises determining the spectra for combinations of source acceleration voltage, pre-filters and/or detectors and after measuring the transmission values of several pre-filters, calculating corrected spectra for the combinations of the source acceleration voltage, pre-filters and/or detectors.
Claims19
An x-ray source spectrum measurement and estimation method in an x-ray CT system, the method comprising:
- determining baseline spectra for x-rays emitted from an x-ray source of the x-ray CT system at different combinations of at least one x-ray acceleration voltage, more than one filter and at least one detector;
- during operation of the x-ray CT system, monitoring the x-rays to determine changes to the x-ray source spectrum;
- and
- in response to determining that the x-ray source spectrum has changed, calculating new baseline spectra based upon measuring transmission values of at least one or more filters by creating an estimated corrected spectrum for an air filter using the measured transmission values of at least 2 or 3 filters and calculating the new baseline spectra from the estimated corrected spectrum for the air filter.
An x-ray source spectrum measurement and estimation method in an x-ray CT system, the method comprising:
- determining baseline spectra for x-rays emitted from an x-ray source of the x-ray CT system at different combinations of at least one x-ray acceleration voltage, more than one filter and at least one detector;
- during operation of the x-ray CT system, monitoring the x-rays to determine changes to the x-ray source spectrum;
- and
- in response to determining that the x-ray source spectrum has changed, calculating new baseline spectra based upon measuring transmission values of at least one or more filters,
- wherein calculating the new baseline spectra comprises:
- identifying a combination of acceleration voltage and detector used to measure the transmission values of at least 2 or 3 filters;
- measuring a transmission value for an air filter at the identified acceleration voltage and detector combination;
- and
- creating a transmission curve using the transmission values for the air filter and for the at least 2 or 3 filters and creating an attenuation curve from the transmission curve.
An x-ray spectrum measurement and estimation method in an x-ray microscope system for applications such as tomographic reconstruction, beam hardening correction, multi (dual) energy computed tomography (CT) and x-ray microscope system diagnosis, the method comprising:
- determining spectra for combinations of x-ray source acceleration voltages, pre-filters and/or detectors;
- and
- before operation of the x-ray microscope, estimating or calculating spectra for the combinations of the source acceleration voltages, pre-filters and/or detectors from the measured transmission values by measuring transmission values for several pre-filters;
- and
- in response to determining that the x-ray source spectrum has changed during the operation of the x-ray microscope, calculating new baseline spectra based upon measuring transmission values of at least one or more filters by creating an estimated corrected spectrum for an air filter using the measured transmission values of at least 2 or 3 filters and calculating a new baseline spectra from the estimated corrected spectrum for the air filter.
A x-ray CT system, the system comprising:
- an x-ray imaging system comprising an x-ray source, filters, and a detector system;
- and
- a computer system for determining baseline spectra for x-rays emitted from the x-ray source at different combinations of at least one x-ray acceleration voltage of the x-ray source, more than one filter and at least one detector of the detector system, monitoring the x-rays to determine changes to the x-ray source spectrum, and in response to determining that the x-ray source spectrum have changed, calculating new baseline spectra by identifying a combination of acceleration voltage and detector used to measure the transmission values of at least 2 or 3 filters, measuring a transmission value for an air filter at the identified acceleration voltage and detector combination, and creating a transmission curve using the transmission values for the air filter and for the 2 or 3 filters and creating an attenuation curve from the transmission curve.
Dependencies are inferred from the claim text.