Improvements in medical CT image reconstruction accuracy in the presence of metal objects by using x-rays up to 1 MeV

Clayton, James E.; Virshup, G. F.; Yang, Ming; Mohan, Radhe; Dong, Lei

doi:10.1117/12.817401

Cited by 1 publication

(1 citation statement)

References 23 publications

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“…The x-ray tube in the GE RT 16 CT scanner (GE Healthcare, Wauwatosa, Wisconsin) was simulated to generate the 100-kVp and 140-kVp beams. The compact linac made by Varian was simulated to generate the 1-MV beams with different filtrations (Clayton et al , 2009). …”

Section: Methodsmentioning

confidence: 99%

Does kV–MV dual-energy computed tomography have an advantage in determining proton stopping power ratios in patients?

Yang¹,

Virshup²,

Clayton³

et al. 2011

Phys. Med. Biol.

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The conventional kilovoltage (kV) x-ray-based dual-energy CT (DECT) imaging using two different x-ray energy spectra is sensitive to image noise and beam hardening effects. The purpose of this study was to evaluate the theoretical advantage of the DECT method for determining proton stopping power ratios (SPRs) using a combination of kV and megavoltage (MV) x-ray energies. We investigated three representative x-ray energy pairs: 100-kVp and 140-kVp comprised the kV-kV pair, 100-kVp and 1-MV comprised the kV-MV pair, and two 1-MV x-ray beams – one with and one without external filtration comprised the MV-MV pair. The SPRs of 34 human tissues were determined using the DECT method with these three x-ray energy pairs. Small perturbations were introduced into the CT numbers and x-ray spectra used for the DECT calculation to simulate the effects of random noise and beam hardening. An error propagation analysis was performed on the DECT calculation algorithm to investigate the propagation of CT number uncertainty to final SPR estimation and to suggest the best x-ray energy combination. We found that the DECT method using each of the three beam pairs achieved similar accuracy in determining the SPRs of human tissues in ideal conditions. However, when CT number uncertainties and artifacts such as imaging noise and beam hardening effects were considered, the kV-MV DECT improved the accuracy of SPR estimation substantially over the kV-kV or MV-MV DECT methods. Furthermore, our error propagation analysis showed that the combination of 100-kVp and 1-MV beams was close to the optimal selection when using the DECT method to determine SPRs. Overall, the kV-MV combination makes the DECT method more robust in resolving the effective atomic numbers for biological tissues than the traditional kV-kV DECT method.

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Section: Methodsmentioning

confidence: 99%