Accuracy of spectral curves at different phantom sizes and iodine concentrations using dual-source dual-energy computed tomography

Kazuhiro Sato, Ryota Kageyama, Yuta Sawatani, Hirokazu Takano, Shingo Kayano, Yumi Takane, Haruo Saito

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


To validate the accuracy of spectral curves obtained by an image-data-based algorithm and clarify the error factors that reduce accuracy. Iodine rods of known composition and different concentrations were inserted into a cylinder or elliptic-cylinder phantom and scanned according to the dual-energy protocol. Spectral curves were obtained by (i) theoretical calculation, (ii) image-data-based 2-material decomposition, and (iii) using a dedicated workstation. Accuracy was verified by comparing the spectral curve obtained by theoretical calculations with those obtained by the image-data-based algorithms or the dedicated workstations. For a quantitative evaluation, the error and relative error (RE) were calculated. In the image-data-based calculation, the errors with respect to the theoretical CT number ranged from − 8.3 to 71.1 HU. For all 192 combinations, 80.7% of the errors were under ± 15 HU, and 97.9% of the REs were under 10%. In the dedicated workstation, the errors ranged from − 94.7 to 26.8 HU. For all combinations, 68.8% of the errors were under ± 15 HU, and 68.2% of the REs were under 10%. By appropriately setting the effective energy corresponding to the CT number of the basis materials, an accurate spectral curve can be obtained. The beam-hardening effect is canceled by the 2-material decomposition process even without beam-hardening correction. Accuracy is primarily reduced by scattered radiation rather than the beam-hardening effect.

Original languageEnglish
Pages (from-to)103-116
Number of pages14
JournalPhysical and Engineering Sciences in Medicine
Issue number1
Publication statusPublished - 2021 Mar


  • Computed tomography
  • Dual-energy computed tomography
  • Dual-source computed tomography
  • Monoenergetic image
  • Spectral curve

ASJC Scopus subject areas

  • Biotechnology
  • Radiological and Ultrasound Technology
  • Biophysics
  • Biomedical Engineering
  • Instrumentation
  • Radiology Nuclear Medicine and imaging


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