Improving Structure Delineation for Radiation Therapy Planning Using Dual-Energy CT

George Noid, Justin Zhu, An Tai, Nilesh Mistry, Diane Schott, Douglas Prah, Eric Paulson, Christopher Schultz, X. Allen Li

Research output: Contribution to journalArticlepeer-review

Abstract

Purpose: We present the advantages of using dual-energy CT (DECT) for radiation therapy (RT) planning based on our clinical experience. Methods: DECT data acquired for 20 representative patients of different tumor sites and/or clinical situations with dual-source simultaneous scanning (Drive, Siemens) and single-source sequential scanning (Definition, Siemens) using 80 and 140-kVp X-ray beams were analyzed. The data were used to derive iodine maps, fat maps, and mono-energetic images (MEIs) from 40 to 190 keV to exploit the energy dependence of X-ray attenuation. The advantages of using these DECT-derived images for RT planning were investigated. Results: When comparing 40 keV MEIs to conventional 120-kVp CT, soft tissue contrast between the duodenum and pancreatic head was enhanced by a factor of 2.8. For a cholangiocarcinoma patient, contrast between tumor and surrounding tissue was increased by 96 HU and contrast-to-noise ratio was increased by up to 60% for 40 keV MEIs compared to conventional CT. Simultaneous dual-source DECT also preserved spatial resolution in comparison to sequential DECT as evidenced by the identification of vasculature in a pancreas patient. Volume of artifacts for five patients with titanium implants was reduced by over 95% for 190 keV MEIs compared to 120-kVp CT images. A 367-cm3 region of photon starvation was identified by low CT numbers in the soft tissue of a mantle patient in a conventional CT scan but was eliminated in a 190 keV MEI. Fat maps enhanced image contrast as demonstrated by a meningioma patient. Conclusion: The use of DECT for RT simulation offers clinically meaningful advantages through improved simulation workflow and enhanced structure delineation for RT planning.

Original languageEnglish (US)
Article number1694
JournalFrontiers in Oncology
Volume10
DOIs
StatePublished - Aug 28 2020

Keywords

  • dual-energy CT
  • image contrast
  • metal artifacts
  • mono-energetic image
  • motion artifacts
  • photon starvation
  • radiation oncology
  • radiation therapy

ASJC Scopus subject areas

  • Oncology
  • Cancer Research

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