Technical Note: Evaluation of kV CBCT enhancement using a liver-specific contrast agent for stereotactic body radiation therapy image guidance

John D. Lincoln, David Parsons, Sharon E. Clarke, Slawa Cwajna, James L. Robar

Research output: Contribution to journalArticlepeer-review

Abstract

Purpose: To evaluate possible use for cone-beam computed tomography (CBCT) guidance, this phantom study evaluated the contrast enhancement provided by Gadoxetate Disodium (Primovist® CAN/EU, or Eovist® USA, Bayer Healthcare, Leverkusen, Germany), a contrast agent that is taken up selectively by liver cells and is retained for up to an hour. Image quality from CBCT was benchmarked against helical fan-beam computed tomography for two phantom geometries. Methods and Materials: Concentrations were diluted to 0.0125–0.1 mmol per kilogram of body weight (mmol/kg) corresponding to expected physiological concentrations in the liver. Kilovoltage CBCT imaging parameters of x-ray tube potential, current, and filtration were investigated using clinically available options on a TrueBeam STx linear accelerator CBCT platform. Two phantoms were created, a cylindrical idealized imaging geometry and an ellipsoidal more realistic abdominal geometry. All parameters were optimized according to the contrast-to-noise ratio (CNR) image quality metric, as a function of concentration, following the Rose criterion for CNR. Results: Acceptable CNR was defined as greater than or equal to three, in accordance with the Rose criterion for CNR. These were found in a range of expected liver concentrations of 0.025–0.1 mmol/kg for a tube potential of 100 kVp, half-fan bowtie filtration and tube currents giving exposures between 2025 and 5085 mAs. Linear correlations were found for all CNR as a function of concentration, in agreement with the literature. Conclusion: Based on this phantom study, with appropriate selection of imaging protocol, Gadoxetate Disodium may provide useful liver CBCT enhancement at physiologically achievable liver concentrations.

Original languageEnglish (US)
Pages (from-to)1175-1181
Number of pages7
JournalMedical physics
Volume46
Issue number3
DOIs
StatePublished - Mar 2019

Keywords

  • Cone-beam CT
  • Gadoxetate Disodium
  • Liver SBRT

ASJC Scopus subject areas

  • Biophysics
  • Radiology Nuclear Medicine and imaging

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