Dual-energy computed tomography imaging with megavoltage and kilovoltage X-ray spectra

Giavanna Jadick; Geneva Schlafly; Patrick J. La Rivière

doi:10.1117/1.JMI.11.2.023501

4 March 2024 Dual-energy computed tomography imaging with megavoltage and kilovoltage X-ray spectra

Giavanna Jadick, Geneva Schlafly, Patrick J. La Rivière

Author Affiliations +

Journal of Medical Imaging, Vol. 11, Issue 2, 023501 (March 2024). https://doi.org/10.1117/1.JMI.11.2.023501

Abstract

Purpose

Single-energy computed tomography (CT) often suffers from poor contrast yet remains critical for effective radiotherapy treatment. Modern therapy systems are often equipped with both megavoltage (MV) and kilovoltage (kV) X-ray sources and thus already possess hardware for dual-energy (DE) CT. There is unexplored potential for enhanced image contrast using MV-kV DE-CT in radiotherapy contexts.

Approach

A single-line integral toy model was designed for computing basis material signal-to-noise ratio (SNR) using estimation theory. Five dose-matched spectra (3 kV, 2 MV) and three variables were considered: spectral combination, spectral dose allocation, and object material composition. The single-line model was extended to a simulated CT acquisition of an anthropomorphic phantom with and without a metal implant. Basis material sinograms were computed and synthesized into virtual monoenergetic images (VMIs). MV-kV and kV-kV VMIs were compared with single-energy images.

Results

The 80 kV-140 kV pair typically yielded the best SNRs, but for bone thicknesses >8 cm, the detunedMV-80 kV pair surpassed it. Peak MV-kV SNR was achieved with ∼90% dose allocated to the MV spectrum. In CT simulations of the pelvis with a steel implant, MV-kV VMIs yielded a higher contrast-to-noise ratio (CNR) than single-energy CT and kV-kV DE-CT. Without steel, the MV-kV VMIs produced higher contrast but lower CNR than single-energy CT.

Conclusions

This work analyzes MV-kV DE-CT imaging and assesses its potential advantages. The technique may be used for metal artifact correction and generation of VMIs with higher native contrast than single-energy CT. Improved denoising is generally necessary for greater CNR without metal.

CC BY: © The Authors. Published by SPIE under a Creative Commons Attribution 4.0 International License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

Citation Download Citation

Giavanna Jadick, Geneva Schlafly, and Patrick J. La Rivière "Dual-energy computed tomography imaging with megavoltage and kilovoltage X-ray spectra," Journal of Medical Imaging 11(2), 023501 (4 March 2024). https://doi.org/10.1117/1.JMI.11.2.023501

Received: 26 June 2023; Accepted: 6 February 2024; Published: 4 March 2024

ACCESS THE FULL ARTICLE

JOURNAL ARTICLE
24 PAGES

DOWNLOAD PAPER SAVE TO MY LIBRARY

GET CITATION

KEYWORDS

Image quality

Signal to noise ratio

Bone

Computed tomography

X-ray computed tomography

Metals

Dual energy imaging

Purpose

Approach

Results

Conclusions

Show All Keywords

Keywords/Phrases

Search In:

Publication Years