Influence of Radiation Dose, Photon Energy, and Reconstruction Kernel on Rho/z Analysis in Spectral Computer Tomography: A Phantom Study

Overview

Journal In Vivo

Specialty Oncology

Date 2022 Mar 4

PMID 35241522

Authors

Vasiliki Chatzaraki

Alessandra Bolsi

Rahel A Kubik-Huch

Bernhard Schmidt

Antony John Lomax

Damien C Weber

Michael Thali

Tilo Niemann

Affiliations

Soon will be listed here.

Abstract

Background/aim: The effective atomic number (Z) and electron density relative to water (ρ or Rho) of elements can be derived in dual-energy computed tomography (DECT). The aim of this phantom study was to investigate the effect of different photon energies, radiation doses, and reconstruction kernels on Z and Rho measured in DECT.

Materials And Methods: An anthropomorphic head phantom including five probes of known composition was scanned under three tube-voltage combinations in DECT: Sn140/100 kV, 140/80 kV and Sn140/80 kV with incremented radiation doses. Raw data were reconstructed with four reconstruction kernels (I30, I40, I50, and I70). Rho and Z were measured for each probe for all possible combinations of scan and reconstruction parameters.

Results: DECT-based Rho and Z closely approached the reference values with a mean and maximum error of 1.7% and 6.8%, respectively. Rho was lower for 140/80 kV compared with Sn140/100 kV and Sn140/80 kV with differences being 0.009. Z differed among all tube voltages with the most prominent difference being 0.28 between 140/80 kV and Sn140/100 kV. Z was lower in I70 compared with those of I30 and I40 with a difference of 0.07. Varying radiation dose yielded a variation of 0.0002 in Rho and 0.03 in Z, both considered negligible in practice.

Conclusion: DECT comprises a feasible method for the extraction of material-specific information. Slight variations should be taken into account when different radiation doses, photon energies, and kernels are applied; however, they are considered small and in practice not crucial for an effective tissue differentiation.

Citing Articles

In vitro blood sample assessment: investigating correlation of laboratory hemoglobin and spectral properties of dual-energy CT measurements (ρ/Z).

Schulz B, Euler A, Schmid H, Kubik-Huch R, Thali M, Niemann T Eur Radiol. 2024; 34(12):7934-7943.

PMID: 38856781 PMC: 11557693. DOI: 10.1007/s00330-024-10820-6.

Assessment of Image Quality in Chest CT With Precision Matrix and Increased Framing Rate Using Single Source CT: A Phantom Study.

Mavridis S, El-Gedaily M, Kubik-Huch R, Knoth F, Leon J, Euler A In Vivo. 2023; 37(1):99-105.

PMID: 36593029 PMC: 9843783. DOI: 10.21873/invivo.13058.

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