Keywords:
Contrast agents, Radiation physics, Radioprotection / Radiation dose, CT, Contrast agent-intravenous, Dosimetry, Dosimetric comparison
Authors:
M. Mazloumi1, G. Van Gompel1, T. Van Cauteren1, P. D. Deak2, J. de Mey1, N. Buls1; 1Brussels/BE, 2Berlin/DE
DOI:
10.26044/ecr2019/C-2340
Aims and objectives
Intravenous iodinated contrast agents are high atomic number materials that enhance the image quality in CT imaging by increasing the image contrast.
Currently,
contrast agents are used in 60% of the CT scans [1].
Several studies have investigated the effect of contrast agents on the absorbed radiation dose in CT [1],
[2],
[3],
[4].
In a study,
increase in the absorbed doses were reported by considering the mass energy-absorption coefficients of blood and iodine and the photon energy spectrum of the CT tube [2].
More recent studies have shown increase in organ doses using Monte Carlo (MC) simulations on anthropomorphic [3] or XCAT phantoms [1].
Alternatively,
investigation on DNA level by looking at DNA double strand breaks (DSBs) have reported an increase in DNA DSBs for CT energy ranges (E < 150 keV [5]) in the presence of contrast agents [6],
[7],
[8],
[9].
These studies mostly use the protein biomarker γ-H2AX on lymphocytes to count the number of DNA DSBs before and after the exposure.
Although the increase in absorbed organ doses and DNA DSB are reported by several studies,
current dosimetry guidelines and CT scan protocols do not take the presence of contrast agents into account [1].
Therefore,
the aim of this study was to investigate the effect of contrast agent concentration on the absorbed radiation dose by experimental and numerical methods.
After the validation of a Monte Carlo dosimetry model,
we investigated the impact of iodine concentration on the absorbed dose in phantoms modeling the aorta.
Finally,
we reported the dose enhancement factors (DEFs) for different iodine concentrations,
representing the dose in the presence over the dose in the absence of iodine contrast agent.