Monte Carlo simulations used to calculate the energy deposited in the coronary artery lumen as a function of iodine concentration and photon energy

Abstract

Purpose: To better understand the risks of cumulative medical X-ray investigations and the possible causal role of contrast agent on the coronary artery wall, the correlation between iodinated contrast media and the increase of energy deposited in the coronary artery lumen as a function of iodine concentration and photon energy is investigated.

Materials and methods: The calculations of energy deposition have been performed using Monte Carlo (MC) simulation codes, namely PENetration and Energy LOss of Positrons and Electrons (PENELOPE) and Monte Carlo N-Particle eXtended (MCNPX). Exposure of a cylinder phantom, artery and a metal stent (AISI 316L) to several X-ray photon beams were simulated.

Results and discussion: For the energies used in cardiac imaging the energy deposited in the coronary artery lumen increases with the quantity of iodine. Monte Carlo calculations indicate a strong dependence of the energy enhancement factor (EEF) on photon energy and iodine concentration. The maximum value of EEF is equal to 25; this factor is showed for 83 keV and for 400 mg Iodine/mL. No significant impact of the stent is observed on the absorbed dose in the artery for incident X-ray beams with mean energies of 44, 48, 52 and 55 keV.

Conclusion: A strong correlation was shown between the increase in the concentration of iodine and the energy deposited in the coronary artery lumen for the energies used in cardiac imaging and over the energy range between 44 and 55 keV. The data provided by this study could be useful for creating new medical imaging protocols to obtain better diagnostic information with a lower level of radiation exposure.

Keywords:

• PENELOPE
• MCNPX
• coronary artery
• stent
• iodine concentration
• energy deposited

Disclosure statement

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.

Additional information

Notes on contributors

Nora Hocine

Nora Hocine, PhD, Engineer Researcher, conducting work using Monte Carlo codes applied to the radiation physics field, with a main focus on cellular dosimetry at the research dosimetry department of the French Institute for Radiological Protection and Nuclear Safety (IRSN) from 2001 till today. Lecturer in radiation physics and radiobiology at University Paris Descartes, France

Michel Meignan

Michel Meignan, MD, PhD, Emeritus Professor of Nuclear Medicine, LYSA Imaging, Henri Mondor Hospital, Paris Est University, Créteil, France; Full Professor of Nuclear Medicine and Biophysics (1990); Head of the Department of Nuclear Medicine (1997–2014); Head of the Department of Imaging, Function and Therapy (2006–2011), Henri Mondor Hospital, Créteil, France

Hélène Masset

Hélène Masset, PhD, Medical Physics, Radiation Protection Officer for workers at the radiotherapy department, Competent Person in statement sealed sources, unsealed generators. Medical Physicist for the Radiotherapy Department and the Nuclear Medicine Department from 2008 till today for French hospitals such as the Oncology Department of the Thiais Center, Henri Mondor Hospital and the Curie Institute.