The doctoral dissertations of the former Helsinki University of Technology (TKK) and Aalto University Schools of Technology (CHEM, ELEC, ENG, SCI) published in electronic format are available in the electronic publications archive of Aalto University - Aaltodoc.
Aalto

Models and Methods for Computational Electromagnetic Dosimetry

Sami Ilvonen

Dissertation for the degree of Doctor of Science in Technology to be presented with due permission of the Faculty of Electronics, Communications and Automation for public examination and debate in Auditorium S4 at Helsinki University of Technology (Espoo, Finland) on the 10th of September, 2009, at 12 noon.

Overview in PDF format (ISBN 978-952-248-009-5)   [352 KB]
Dissertation is also available in print (ISBN 978-952-248-008-8)

Abstract

The interaction between electromagnetic fields and the human body is a very complicated issue. In most cases it is not possible to measure accurately the electrical response of the human body to external sources. Because of this computational methods are used as an aid when determining the safety levels for human exposure to electromagnetic fields.

In this thesis the field distribution caused by various sources is determined in different parts of the human body using detailed and anatomically correct human body models and computational methods. Both the distribution of electric currents induced by low-frequency magnetic fields and the absorption of radio-frequency fields are studied. The accuracy and reliability of the models and methods used is verified by comparing the acquired results to known closed-form solutions and calibration measurements.

The obtained results can be utilised in the reliability analysis of computational methods used in electromagnetic dosimetry. Furthermore, some of the results are needed, for example, in the safety guidelines of medical personnel working close to magnetic resonance imaging scanners.

This thesis consists of an overview and of the following 6 publications:

  1. Sami Ilvonen, Ari-Pekka Sihvonen, Kimmo Kärkkäinen, and Jukka Sarvas. 2005. Numerical assessment of induced ELF currents in the human head due to the battery current of a digital mobile phone. Bioelectromagnetics, volume 26, number 8, pages 648-656.
  2. Sami Ilvonen and Jukka Sarvas. 2007. Magnetic-field-induced ELF currents in a human body by the use of a GSM phone. IEEE Transactions on Electromagnetic Compatibility, volume 49, number 2, pages 294-301. © 2007 IEEE. By permission.
  3. Ilkka Laakso, Sami Ilvonen, and Tero Uusitupa. 2007. Performance of convolutional PML absorbing boundary conditions in finite-difference time-domain SAR calculations. Physics in Medicine and Biology, volume 52, number 23, pages 7183-7192.
  4. T. M. Uusitupa, S. A. Ilvonen, I. M. Laakso, and K. I. Nikoskinen. 2008. The effect of finite-difference time-domain resolution and power-loss computation method on SAR values in plane-wave exposure of Zubal phantom. Physics in Medicine and Biology, volume 53, number 2, pages 445-452.
  5. Sami Ilvonen, Tommi Toivonen, Tim Toivo, Tero Uusitupa, and Ilkka Laakso. 2008. Numerical specific absorption rate analysis and measurement of a small indoor base station antenna. Microwave and Optical Technology Letters, volume 50, number 10, pages 2516-2521.
  6. Sami Ilvonen and Ilkka Laakso. 2009. Computational estimation of magnetically induced electric fields in a rotating head. Physics in Medicine and Biology, volume 54, number 2, pages 341-351.

Keywords: computational dosimetry, low-frequency magnetic fields, specific absorption rate

This publication is copyrighted. You may download, display and print it for Your own personal use. Commercial use is prohibited.

© 2009 Helsinki University of Technology

Last update 2011-05-26