• University of Versailles - Saint Quentin en Yvelines, France, 1999
• Dublin Institute of Technology, Ireland, 2001
• Shahid Beheshti University, Tehran, Iran, 2003
• McMaster University, Hamilton, Canada, 2005
• Banaras Hindu University, Varanasi, India, 2006
• National Research Institute for Radiobiology and Radiohygiene, Budapest, Hungary, 2007
• Nuclear and Technological Institute, Lisbon, Portugal, 2008
• Institute of Radioprotection and Dosimetry, Rio de Janeiro, Brazil, 2009
• Escola Universitaria d'Enginyeria Technica Industrial de Barcelona, Spain, 2010
• Research Center for Radiation Medicine, Kiev, Ukraine, 2011