Johan Thijssen is Emeritus Professor Medical Ultrasound Techniques and Senior Scientist at the Department of Radiology of the Radboud university medical center. He studied Technical Physics at the Delft University of Technology and Experimental Physics at the Radboud University Nijmegen. In 1969, he obtained his Ph.D. at the Medical Physics Department of the Radboud University on his thesis "Differential Luminance Sensitivity of the Human Visual System". In 1968 he took the position of Head of the Biophysics Laboratory of the Department of Ophthalmology, Radboud university medical center. As of 1995 he was appointed as Head of the Clinical Physics Laboratory, Department of Pediatrics of the Radboud university medical center. In 2001 he was appointed Professor in Medical Ultrasound Technology. On June 1, 2004 he formally retired from his Chair and he continued his scientific work as a senior scientist ever since that date.