Niels A. Lassen
His father, H.C.A. Lassen, was professor at the University of Copenhagen, and Niels Lassen graduated as medical doctor from the same university in 1951. With his colleague Ole Munck he began in the 1950s to use radioactive isotopes for the measurement of the blood circulation in the brain, and in the beginning of the 1960s he together with David H. Ingvar from University of Lund began the development of methods for regional measurements on the brain with krypton-85 and xenon-133 isotopes. These efforts were summarized in a Scientific American article in 1978. Lassen has been called the greatest Danish brain researcher since Niels Steensen.
He was employed at the Bispebjerg Hospital from 1962 to 1996 and wrote more than 600 articles. He was married to Edda Sveinsdottir who as a computer scientist helped with the development of the (at that time) advanced computer technology for image construction of the regional brain measurements.
Niels Lassen Award
There is a Niels Lassen Award (Danish: "Niels A. Lassen Prisen").  The Danish medical doctor, brain researcher and "science entertainer" Peter Lund Madsen was a student of Niels A. Lassen, and Peter Lund Madsen received the Niels A. Lassen Award in 2002.
Previous recipients have included :
- 1999 - Matthias Endres, Mass. General Hospital, Harvard University, Boston, USA and the Exp. Neurology, Charite, Humboldt University, Berlin, Germany
- 2001- Sylvain Doré, Departments of Anesthesiology/Critical Care Medicine and Neuroscience, Johns Hopkins School of Medicine, Baltimore, Maryland, USA
- 2003 - Fahmeed Hyder, Department of Diagnostic Radiology, Yale University, New Haven, CT, USA
- 2005 – Kirsten Caesar, Department of Medical Physiology, Copenhagen University, Copenhagen, Denmark
- 2007 - Kazuhiko Hayashi, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
- 2009 - Alyson A. Miller, Monash University, Melbourne, Australia
- 2011 - Virginia Newcombe, University of Cambridge, Cambridge, UK
Lassen himself received the Novo Nordisk Prize in 1968, from the Novo Nordisk Foundation. and was the first recipient of the inaugural International Society for Cerebral Blood Flow and Metabolism (ISCBFM) Lifetime Achievement Award in 1997. 
- Niels A. Lassen, William A. Perl, Tracer kinetic methods in medical physiology, Raven, New York, 1979. ISBN 0-89004-114-8.
- Olaf B. Paulson, "Niels A. Lassen (1926-1997)", In Festskrift. Dansk Neurologisk Selskab 1900-2000, Jørgen Therkelsen(editor), Lægeforeningens forlag, Copenhagen, 2000.
- Lars Friberg, Albert Gjedde (September 1997). "In memoriam: Niels A. Lassen, 7 December 1926 - 30 April 1997". European Journal of Nuclear Medicine 24 (9): 1083–1084. doi:10.1007/BF01254237.
- Olaf B. Paulson (1997). "Niels A. Lassen, M.D., Ph.D.: 1926–1997". Journal of Cerebral Blood Flow & Metabolism 17: 1005–1006. doi:10.1097/00004647-199710000-00001.
- Niels A. Lassen, David H. Ingvar, Erik Skinhøj (October 1978). "Brain Function and Blood Flow". Scientific American 239 (4): 50–59. doi:10.1038/scientificamerican1078-62.
- The Niels Lassen Award
- "Niels A. Lassen Prisen 2002". Ugeskrift for Læger 165 (4): 354. 2003.
- The Novo Nordisk Prize
- The Lifetime Achievement Award