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In Memory

John Terrence Lett, 75, retired radiation biology professor, died Oct. 6

November 15, 2009

John Terrence Lett, 75, died on October 6, 2009, after residing for several days at the Lemay Health and Rehabilitation Center in Fort Collins.

John Lett was born Dec. 23, 1933, to John and Alice Lett in London, England, where he grew up and received his education. John received a Bachelor of Science degree in chemistry and graduated with first class honors from the University of London in 1956. He subsequently earned a Ph.D. in physical organic chemistry in 1960 from the same institution.

Started at CSU in 1968

For 10 years John held the position of Senior Lecturer at the Chester Beatty Research Institute at the Royal Cancer Hospital in London. In 1968, John immigrated to the United States to take the position of Professor of Radiation Biology at Colorado State University, where he taught classes and carried out research until his retirement. 

John's research focused on the ability of cells to repair their DNA after having been damaged by radiation, and he performed some of the definitive experiments that describe cellular repair after damage by accelerated heavy ions such as would accost astronauts in flight. In particular, he studied damage to the retina and the formation of cataracts after irradiation. His research with heavy ions and with radiation-sensitive cells has impacted the theories of cellular and tissue radiosensitivity and he published more than 100 articles in scientific journals.

Active scholar, researcher, mentor, and administrator 

During his tenure at CSU, John carried out a year of sabbatical research at Harvard Medical School and one year at the University of California at Berkeley. He also served for 6 years as Associate Director of NASA Specialized Center of Research and Training in Radiation Health in Consortium with the Lawrence Berkeley Laboratory, where the heavy ion experiments were carried out.

John served as editor of Advances in Radiation Biology for more than 20 years and also as editor of Radiation and Environmental Biophysics. He also served on several committees at CSU, very notably the committee for equal opportunity in student recruitment.

John was an extraordinary man in his intellect and his scientific ethics. These traits translated to his outstanding mentorship of graduate students, who admired him greatly, even after they had graduated and worked under other professors at other institutions. John treated his students with respect and had the ability to bring out the best in each one. He also engendered a sense of teamwork in his laboratory.

Student of history, music lover

John's knowledge extended to many subjects other than science. He was an ardent student of history, and knew, for example, the details of many battles of wars of the world and the history of many of the Native American Indian tribes. He was a lover of good music, whether it be classical, jazz, or popular, including the Beatles. He had an uncanny talent for learning languages, and picked up elements of German and Russian, even though he had no formal training in them.

John married Patricia Walker in England in 1956. She bore him a son, Mark, who survives him and lives in Northern England. He is also survived by two grandsons, Michael and Daniel. John leaves his dear friends, Ursula K. Ehmann and Ann B. Cox, his special care-givers Gloria and Carmen, who became part of his family, as well as his admiring and loyal students.

Celebration of life Dec. 9

A service in celebration of John's life will be held at 1 p.m. Dec. 9, 2009, at Foothills Unitarian Church, 1815 Yorktown Ave., Fort Collins. Following the service, a reception in John's honor will be held in the fellowship hall at the church.

Please go to to sign the online guestbook and share your own thoughts and memories of John.


Originally published in the Coloradoan, Nov. 15, 2009.