Before that he was a visiting professor at the Universidade Federal de Pernambuco in Recife, Brasil for two years, and was a scientist at the Radiation Internal Dose Information Center of Oak Ridge Institute for Science and Education for 15 years. He has a Bachelor of Science and a Master of Engineering degree in Environmental Engineering (Health Physics emphasis) from the University of Florida and received his PhD in Nuclear Engineering (Health Physics emphasis) from the University of Tennessee. He is a Certified Health Physicist (1988, recertified in 1992, 1996, 2000, and 2004). He is a member of the Health Physics Society, the Society of Nuclear Medicine, and the Sigma Xi scientific research societies and Tau Beta Pi engineering honors society.