Aggrey began his career as a Radiation Protection Officer with the Government of Kenya before moving to Kenyatta National Hospital as a Medical Physicist. He is currently the Chairman of Association of Medical Physicists of Kenya (AMPKen) and has been a part-time Lecturer at the Technical University of Kenya (TUK)

He holds a Bachelor of Science degree in Physics from the University of Nairobi Kenya, and Master of Science in Medical Physics from the University of Surrey, United Kingdom where he was awarded Hounsfield Prize for the best dissertation in Medical Physics program at the University of Surrey, UK

He received his Clinical training in Medical Physics from the Royal Surrey County Hospital and has been a fellow of Stellenbosch University, South Africa. He has attended several short trainings organized by the International Atomic Energy Agency (IAEA) in Kenya, South Africa, Algeria, Tunisia, Nigeria, Tanzania, Austria and USA

He serves on the Cancer Project Implementation team for Kenyatta National Hospital and sits on the Technical Advisory Committee of the National Cancer Institute. He is also a member of the Kenya Research Reactor Project team.