Professor Isaacson works in two areas: mathematical physics and medical imaging. His work in mathematical physics has centered on the development of methods for approximating energy levels, particle masses, and critical exponents in quantum mechanics, quantum field theory, and statistical mechanics. His work in medical imaging has centered on the development of algorithms and devices for measuring and displaying the electrical state of the interior of a body from measurements made on the body's exterior. The long term goal of this research is to improve the diagnosis and treatment of heart disease and cancer.