During his medical physics career, Cunningham published over 70 peer-reviewed papers, book chapters, and conference proceedings, and is widely known for co-authoring The Physics of Radiology (1953) with Dr. Harold E. Johns. The final fourth edition (1983) remains a staple in medical physics education for medical physicists, technologists, and physicians. He is a pioneer in developing computational techniques for calculating absorbed dose from radiation beams, and computer software and algorithms he developed continue to be used in both commercial and open source treatment planning systems. Upon retirement from clinical medical physics in 1989, Cunningham became a consultant with Theratronics/MDS Nordion (Kanata, Ontario) until 1998 when he moved to Camrose Alberta.