Mr Tanaka is newly retired from Biosense Webster, a Johnson & Johnson company, where he most recently served as worldwide president.
Mr Tanaka has received a bachelor of science degree in mechanical engineering from Purdue University and an MBA from Illinois Benedictine College.
Fred Robertson, CEO of TomoTherapy, said: “We welcome Roy to our board and look forward to tapping into his experience leading a game-changing medical device company. Roy also brings varied skills and knowledge from numerous leadership positions in operations and engineering. His experience will be a great addition to our board.”