Bernard J. Cosman, MS

Historical Figure (1914-1993)

Bernard J. Cosman is the inventor of the first radiofrequency generator used in medicine, and the founder of Radionics, Inc., the world leader in RF medicine until its sale in 2000. In the early 1950s, he worked with Dr. William H. Sweet, MD, Chief of Neurosurgery at the Massachusetts General Hospital (MGH) to develop the RF generator for lesioning in the deep brain for the treatment of obsessive compulsive and other mood disorders. In 1952, he designed and built the first commercial RF lesion generator, the Radionics RFG-2. Mr. Cosman also developed the first impedance monitor for use with medical radiofrequency generators, the Radionics IM-1, and the first RF generator with a built-in nerve stimulation (Radionics RFG-3A). At Radionics, Mr. Cosman engineered numerous models of RF generators that were used by tens of thousands of physicians around the world. These generators include the RFG-2, RFG-3A, RFG-3AV, RFG-5, and RFG-6. Working with Drs. Sweet, Ballantine, Rosomoff, Tew, Shealy, Zervas, and his son, Professor Eric Cosman, Bernard Cosman also created numerous pioneering electrode systems for stereotactic and percutaneous techniques, notably for percutaneous cordotomy, trigeminal neuralgia, facet denervations, and hypophysectomy.

Bernard Cosman’s brilliant engineering talents led to frontier developments in many other areas of medicine. In 1937, after receiving his bachelors and masters degrees in Electrical Engineering from the Massachusetts Institute of Technology (MIT), he built the first accelerator based million volt x-ray generator for radiation treatment of cancer with MIT Professors John Trump and Robert Van de Graaff. It was the progenitor of the modern radiation generators of the linear accelerator type (LINACS).  In the 1940s through the 1960s, he designed the most popular high-frequency bipolar coagulators, a technology that is among the most common seen in today’s operating rooms.  During World War II, he was a leading scientist in the Ultrasonic Laboratory at MIT, developing submarine SONAR systems, work that involved some hazardous active testing in the Pacific theater. He was also a lead engineer at MIT’s Lincoln laboratory and in the Harvey Radio Laboratory, constructing the world’s most powerful radio transmitters. This work led to his development in 1950 of one of the first trackless ultrasonic lesion generators for neurosurgery with Dr. Thomas Ballantine at the MGH, a technology that is still very active today.


M.S. Electrical Engineering, Massachusetts Institute of Technology, 1937

B.S. Electrical Engineering, Massachusetts Institute of Technology, 1936


President and CEO, Radionics, Inc., 1938-1989

Invented dozens of RF generators, the first temperature measuring RF electrodes, and the first clinical impedance monitors, 1952-1985

Invented and produced the first clinical RF generator for neurological disorders, 1952

Engineering Consultant, MIT’s Lincoln laboratory and Harvey Radio Laboratory, 1945-1950

Senior Scientist in the Ultrasonics Laboratory at MIT, part of the team that invented SONAR for underwater submarine detection, involving some hazardous active testing in the Pacific theater of World War II, 1940-1945

Founded Radionics, Inc. (originally named Cosman & Co.) with early products including ultrasonic generators, x-ray photoelectric timers, broad band amplifiers, and pulsed oscillators, 1938

Built the first million-volt X-ray generator for radiation treatment of cancer at Harvard Medical School, 1937


  1. E. R. Cosman and B. J. Cosman. Radiofrequency Lesion Making in the Nervous System., from Wilkins and Rengachary (eds.) Neurosurgery, Second Edition, New York, NY: McGraw-Hill, 1996.
  2. E. R. Cosman and B. J. Cosman. Methods of Making Nervous System Lesions., in Neurosurgery , Vol. 3, pp. 2490-2499, edited by R. H. Wilkins and S. S. Rengachary, McGraw-Hill, 1984.
  3. E. R. Cosman, N. T. Zervas, P. H. Chapman, B. J. Cosman, and M. A. Arnold A Telemetric Pressure Sensor for Ventricular Shunt Systems., Surgical Neurology 1979; 11: 287-294.
  4. N. T. Zervas, E. R. Cosman, and B. J. Cosman. A Pressure-Balanced Radio-Telemetry System for the Measurement of Intracranial Pressure., Journal of Neurosurgery 1977; 47: 99-911.
  5. B. J. Cosman and E. R. Cosman. Guide to Radio Frequency Lesion Generation in Neurosurgery.  Burlington, MA: Radionics, 1974.
  6. B.J. Cosman and T. F. Hueter. Instrumentation for Ultrasonic Neurosurgery. ELECTRONICS, 1959, May issue: 53-57.
  7. Richard Dresser and Bernard J. Cosman, Million Volt Roentgen-Ray Protection. The American Journal of Roentgenology and Radium Therapy, 39, no.6, 1938.
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