Memorial Resolution: Clarence J. Karzmark
Clarence J. Karzmark
Physicist Clarence J. Karzmark, Professor Emeritus of Radiation Oncology, known to most as "Karz" or simply "CJ", passed away on January 16, 2005. He died peacefully in a Menlo Park care facility, close to his home for 45 years in Palo Alto.
Karz was born July 4, 1920 in Casselton, North Dakota. He grew up near Fargo, and attended the University of North Dakota in Grand Forks where he majored in physics and electrical engineering, with emphasis on microwaves and RF technology. (A C.J. Karzmark scholarship has been endowed there for physics and electrical engineering students "of high moral character and high academic achievement".) While serving in the United States Air Force and during graduate school from 1942 - 1945, he worked in the burgeoning field of radar development. In 1952 he earned a Ph.D. in Nuclear Physics at the University of Indiana. One of his publications from this work was referenced in the landmark Nobel Laureate acceptance speech by Luis W. Alvarez in 1968.
Karz's background made him a natural to join the pioneering team developing a linear accelerator for high energy X-ray (6 MV) cancer treatment at Stanford Lane Hospital. The year was 1954, when the Stanford Lane Hospital was still in San Francisco. This groundbreaking medical linear accelerator, the first in the U.S., was dubbed LA-1 and was commissioned in 1956. This device pioneered the way for modern radiotherapy with its greatly improved dose deposition, localization and accuracy. In 1958, in recognition that physics research and support were vital to the radiation therapy mission, the late Henry S. Kaplan, M.D., Chairman of Radiology, established a Radiologic Physics Section in the Department of Radiology, with the late Mitch Weissbluth, Ph.D. as Head. In 1959, the Stanford School of Medicine moved to its present location on the campus in Palo Alto and Mitch Weissbluth transferred his activities to the Department of Applied Physics. Karz then became Head of the Radiologic Physics Section, remaining so until 1980, when Peter Fessenden, Ph.D. took over that responsibility. Karz continued to be actively involved with Stanford Radiologic Physics activities until his retirement in 1988, after 33 years of service to the University. The LA-1 medical linear accelerator retired well before Karz did, and now resides in the Smithsonian Museum. A successor to LA-1, the Clinac-10 developed by Karz in collaboration with Varian Associates, was the first commercial linear accelerator (linac) in the U.S. to have both clinical X-ray and electron beam capabilities.
Even after retirement, Karz retained an interest in radiation physics and medical linear accelerators. In 1993, he co-authored the reference text Medical Electron Accelerators (McGraw-Hill) with Eiji Tanabe and the late Craig Noonan. He was also co-author with Bob Morton of a text directed at radiation oncologists and technologists entitled A Primer on the Theory of Radiation Accelerators in Radiation Therapy (Medical Physics Publishing, 1998). Both of these texts remain important references today.
Karz made many seminal contributions to the technical advances of radiation oncology, particularly in the realm of state-of-the-art equipment, treatment techniques, and radiation safety, and he was author or co-author of more than 100 publications. Karz was unwavering in his opinion that medical linear accelerators were the wave of the future and that they were practical and safe with proper physics support. He often challenged the stance of many radiation physicists and oncologists around the world who favored Cobalt-60 technology. Time has proved Karz to be right.
In close cooperation with clinical colleagues, especially Henry Kaplan and Malcolm A. Bagshaw, M.D., Karz and his group came up with a rigorous and successful dosimetry and treatment planning system for the treatment of Hodgkin's disease. This was well before the availability of computerized system aids to rapidly and accurately calculate dose at multiple points in large radiation fields such as the "mantle", used to treat lymphoma. The Stanford technique used a system of boosts and carefully blocked fields to achieve a near uniform dose throughout the mantle. This was extremely successful and subsequently served as a model for most other treatment facilities around the world. This physics development played a key role in the tremendous advance in the clinical outcomes of Hodgkin's disease treatment at Stanford in the 60s and 70s led by the team of Henry Kaplan and oncologist Saul A. Rosenberg, M.D.
Another of Karz's major accomplishments was developing, with his physics and clinical colleagues, a very successful treatment for the aggressive skin lymphoma called mycosis fungoides. Supported by funding from University Trustee President Lloyd W. Dinkelspiel, a unique setup was devised to literally bathe the entire skin surface in low-energy electrons. This technique, devised originally for LA-1, is used today with minor modifications around the world on a variety of medical linear accelerators. It is still referred to as the 'Stanford technique".
Karz vigorously promoted the development of dedicated simulators as part of the radiation therapy treatment planning process. Simulators, distinct from treatment linacs, incorporate all the geometric parameters of the linac, but employ a diagnostic quality rather than a high-energy beam. Thus, while previously the linac had to be used to accomplish a lengthy radiation field design and setup, the simulator allowed an accurate setup to be done independently, freeing up the linac exclusively for treatment. Karz's team efforts resulted in one of the first dedicated simulators (soon thereafter three, one for each of the then three Stanford medical linacs) in the United States. Later, companies began to manufacture simulators and their use became the norm in quality radiation therapy. Today's reliance on accurate computed tomographic simulation is a result of ideas promoted and developed by physicists such as Karz.
When early linacs were installed in hospitals, the radiation shielding data necessary for their safe operation at higher energies were grossly insufficient. Karz and colleagues enlisted a physics workout program (pun intended) by hauling blocks of concrete, lead and steel into the linac beam path to measure narrow- and broad- beam transmission and scatter data. These data became the standard ICRP (International Commission of Radiation Protection) linac shielding data for many years. This played an important role in the advance of radiation therapy for the treatment of cancer.
Karz was a stickler for safety and compulsive with respect to quality assurance. He and his group developed the idea for systematic linac preventive maintenance. The proximity of Stanford to the Varian Associates Radiation Division Facility offered new linac users, as well as Varian personnel, the opportunity to tour, and in some cases have prolonged visits in, the Stanford Radiation Therapy Department. Many adopted the preventive maintenance schedules that Karz oversaw.
One of the first programs for the training of physicists to enter clinical physics was at Stanford under Karz. (One of us, PF, gave up a tenured Physics Faculty position at another University to come to Stanford and train under Karz.) A unique aspect of Karz's "program" was to encourage linac engineers and even administrators to spend time in the facility learning about radiation oncology and the important role of physicists.
C. J. Karzmark was a major force in the American Association of Physicists in Medicine (AAPM) for many years. His activity and influence was most apparent when he served as the 14th AAPM President, 1972-1973, but he contributed in innumerable ways beyond those years. Karz's presidency, and his membership in various committees, was at a time of rapid expansion and development of medical physics in the United States. At that time, U.S. medical physicists had only the British journal Physics in Medicine and Biology in which to publish, and they demanded their own journal. Shortly after a landmark editorial in the AAPM Bulletin (Vol 6, #4, December 1972) addressing this need, co-authored by Karz and the United Kingdom Hospital Physics Association President John Mallard, the inaugural issue of the new journal Medical Physics was published by the AAPM in 1974. During his presidency he instituted the Council organization of the AAPM, by establishing the Science Council. A derivative of this Council organization remains today.
Karz's concept of the important role of physics in radiation oncology was sometimes met with resistance from medical colleagues. Karz, however, usually prevailed, due to his unwavering belief that quality radiation physics was prerequisite to quality radiation therapy. He commanded respect from oncologists in training because of his physics teaching. A generation of influential radiation oncologists, many of whom went on to become Department Chairs at other Universities, received their training in radiation physics from Karz. They appreciate the importance of their physics colleagues, because Karz drilled it into them!
Karz had a cheerful disposition and was easily approached for consultation, leadership and exchange of ideas. He liked to garden, he traveled widely, and explored a myriad of subjects. His curiosity served him well, and he strongly encouraged those around him to pursue their interests. He will be missed. Karz is survived by his four children, Peter, Kathleen, Sarah and Cameron, as well as three grandchildren. We close by mentioning it is our fortune that our lives and medical careers were intertwined with that of C. J. Karzmark, a true pioneer in the application of physics to the radiation treatment of cancer.
Committee: Richard T. Hoppe, M.D. Chair, Department of Radiation Oncology Peter Fessenden, Ph.D. Professor Emeritus, Radiation Oncology
