5 July 2015
Question: How would you define your profession?
JC: Medical physics is an applied area of physics. Most medical physicists work in the physics of radiation oncology making sure that the desired dose is given to the cancer and the dose to normal tissues are minimized. Medical physicists work in cooperation with doctors. A few medical physicists devote their time to research and teaching. A few get involved with administrative duties. Many medical physicists take responsibility for radiation safety in their hospital.
Question: How and why did you go into Medical Physics/your profession? Why the switch from nuclear to medical physics?
JC: I found I liked practical applications of physics that are of benefit to society rather than basic research in nuclear physics. Nuclear physics is interesting but it is unlikely to help society. I am sure that I have been much more useful to society as a medical physicist. When I entered medical physics in 1958 there were fewer than 100 in the U.S. and I could see many opportunities to apply my knowledge of nuclear physics. I started the nuclear medicine laboratory at UW Hospitals in 1959 and trained radiology residents in the field. It was 1965 before they found a trained MD (doctor) to take over my role.
Question: In the beginning were you ever afraid of radiation? (I am aware you now believe that a moderate dose rate radiation is probably beneficial.)
JC: When I entered the field in July 1958 I believed what they told me about radiation risks. I spent much effort reducing the dose to patients in radiology. In 1970 I realized that there was negligible risk from x-rays but many radiographs had poor image quality so that the risk from a false negative was significant.
We developed simple test tools to optimize imaging parameters. No company was interested in our idea. The radiologists said quality control tools weren’t necessary as they would see any problem in the x-ray image. In 1974 I started the nonprofit Radiation Measurements Inc (RMI) to manufacture and sell these QC test tools. The profits and my salary from RMI were donated to the University to support medical physics research.
I am now almost certain that we need more radiation for better health. See my article on longevity as a measure of health effects of radiation. It is in the October 2003 issue of Radiology. (Longevity Is the Most Appropriate Measure of Health Effects of Radiation. Radiology, October 1, 2003; 229(1):14-15)
Ed: See John Cameron’s paper on benefits of low dose radiation and another article, Is radiation an Essential Trace Energy
Question: What do you find professionally satisfying about your profession? (What do you like about your career/profession?)
JC: I found collaborating with congenial doctors about problems that physicists could help solve was very satisfying. I also like educating anybody who would listen!
Question: Your first major discovery/major project – What was it, how was it, what happened after this?
JC: In 1959 I learned from Dr Lester Paul, Chair of Radiology at UW that there was no method to detect early osteoporosis. Many women were dying each year from broken hips. I invented bone densitometry in the early 1960s. It was of little interest at first because there was no known treatment. My invention was used to evaluate the different possible therapies. There are now over 50,000 bone densitometers in the world. I doubt if more than 50 radiologists in the world know who invented the instrument. I have received little recognition for this contribution.
I am not unhappy that my contribution was not recognized. I am sure it helped my career. Many of my graduate students received useful training doing their Ph.D. thesis on some related subject. I have the satisfaction of knowing I did something useful for society.
Question: What is your favourite discovery and why?
JC: In addition to bone densitometry I greatly enjoyed making thermoluminescent dosimetry (TLD) a useful technique. I didn’t invent TLD but together with my graduate students we made it a useful technique.
Question: Some memorable highlights and frustrations?
JC Highlights: I’ve touched several of the highlights. However, one of my ambitions in 1958 when I entered the field was to establish a department of medical physics in our medical school. I succeeded in 1981. I was the Chair of the first department of medical physics in a medical school in the U.S.
Many large hospitals have physics departments to do hospital work but not for training or research in medical physics. In the last 25 years, staff in medical physics has invented many useful instruments. The royalties paid to the Wisconsin Alumni Research Foundation on their patents are now over $35 million. I am pleased that our department at UW has been so successful. I deserve a little of the credit but Dr.John Juhl, Chair of Radiology from 1966 to about 1978 was a huge help. He always supported my initiatives.
JC Frustrations: There aren’t many and some will continue for many years. My main frustration is the fear of cancer from low dose radiation, even by radiologists. It is likely that we need more radiation to improve our longevity. In some cases radiation reduces the incidence of cancer. See my article in the October 2003 of Radiology.
Moderate radiation to British radiologists (1955-1979) greatly reduced their death rates from non-cancer and improved their longevity by about three years – that is the increase in longevity that would occur if no one died from cancer! (It is a worthy candidate for a Nobel Prize but I can’t even get the newspapers to mention it on a back page).
Question: In 1995 the Radiological Society of North America awarded the first Roentgen Centennial Commemorative Medal to you – how did you react to this? What does this mean to you?
JC: I was pleased to be chosen but I realized that many others are equally or more deserving. An example is Hal Anger, the inventor of the Gamma Camera. He has not gotten the recognition he deserves. I don’t display my plaques and honors. They are hidden behind a black curtain in my work room at home. I would gladly trade any honorary award for the chance to give a lecture to the ACR or RSNA. Too many radiologists still believe there is a risk from a chest x-ray. Few radiologists can explain radiation to the patient in words the patient can understand. I am pleased that I helped reduce this problem by promoting the BERT approach.
Ed: Find out more about the BERT approach in our Medical Physics section
Question: Public perception of this career? (I am aware that in the USA, the perception may be different)
JC: Since medical physicists are a small fraction of the population, it is understandable that the profession is not well known. In the U.S. it is a well paid profession. When I retired in 1986 my top salary had just reached $50,000/year. It was adequate for our needs. Many new medical physicists start at that salary. It doesn’t bother me.
Contributions of John Cameron/Philanthropy
My wife and I have managed to give away money to worthy projects. For example in 1985 we started Medical Physics Publishing (MPP) a nonprofit publisher. We gave over USD100,000 spread over ten years to establish MPP. Now it is doing well thanks to three competent women!
I have devoted much time and energy to helping medical physics in developing countries. I gave numerous QC courses in Spanish or Portuguese to students in Latin America. In October 1954 we returned from two years in Brazil where I did nuclear physics. In 1969 I started the ABFM- the Brazilian Medical Physics Association. I have enjoyed learning about other cultures and helping where I can.
Question: Comparison of the field today and where it was when you began?
JC: There are now over 5,000 medical physicists in the U.S more than 50 times the number in 1958. The growth of technology is such that it is not possible today for a nuclear physicist to switch into medical physics without training. The field is now much more technical. More training is needed to do the job.
With complex equipment medical physicists have to be well trained – otherwise and especially in radiation oncology (radiation therapy), death may be the outcome. I have seen this happen before where I was helping to train medical physicists in a developing country.
Question: Would you encourage people to take up this profession? What or how would you advise those who are contemplating taking up this profession?
JC: I would not encourage everyone to take up this profession. Not everyone is suited for any particular field. If someone is interested in medicine and also in physics and they like working with people and communicate well with others, I would strongly encourage them.
It is underpaid and not as satisfying in developing countries where the radiologists and radiation oncologists are not as aware for the need for good medical physicists to do good imaging and good radiation therapy.
Question: Future plans or what you would like to see in your profession – with regards to growth and development, recognition…
JC: I have long been convinced that medical physicists (and biomedical engineers) have useful roles to play in many clinical and basic science departments of medical schools. For example, there are very few physicists working in the research area I call the physics of physiology. Many Nobel Prizes are awaiting good research to understand and explain the many mysteries of our bodies, such as the basic mechanism of memory or imagination.
See my article: Cameron J.R. A proposed model of imagination and creativity Wisconsin Academy Review Vol. 34, No. 3 pp33-36 June 1988
I hope to expand on that article and change the title to “Origin of Ideas.” My model is analogous to our present understanding of the Origin of Species. In producing new species, “genetic noise” (i.e., mutations) provide the basic mechanism for a change.
Perhaps in 50 years they will refer to “Cameron’s Origin of Ideas”. The driving mechanism is “brain noise” (i.e., random action potentials which I call “subconscious imagination”) that produces new combinations of stored knowledge in our memory. Our subconscious mind monitors the results of any new combinations to see if any of them solve an old problem. Once a useful combination is recognized it is stored in the subconscious mind.
Einstein said he first thought of his relativity idea while riding his bicycle. I know many other examples. I still hope to find a biological scientist to test some of the basic ideas of my model of imagination and creativity.