Australasian Physical & Engineering Sciences in Medicine Volume 31 Number 2, 2008

THE SECOND JOHN CAMERON MEMORIAL LECTURE DELIVERED AT SEACOMP'07, MANILA, NOV 21-23, 2007

Medical Physics in 2020: Will we still be relevant? K. H. Ng Department of Biomedical Imaging and Medical Physics Unit, University of Malaya, Kuala Lumpur, Malaysia

Dedication To my mentor and friend, the late Professor John Cameron who had inspired me and also taught me great lessons in life.

Abstract From the time when Rentgen and other physicists made the discoveries which led to the development of radiology, radiotherapy and nuclear medicine, medical physicists have played a pivotal role in the development of new technologies that have revolutionized the way medicine is practiced today. Medical physicists have been transforming scientific advances in the research laboratories to improving the quality of life for patients; indeed innovations such as computed tomography, positron emission tomography and linear accelerators which collectively have improved the medical outcomes for millions of people. In order for radiation-delivery techniques to improve in targeting accuracy, optimal dose distribution and clinical outcome, convergence of imaging and therapy is the key. It is timely for these two specialties to work closer again. This can be achieved by means of cross-disciplinary research, common conferences and workshops, and collaboration in education and training for all. The current emphasis is on enhancing the specific skill development and competency of a medical physicist at the expense of their future roles and opportunities. This emphasis is largely driven by financial and political pressures for optimizing limited resources in health care. This has raised serious concern on the ability of the next generation of medical physicists to respond to new technologies. In addition in the background loom changes of tsunami proportion. The clearly defined boundaries between the different disciplines in medicine are increasingly blurred and those between diagnosis, therapy and management are also following suit. The use of radioactive particles to treat tumours using catheters, high-intensity focused ultrasound, electromagnetic wave ablation and photodynamic therapy are just some areas challenging the old paradigm. The uncertainty and turf battles will only explode further and medical physicists will not be spared. How would medical physicists fit into this changing scenario? We are in the midst of molecular revolution. Are we prepared to explore the newer technologies such as nanotechnology, drug discovery, pre-clinical imaging, optical imaging and biomedical informatics? How are our curricula adapting to the changing needs? We should remember the late Professor John Cameron who advocated imagination and creativity - these important attributes will make us still relevant in 2020 and beyond. To me the future is clear: "To achieve more, we should imagine together."

One of Professor Cameron’s contributions was to develop several non-invasive techniques to assess bone structure and bone mineral. This has resulted, in particular, in the development of the bone mineral densitometry that is currently used in the detection and monitoring of osteoporosis1. The bone mineral densitometer, has given us the opportunity to detect osteoporosis early and pave the way for early intervention and management of the disease. With increased clinical application, it can lead to a better quality of life for many women. This has tremendous implications in healthcare today. The World Health Organization (WHO) estimates that over the next 25 years the population aged 65 years and over will increase by 88%. The most striking changes during the next 50 years will be observed in the oldest age group (80 years and above), which is the one most affected by osteoporotic fractures About 40% of women aged 50

Key words

Medical physics, professional practice, education and training, medical imaging, radiotherapy

Introduction Professor John Cameron (1922-2005), Emeritus Professor of Medical Physics at the University of Wisconsin (UW)Madison, U.S.A. devoted considerable time, energy, and money to helping medical physicists throughout the world, particularly in developing countries in the Latin American and Asian regions. Corresponding author: Kwan-Hoong Ng, Department of Biomedical Imaging, University of Malaya, 50603 Kuala Lumpur, Malaysia, Email: [email protected] Received: 11 March 2008; Accepted: 7 May 2008 Copyright © 2008 ACPSEM

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years are predicted to sustain at least one fracture in the remainder of their lifetime, of whom 20% are expected to suffer from multiple fractures2. This statistic indicates that attention has to be given to the problem immediately. The scenario painted above is a good example of how a medical physicist has contributed to healthcare with the potential of health promotion and disease management. Medical physics and biomedical engineering have contributed to healthcare advancement in many other ways. Technological innovations include computed tomography (CT), positron emission tomography (PET), the compact linear accelerator, and many other developments, which collectively have improved the medical outcomes for millions of people. Among medical physicists, there is a belief that this is a noble profession that can transform scientific advances. There are members of the profession conducting fundamental work in the research laboratories, while others work in the hospitals – all working towards improving the quality of life for everyone. As defined by the American Association of Physicists in Medicine (AAPM)3, medical physics is a profession that specialises in the application of the concepts and methods of physics to the diagnosis and treatment of human diseases3. Medical physicists are working to bridge the gap between physics and medicine, serving as an interface between medical doctors, engineers and scientists. The roots of medical physics practice go back more than a hundred years, when Rentgen and other physicists made discoveries that led to new medical disciplines such as radiology, radiotherapy and nuclear medicine. Within these disciplines, new technologies were born, that have revolutionised the way medicine is practiced today. To understand the importance of these inventions, one only needs to imagine how hospitals today would function without an ultrasound scanner or a CT scanner. In the last 30 years, physicists have been working closely with radiation oncologists and have made fantastic progress in improving the accuracy of tumour irradiation and precise localisation and delivery of radiation, while minimising the damage to healthy tissue. This significant progress is a result of new gadgets like intensity modulated radiation therapy (IMRT) and image-guided radiation therapy (IGRT). However, despite all these technological and clinical innovations, however, radiation oncologists have observed that, in many cases, it is still not possible to control local tumour growth. Metastases still occur, forming secondary tumours. Professor Harold Johns, one of the pioneers in radiotherapy who developed the Cobalt machine, once said, “If you can’t see it, you can’t hit it and if you can’t hit it, you can’t cure it”. Therefore, advanced imaging techniques are needed to visualise at the microscopic level in order to irradiate the tumour cells completely. The challenge facing clinicians today is that very little is known about the precise delineation of target volume. Thus, radiation oncologists are still delineating tumour volume with a large margin to prevent missing any microinvasion to the normal tissue. The innovations described above have resulted in

x Medical Physics in 2020: Will we still be relevant?

radiation delivery techniques with nearly optimal dose distributions. What is needed now is a roadmap, charting a new direction so that oncology can exploit the cutting-edge developments in imaging to bring about significant improvements in targeting accuracy, dose distribution and clinical outcomes for cancer treatment. This is the reason that all the current technologies are focusing on imageguided treatments.

Convergence of imaging and therapy Medical physics should be looking towards the convergence of imaging and therapy. While imaging technology, such as PET and CT, has proven to be very useful in planning oncology treatment, it needs to be integrated more efficiently and more cost-effectively into the work flow of radiotherapy. The current situation sees PET/CT located in the nuclear medicine or imaging department, while radiation therapy treatment is usually provided in a quite separate department. Historically, the two disciplines of imaging and radiation oncology have been divided for the past 50 years into very separate, specialised, self-contained disciplines. This divide is seen across the research institutions, universities, hospital departments and even equipment manufacturers. It is time for the gulf between these two professions to be narrowed. To quote Dr Norman Coleman, M.D. during the 2002 RSNA Annual Oration in Radiation Oncology, “Now that therapy and diagnosis have separated, it is time to get these two disciplines back together again”4. However, reconciliation will not be an easy task. Below are some suggested ways to renew the relationship: x Cross-disciplinary research networks that include expert groups from both fields. x Common workshops, seminars and conferences to improve communication and education across the disciplines. x Collaboration on education and training among relevant professional and learned societies. The effort to bridge the gap will also require the collaboration of sister organisations from radiology, oncology, engineering and other related clinical specialties.

Changing landscape Currently, the emphasis is on cost containment, optimisation with the limited resources in healthcare. At the medical physicists’ level, the emphasis translates to enhancing specific skill development and competency, be it in radiation oncology physics or diagnostic imaging physics. However, many opportunities created by translational and frontier research may slip by because the profession is too focused on achieving greater competency and overspecialisation, which is, unfortunately, driven by economics or political pressure. The focus on the above has raised serious concerns about the ability of the next generation of medical physicists

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to respond to new technology and the changing medical landscape. The boundaries between disciplines are becoming increasingly blurred, particularly within diagnosis, therapy and management. In many universities and established medical centres, clusters are formed to optimize interdisciplinary and translational research. For instance, there are clusters that cross the boundaries of existing academic departments to foster collaborative research, education and outreach. Two such examples are Cluster Hiring Initiative at the University of Wisconsin-Madison5 and the Biomedical Sciences Cluster at the University of Chicago6. Hospitals are going beyond radioactive iodine treatment and exploring the use of catheter-guided radioactive particles to treat tumours. They are also using high-intensity focused ultrasound (HIFU), electromagnetic wave ablation, including radiofrequency and microwave ablation, or laserphotodynamic therapy for cancer treatment. Many of these therapies do not belong to a specific department, but exist in a ‘no-man’s land’. What role can medical physicists play in the changing landscape? If a surgeon is interested in using photodynamic therapy, he may need support on laser physics and protection. A clinician may want to use new biotechnology techniques, where nano-particles are delivered into the body and activated through radio waves, radiation or ultrasound. Medical physicists have the opportunity to contribute here, as these therapies are traditionally not under radiology or oncology. As the line between disciplines blurs, there will be more uncertainties, leading to turf battles among the medical specialties. Unfortunately, the medical physics community will most likely be caught in between. Nonetheless, the outlook for medical physics is encouraging. Physics serves as the foundation for many breakthrough technologies, such as nanotechnology and other new detectors and sources. These technologies can be applied in major areas such as cancer, stroke and brain disorders, cardiovascular diseases, minimal basic intervention and decision-support systems. The healthcare scenario of the next generation will see the changing trends in imaging being applied clinically. Advances in human genome research have provided scientists with an extensive knowledge base to change the nature of imaging from diagnosis and disease recognition to prediction and prevention. The hope for the future is highrisk individuals with predisposed diseases can be identified, the onset of diseases can be predicted and prevented from becoming clinically aggressive. This is the age of molecular medicine. Molecular imaging is developing rapidly, with PET/CT, PET/MRI, optical imaging and other modalities that will improve the ability to describe diseases, stage cancers and provide better treatment. With the combination of molecular imaging and image-guided therapies, treatment can be aimed directly at the disease at the time of early detection, long before it would usually be diagnosed. Again, what role do medical physicists have to play here? They can validate these innovative treatments and

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contribute towards the improvement of diagnostic imaging and therapeutic techniques.

Staying relevant Physics underlines all the innovative techniques applied in both imaging and therapy. Core knowledge of the physics of quantum mechanics and solid state physics, molecular physics and computational physics are required to drive new developments in diagnostic and therapeutic medicine. If medical physicists wish to remain relevant, they have to become actively involved in the task of health promotion and disease management, alongside their medical colleagues. They have to begin learning about molecular biology, and take advantage of the opportunities available in the development of new therapeutic and diagnostic procedures. Medical physicists can also contribute significantly by transforming scientific advances in the laboratory into clinical applications. Equipment that has been developed in research labs can be integrated into clinics, and even modified to be more cost-effective and safe for human use. Medical physicists can also help their colleagues tremendously by investigating and evaluating the outcomes of therapeutic or diagnostic modalities. Their foundation in mathematics, statistics, physics, engineering, anatomy and physiology puts them in a unique position within the hospital environment. The medical physics profession should take advantage of this position to work with their medical colleagues in health promotion and disease management. Lastly, the medical physics profession should not abandon basic scientific research, without which there would not be any progress. So what skills are required for future medical physicists? Besides possessing scientific knowledge, they must also acquire professional skills, including computer skills, as all the modern modalities now depend on computers. The profession should also use their imagination and creativity to think beyond the narrow confines of their own discipline – chemistry, engineering and molecular biology are equally relevant to their interests. Unfortunately, the profession still isn’t there yet. For instance, not many medical physicists are seizing the opportunity to work in pre-clinical animal imaging. It is the life scientists who are working on this modality and learning more about radiation. A grounding in biology is important because it enables the medical physicist to communicate with his/her medical colleagues about molecular genes. It is encouraging to note that some medical physics programs are introducing molecular biology into the curriculum to prepare the future generation7,8. Medical physicists also need to keep up to date with science in general, by reading widely, finding out what other scientists are doing, as well as talking to colleagues from biochemistry, biology and engineering. This will lead to cross-fertilisation of ideas, and fuel the imagination of 87

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the physicists. Curiosity breeds new ideas – probing the minds of medical doctors will bring to light the problems that they encounter that medical physicists may help to solve. To sum up, a ‘relevant’ medical physicist should: • Have a high level of ability and interest in physical sciences and computing. • Have an interest in medicine and in the development of new methods of patient care and treatment. • Be precise, able to concentrate for long periods, and have a high level of attention to detail. • Have high ethical standards and the ability to take responsibility for making decisions. • Have an enquiring mind and good problem-solving skills to lead a research and development team. • Have excellent oral and written communication skills. • Be able to reassure nervous patients. Although many of these skills are not scientificallybased, they are, nevertheless, very important skills that need to be developed for future advancement. The profession should be looking towards a future of becoming multi-talented and multi-skilled, where one will be familiar with the whole gamut, from imaging to therapy. Medical physics has to be prepared for this future, as perhaps the only profession, along with biomedical engineering, that can truly understand the source of these technologies. In January 2006 the American Association of Physicists in Medicine (AAPM) hosted a three-day summit to examine the challenges of medical physics education and training, and the growing demands for quality and accountability in these endeavours9. One conclusion was that the process of educating and training medical physicists in the US (and

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presumably in other countries as well) does not measure up to the accountability standards already in place for medical practitioners and many other health-care professionals. The recommended activities to be initiated for assuring the competent and safe practice of medical physics in the clinical arena. The conclusion of the summit was to enhance medical physics education, training and assurance of competence. Medical physicists as physical scientists in clinical departments must plan to take on the roles of integrating new technologies into clinical practice for the radiology and radiation oncology departments. This will include a wide array of new medical devices. In January 2008 Bioengineering and Imaging Research Opportunities Workshop 5 (BIROW 5)10 was held on the topic Imaging And Characterizing Structure And Function In Native And Engineered Tissue with input from physicists, biologists, bioengineers, radiologists, nuclear medicine specialists, image processing specialists and many others. We have a lot to learn but are in the best position to integrate these new devices into routine clinical practice. In conclusion, will medical physics still be relevant in 2020? Yes, it will, but only if the two disciplines of imaging and oncology can come closer together – to be imaginative and creative on how to contribute their knowledge and ideals to save lives. Never have the opportunities been greater for medical physicists to contribute to the wellbeing of patients around the world. To me the future is clear: "To achieve more, we should imagine together."

Acknowledgement I thank Professor Gary Fullerton, University of Texas, San Antonio and Professor James Zagzebski, University of Wisconsin, Madison for their helpful comments.

Figure 1. The author with Professor John Cameron, Little Rock, Wisconsin 1996.

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x Medical Physics in 2020: Will we still be relevant?

References 1. Cameron, J.R. and Sorenson, J.S., Measurement of bone mineral in vivo: An improved method. Science, 142:230-232, 1963. 2. Reginster, J.Y., Sarlet, N. and Lecart, M.P., Fractures in osteoporosis: the challenge for the new millennium. Osteoporosis Int; 16, Supplement 01, S1-S3, 2005. 3. American Association of Physicists in Medicine http://www.aapm.org/medical_physicist/fields.asp 4. Coleman, C.N., Linking radiation oncology and imaging through molecular biology (or now that therapy and diagnosis have separated, it's time to get together again!), Radiology, 228(1):29-35, 2003. 5. Hiring Initiative at the University of Wisconsin-Madison http://www.clusters.wisc.edu/

6. Biomedical Sciences Cluster at the University of Chicago http://biomed.uchicago.edu/common/ 7. University of Manchester, Physics and computing in medicine and biology http://www.medicine.manchester.ac.uk/ postgraduate/taught/pcmb/ 8. University of Surrey, Medical physics http://www.ph.surrey.ac.uk/msc/medical/content/module1 9. Hendee, W.R. and Mower, H.W., A time of opportunity in the education of medical physicists: Report of a multiorganizational summit on the education of medical physicists, Medical Physics, 33:3327-3332, 2006. 10. Bioengineering and Imaging Research Opportunities Workshop (BIROW 5) http://www.birow.org/

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