This theme broadly represents research programs in radiation oncology physics, basic dosimetry, radiation detectors, Monte Carlo simulations in radiation therapy, physics of four-dimensional adaptive radiation therapy, physics of brachytherapy, novel computational techniques, instrumentation hardware and computational software, radiation physics applied to shielding and radioprotection, etc. Research by Beaulieu and his group investigates advanced dose calculation for brachytherapy and applications of fiber detectors in accurate dosimetry. Devic is an expert on radiochromic film dosimetry and his group develops new film-based detectors with advanced properties for applications in radiation therapy and diagnostic radiology. Després’ group uses graphical processor units to advance dose calculation and image processing in radiation oncology and radiology while Seuntjens’ group combines experimental and computational methodologies for accurate dosimetry in reference conditions as well as for applications in the clinical domain such as the development of new treatment techniques. Collaborators at the National Research Council, McEwen and Ross , develop new primary dosimetry standards and are key figures in radiation dosimetry protocol development. Paganetti is a key research scientist, heading the Harvard research group on computational proton therapy physics in Boston. Over thirty staff clinical medical physics collaborators at MUHC , JGH and CHUQ play an important role in the clinical translation aspects of the research projects and in some of the courses established in the MPRTN CREATE program.
Radiation Physics; Monte Carlo Simulations in Proton Therapy
Dr. Harald Paganetti is the Director of Physics Research at the Department of Radiation Oncology at Massachusetts General Hospital and a Professor of Radiation Oncology at Harvard Medical School, Boston, USA. He received his PhD in experimental nuclear physics in 1992 from the RheinischeGFriedrichGWilhelms University in Bonn, Germany, and has been working in radiation therapy research on experimental as well as theoretical projects since 1994. He has authored and coGauthored more than 120 peerGreviewed publications and is renowned particularly for his work on proton therapy. In 2012 he edited a book on “Proton Therapy Physics”. Dr. Paganetti has been awarded numerous research grants from the National Cancer Institute in the United States. He is a member of taskGgroups and committees for various associations such as the American Association of Physicists in Medicine (AAPM), the American Society for Therapeutic Radiology and Oncology (ASTRO), and the National Institutes of Health / National Cancer Institute. Further, he is an elected member of the National Council on Radiation Protection and Measurements (NCRP) and an Associate Senior Editor of the International Journal of Radiation Oncology, Biology, Physics. In 2013 he received the A. Clifford Barger Excellence in Mentoring Award from Harvard Medical School.
The mission of physics research as given on our website (http://gray.mgh.harvard.edu/) is to improve outcome through physics innovation. Improving treatment outcome is the centerpiece of any research mission in radiation oncology. Specifically, physics traditionally has dealt with increasing the precision of treatment delivery, the accuracy of treatment dose prescription, and the quest for treatment plan optimization. The majority of topics in physics research is not considered basic research but is truly translational. Thus, physics research in radiation oncology is typically not aiming at long term goals where research results only find their way into the clinic via translation by vendors, but is aiming at developments together with the clinical staff that changes treatment delivery and planning for our patients in the short term, sometimes even while the patient is undergoing treatment. At the same time we also strive to create visions for longGterm improvements and even paradigm shifts in radiation oncology.
Our physics division has traditionally focused on five main areas:
Recent publications:
Radiation Physics and Dosimetry; Monte Carlo Calculations; Calorimetry; Detectors; Small Fields
Seuntjens is Professor and Director of Medical Physics at the Medical Physics Unit, McGill University. His research topics revolve around the applications of advanced dosimetry techniques in clinical radiation therapy. This includes development of new detectors in small field dosimetry, radiation standards, as well as the application of Monte Carlo techniques for radiation transport calculations at the macro and microscopic level. Dr. Seuntjens is also investigating the application and clinical translation of modulated electron radiation therapy as well as other clinically-inspired research topics in a collaborative context with other PIs. Dr. Seuntjens’ research
Research topics revolve around the applications of advanced dosimetry techniques in clinical radiation therapy. This includes development of new detectors in small field dosimetry, radiation standards, as well as the application of Monte Carlo techniques for radiation transport calculations at the macro and microscopic level. Dr. Seuntjens is also investigating the application and clinical translation of modulated electron radiation therapy as well as other clinically-inspired research topics in a collaborative context with other PIs. Dr. Seuntjens’ research is supported by the CIHR and NSERC.
Recent publications:
Scintillation Fiber Dosimetry; Radiotherapy Physics; Brachytherapy Physics; Dose Calculations
Luc Beaulieu received his PhD from Université Laval in 1996. After a postdoctoral fellowship in Berkeley, California, he worked as a research scientist at the Indiana University Cyclotron Facility in Bloomington. In 2000, he took the leadership of the medical physics research group at Quebec City University Hospital. Under his leadership, a formal graduate medical physics teaching curriculum was setGup and became CAMPEP accredited in 2011. Dr. Beaulieu is a full professor (tenured) at Université Laval and Director of the CAMPEP graduate program. He is a member of the AAPM Brachytherapy Subcommittee, of TGG192, was the Chair of TGG186 (published in 2012) and now leads the AAPM/ESTRO/ABG Working Group on ModelGBased Dose Calculations in brachytherapy. As of 2014, he has mentored more than 65 graduate students and postdoctoral fellows, published 169 peerGreviewed manuscripts and over 330 abstracts at national and international meetings. He is a recognized expert in scintillation dosimetry and brachytherapy.
The ongoing objective of Prof. Beaulieu’s research program is to increase the accuracy of dose measurements and dose calculations for any radiation based procedures including, but not limited to, radiation therapy, diagnostic and interventional radiology. This is achieved through a comprehensive research program combining elements of basic and applied research in medical physics and biomedical engineering. The program hinges on radiation physics, optics, numerical optimization problems, image and signal processing and highGperformance computing. The program is subGdivided along four main research tracks, namely 1) development of new radiation dosimeters, 2) applied medical image processing, 3) numerical computation in optimization problems and high precision particle transport and dose calculations, and 4) a developing trac.
Recent publications:
Radiation Physics and Dosimetry; Experiments; Detectors; Accelerators; Calorimeters
Malcolm McEwen joined the Ionizing Radiations Standards Group at NRC in 2002 from the National Physical Laboratory in the UK. He has over 20 years experience in the field of ionizing radiation metrology and is actively involved with national and international organizations focusing on radiation dosimetry and medical physics including the Ottawa Medical Physics Institute, American Association of Physicists in Medicine and the Sistema Interamericano de Metrología. He is Adjunct Professor in the Department of Physics at Carleton University and participates in the medical physics graduate program there through supervision, teaching and providing access to NRC research facilities. Dr McEwen’s main area of interest is in the dosimetry for highGenergy photon and electron beams, as produced by linear accelerators and he has developed calibration services and protocols that enable medical physicists in cancer centres to deliver radiation therapy treatments with improved accuracy.
Expertise:
Development of primary standard calorimeters for highG energy photon and electron beam dosimetry at industrial and radiotherapy levels. Performance of secondary dosimeters G ionization chambers, diodes, chemical dosimeters (Fricke, alanine, etc). Operation of linear accelerators in the MeV energy range. Development of calibration services, codes of practice and audit systems for radiotherapy centres in Canada and worldwide.
The Ionizing Radiation Standards Group is responsible for maintaining and developing measurement standards for Canada in the areas of radiation dosimetry and radioactivity. In addition to physical measurements it has a long history of developing radiation transport codes and maintains the wellG known EGSnrc system. The group has an impressive array of facilities including: CoG60, kV xGrays and betaGsource irradiation facilities, a lowGscatter radiation protection laboratory (with neutron and CsG137 beams), a comprehensive radioactivity and radiochemistry laboratory and a linear accelerator lab housing two MV electron linacs.
Current and planned projects within the group include:
• Development of a primary standard water calorimeter for electron beam dosimetry.
• Investigation of dose standards for small photon beams.
• Evaluation of new ion chamber designs for reference dosimetry.
• Investigation of novel detectors for high accuracy applications in radiation dosimetry.
• Measurement of ‘fundamental’ parameters used in radiation dosimetry (e.g., stopping powers for electron beams, the average energy required to produce an ion pair in air)
• Application of the Fricke dosimeter system to brachytherapy and kV dosimetry
• Performance comparison of integrating dosimeters (e.g., alanine, OSL, radiochromic film) and application as secondary standard and/or audit dosimeters
• Development of standards for LDR brachytherapy
• Development of techniques to determine absolute activity of alpha, beta and gamma radioactive sources.
• Investigation of the production, extraction, standardization and delivery of diagnostic radionuclides.
• Measurement of the absolute neutron fluence and energy spectra of neutron sources.
Projects are generally carried out in a team environment giving students the opportunity to work with several experts within the IRS group.
Recent publications:
Image Processing; X-ray; CT; PET; SPECT; GPU Processing
Philippe Després is an Assistant Professor in the Department of Physics, Engineering Physics and Optics at Université Laval and a Medical Physicist at CHU de Québec. He was trained at Université Laval (MSc 2000, Physics), Université de Montréal (PhD 2005, Physics) and University of California, San Francisco (postdoc 2005G2007, Biomedical Engineering, Molecular Imaging). He has been involved in numerous projects encompassing hardware and software aspects of medical imaging modalities such as XGray, CT, PET and SPECT. He has worked on lowGdose XGray imaging (scanningGslit xenon microstrip detector), advanced imaging techniques (multiG energy XGray imaging), and solidGstate detectors for molecular imaging (PSAPD and CZTGbased PET and SPECT). He also has developed highGperformance computing approaches with commodity graphics hardware (GPUs) that have led to innovative applications in image processing/reconstruction and radiation dose calculation, including a fast GPUGbased Monte Carlo engine to simulate energy transport in matter. He holds grants from NSERC, CIHR, FRQGS and has established research collaborations with numerous industrial and academic partners both locally and abroad.
The research program pursued by Prof. Després is geared towards the use of highGperformance computing to tackle problems in Medical Physics. Specifically, physicsGrich models are used to reach better, more accurate solutions in a variety of clinical situations. These physicsGrich models however are numerically challenging and usually require large computing resources. As these problems are often intrinsically parallel, they can be implemented on Graphics Processing Units (GPUs) and benefit from their massively parallel architecture (hundreds of cores per processor). Therefore, the numerical burden of realistic modeling is alleviated by the use of GPUs; acceleration factors of 10 to 1000x have been achieved with this technology compared to traditional CPU implementations. This level of performance lets envision the clinical deployment of better solutions in radiation dose calculation and tomographic image reconstructionG. In the first case, a fast GPUG based Monte Carlo engine was developed to simulate the transport of energy in matter. This allows for more accurate dose calculations in external beam radiation therapy, brachytherapy, radiology and nuclear medicine while maintaining calculation times that are compatible with a clinical workflow. In tomographic image reconstruction, GPUG accelera ed iterative algorithms integrating physicsGbased priors have been developed to achieve fewGviews, lowGdose or artefact suppressing solutions.
In PET and SPECT molecular imaging, efforts are invested in the development of a quantitative imaging platform. An automatic blood activity counter is being developed to monitor the amount of radiotracer available for uptake as a function of time in order to feed pharmacokinetic models and extract valuable physiological information from imaging studies.
Recent publications:
Radiochromic Flim Dosimetry; Brachytherapy Physics; PET Imaging in Radiotherapy
Slobodan Devic obtained his M.Sc. degree in nonGideal plasma physics and his Ph.D. degree in Solid State Physics in 1997 at the University of Belgrade, Serbia. He moved to the USA in 1998 where he worked as a Research Associate in Radiation Oncology Physics at the Mallinckrodt Institute of Radiology, St. Louis, Missouri. Subsequently, he moved in 2000 to the Montreal General Hospital and McGill University where he was enrolled into the Medical Physics Residency program. Upon finishing his residency in 2002 he joined the Medical Physics Unit at the McGill University and, in 2008, he moved to his current position at the SMBD Jewish General Hospital in Montreal. He is a Fellow of the Canadian College of Physicists in Medicine and his major research interests are radiochromic film dosimetry and its applications, image guided brachytherapy with particular interest in preGoperative endorectal brachytherapy, and the incorporation of the functional imaging information into radiotherapy treatment planning process. Dr. Devic is also teaching Physics in Nuclear Medicine course at the McGill University and as of 2009 he became a member of the Editorial board of the Medical Physics journal.
Research program of Slobodan Devic revolves around:
Recent publications:
Radiation Physics; Monte Carlo Simulations in Proton Therapy
Radiation Physics and Dosimetry; Monte Carlo Calculations; Calorimetry; Detectors; Small Fields
Scintillation Fiber Dosimetry; Radiotherapy Physics; Brachytherapy Physics; Dose Calculations
Radiation Physics and Dosimetry; Experiments; Detectors; Accelerators; Calorimeters
Image Processing; X-ray; CT; PET; SPECT; GPU Processing
Radiochromic Flim Dosimetry; Brachytherapy Physics; PET Imaging in Radiotherapy