Research

Research Priorities: Medical physics, intensity-modulated radiation therapy (IMRT), proton therapy, optimisation methods

Thomas Bortfeld is a German-American physicist who has made substantial contributions to developments in radiation therapy. When it comes to treating tumours, the main challenge relates to delivering a therapeutically effective dose to the tumour without exceeding the threshold that can be tolerated by the surrounding normal tissue. Together with his team, Thomas Bortfeld is developing models and algorithms for calculating the best-possible treatment strategy in each case as well as technologies for its clinical implementation. The intensity-modulated radiation therapy (IMRT) method – a development to which he has substantially contributed – has now been used in the treatment of 30 million patients worldwide.

From a mathematical perspective, radiation therapy is an inverse problem in which the intensity and direction of the radiation fields used must be inferred from the desired dose in the target volume of the tumour. This problem is mathematically linked to the reconstruction of computed tomography (CT) images from measured X-ray projections. Unlike image reconstruction, there is no exact solution to be found when planning treatment; rather, the best possible compromise, taking into account objectives and side conditions, must be sought. This is known as multi-objective optimisation. Thomas Bortfeld and his team focus on formulating and solving this optimisation problem during the treatment planning process.

Another aspect is delivering intensity-modulated radiation fields with multileaf collimators that match the treatment volume irradiated to the object to be treated and to enable geometrically differentiated dosing. This work has led to inverse intensity-modulated radiation therapy (IMRT) planning in which the intensity of the radiation dose within the radiation field can be changed and adapted to the radiosensitivity of the tissue with pinpoint accuracy. This enables radiotherapy to be targeted very precisely at the tumour while protecting the healthy surrounding structures from radiation. In turn, this means that a higher radiation dose can be used, thus improving the chances of patient recovery. IMRT is now considered the state of the art in radiation therapy worldwide.

Current research priorities include developing optimal stopping methods for improving tailored therapies, systematically determining the clinical target volume (CTV), and developing methods for cutting proton therapy costs with a view to making this type of treatment accessible to more patients.

Career

• since 2017 Honorary Professor, Faculty of Medicine, University of Freiburg, Freiburg, Germany
• since 2008 Professor of Radiation Oncology, Harvard Medical School, Boston, USA
• since 2008 Chief, Division of Radiation Biophysics, Department of Radiation Oncology, Massachusetts General Hospital, Boston, USA
• 2001-2008 Associate Professor of Radiation Oncology, Harvard Medical School, Boston, USA
• 2001-2008 Director of Physics Research, Department of Radiation Oncology, Massachusetts General Hospital, Boston, USA
• 1996-2001 Deputy Head, Division of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Heidelberg, Germany
• 1995-2001 Independent Lecturer, Faculty of Physics and Astronomy, Heidelberg University, Heidelberg, Germany
• 1995 Habilitation and Venia Legendi (authorisation to teach) in Physics, Heidelberg University, Heidelberg, Germany
• 1994-2001 Head of the “Physical Models” Working Group, German Cancer Research Center, Heidelberg, Germany
• 1993-1994 Research Associate, Division of Medical Physics in Radiation Oncology, German Cancer Research Center, Heidelberg, Germany
• 1992-1993 Postdoc, Institute of Radiation Physics, MD Anderson Cancer Center, Houston, USA
• 1991-1992 Research Associate, Division of Biomedical Physics in Radiation Oncology, German Cancer Research Center, Heidelberg, Germany
• 1990 PhD in Physics, Heidelberg University, Heidelberg, Germany
• 1988 Diplom degree in Physics, Heidelberg University, Heidelberg, Germany

Functions

• since 2021 Member, Scientific Advisory Board, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, (HZDR), Germany
• 2019 Co-Organiser, Think Tank Meeting “The most provocative questions for medical physicists in Radiation Oncology”, European Society for Therapeutic Radiology and Oncology (ESTRO)
• 2019 Member, Scientific Committee, International Conference on the Use of Computers in Radiation Therapy (ICCR), Montreal, Canada
• since 2018 Co-Founder and Co-Chair, International Consortium “Optimal Stopping in Radiation Therapy” (OSRT)
• 2017-2020 Secretary and Treasurer, Topical Group on Medical Physics (GMED), American Physical Society (APS), American Association of Physicists in Medicine (AAPM), USA
• 2014-2017 Member, Subcommittee of Professors, Harvard Medical School, Boston, USA
• since 2014 Member, Steering Committee, Proton Program Project Grant (P01), Department of Radiation Oncology, Massachusetts General Hospital, Boston, USA
• since 2013 Chair/Co-Chair, Medical Physics Residency Program Oversight Committee, Harvard Medical School, Boston, USA
• since 2012 Chair, Proton Projects Oversight Committee, Department of Radiation Oncology, Massachusetts General Hospital, Boston, USA
• 2010-2017 Co-Chair, Working Group on Future Research and Academic Medical Physics (FUTURE), AAPM, USA
• 2009-2013 Member, Promotions, Reappointments, and Appointments Committee (P&R), Harvard Medical School, Boston, USA
• 2007-2008 Scientific Program Director, Therapy, AAPM 50th annual meeting, AAPM, USA
• 2004 Member, Scientific Committee, ICCR 2004, Seoul, South Korea
• 1999-2001 Member, Budget Committee, German Cancer Research Center, Heidelberg, Germany
• 1999 Member, Steering Council, IMRT School, Heidelberg University, Heidelberg, Germany

Honours and Memberships

• since 2022 Honorary Member, ESTRO
• since 2021 Member of the German National Academy of Sciences Leopoldina, Germany
• 2019 Australia-Harvard Fellowship, Harvard Club of Australia Foundation, Harvard Club of Australia, Bondi Junction, Australia
• 2018 Glocker Medal, German Society for Medical Physics (DGMP), Germany
• 2016 Stifterverband Science Prize, Fraunhofer Society, Munich, Germany
• 2015 Alfred Breit Prize, German Society of Radiation Oncology (DEGRO), Germany
• 2009 Fellow, AAPM, USA
• 2008 Artium Magistrum honoris causa, Harvard University, Boston, USA
• since 2004 Fellow, Institute of Physics, London, UK
• 2001 Nominated for the Deutscher Zukunftspreis (Finalist, Top 4), German Federal President's Award for Technology and Innovation, Germany
• 1995 Young Investigator Award (third place), AAPM, USA
• 1994 Helax Award, Helax AB, Uppsala, Sweden
• 1990 Richtzenhain Prize, German Cancer Research Center, Heidelberg, Germany