University of California San Francisco
Helen Diller Family Comprehensive Cancer Center
Bruce Faddegon, PhD

Bruce Faddegon, PhD

Professor in Residence, Department of Radiation Oncology, UCSF

Cancer Center Program Memberships


Research Summary

Dr. Faddegon is a board certified clinical medical physics who is internationally recognized for his research in developing and using Monte Carlo methods for treatment head simulation and dose calculation and his development of new technology to improve accuracy and precision in radiotherapy. The overall objective of Dr. Faddegon’s research is to allow for more aggressive treatment in sites where side effects, local control, and even metastases are a problem through cost-effective solutions to improve the therapeutic ratio.

Current research includes developing TOPAS, the Tool for Particle Simulation, a collaboration of UCSF, MGH and SLAC supported by NIH to improve advanced simulation of radiotherapy in conjunction with the open source Geant4 Monte Carlo simulation toolkit. The initial grant focussed on proton therapy. The renewal grant focused on organ and cell radiobiology. The current NIH U24 grant is through the NCI Informatics Technology for Cancer Research (ITCR) to extend TOPAS to conventional radiotherapy and imaging. Work in parallel is being done to develop TOPAS-nBio with enhanced track structure simulation capabilities in conjunction with Geant4-DNA for physicists, chemists and biologists to better establish the relationship between ionization deposition details, radiation chemistry, and biological effect.

Dr. Faddegons clinical responsibility is physics support of radiotherapy. This includes installation, commissioning, maintenance and quality assurance of equipment and procedures used in radiation treatment planning and delivery. Highlights of Dr. Faddegon’s published clinical development work at UCSF include developing the means to treat the whole body over a short distance (3 meters), developing new x-ray targets to reduce downtime that are implemented on linacs worldwide, implementing high precision graticules for patient localization, and determining the means to detect and correct defective circuitry in treatments using virtual wedges.


University of Victoria, Victoria, Canada, B.Sc., 1977, Physics (honors)
University of British Columbia, Vancouver, Canada, M.Sc., 1983, Physics (radiobiology)
Carleton University, Ottawa, Canada, Ph.D., 1990, Physics (radiotherapy)

Professional Experience

  • 1977-80
    Geophysicist, Amoco Canada, Calgary, Alberta
  • 1982-84
    Sessional Lecturer and Laboratory Instructor, University of Victoria, Victoria, BC
  • 1984-86
    Medical Physics Resident, Ottawa Regional Cancer Center, Ottawa, Ontario
  • 1990-92
    Research Associate, Ionizing Radiation Standards, National Research Council of Canada, Ottawa, Ontario
  • 1992-93
    Medical Physicist, BC Cancer Agency, Vancouver, BC
  • 1994-98
    Medical Physicist, Toronto-Sunnybrook Regional Cancer Center, Toronto, Ontario
  • 1994-2000
    Assistant Member, School of Graduate Studies, University of Toronto, Toronto, Ontario
  • 1998-2000
    Senior Medical Physicist, Toronto-Sunnybrook Regional Cancer Center, Ontario
  • 2000-2010
    Associate Professor in Residence, Department of Radiation Oncology, University of California San Francisco
  • 2010-present
    Professor in Residence, Department of Radiation Oncology, University of California San Francisco

Honors & Awards

  • 1980
    National Science and Engineering Research Council of Canada (NSERC) scholarship for M.Sc. studies
  • 1982
    NSERC scholarship for Ph.D. studies - declined
  • 1986
    Ontario Cancer Foundation fellowship for Ph.D. studies
  • 1988
    Ontario Graduate Scholarship for Ph.D. studies
  • 1989
    American Association Physicists in Medicine (AAPM) Young Investigator's Award, Second Prize
  • 1991
    Farrington Daniels Award (AAPM)
  • 1992
    Runner-up to Sylvia Fedoruk Prize (Canadian Organization of Medical Physics)
  • 1996
    Runner-up to Sylvia Fedoruk Prize (Canadian Organization of Medical Physics)
  • 2007
    Appointed Fellow of the American Association of Physicists in Medicine

Selected Publications

  1. Zhu H, McNamara AL, Ramos-Mendez J, McMahon SJ, Henthorn NT, Faddegon BA, Held K, Perl J, Li J, Paganetti H, Schuemann J. A parameter sensitivity study for simulating DNA damage after proton irradiation using TOPAS-nBio. Phys Med Biol. 2020 Feb 26.
    View on PubMed
  2. Ma CMC, Chetty IJ, Deng J, Faddegon B, Jiang SB, Li J, Seuntjens J, Siebers JV, Traneus E. Beam modeling and beam model commissioning for Monte Carlo dose calculation-based radiation therapy treatment planning: Report of AAPM Task Group 157. Med Phys. 2020 Jan; 47(1):e1-e18.
    View on PubMed
  3. Blakely EA, Faddegon B, Tinkle C, Bloch C, Dominello M, Griffin RJ, Joiner MC, Burmeister J. Three discipline collaborative radiation therapy (3DCRT) special debate: The United States needs at least one carbon ion facility. J Appl Clin Med Phys. 2019 Nov; 20(11):6-13.
    View on PubMed
  4. Abhyankar YS, Dev S, Sarun OS, Saxena A, Joshi R, Darbari H, Sajish C, Sonavane UB, Gavane V, Deshpande A, Dixit T, Harsh R, Badwe R, Rath GK, Laskar S, Faddegon B, Perl J, Paganetti H, Schuemann J, Srivastava A, Obcemea C, Nath AK, Sharma A, Buchsbaum J. Monte Carlo Processing on a Chip (MCoaC)-preliminary experiments toward the realization of optimal-hardware for TOPAS/Geant4 to drive discovery. Phys Med. 2019 Aug; 64:166-173.
    View on PubMed
  5. Zhu H, Chen Y, Sung W, McNamara AL, Tran LT, Burigo LN, Rosenfeld AB, Li J, Faddegon B, Schuemann J, Paganetti H. The microdosimetric extension in TOPAS: development and comparison with published data. Phys Med Biol. 2019 07 11; 64(14):145004.
    View on PubMed
  6. Burigo LN, Ramos-Méndez J, Bangert M, Schulte RW, Faddegon B. Simultaneous optimization of RBE-weighted dose and nanometric ionization distributions in treatment planning with carbon ions. Phys Med Biol. 2019 01 04; 64(1):015015.
    View on PubMed
  7. Schuemann J, McNamara AL, Ramos-Méndez J, Perl J, Held KD, Paganetti H, Incerti S, Faddegon B. TOPAS-nBio: An Extension to the TOPAS Simulation Toolkit for Cellular and Sub-cellular Radiobiology. Radiat Res. 2019 02; 191(2):125-138.
    View on PubMed
  8. Ramos-Méndez J, Burigo LN, Schulte R, Chuang C, Faddegon B. Fast calculation of nanodosimetric quantities in treatment planning of proton and ion therapy. Phys Med Biol. 2018 Nov 28; 63(23):235015.
    View on PubMed
  9. Schuemann J, McNamara AL, Warmenhoven JW, Henthorn NT, Kirkby KJ, Merchant MJ, Ingram S, Paganetti H, Held KD, Ramos-Mendez J, Faddegon B, Perl J, Goodhead DT, Plante I, Rabus H, Nettelbeck H, Friedland W, Kundrát P, Ottolenghi A, Baiocco G, Barbieri S, Dingfelder M, Incerti S, Villagrasa C, Bueno M, Bernal MA, Guatelli S, Sakata D, Brown JMC, Francis Z, Kyriakou I, Lampe N, Ballarini F, Carante MP, Davídková M, Štepán V, Jia X, Cucinotta FA, Schulte R, Stewart RD, Carlson DJ, Galer S, Kuncic Z, Lacombe S, Milligan J, Cho SH, Sawakuchi G, Inaniwa T, Sato T, Li W, Solov'yov AV, Surdutovich E, Durante M, Prise KM, McMahon SJ. A New Standard DNA Damage (SDD) Data Format. Radiat Res. 2019 01; 191(1):76-92.
    View on PubMed
  10. Lazar AA, Schulte R, Faddegon B, Blakely EA, Roach M. Clinical trials involving carbon-ion radiation therapy and the path forward. Cancer. 2018 12 01; 124(23):4467-4476.
    View on PubMed
  11. McNamara AL, Ramos-Méndez J, Perl J, Held K, Dominguez N, Moreno E, Henthorn NT, Kirkby KJ, Meylan S, Villagrasa C, Incerti S, Faddegon B, Paganetti H, Schuemann J. Geometrical structures for radiation biology research as implemented in the TOPAS-nBio toolkit. Phys Med Biol. 2018 09 06; 63(17):175018.
    View on PubMed
  12. Piersimoni P, Faddegon BA, Méndez JR, Schulte RW, Volz L, Seco J. Helium CT: Monte Carlo simulation results for an ideal source and detector with comparison to proton CT. Med Phys. 2018 Jul; 45(7):3264-3274.
    View on PubMed
  13. Ramos-Méndez J, Perl J, Schuemann J, McNamara A, Paganetti H, Faddegon B. Monte Carlo simulation of chemistry following radiolysis with TOPAS-nBio. Phys Med Biol. 2018 05 17; 63(10):105014.
    View on PubMed
  14. Ramos-Méndez J, Schuemann J, Incerti S, Paganetti H, Schulte R, Faddegon B. Flagged uniform particle splitting for variance reduction in proton and carbon ion track-structure simulations. Phys Med Biol. 2017 Jul 06; 62(15):5908-5925.
    View on PubMed
  15. Piersimoni P, Ramos-Méndez J, Geoghegan T, Bashkirov VA, Schulte RW, Faddegon BA. The effect of beam purity and scanner complexity on proton CT accuracy. Med Phys. 2017 Jan; 44(1):284-298.
    View on PubMed
  16. McNamara A, Geng C, Turner R, Mendez JR, Perl J, Held K, Faddegon B, Paganetti H, Schuemann J. Validation of the radiobiology toolkit TOPAS-nBio in simple DNA geometries. Phys Med. 2017 Jan; 33:207-215.
    View on PubMed
  17. Sudhyadhom A, Kirby N, Faddegon B, Chuang CF. Technical Note: Preferred dosimeter size and associated correction factors in commissioning high dose per pulse, flattening filter free x-ray beams. Med Phys. 2016 Mar; 43(3):1507-13.
    View on PubMed
  18. Roach M, Schulte R, Mishra K, Faddegon B, Barani I, Lazar A, Blakely EA. New Clinical and Research Programs in Particle Beam Radiation Therapy: The University of California San Francisco Perspective. Int J Part Ther. 2016; 2(3):471-473.
    View on PubMed
  19. Geng C, Moteabbed M, Seco J, Gao Y, Xu XG, Ramos-Méndez J, Faddegon B, Paganetti H. Dose assessment for the fetus considering scattered and secondary radiation from photon and proton therapy when treating a brain tumor of the mother. Phys Med Biol. 2016 Jan 21; 61(2):683-95.
    View on PubMed
  20. Faddegon BA, Shin J, Castenada CM, Ramos-Méndez J, Daftari IK. Experimental depth dose curves of a 67.5 MeV proton beam for benchmarking and validation of Monte Carlo simulation. Med Phys. 2015 Jul; 42(7):4199-210.
    View on PubMed

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