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 new x-ray targets that are implemented on linacs worldwide for low-dose megavoltage imaging and to reduce downtime, developing the means to treat the whole body over a short distance (3 meters), implementing high precision graticules for patient localization, and determining the means to detect and correct defective circuitry in treatments using virtual wedges.

Research Funding

  • June 4, 2018 - May 31, 2023 - The TOPAS Tool for Particle Simulation, a Monte Carlo Simulation Tool for Physics, Biology and Clinical Research, Principal Investigator. Sponsor: NIH/NCI, Sponsor Award ID: U24CA215123
  • April 1, 2015 - March 31, 2019 - TOPAS-nBio, A Monte Carlo tool for radiation biology research, Co-Investigator. Sponsor: NIH, Sponsor Award ID: R01 CA187003
  • April 15, 2017 - April 14, 2018 - PRISM: Precision Radiotherapy and Imaging of Small Mammals, Principal Investigator. Sponsor: NIH, Sponsor Award ID: S10OD021818
  • February 10, 2015 - January 31, 2017 - NAPTA: Optimizing clinical trial design & delivery of particle therapy for cancer, Co-Investigator. Sponsor: NIH/NCI, Sponsor Award ID: P20CA183640


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)

Qualified Medical Physicist by the standards of Cancer Care Ontario (1987)
Certified clinical physicist as member (1987) by Canadian College of Physicists in Medicine

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
    Elected Fellow of the Canadian College of Physicists in Medicine
  • 2007
    Appointed Fellow of the American Association of Physicists in Medicine

Selected Publications

  1. Ramos-Méndez J, LaVerne JA, Domínguez-Kondo N, Milligan J, Štepán V, Stefanová K, Perrot Y, Villagrasa C, Shin WG, Incerti S, McNamara A, Paganetti H, Perl J, Schuemann J, Faddegon B. TOPAS-nBio validation for simulating water radiolysis and DNA damage under low-LET irradiation. Phys Med Biol. 2021 Sep 03; 66(17).  View on PubMed
  2. von der Linden J, Ramos-Mendez J, Faddegon B, Massin D, Fiksel G, Holder JP, Willingale L, Peebles J, Edwards MR, Chen H. Publisher's Note: "Dispersion calibration for the National Ignition Facility electron-positron-proton spectrometers for intense laser matter interactions" [Rev. Sci. Instrum. 92, 033516 (2021)]. Rev Sci Instrum. 2021 May 01; 92(5):059902.  View on PubMed
  3. von der Linden J, Ramos-Méndez J, Faddegon B, Massin D, Fiksel G, Holder JP, Willingale L, Peebles J, Edwards MR, Chen H. Dispersion calibration for the National Ignition Facility electron-positron-proton spectrometers for intense laser matter interactions. Rev Sci Instrum. 2021 Mar 01; 92(3):033516.  View on PubMed
  4. Tran HN, Ramos-Méndez J, Shin WG, Perrot Y, Faddegon B, Okada S, Karamitros M, Davídková M, Štepán V, Incerti S, Villagrasa C. Assessment of DNA damage with an adapted independent reaction time approach implemented in Geant4-DNA for the simulation of diffusion-controlled reactions between radio-induced reactive species and a chromatin fiber. Med Phys. 2021 Feb; 48(2):890-901.  View on PubMed
  5. Arce P, Bolst D, Bordage MC, Brown JMC, Cirrone P, Cortés-Giraldo MA, Cutajar D, Cuttone G, Desorgher L, Dondero P, Dotti A, Faddegon B, Fedon C, Guatelli S, Incerti S, Ivanchenko V, Konstantinov D, Kyriakou I, Latyshev G, Le A, Mancini-Terracciano C, Maire M, Mantero A, Novak M, Omachi C, Pandola L, Perales A, Perrot Y, Petringa G, Quesada JM, Ramos-Méndez J, Romano F, Rosenfeld AB, Sarmiento LG, Sakata D, Sasaki T, Sechopoulos I, Simpson EC, Toshito T, Wright DH. Report on G4-Med, a Geant4 benchmarking system for medical physics applications developed by the Geant4 Medical Simulation Benchmarking Group. Med Phys. 2021 Jan; 48(1):19-56.  View on PubMed
  6. Ramos-Méndez J, Shin WG, Karamitros M, Domínguez-Kondo J, Tran NH, Incerti S, Villagrasa C, Perrot Y, Štepán V, Okada S, Moreno-Barbosa E, Faddegon B. Independent reaction times method in Geant4-DNA: Implementation and performance. Med Phys. 2020 Nov; 47(11):5919-5930.  View on PubMed
  7. Ramos-Méndez J, Domínguez-Kondo N, Schuemann J, McNamara A, Moreno-Barbosa E, Faddegon B. LET-Dependent Intertrack Yields in Proton Irradiation at Ultra-High Dose Rates Relevant for FLASH Therapy. Radiat Res. 2020 10 02; 194(4):351-362.  View on PubMed
  8. Lee K, Scholey J, Norman EB, Daftari IK, Mishra KK, Faddegon BA, Maharbiz MM, Anwar M. A Millimeter-scale Single Charged Particle Dosimeter for Cancer Radiotherapy. IEEE J Solid-State Circuits. 2020 Nov; 55(11):2947-2958.  View on PubMed
  9. Carrasco-Hernández J, Ramos-Méndez J, Faddegon B, Jalilian AR, Moranchel M, Ávila-Rodríguez MA. Monte Carlo track-structure for the radionuclide Copper-64: characterization of S-values, nanodosimetry and quantification of direct damage to DNA. Phys Med Biol. 2020 07 27; 65(15):155005.  View on PubMed
  10. Zhu H, McNamara AL, McMahon SJ, Ramos-Mendez J, Henthorn NT, Faddegon B, Held KD, Perl J, Li J, Paganetti H, Schuemann J. Cellular Response to Proton Irradiation: A Simulation Study with TOPAS-nBio. Radiat Res. 2020 07 08; 194(1):9-21.  View on PubMed
  11. Zhu H, McNamara AL, Ramos-Mendez J, McMahon SJ, Henthorn NT, Faddegon B, Held KD, 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 04 23; 65(8):085015.  View on PubMed
  12. Faddegon B, Ramos-Méndez J, Schuemann J, McNamara A, Shin J, Perl J, Paganetti H. The TOPAS tool for particle simulation, a Monte Carlo simulation tool for physics, biology and clinical research. Phys Med. 2020 Apr; 72:114-121.  View on PubMed
  13. 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
  14. 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
  15. 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
  16. 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
  17. 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
  18. 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
  19. 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
  20. 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

Go to UCSF Profiles, powered by CTSI