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University of California San Francisco

Our Team

Bruce Faddegon, Ph.D., FCCPM, FAAPM

Division of Physics
Department of Radiation Oncology

Precision radiotherapy developer, particle therapy advocate, cyclist

Meet Dr. Faddegon

I want to make radiotherapy treatments safer, more effective and easier for patients at UCSF and around the world.

Dr. Faddegon’s research goal is to improve accuracy and precision in radiotherapy through cost-effective solutions to improve the therapeutic ratio. This will allow for more aggressive treatment in sites where side effects, local control, and even metastases are a problem. The National Institute of Health (NIH) has fully funded Dr. Faddegon’s project to help establish Monte Carlo, a highly accurate method of radiation transport, as a critical tool in radiotherapy, including treatment planning. Related projects include adding electrons to intensity-modulated radiotherapy with x-rays, using Monte Carlo methods for dose calculation, and establishing fast means of dose calculation for depth penetration and output calculation using the accurate beam models developed for the NIH project. Dr. Faddegon is also working to establish image-guided radiotherapy with portal imaging for more precise targeting of tumors and avoidance of critical structures.

Dr. Faddegon’s clinical responsibility is physics support of linear accelerators (linacs). This includes management, installation, commissioning, maintenance and quality assurance (QA), along with supervision of engineers and physicists. At UCSF, Dr. Faddegon commissioned Total Body Irradiation on several linacs, developing the means to treat the whole body over a short distance (3 meters). He also developed new targets to resolve a water leakage problem, implemented high precision graticules for patient localization, commissioned a missing tissue compensator system, and determined the means to detect and correct defective circuitry he discovered in treatments using virtual wedges. He is currently working on implementing a new, more accurate and efficient system for electron output calculation. He routinely consults for Intraoperative Radiotherapy, special procedures, electron treatment, and dose calculation in complex treatments including those where dose delivery is influenced by air cavities, bone, and prosthesis.



1977 University of Victoria, BC, Canada BS Physics
1983 University of Victoria, BC, Canada MS Physics (radiobiology)
1986-90 Carleton University, Ottawa, Canada Ph.D. Physics
Professional Experience

Professional Experience

2010-present UCSF Professor in Residence Radiation Oncology
2000-2010 UCSF Associate Professor in Residence Radiation Oncology
2002-present Joint UCSF/UC-Berkeley Bioengineering Department Faculty Member  
1998-2000 Toronto-Sunnybrook Cancer Center Senior Medical Physicist Radiation Oncology
1994-1998 Toronto-Sunnybrook Cancer Center Medical Physicist Radiation Oncology
1992-1993 BC Cancer Agency, Vancouver Medical Physicist Radiation Oncology
1990-1992 National Research Council of Canada Research Associate Standards
1984-1986 Ottawa Regional Cancer Center, Ontario Junior Medical Physicist Radiation Oncology
1982-1984 University of Victoria, Victoria, BC Lecturer, Lab Instructor Physics
1977-1980 Amoco Canada, Calgary, Alberta Geophysicist Exploration

Awards & Honors

1973 BC government undergraduate scholarship, first year, University of Victoria
1980 National Science and Engineering Research Council scholarship, MSc
1982 National Science and Engineering Research Council scholarship, PhD (declined)
1986 Ontario Cancer Foundation fellowship, PhD, Carleton University
1988 Ontario Graduate Scholarships, PhD, Carleton University
1989 AAPM Young Investigator’s Award, Second Prize
1991 Farrington Daniels Award
1992 Runner-up to Sylvia Fedoruk Prize
1997 Runner-up to Sylvia Fedoruk Prize



Recent Significant Publications


Ramos-Méndez J, LaVerne J, Domínguez-Kondo N, Milligan J, Štěphán V, Stefanová, Klára, Perrot Y, Villagrasa C, Shin W-G, Incerti S, McNamara A, Paganetti H, Perl J, Schuemann J, and Faddegon B, TOPAS-nBio validation for simulating water radiolysis and DNA damage under Low-LET irradiation, Phys Med Biol. 2021 Sep 3; 66(17):10.1088/1361-6560/ac1f39. doi: 10.1088/1361-6560/ac1f39.PMID: 34412044

Domínguez-Kondo, Jorge; Moreno, Eduardo; Stepan, Vaclav; Stefanová, Klára; Perrot, Yann; Villagrasa, Carmen; Incerti, Sebastien; De Celis Alonso, Benito; Schuemann, Jan; Faddegon, Bruce; Ramos-Mendez, Jose, DNA damage modeled with Geant4-DNA: Effects of plasmid DNA conformation and experimental conditions, Phys. Med. Biol. 66, Dec 2021, 245017; doi: 10.1088/1361-6560/ac3a22

P Arce, D Bolst, D Cutajar, S Guatelli, D Sakata, M-C Bordage, P Cirrone, G Cuttone, L Pandola, G Petringa, MA Cortes-Giraldo, JM Quesada, L Desorgher, P Dondero, A Mantero, A Dotti, D Wright, B Faddegon, J Ramos-Mendez, C Fedon, S Incerti, V Ivanchenko, D Konstantinov, G Latyshev, I Kyriakou, C Mancini-Terraccciano, M Maire, M Novak, C Omachi, T Toshito, A Perales, V Perrot, F Romano, L Sarmiento, T Sasaki, I Sechopoulos, EC Simpson, Report on G4-Med, a Geant4 benchmarking system for medical physics applications developed by the Geant4 Medical Physics Benchmarking Group, Med Phys. 2021 Jan;48(1):19-56. doi: 10.1002/mp.14226. Epub 2020 Dec 12. PMID: 32392626, NIHMS 1690578.

Kyoungtae Lee, Jessica Scholey, Eric B. Norman, Inder K. Daftari, Kavita K. Mishra, Bruce A. Faddegon, Michel M. Maharbizy, and Mekhail Anwar, A Millimeter-scale Single Charged Particle Dosimeter for Cancer Radiotherapy, IEEE Journal of Solid-State Circuits, 55(11):2947-2956, September 2020, doi: 10.1109/JSSC.2020.3024231, PMID: 33281206

Ramos-Méndez, N. Domínguez-Kondo, J. Schuemann, A. McNamara, E. Moreno-Barbosa, and Bruce Faddegon, LET-dependent intertrack yields in proton FLASH therapy, Radiat. Res. 194(4):351-362, October 2020, PMID: 32857855

Hongyu Zhu, Aimee L. McNamara, Stephen J. McMahon, Jose Ramos-Mendez, Nicholas T. Henthorn, Bruce Faddegon, Kathryn D. Held, Joseph Perl, Junli Li, Harald Paganetti, Jan Schuemann, Cellular response to proton irradiation: a simulation study with TOPAS-nBio, Rad Res 194(1):9-21, July 2020, PMID: 32401689

Bruce Faddegon, José Ramos-Méndez, Jan Schuemann, Aimee McNamara, Jungwook Shin, Joseph Perl, Harald Paganetti, The TOPAS Tool for Particle Simulation, a Monte Carlo Simulation Tool for Physics, Biology and Clinical Research, Physica Medica: European Journal of Medical Physics, Volume 72, April 2020, Pages 114-121, PMID: 32247964

Chang Ming Charlie Ma, Indrin Chetty, Jun Deng, Bruce Faddegon, Steve Jiang, JinSheng Li, Jan Seuntjens, Jeffrey Siebers, and Erik Traneus, Beam modeling and beam model commissioning for MC dose calculation based radiation therapy treatment planning – The AAPM Task Group 157 Report, Med. Phys. 47 (1):e1-e18, Jan 2020, PMID: 31679157

Hongyu Zhu, Yizheng Chen, Wonmo Sung, Aimee L. McNamara, Linh T. Tran, Lucas N. Burigo, Anatoly B. Rosenfeld, Junli Li, Bruce Faddegon, Jan Schuemann, Harald Paganetti, The microdosimetric extension in TOPAS: development and comparison with published data, Phys Med Biol. 2019 Jul 11;64(14):145004 PMID 31117056

Schuemann, A.L. McNamara, J. Ramos-Méndez, J. Perl, K.D. Held, H. Paganetti, S. Incerti, B. Faddegon, TOPAS-nBio: An extension to the TOPAS simulation toolkit for cellular and sub-cellular radiobiology, Rad Res 191: 125-138, 2019

Lucas N Burigo, José Ramos-Méndez, Mark Bangert, Reinhard W Schulte, Bruce Faddegon, Simultaneous optimization of RBE-weighted dose and nanometric ionization distributions in treatment planning with carbon ions, Phys. Med. Biol. 64: 015015-27, Jan, 2019 PMID:30523890, PMCID:PMC7164666

Ramos-Méndez, L. Burigo, R. Schulte, Cynthia Chuang and B. Faddegon, Fast calculation of nanodosimetric quantities in treatment planning of proton and ion therapy, Phys Med Biol 63:235015-28, 2018 PMID:30484432

Ann A. Lazar, Reinhard Schulte, Bruce Faddegon, Eleanor A Blakely, Mack Roach III, Clinical Trials Involving Carbon Ion Radiation Therapy and the Path Forward, Cancer Dec, 2018, pages 4467-4476, wileyonlinelibrary.com DOI: 10.1002/cncr.31662, PMID: 30307603

Pierluigi Piersimoni, Bruce A. Faddegon, José Ramos Méndez, Reinhard W. Schulte, Lennart Volz, Joao Seco, Helium CT: Monte Carlo simulation results for an ideal source and detector with comparison to proton CT, Med Phys 45(7):3264-74, July, 2018, PMID: 29727481

José Ramos-Méndez, Joseph Perl, Jan Schuemann, Aimee McNamara, Harald Paganetti, Bruce Faddegon, Monte Carlo simulation of chemistry following radiolysis with TOPAS-nBio, Phys Med Biol 63(10):105104, May, 2018, PMCID: PMC6027650, PMID: 29697057

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. doi: 10.1118/1.4922501.

Shiao SL, Ruffell B, DeNardo DG, Faddegon BA, Park CC, Coussens LM., TH2-Polarized CD4(+) T Cells and Macrophages Limit Efficacy of Radiotherapy. Cancer Immunol Res. 2015 May;3(5):518-25. doi: 10.1158/2326-6066.CIR-14-0232. Epub 2015 Feb 25.

Shin J, Perl J, Schümann J, Paganetti H, Faddegon BA., A modular method to handle multiple time-dependent quantities in Monte Carlo simulations. Phys Med Biol. 2012 Jun 7;57(11):3295-308.

Schreiber EC, Sawkey DL, Faddegon BA., Sensitivity analysis of an asymmetric Monte Carlo beam model of a Siemens Primus accelerator. J Appl Clin Med Phys. 2012 Mar 8;13(2):3402.

O’Shea TP, Ge Y, Foley MJ, Faddegon BA., Characterization of an extendable multi-leaf collimator for clinical electron beams. Phys Med Biol. 2011 Dec 7;56(23):7621-38.

Ge Y, Faddegon BA., Study of intensity-modulated photon-electron radiation therapy using digital phantoms. Phys Med Biol. 2011 Oct 21;56(20):6693-708.

O’Shea TP, Foley MJ, Faddegon BA., Accounting for the fringe magnetic field from the bending magnet in a Monte Carlo accelerator treatment head simulation. Med Phys. 2011 Jun;38(6):3260-9.

Nakamura JL, Phong C, Pinarbasi E, Kogan SC, Vandenberg S, Horvai AE, Faddegon BA, Fiedler D, Shokat K, Houseman BT, Chao R, Pieper RO, Shannon K., Dose-dependent effects of focal fractionated irradiation on secondary malignant neoplasms in Nf1 mutant mice. Cancer Res. 2011 Jan 1;71(1):106-15.

Halabi T, Faddegon B., Practical quantitative measurement of graticule misalignment relative to collimator axis of rotation. J Appl Clin Med Phys. 2010 Aug 15;11(4):3318.

O’Shea TP, Sawkey DL, Foley MJ, Faddegon BA., Monte Carlo commissioning of clinical electron beams using large field measurements. Phys Med Biol. 2010 Jul 21;55(14):4083-105.

Faddegon BA, Aubin M, Bani-Hashemi A, Gangadharan B, Gottschalk AR, Morin O, Sawkey D, Wu V, Yom SS., Comparison of patient megavoltage cone beam CT images acquired with an unflattened beam from a carbon target and a flattened treatment beam. Med Phys. 2010 Apr;37(4):1737-41.

Fragoso M, Kawrakow I, Faddegon BA, Solberg TD, Chetty IJ., Fast, accurate photon beam accelerator modeling using BEAMnrc: a systematic investigation of efficiency enhancing methods and cross-section data. Med Phys. 2009 Dec;36(12):5451-66.


Redefining Possible