Benjamin Clasie, PhD

Technical Director, Proton Therapy
Assistant Professor
E-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.
Address: Massachusetts General Hospital
Department of Radiation Oncology
Francis H. Burr Proton Therapy Center
30 Fruit St
Boston MA, 02114

Areas of Interest

Intensity modulated proton therapy
Pencil beam scanning


B.Sc. (Hons.) Adv., University of Wollongong, Australia, 1998
Ph.D. Massachusetts Institute of Technology, 2006

Licensure and Certification

Certificate in Therapeutic Medical Physics, American Board of Radiology, 2013


1.Suit H, Kooy H, Trofimov A, Farr J, Munzenrider J, DeLaney T, Loeffler J, Clasie B, Safai S Paganetti H. Should positive phase III clinical trial data be required before proton beam therapy is more widely adopted? No. Radiother. Oncol. 2008;86:148-53.

2.Wroe W, Clasie B, Kooy H, Flanz J, Schulte R, Rosenfeld A. Out-of-field dose equivalents delivered by passively scattered therapeutic proton beams for clinically relevant field configurations. Int. J. Radiat. Oncol. Biol. Phys. 2009:73;306-13.

3.Dowdell S, Clasie B, Wroe A, Guatelli S, Metcalfe P, Schulte R, Rosenfeld A. Tissue equivalency of phantom materials for neutron dosimetry in proton therapy. Med Phys. 2009;36:5412-9.

4.Kooy H, Clasie B, Lu HM, Madden T, Bentefour H, Depauw N, Adams J, Trofimov A, Demaret D, DeLaney T, Flanz J. A case study in proton pencil-beam scanning delivery. Int. J. Radiat. Oncol. Biol. Phys. 2010;76:624-30.

5.Clasie B, Wroe A, Kooy H, Depauw N, Flanz J, Paganetti H, Rosenfeld A. Assessment of out-of-field absorbed dose and equivalent dose in proton fields. Med. Phys. 2010;37:311-21.

6.Suit H, DeLaney T, Goldberg S, Paganetti H, Clasie B, Gerweck L, Niemierko A, Hall E, Flanz J, Hallman J, Trofimov A. Proton vs carbon ion beams in the definitive radiation treatment of cancer patients. Radiother. Oncol. 2010;95:3-22.

7.Sarfehnia A, Clasie B, Chung E, Lu HM, Flanz J, Cascio E, Engelsman M, Paganetti H, Seuntjens J. Direct absorbed dose to water determination based on water calorimetry in scanning proton beam delivery. Med Phys. 2010;37:3541-50.

8.Clasie B, Depauw N, Fransen M, Goma C, Panahandeh H, Seco J, Flanz J, Kooy H. Golden beam data for proton pencil beam scanning. Phys. Med. Biol. 2010;57:1147-58.

9.Dowdell S, Clasie B, Depauw N, Rosenfeld A, Kooy H, Flanz J, Paganetti H. Monte Carlo study of the potential reduction in out-of-field dose using a patient-specific aperture in pencil beam scanning proton therapy. Phys. Med. Biol. 2010;57:2829-42.

10.Hälg R, Besserer J, Boschung M, Mayer S, Clasie B, Kry S, Schneider U. Field calibration of PADC track etch detectors for local neutron dosimetry in man using different radiation qualities. Nucl. Instrum. and Meth. Section A. 2010;694:205-10.

11.Butterworth K, McGarry C, Clasie B, Carabe-Fernandez A, Schuemann J, Depauw N, Tang S, McMahon S, Schettino G, O’Sullivan J, Lu HM, Kooy H, Paganetti H, Hounsell A, Held, K. Prise. Relative biological effectiveness (RBE) and out-of-field cell survival responses to passive scattering and pencil beam scanning proton beam deliveries. Phys. Med. Biol. 2010;57:6671-80.

12.Clasie B, Sharp G, Seco J, Flanz J, Kooy H. Numerical solutions of the gamma-index in two and three dimensions. Phys. Med. Biol. 2012;57:6981-97.

13.Clasie B, Flanz J, Kooy H. Interpolation of tabulated proton Bragg peaks. Phys. Med. Biol. 2012;57:N405-9.

14.Seco J, Clasie B, Partridge M. Review on the characteristics of radiation detectors for dosimetry and imaging. Phys. Med. Biol. 2014;59;R303-47.

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