Monte Carlo Simulation in Medicine with TOPAS

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June 29 - July 1, 2020,  12 - 5:15 PM Eastern Daylight Time
Online via Zoom

Cost: Free


Format/Educational methodsA 15 hour on line course divided evenly over three days (5 hours a day with a 15-minute break) with lectures and practical examples. The students will use the TOPAS system hands-on to simulate the examples shown by the instructors and observe the effect of changing parameters used in the different simulations.

Participants must have a computer capable of running TOPAS.

  • Mac OSX 10.12 or newer
  • Linux Debian 8, 9 or 10 or a Debian 8, 9 or 10 variant
  • CentOS 6, 7 or 8 or a CentOS 6, 7 or 8 variant
  • Other OS with a Virtual Machine system pre-installed and one of the above Linux variants
    (note: Windows 10 already comes with an appropriate Linux subsystem)
Target audienceMedical physicists with basic knowledge of Monte Carlo simulations. The course is designed for new as well as experienced TOPAS users.

Requirement: Participants are required to complete the 2-hour on-line TOPAS introductory course and have TOPAS installed on their computer prior to the course. Sign-up for the introductory course is available at Installation instructions are given as part of the course.

Course objectivesTo provide the background necessary for participants to reliably use the TOPAS Tool for Particle Simulation for Monte Carlo simulation in medicine. Participants will learn the fundamentals of the Monte Carlo method and its application in medicine. They will then learn through lectures and examples how TOPAS provides a simple, effective means to access the Geant4 Monte Carlo toolkit. Participants will leave the course with practical knowledge on how to use TOPAS for their own application.

Registration period: April 20, 2020, closing June 20, 2020 (or when reach 50 participants, first come first served). The course might be cancelled if fewer than 20 participants register.

Registration method: Register online at

Activity location: The course will be given online. The institutions of the instructors are listed below.

Zoom: Zoom login information and password will be distributed to registered participants prior to the course. 

CAMPEP application statement: This meeting has applied to CAMPEP for approval of 15 MPCEC hours. The online system to be used will allow tracking of attendance. 

Sources of support: This course is supported under NIH grant U24CA215123.

Instructors (in alphabetical order):

  • Bruce Faddegon, Ph.D., TOPAS U24 PI, UCSF (Bruce)
  • Harald Paganetti, Ph.D., Director of Physics Research, MGH (Harald)
  • Joseph Perl, Chief TOPAS architect, SLAC (Joe)
  • Jose Ramos Mendez, Ph.D., TOPAS Developer, UCSF (Jose)
  • Jan Schuemann, Ph.D., Head of Multi-Scale Monte Carlo lab, MGH (Jan)
  • Aimee McNamara, Ph.D., TOPAS Developer, MGH (Aimee)
  • Jungwook Shin, Ph.D., TOPAS Developer, MGH (Jungwook)

TOPAS Course Outline


Time given is Eastern Daylight Time

Each lecture includes a 15-minute Question and Answer session


Day 1 (Monday, June 29 2020)

Introduction to Monte Carlo simulation and TOPAS
12:00 pm       Welcome and introductions (Joseph, Bruce, Harald)

12:15 pm       Lecture 1 - Review of fundamentals of the Monte Carlo method (Jose)

1:15 pm         Lecture 2 - Monte Carlo in medicine (Bruce)

2:15 pm         Lecture 3 - Monte Carlo in proton therapy (Harald)

3:00 pm         Break

3:15 pm         Lecture 4 - Geant4 and TOPAS (Jan)

4:00 pm         Lecture 5 - TOPAS basics (Joseph)

5:15 pm         Adjourn


Day 2 (Tuesday, June 30 2020)

Hands-on experience with TOPAS
12:00 pm       Example 1 - Dose, fluence, and LET from protons in water (Harald)

12:45 pm       Example 2 - Linac treatment head simulation (Bruce)
1:30 pm         Example 3 - Generic double-scattering proton treatment head (Joseph)

2:15 pm         Hands on examples 1-3

3:00 pm         Break

3:15 pm         Example 4 - Extensions (Jose)
4:00 pm    Example 5 - Proton patient dose, LET and RBE calculation using pre-made extensions (Jan)
4:45 pm         Hands on examples 4-5

5:15 pm         Adjourn


Day 3 (Wednesday, July 1 2020)

Hands-on advanced examples
12:00 pm       Example 6 - Target tracking for a scanning beam proton system (Joseph)
12:45 pm       Example 7 - Variance reduction for a generic x-ray linac (Jose)

1:30 pm         Example 8 - Scanning beam simulations with DICOM-interface (Jungwook)

2:15 pm         Hands on examples 6-8

3:00 pm         Break
3:15 pm         Example 9 - Advanced extensions – TOPAS-nBio (Aimee)

4:00 pm         Hands on example 9
4:45 pm         General Q&A (Moderated by Bruce)

5:15 pm         Adjourn