Ian C. Smith1

1

A portal-based system for quality assurance of
radiotherapy treatment plans using Grid-enabled
High Performance Computing clusters
Ian C. Smith1
CR Baker2, V Panettieri3, C Addison1, AE Nahum3
1 Computing Services Dept, University of
Liverpool 2 Directorate of Medical Imaging and
Radiotherapy, University of Liverpool 3 Physics
Department, Clatterbridge Centre for Oncology
2
Rationale

• MC codes can provide accurate absorbed dose
  calculations but are computationally demanding
• Desktop machines not powerful enough, need
  parallel hardware e.g. High Performance Computing
  (HPC) clusters
• Aim to exploit local and centrally funded HPC
  systems in a user-friendly manner
• Two MC codes have been investigated to date
• MCNPX (beta v2.7a)
• Parallel (MPI-based) code
• General purpose transport code, tracks nearly all
  particles at nearly all energies
  (https//mcnpx.lanl.gov/).
• PENELOPE
• serial implementation
• general purpose MC code implemented as a set of
  FORTRAN routines
• coupled electron-photon transport from 50 eV to 1
  GeV in arbitrary materials and complex
  geometries1.

1 Salvat F, Fernández-Varea JM, Sempau J.
PENELOPE, a code system for Monte Carlo
simulation of electron and photon transport.
France OECD Nuclear Energy Agency,
Issy-les-Moulineaux 2008. ISBN 9264023011.
Available in pdf format at http//www.nea.fr.
3
Grid Computing Server / UL-GRID Portal
4
Grid Computing Server / UL-GRID software stack
5
(No Transcript)
6
MCNPX Job Submission
7
PENELOPE Job Submission
8
PENELOPE (serial code) workflows

• Rereasdasdas

create random seeds for N input files using
clonEasy1
create random seeds for N input files using
clonEasy1
stage-in phase-space file (only if necessary)
repeat for other patients
compute individual phase-space file
compute partial treatment simulation results
combine N individual phase-space files
combine partial treatment simulation results
using clonEasy1
phase-space file calculation
patient treatment simulation
HPC cluster
Portal
1 Badal A and Sempau J 2006 A package of Linux
scripts for the parallelization of Monte Carlo
simulations Comput.Phys. Commun. 175 44050
9
(No Transcript)
10
External beam photon treatment modelled using
PENELOPE

• Three 6 MV beams
• Resolution 256 x 256 ( x 51 CT slices)
• Final average dose uncertainty 2 (2s)

11
MCNPX Proton beam modelling
Clatterbridge proton facility
Protons transported through the beam-line
(scattering system, range-shifters, modulators
and collimators).
Incident spectrum fitted to measured Bragg
peak Generic phase-space file generated at the
position of the modulator and subsequently
transported through patient-specific
range-shifter and modulator
Baker, Quine, Brunt and Kacperek (2009) Applied
Radiation and Isotopes 67 3402
12
Proton absorbed dose in water
2.5cm diameter beam, full energy (60 MeV at
patient, 3.2 cm range in water) 500 million
histories 0.5x0.5x5 mm voxels 50keV proton
cut-off lt1 statistical uncertainty in absorbed
dose in high dose region (1s)
13
Timing Results

• PENELOPE (Serial)
• Phase-space file calculation
• 4 days per beam on 7 cores
• 700 x 106 particles per file
• Patient calculation
• 1 simulation required 4 days on 1 core
• 1 simulation on 32 cores should only require 3
  hours
• MCNPX (Parallel under MPI)
• 500 million histories over 32 cores, lt 4 hours,
  without variance reduction applied.

14
Future Directions

• Expand portal interface to include submission of
  job workflows
• Provide support for BEAM1 and DOSxyz3
  (based on the EGSnrc MC code 2)
• Possible use of Windows Condor Pool to create
  PSFs for PENELOPE

References 1 23D. W. Rogers, B. Faddegon, G.
X. Ding, C. M. Ma, J. Wei, and T. Mackie, BEAM
A Monte Carlo code to simulate radiotherapy
treatment units, Med. Phys. 22, 503524
_1995_. 2 Kawrakow and D. W. O. Rogers. The
EGSnrc Code System Monte Carlo simulation of
electron and photon transport. Technical Report
PIRS-701 (4th printing), National Research
Council of Canada, Ottawa, Canada, 2003. 3
Walters B, Kawrakow I and Rogers D W O 2007
DOSXYZnrc Users Manual Report PIRS 794 (Ottawa
National Research Council of Canada)