Speaker
Describe the scientific/technical community and the scientific/technical activity using (planning to use) the EGEE infrastructure. A high-level description is needed (neither a detailed specialist report nor a list of references).
Number of patients cared with radiotherapy methods has recently
increased due to the
development of linac and multi leaf technologies. The high
precision in the dose
distribution possible with the new machines needs the development
of more accurate
codes to determine the treatment plan. MonteCarlo methods allow
big precision in the
dose distribution calculation but are very CPU time consuming.
The application makes
use of the power of the GRID to validate treatment plan systems
(TPS).
With a forward look to future evolution, discuss the issues you have encountered (or that you expect) in using the EGEE infrastructure. Wherever possible, point out the experience limitations (both in terms of existing services or missing functionality)
Sometimes jobs stay “Scheduled” for a very long time even if
there are some free CPUs
available. WMS, on matchmaking phase, does not take in account
the real
status of resources. In fact, during the submission of a large
production, the
matchmaking of the n-th job does not take into account that the
(n-1) jobs have just
been submitted, so jobs are not uniformly spread across the CEs.
Another problem is the low efficiency (about 60%) due to many
jobs aborted for
unknown reasons.
Describe the added value of the Grid for the scientific/technical activity you (plan to) do on the Grid. This should include the scale of the activity and of the potential user community and the relevance for other scientific or business applications
The GRID can represent the solution for the large computing
requirements of Monte
Carlo applications in radiotherapy which are embarrassingly
parallel. The GRID can,
in fact, be of great utility to provide physicians with a fast
computing resource
able to calculate detailed and precise Monte Carlo based
treatment plans without
requiring the hospital to set-up and manage a dedicated computing
centre.
In this contribution we refer to a Monte Carlo application
created to simulate the
Elekta Gamma Knife, a stereotactic radiotherapy machine to treat
the brain lesions.
The application makes use of the Geant4 toolkit and reproduces
all Gamma Knife
features (like collimators’ geometry) so to simulate a realistic
energy deposition.
Report on the experience (or the proposed activity). It would be very important to mention key services which are essential for the success of your activity on the EGEE infrastructure.
In order to run a Geant4 application on the GRID, the first step
was to install the
used libraries at the various sites. The second step was to
prepare a shell script to
automatically submit jobs and download the outputs at their end.
In this respect, it
has been very useful to set a threshold in the number of jobs
“done” before starting
the downloading & merging phase. The last step was to choose the
best quality factor
between the number of events and the number of jobs to be
submitted.
The key services, that are essential to run a TPS Monte Carlo
application on GRID,
are a low-latency Workload Management System and a more reliable
monitoring system of
available computing resources.
