UK National Grid Service - Grid Computing: Infrastructure, Service, and Applications - page 162

FIGURE 6.2 Demographic modeling on the NGS.

In order for radiation-dose simulations to be clinically relevant, they
need to be completed in a matter of hours. Unfortunately this is often not
the case, with many simulations taking days, which is where the NGS has
been brought in. Dr. Mary Chin from the University of Surrey and the
Welsh e-Science Center have worked together to tackle this problem.
Radiation doses in patients are calculated using the Monte Carlo method
to simulate the creation, path, and destruction of each particle. The statisti-
cal sampling of the Monte Carlo method means that the greater the number
of simulated events, the better the coni dence level of the result as the
entry of trillions of particles into the body can be simulated. Using the
NGS has enabled the simulation time to be reduced from almost a week to
3 hours. This obviously has implications for the clinical usefulness of such
simulations. Medical physicists can verify treatment programs before and
during the treatment. As complex radiotherapy modalities become increas-
ingly common, verii cation of the treatment is vital.

Acknowledgments
We would like to acknowledge all those who have contributed to and made
possible the various grid activities within the UK, especially those who
have worked for the Grid Support Center, the Grid Operations Support
Center, the National Grid Service, and the Engineering Task Force.