1. Monte carlo radiation transport simulation in dosimetry from environmental modeling to multimillion voxel human phantom Valery Taranenko Institute of Radiation Protection, GSF Research Center, Munich, Germany

2. outline Monte Carlo method in radiation transport 3D geometry Photon transport Examples of dosimetric problems –Verification of dose in air –Exposure of non-human biota –Human voxel phantom

3. Monte Carlo method Mimics the physics processes Source sampling Tracks the particles in model geometry Samples collision events Production of secondaries Averages over millions of histories Estimators (fluence, current, point detector, …) Variance reduction techniques

4. 3D geometry Surface definition (1st, 2nd degree, tori) Macrobodies Boolean operators (intersection, union) Repeated structures (lattices)

5. Event sampling E 1, E 2, …, E n – independent, mutually exclusive p 1 + p 2 + … + p n = 1

6. Sampling distance to collision

7. photons

8. EPDL97 Evaluated Photon Data Library 1997, LLNL Z = 1 … 100 (fermium) E = 1 keV … 100 GeV Cross sections for: –Photoionization –Coherent scattering –Incoherent scattering –Pair and triplet production –Form factors –Scattering functions –Anomalous scattering func –Average energy of all secondaries