Monte carlo radiation transport simulation in

dosimetryfrom environmental modelingto multimillion voxel human

phantom

Valery TaranenkoInstitute of Radiation Protection, GSF Research

Center, Munich, Germany

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

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

3D geometry

• Surface definition (1st, 2nd degree, tori)

• Macrobodies• Boolean operators (intersection,

union)• Repeated structures (lattices)

Event sampling

• E1, E2 , …, En – independent, mutually exclusive

• p1 + p2 + … + pn = 1

1 1 1

1 2 3

0 1

... ...

, , ,s s

s s

i i

e i

c

t t t

e it c

p p p p

p p p

Sampling distance to collision

0

( )

1

1ln(1 )

t

t t

lt

ls lt

t

p l dl e dl

e ds e

l

photons

EPDL97 Evaluated Photon Data Library

1997, LLNL• Z = 1 … 100 (fermium)

• E = 1 keV … 100 GeV

Cross sections for:– P hotoionization– Coherent scattering– Incoherent scattering– Pair and triplet

production– Form factors– Scattering functions– Anomalous scattering

func– Average energy of all

secondaries