[Gate-users] Unexpected results when validating simulation

[Gustav Murquist]

Dear Gate users


I'm validating my simulations using a unit density sphere source of F-18 surrounded by water and comparing the simulation results to Stabin & Siegel (2003) and Stabin & Konijnenberg (2000). My simulation consists of a F-18 ion source and a voxelized phantom containing the sphere. To my, limited, knowledge everything seems to be working as intended, except I'm getting a self-absorption dose, to the sphere, that is consistently (independent of the size of the sphere) ~10% higher than the values in the reference articles. Could this be caused by the difference in physics (treatment of secondary particles etc.) between Gate/Geant4 and EGS4/MCNP4B (used in the reference articles)?

I would be very thankful for any help/advice!

Have a nice weekend!


Ref:

Stabin MG. and Siegel JA. Physical models and dose factors for use in internal dose assessment. Health Phys. 85(3):294 –310; 2003.

Stabin MG, Konijnenberg M. Re-evaluation of absorbed fractions for photons and electrons in small spheres. J Nucl Med 41:149–160; 2000.


Regards
Gustav

[1489736892538_KAROLINSKA_LOGO_sRGB2.jpg]

Gustav Murquist
Medical physicist

Nuklearmedicin Inflammation, Huddinge (C2:74)
Medicinsk Strålningsfysik och Nuklearmedicin
Karolinska Universitetssjukhuset
141 86 Stockholm
Telefon 08-585 862 92, mobil 070-001 73 03
e-post gustav.murquist at karolinska.se
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