[Gate-users] Dose actor and uncertainties

[REUZE SYLVAIN]

Dear Gate users,

I have an issue with dose actor uncertainties. I've read several threads on the mailing list about uncertainty calculation, but I don't understand the output of the dose-uncertainty file.
In my simulation, I have a linac model with an input phase space at the end of the patient-independent part, and I would like to know uncertainty in a region of interest of my dose chart, recorded in a water phantom.

Values of the dose chart very low (~ 10^-8), and values of the uncertainty chart are between 6 and 10. Are these values relative (in %) or absolute ?

And when I try to use dose squared and dose with a formula (Visvikis et al.: https://hal.archives-ouvertes.fr/in2p3-00025095/document), I have negative values under the square root.

Could you help me ?

Best regards,

Sylvain Reuzé
Intern in medical physics
GUSTAVE ROUSSY
Radiotherapy - Medical Physics Department
Tél. : (+0033) 1 42 11 54 06
www.gustaveroussy.fr<http://www.gustaveroussy.fr/>
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