Re: [fluka-discuss]: Dose Scoring

From: Francesco Cerutti <Francesco.Cerutti_at_cern.ch>
Date: Wed, 21 Mar 2018 22:16:29 +0100

Dear Yuri,

> Is there a way to reconstruct this integrated 2D dose to a 3D distribution, i.e. to separate
> the contribution from each different Range Shifter depth?

since you change the Range Shifter depth runtime, you should alter
accordingly the index associated to the longitudinal position of your
scoring grid (USRBIN) cell, which does not look possible by means of user
routines.
The correlation between actual depth and dose value can be preserved
through an event-by-event EVENTBIN scoring, still requiring customized
post-processing to build a cumulative 3D grid.

Not sure it helps much

Cheers
Francesco

**************************************************
Francesco Cerutti
CERN-EN/STI
CH-1211 Geneva 23
Switzerland
tel. +41 22 7678962
fax +41 22 7668854

On Tue, 20 Mar 2018, Yuri Simeonov wrote:

> Dear Fluka experts,
>
> We measured the 3D dose distribution from a scanned 5x5 cm2 field proton beam using an in-house
> built binary "Range Shifter" and a 2D PTW dose chamber array.  The range shifter consists of
> many precisely cut PMMA plates of different
> thicknesses and was used as a water phantom substitute. These plates can be moved quickly and
> independently in and out of the beam. By combining different
> plates, we can simulate different water equivalent depths. A scematic figure of the
> RangeShifter is attached.
> The dose was measured continuously by the 2D array (integration mode). In order to reconstruct
> a 3D dose distribution from the single integrated dose measurement, the time frame of the dose
> measurement was synchronised with the time frame of the range shifter movements and the dose
> was "divided" in many 2D slices, corresponding to the different water depths.
> Due to a variaty of reasons, we would like to reproduce this measurement setup in FLUKA,
> instead of simply simulating it in a water phantom. The idea is to use the source.f routine
> (which we anyway use for raster scanning) in combination with the "SETBDY " command. For
> example, we want to simulate 10 depths (resp. 10 different range shifter configurations) with
> 1000 primaries. After a stack of 100/200/300... particles, the thickness and position of a
> single slab body will be changed according to the original Range Shifter sequence.
>
> The dose will be scored in e.g. 1mm water slice (one bin in beam direction!), representing the
> real 2D Dose array. This way, at the end of the simulation we will obtain dose distribution
> integrated over all depths.
>
> Is there a way to reconstruct this integrated 2D dose to a 3D distribution, i.e. to separate
> the contribution from each different Range Shifter depth?
>
> Regards
> Yuri
>
>

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Received on Wed Mar 21 2018 - 23:40:19 CET

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