# Re: [fluka-discuss]: Voxel geometry - region dose scoring - it it valid?

From: Francesco Cerutti <Francesco.Cerutti_at_cern.ch>
Date: Sat, 11 Mar 2017 12:54:26 +0100

Dear Alex,

there are two basic flaws in your approach, already discussed in this forum,
e.g. here:
http://www.fluka.org/web_archive/earchive/new-fluka-discuss/6342.html

First, you talk about "integral" dose and "total" absorbed dose of the specific
region, suggesting that you aim for a sum over the region. But dose is not an
extensive quantity, as instead deposited energy is, therefore its value on a
region represents the *average* over the region, which - in case of not uniform
distribution - is lower than local dose values inside the same region.

Second, you forget that USRBIN *per region* (contrary to Cartesian or
cylindrical USRBIN) cannot normalize by the (region) volume, so the quantity
that you find is GeV/(g/cm3), i.e. GeV*cm3/g and not GeV/g. This implies the
need for dividing a posteriori by your region volume (in addition to the GeV ->
mJ conversion). This way you will get the *average* dose over the region.

Cheers

Francesco

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

On Sat, 11 Mar 2017, Ševčik Aleksandras wrote:

>
> Dear experts,
>
>
> Currently I'm simulating an isotope dose distribution in the anthropomorphic
> regions representing different tissues). For the overall picture USRBIN Dose
> tally goes well, but I
> also need the integral dose over the specific voxel regions(organs), i.e. to
> know total absorbed
> dose of the specific region.
>
>
> For that purpose I used USRBIN Region point parameter and selected the
> particular region. The
> result I got is attached, i.e. simply the number which supposedly  should be
> normalized (multiplied
> by 1.602176462E-7) to get it in Gy.
>
>
> My question if this approach is correct as I have some doubts that I am
> oversimplifying it
>
>
> Many thanks for any comments/input,
>
>
> Rgds
>
> Alex
>
>
>

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Received on Sat Mar 11 2017 - 13:51:15 CET

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