[fluka-discuss]: Re: FW: Dose simulation for lungs (sponge like material) of different densities

From: Alberto Fasso' <fasso_at_slac.stanford.edu>
Date: Tue, 31 Mar 2015 07:03:53 -0700 (PDT)

Dear Andrej,

I am sorry that your email to the discussion list was not published
(I wonder why). But your question is correct and could interest other users,
therefore I send it again to the discussion list, hoping it will work
this time, together with my answer.
You are right: there was a mistake in the manual, that we corrected a few
weeks ago without informing the users. The correction will appear in the
next FLUKA release, but I am giving it to you here below.

In Example 2 of command MAT-PROP, instead of:
* Average density of lung is 1.05*0.286 = 0.3 g/cm3.
MAT-PROP 0.0 0.286 75.3 LUNG 0. 0.

we should have written:
* Local density of lung is 1.05 = 0.3*3.50 g/cm3
MAT-PROP 0.0 3.50 75.3 LUNG 0. 0.

In other words, instead of the correct multiplying factor 3.50, we had
written in the example its inverse 1/3.50 = 0.286

Apologies

Alberto


On Tue, 31 Mar 2015, Sipaj Andrej wrote:

> Dear Giuseppe and Alberto,
>
> I am very sorry write to you directly but I sent email to FLUKA discussion
> forum on Friday last week but my question about "dose in lungs (sponge like
> material) of different densities" was never published. Therefore, I would like
> to kindly ask you if you could help to answer it or publish it on the forum. I
> can resend the topic again but I don't want to spam the forum email.
>
> Thank you very much for your help and time,
> Andrej
>
> -----Original Message-----
> From: Sipaj Andrej
> Sent: Freitag, 27. März 2015 16:03
> To: 'fluka-discuss_at_fluka.org'
> Subject: Dose simulation for lungs (sponge like material) of different densities
>
> Dear FLUKA experts,
>
> I am trying to simulate dose to lungs and surrounding tissue during conventional therapy treatments. I am using example from the FLUKA manual for material definition of ICRU lungs including MAT-PROP and STERNHE (http://www.fluka.org/fluka.php?id=man_onl&sub=51 , Example 2).
>
> However, when I am changing the average lung density (0.2, 0.3, 0.4 g/cm3) due to breathing by the use of RHOR in MAT-PROP card and keeping the same local density RHO (=1.05 g/cm3) in MATERIAL card with same input, I am not noticing any differences in dose or energy absorption.
>
> Average lung density 0.2 g/cm3 = 1.05 * 0.190,
> MAT-PROP 0.190 75.3 LUNG
> STERNHEI 3.4708 0.2261 2.8001 0.08588 3.5353 LUNG
>
> Average lung density 0.3 g/cm3 = 1.05 * 0.286
> MAT-PROP 0.286 75.3 LUNG
> STERNHEI 3.4708 0.2261 2.8001 0.08588 3.5353 LUNG
>
> Output from total energy and dose absorbed in lungs
> Average lung density 0.2 g/cm3: ENERGY: 1.1657E-03 DOSE: 1.1102E-03
> Average lung density 0.3 g/cm3: ENERGY: 1.1657E-03 DOSE: 1.1102E-03
>
> Therefore, I would like to ask you if you could explain how to change correctly the average density of the lungs for different breathing phases (density 0.2, 0.3, 0.4 g/cm3) please. Simplified FLUKA runs of this problem are included in the attachment.
>
> Thank you very much,
> Andrej
>
> --------
> AIT Austrian Institute of Technology GmbH Donau-City-Strasse 1 | 1220 Vienna   |  Austria T +43(0) 50550-4306 |  M +43(0) 669 17358884  |  F +43(0) 50550-2136 andrej.sipaj_at_ait.ac.at  |  http://www.ait.ac.at

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Received on Tue Mar 31 2015 - 17:29:05 CEST

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