[fluka-discuss]: Scoring the linear energy transfer (LET)/dose-averaged LET on a voxel-bt-voxel basis

From: Lars Fredrik Fjæra <lfj049_at_student.uib.no>
Date: Sat, 27 Aug 2016 18:19:03 +0200

Dear FLUKA experts,

After over a week's worth of trying I am stumped on how to score
LET/dose-averaged LET in FLUKA on a voxel-by-voxel basis, i.e. not using
USRYIELD as described in the manual.
Looking through previous FLUKA discuss threads have unfortunately not been
of much help, as none of the relevant threads have concluded with a proper
solution.

So, what I want to do is score LET for each voxel in CT-images. Therefore,
to utilize a USRBIN-card with the same scoring mesh as the CT-image to
obtain LET would be ideal.

I have tried to use the GETLET-function (which I really miss some
documentation on) to score the LET. I am able to use the function in either
the COMSCW-routine and the FLUSCW-routine, but as these routines as used as
weighting fluence, energy etc. I am unable to obtain the normalized
GETLET-values, i.e. divided by the USRBIN scoring quantity (see previous
post <http://www.fluka.org/web_archive/earchive/new-fluka-discuss/9410.html>).
I need to do this normalization within the routines, as normalizing offline
(described) in the previous post will *not* be correct.
Is there any way to obtain the scored USRBIN-value in either the FLUSCW- or
COMSWC-routine? I thought the the RULL-variable in the latter routine was
the scored quantity, but normalizing to by the RULL-variable did not work.
By properly normalizing I would hope to plot e.g. a 1D curve of the
LET-values directly in FLAIR.

I have also tried to score dose and fluence and dividing the former by the
latter to obtain the dose-averaged unrestricted LET (LET = Dose/Fluence),
but then again the LET values I obtain was incorrect.

Maybe there is another way? Maybe by scoring QLET? I don't know..

Any help what so ever to score LET voxel-by-voxel would be much appreciated!

I've attached my COMSCW-routine and input-file (note: only a regular water
RPP) where I use the GETLET-function. The printed LET-values are correct,
but than doesn't help if I can't obtain the values within FLUKA/FLAIR.

---
*Lars Fredrik Fjæra*




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Received on Sat Aug 27 2016 - 20:08:31 CEST

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