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

From: Paola Sala <>
Date: Mon, 29 Aug 2016 10:02:09 +0200

Dear Lars,
yes, the scored quantity is RULL.
No, the printed values are not the comscw you attach, the
value from GETLET is received in an integer variable (LETV is integer
according to standart fortran implicits), thus LETV always contains Zero.
For info: Getlet returns (un)restricted LET in (keV/(um g/cm3)).
One should NOT change sign to the particle ID in the call to getlet ( yes,
changing sign is needed to retrieve the mass if iJ<-6, but getlet does
this on its side.)
Be also careful to normalization: USRBIN energy values are normalized per
cubic centimeter, and normalization occurs a the end of the run. So, your
results will depend on the bin size.
Hope this helps

> 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
> <>).
> 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*

Paola Sala
INFN Milano
tel. Milano +39-0250317374
tel. CERN +41-227679148

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Received on Mon Aug 29 2016 - 11:44:15 CEST

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