Dear Lars, dear FLUKA Users,
I want to adress only the question of 'So where are these CORRFACT cards?'
You can, on a linux machine, adress the ASCII content of the binary
.vlx file by typing 'strings FILE.vlx'. There you will find the
automatically generated cards.
Best,
Franz
Quoting Lars Fredrik Fjæra <lfj049_at_student.uib.no>:
> Dear FLUKA users,
>
> I have two problems I want to address.
>
> First, is there an error in the Flair Dicom/Voxel tab? The unit range on
> the far left specifies Hounsfield units "less than" (<), however, when I
> was using artificial CT-scans, I noticed that Flair applies materials
> according to units of "less or equal" (<=). As an example, I have the
> following defined:
>
> < Unit Material Crho_min Crho_max
> 1000 HU<1000 0.9810 1.0168
> 1100 HU<1100 0.9852 1.0144
>
> In my CT scan I have only two Hounsfield units, HU=1000 and HU=-1000. Using
> the HU=1000 as an example, it should, according to Flair, be assigned the
> material called HU<1100 considering that 999<HU1000<1100. However, the HU
> of 1000 gets assigned the material HU<1000. This then means that the unit
> specification in Flair should be (=<). I have also noticed that this was
> the case in previous versions in Flair referring to for example the image
> in the manual. I have also attached images of my voxel/geometry setup to
> further illustrate the problem. The same also happens for my HU=-1000. It
> gets assigned the material HU<-1000 specified with the unit <-1000, where
> it really should be assigned the material HU<-1010.
>
> Next problem. I really miss a proper explanation/documentation of the
> stopping power calibration in the voxel tab. Performing the density
> calibration (Crho_min and Crho_max) is straight forward and works
> perfectly. I am however struggling with dE/dx calibration. First off, it is
> specified that the dE/dx correction are relative corrections. Relative to
> what? According to the manual, "dE/dx is applied relative to the correction
> of density (negative WHAT(1) in CORRFACT)". However, I was under the
> impression that if you perform the calibration in the .vxl file itself, you
> don't need any separate CORRFACT cards? The manual also states:
> "CdEdx_rel_min: relative correction factor on dE/dx for the minimum unit
> in the range CdEdx_rel_max: relative correction factor on dE/dx
> for the maximum unit in the range". So then I wonder, is the correction
> applied to the density corrections? I.e. If I have rho = 1, and Crho_max =
> 1.5 and CdEdx_rel_max = 1.5, the effective density for the stopping power
> will be 2.25?
> Further, from the FLUKA course slides about medical application, there is a
> sentence that states "FLAIR automatically appends the CORRFACT cards
> calculated taking into account the calibration curves provided by the user
> at the end of the .vxl file." So where are these CORRFACT cards?
> And to add to all this, I have been playing around with the CdEdx_rel_min
> and CdEdx_rel_max, just trying to change them to see if I can obtain some
> difference in the simulated ranges for Bragg peaks. However, I can apply
> whatever value to CdEdx_rel_min and CdEdx_rel_max, and still obtain
> exactly the same curves. I've even tried to obtain an error in my
> simulations by setting the CdEdx_rel_min and CdEdx_rel_max beyond the
> range [2/3,3/2], however the simulation runs fine. I did the same thing for
> the Crho_min and max, where I successfully obtained an error. So it seems
> that FLUKA doesn't even take into account my input to CdEdx_rel_min and
> CdEdx_rel_max. On the other hand, I am perfectly able to apply corrections
> using regular CORRFACT cards. Can someone please explain thoroughly how to
> properly use CdEdx_rel_min and CdEdx_rel_max?
>
> Thank you!
>
> ---
> *Lars Fredrik Fjæra*
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Received on Mon Oct 17 2016 - 13:20:53 CEST