[Gate-users] GateDoseSpectrumActor

Maikol Salas Ramirez mmsalas at gmail.com
Wed Feb 2 08:52:17 CET 2022


Hi Andreas,

I see the practicality in the GateDoseSpectrumActor. As far as I know, no
other actor calculates the energy and its uncertainty so quickly (at least
for a logical volume). The ESpectrActor always requires some
post-processing, normally it is no big deal, but it is nice to have the
result without intermediate steps.

On the other hand, your approach "square of the bin vector in a post
processing step" will not lead to the same result. The
uncertainty calculation in one single simulation is a history-by-history
method (error = sqrt( (1.0 / ( numPart - 1)) * ( avgEnergySq - pow(
avgEnergyOut, 2)))), it means the energy contribution (square) is scored
per history. The ESpectrActor does not make this distinction. It mixes all
the contributions.

>From my point of view, the GateDoseSpectrumActor does not cause any damage.
It can continue inside of GATE, but if there is a change to update it or
translate its features to the ESpectrActor it would be nice.

Best,
Maikol




El mar, 1 feb 2022 a las 15:10, Andreas Resch (<
andreas.resch at meduniwien.ac.at>) escribió:

> Hi David, Maikol,
>
> just had a brief look into the source code of DoseSpectrumActor. Looks
> fine at the first glance, but is obsolete as 1 of the two scoring results
> is also part of ESpectrActor. Would be only few lines of extra code to add
> the second option (square of energy deposit) to ESpectrActor. Although I
> wonder if it is really necessary. Shouldn't it be enough to do the square
> of the bin vector in a post processing step? (using a high resolution
> binning of course)
>
> best,
>
> Andreas
>
> Am 2022-02-01 10:17, schrieb Maikol Salas Ramirez:
>
> Hello David,
>
> Thank you for the answer. I re-check my calculation, and I found out
> that the units are well (I mean the EnergySpectrumActor and
> GateDoseSpectrumActor agree in the deposited energy calculations).
>
> To check it, I attached both actors to the same logical volume and
> calculated the deposited energy for comparison. In the case of
> EnergySpectrumActor, I summed the energy spectrum, and for
> GateDoseSpectrumActor, it provides the total energy (sum) plus the
> uncertainty directly.
>
> The GateDoseSpectrumActor has the advantage that it provides the total
> deposited energy with its uncertainty. This information is impossible to
> obtain with the EnergySpectrumActor, because it does not give the square of
> the sum of the energies.
>
> I think the GateDoseSpectrumActor could be useful for the community. But,
> it is not documented in the opengate.readthedocs.io, and the C++ classes
> are probably incomplete (probably the goal was the absorbed dose
> calculation, but its development stops with the energy calculation). At
> this moment, the GateDoseSpectrumActor help me resolve my
> task straightforwardly. I think it is better to keep it. Hopefully, it will
> be a chance to improve it in the future.
>
> I am finalizing some details of the simulation (blood irradiation with
> radionuclides); if it would interest you, I can share it for the GATE
> examples with some documentation.
>
> Best regards,
> Maikol
>
> El mar, 1 feb 2022 a las 8:05, David Sarrut (<
> david.sarrut at creatis.insa-lyon.fr>) escribió:
>
> Hello Maikol,
>
> I don't know this actor and, looking at the history, it was started before
> we started the git version (2015), so the original author is lost.
> As there is no doc and I don't really get what it means compared to the
> EnergySpectrumActor, I would suggest to remove it.
>
> However, if you think it could be useful for you, please let us know. The
> idea would be to propose some docs and use case.
>
> thanks,
> David
>
> On Mon, Jan 31, 2022 at 5:50 PM Maikol Salas Ramirez <mmsalas at gmail.com>
> wrote:
>
> Dear Gate users,
>
> Recently I found the .cc and .hh files of a *GateDoseSpectrumActor*. This
> actor is not mentioned in opengate.readthedocs.io or any webpage.
> I would like to ask if someone is working on it. Is it a prototype?
>
> I tested the energy calculation using the EnergySpectrumActor and the
> energy units differ:
>
> I simulated a Ac-225 source using the Ion source definition. I scored the
> deposited energy with both actors (EnergySpectrumActor and
> GateDoseSpectrumActor). The deposited energy differs by a factor of 1000. *The
> only justification that I can find is that, in the GateDoseSpectrumActor,
> the deposited energy is expressed in keV/(1000 events) OR (eV/event) and
> there is a typo in the code (the units shoud be eV instead of keV):*
> #-------------------------------------------
> /// Save data
> void GateDoseSpectrumActor::SaveData()
> {
>   GateVActor::SaveData();
>   std::ofstream DoseResponseFile;
>   OpenFileOutput(mSaveFilename, DoseResponseFile);
>   DoseResponseFile << "Incoming energy (*keV*)" << " "
>                    << "Average energy deposit (*keV*)" << " "
>                    << "Energy uncertainty (*keV*)"  << Gateendl;
>   std::map< G4double, G4double>::iterator itermEnergy;
>   for( itermEnergy = mEnergy.begin(); itermEnergy != mEnergy.end();
> itermEnergy++)
>   {
>     G4double energyIn = itermEnergy->first;
>     G4double totEnergyOut = mEnergy[energyIn];
>     G4double numPart = mNumParticPerEnergy[energyIn];
>     G4double avgEnergyOut = totEnergyOut / numPart;
>     G4double avgEnergySq  = mEnergySquare[energyIn] / numPart;
>     G4double error = sqrt( (1.0 / ( numPart - 1)) * ( avgEnergySq - pow(
> avgEnergyOut, 2)));
>     DoseResponseFile << energyIn/*keV* << " "
>                      << avgEnergyOut/*keV* << " "
>                      << error/*keV*  << Gateendl;
>   }
> #-------------------------------------------
>
> Is anyone working on this?
>
>
>
> Best regards
> Maikol
>
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>
> --
> David Sarrut, Phd
> Directeur de recherche CNRS
> CREATIS, UMR CNRS 5220, Inserm U1294
> Centre de lutte contre le cancer Léon Bérard
> 28 rue Laënnec, 69373 Lyon cedex 08
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