[Gate-users] Gate dose to water problem

[Andreas Resch]

Hi,

when you look into GateDoseActor.cc
these are your lines
  if (mIsDoseToWaterImageEnabled){
   ...
       if (PartName== "proton" || PartName== "e-" || PartName== "e+" || 
PartName== "deuteron") {

         DEDX = emcalc->ComputeTotalDEDX(Energy, PartName, material, 
cut);
         DEDX_Water = emcalc->ComputeTotalDEDX(Energy, PartName, 
"G4_WATER", cut);

         
doseToWater=edep/density/Volume/gray*(DEDX_Water/1.)/(DEDX/(density*e_SI));
       }
       else {
         DEDX = emcalc->ComputeTotalDEDX(100, "proton", material, cut);
         DEDX_Water = emcalc->ComputeTotalDEDX(100, "proton", "G4_WATER", 
cut);
         
doseToWater=edep/density/Volume/gray*(DEDX_Water/1.)/(DEDX/(density*e_SI));
       }
it seems to me, that the dose to water was created for proton beams. 
Secondly, you need to check or set the Ionization potential of G4_WATER 
(the I value of your Water and G4_WATER could be different). Yet, it 
does not explain the NaN values.

Best,
Andreas

Am 2017-01-31 16:22, schrieb Grevillot Loic:
> Hi,
> 
> Could you send macros and output files?
> 
> Best,
> 
> Loïc
> 
> FROM: tony youness [mailto:tony_youness at live.com]
> SENT: Tuesday, January 31, 2017 3:14 PM
> TO: Grevillot Loic; gate-users at lists.opengatecollaboration.org
> SUBJECT: Re: Gate dose to water problem
> 
> Hi,
> 
> I am simulating high energy photon beams (6 and 10 MeV) for external
> radiotherapy applications.
> 
> I tried both ("Water" and "G4_WATER") and I am still getting NAN
> values (only when the absorbed dose is reported as absorbed dose to
> water). The voxel values between both absorbed dose report (Dose to
> medium and Dose to water) are also different even though that the
> medium is WATER.
> 
> Regards,
> 
> Tony
> 
> On 31/01/17 8:37 am, Grevillot Loic wrote:
> 
>> Hello,
>> 
>> Which beam are you simulating? (photons, electrons, light ions,
>> etc.)
>> 
>> Which water did you define in your simulation? “Water” is
>> different from “GEANT4_WATER” -> could you try using
>> GEANT4_WATER?
>> 
>> Best,
>> 
>> Loïc
>> 
>> FROM: Gate-users
>> [mailto:gate-users-bounces at lists.opengatecollaboration.org] ON
>> BEHALF OF tony youness
>> SENT: Monday, January 30, 2017 1:04 PM
>> TO: gate-users at lists.opengatecollaboration.org
>> SUBJECT: [Gate-users] Gate dose to water problem
>> 
>> Dear All,
>> 
>> I am facing a problem with gate dose actor. When enabling dose to
>> water i get Nan values in some of the voxels in the water region of
>> my phantom. I also get different values in the water voxels between
>> both dose reports (dose to medium and dose to water). It seems like
>> there's a bug when gate tries to converts dose to medium into the
>> dose to water when in the water region. Has anyone already faced
>> this problem? Any help would be much appreciated.
>> 
>> Kind Regards,
>> 
>> Tony Younes
>> 
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-- 
-------------------------

ANDREAS RESCH, M.SC.
PhD student, Medical Physics

MEDICAL UNIVERSITY OF VIENNA
Department of Radiotherapy
Christian Doppler Laboratory for Medical Radiation Physics for Radiation
Oncology

Waehringer Guertel 18-20, 1090 Wien
Ph: +43 (0)1 40400-72710
Ph: +43 (0)2622 26100-931
andreas.resch at meduniwien.ac.at
www.meduniwien.ac.at/radonc