Message: RE: about step limitation in Hadrontherapy Not Logged In (login)
 Next-in-Thread Next-in-Thread
 Next-in-Forum Next-in-Forum

None RE: about step limitation in Hadrontherapy  

Forum: Medical Applications
Re: Question about step limitation in Hadrontherapy
Date: 11 Mar, 2008
From: Makoto Asai <Makoto Asai>

Hi,

 This is done by two steps.

Firstly, register G4StepLimiter process to electron. 
 pmanager->AddDiscreteProcess(new G4StepLimiter);

Then, define G4UserLimit object to the logical volume
of your sphere.
 G4double maxStepLength = ...;
 logSphere->SetUsetLimits(new G4UserLimits(maxStepLength);

Hope this helps.
Makoto
  

> -----Original Message-----
> From: jfgao@mdanderson.org [mailto:jfgao@mdanderson.org] 
> Sent: Tuesday, March 11, 2008 9:30 AM
> To: medical_app-g4hn
> Subject: about step limitation in Hadrontherapy 
> 
> *** Discussion title: Medical Applications
> Email replies to medical_app-g4hn@slac.stanford.edu must include:
>   In-Reply-To: <"/medical_app/165"@geant4-hn.slac.stanford.edu>
>   Subject: ...change this to be about your reply.
> 
> Dear G4 Developers:
> I try to simulate protons irridiating a nanometer scale 
> sphere ( diameter 
> 40 nm). In the visulation, I can see the protons and 
> secondary electrons
> going around the nanosphere. But when I collect the energy 
> depositted in
> my 40 spherical sensititive detectors (  ridius range from 0-80 nm),
> there is always two high peaks around the surface even the materials 
> incide and outside nanometer sphere are same. Then I check 
> the tracking 
> information and I found the proton info is resonable as 
> following several
> steps,
>    
>  
> **************************************************************
> *******************************************
> * G4Track Information:   Particle = proton,   Track ID = 1,   
> Parent ID = 0
> **************************************************************
> *******************************************
> 
> Step#    X(mm)    Y(mm)    Z(mm) KinE(MeV)  dE(MeV) StepLeng 
> TrackLeng  NextVolume ProcName
>     0   -4e-05 -2.74e-06 1.19e-05      2.53        0        0 
>         0 PhantomNPhys initStep
>     1 -2.62e-05 -2.75e-06 1.19e-05      2.53  1.2e-05 
> 1.38e-05  1.38e-05 PhantomNPhys msc
>     2 -1.59e-05 -2.75e-06 1.19e-05      2.53 2.03e-05 
> 1.03e-05  2.41e-05     NanoPhy Transportation
>     3 -6.8e-06 -2.75e-06 1.19e-05      2.53 0.000109 9.07e-06 
>  3.32e-05     NanoPhy msc
>     4 2.26e-06 -2.75e-06 1.19e-05      2.53 3.05e-05 9.07e-06 
>  4.23e-05     NanoPhy msc
>     5 1.13e-05 -2.74e-06 1.19e-05      2.53        0 9.07e-06 
>  5.13e-05     NanoPhy msc
>     6 1.59e-05 -2.74e-06 1.19e-05      2.53 5.56e-05 4.54e-06 
>  5.59e-05 PhantomNPhys Transportation
>     7 0.000339 -3.2e-06  1.2e-05      2.52  0.00474 0.000323  
> 0.000379 PhantomNPhys hLowEIoni
>     8 0.000626 -3.61e-06 1.19e-05      2.51  0.00401 0.000287 
>  0.000666 PhantomNPhys hLowEIoni 
> 
> But the secondary electrons step is inncorrect as following,
> 
> **************************************************************
> *******************************************
> * G4Track Information:   Particle = e-,   Track ID = 172,   
> Parent ID = 1
> **************************************************************
> *******************************************
> 
> Step#    X(mm)    Y(mm)    Z(mm) KinE(MeV)  dE(MeV) StepLeng 
> TrackLeng  NextVolume ProcName
>     0    0.101 -0.00038  0.00363  0.000999        0        0  
>        0 PhantomNPhys initStep
>     1    0.101 -0.000368  0.00363         0 0.000999   0.0215 
>    0.0215 PhantomNPhys msc
> Track (trackID 172, parentID 1) is processed with stopping code 2
> ### pop requested out of 170 stacked tracks.
> 
> I noticed that the StepLeng is always 0.0215 mm. This is 
> obviously outside nanosphere. 
> Can you tell me how to setup steplimiter for secondary 
> electrons? (I noticed others
> have similar problem)
> thank you!
>   
> 

Inline Depth:
 1 1
 All All
Outline Depth:
 1 1
 2 2
 All All
Add message: (add)

 Add Message Add Message
to: "RE: about step limitation in Hadrontherapy "

 Subscribe Subscribe

This site runs SLAC HyperNews version 1.11-slac-98, derived from the original HyperNews


[ Geant 4 Home | Geant 4 HyperNews | Search | Request New Forum | Feedback ]