[Gate-users] how to set MU prescription dose lines

Wed May 15 10:41:42 CEST 2013

yes, but only 4 values [10;5], [5;0], [0;-5] and [-5;-10].

The SetPosition could be used to move the actor inside the attached volume
(waterbox in your case), in the coordinate system of the waterbox. So if
you set position to "0 0 5" for example, you will still have 4 dosels (dose
in volume) :  [15;10] [10;5], [5;0], and [0;-5]. But the first one is thus
outside the volume so no dose deposition will be stored in the first dosel.

Note that if you are saving the dose actor in mhd image file format, the
"origin" of the image is updated according this position.

David

On Wed, May 15, 2013 at 4:30 AM, 刘斌信件 <golder_time at 163.com> wrote:

> **
> Hi david ,
>
>     What is the relationship between Doseactor and setPostion ,do the
> "setPostion " set the origin of the scored dose voxel ? As the following is
> an example,
>
>
> /gate/world/daughters/name WaterBox******
>
> /gate/world/daughters/insert box****
>
> /gate/WaterBox/setMaterial Water****
>
> /gate/WaterBox/geometry/setXLength 20 mm****
>
> /gate/WaterBox/geometry/setYLength 20 mm****
>
> /gate/WaterBox/geometry/setZLength 20 mm****
>
> /gate/WaterBox/placement/setTranslation 0.0 0.0 0.0 mm****
>
>
> /gate/actor/addActor                   DoseActor dose****
>
> /gate/actor/dose/attachTo              WaterBox****
>
> /gate/actor/dose/setPosition           0 0 0 mm****
>
> /gate/actor/dose/setSize               5 5 20 mm****
> /gate/actor/dose/setVoxelSize          5 5 5 mm
>
> as above , in my view , the actor will gets five dose points , their
> z-axis coordinates are  10 ,5, 0, -5,-10, is that right? The "setpostion
> " is used to set the symmetrical center of the volume of detected by
> doseactor .
>
> Thank you so much
>
> Yours sincerely
>
> Bin.
>
>
> ----- Original Message -----
> *From:* David Sarrut <David.Sarrut at creatis.insa-lyon.fr>
> *To:* 刘斌信件 <golder_time at 163.com>
> *Sent:* Friday, May 10, 2013 6:58 PM
> *Subject:* Re: [Gate-users] how to set MU prescription dose lines
>
> this is classical "variance reduction technique" that consists in
> producing n photons (instead of a single one), each of them with a relative
> weight of 1/n. It means that such photons behave like 1/n part of photon.
>
> Look for articles/chapter on "variance reduction technique"
>
> Sincerely,
> David
>
>
> On Fri, May 10, 2013 at 10:42 AM, 刘斌信件 <golder_time at 163.com> wrote:
>
>> **
>> Hi,
>>
>>    I'm sorry that I  yet can't understand clearly  the "weight" and  "the
>> splitting factor n ", the following are the part of the text in the paper :
>>
>> When a primary electron hit the target and produce a bremsstrahlung
>> photon, the SBS tool sampled n photons at once, with a weight of 1/n each,
>> all having the same energy and starting from the electron hit point in the
>> target, only the photon direction was sampled, according to the direction
>> criterion. User can define the splitting factor n, as well as the direction
>> criterion.
>>
>>    What is  meaning of the setence "the SBS tool sampled n photons at
>> once, with a weight of 1/n each"? Thank you very much .
>> yours sincerely,
>> Bin
>>
>>
>>
>>  ----- Original Message -----
>> *From:* David Sarrut <David.Sarrut at creatis.insa-lyon.fr>
>> *To:* 刘斌信件 <golder_time at 163.com>
>> *Cc:* gate-users <gate-users at lists.opengatecollaboration.org>
>> *Sent:* Friday, May 10, 2013 3:20 PM
>> *Subject:* Re: [Gate-users] how to set MU prescription dose lines
>>
>>  Hello,
>>
>> there is no direct relationship between MU and number of primaries. You
>> need to somehow calibrate your system such as a given number of particles
>> gives you a given dose (ie 1 Gy at 10 cm in  water), and make the link with
>> the MU.
>>
>> Yes the weight (1/N) of the particle is taken into account in the
>> doseactor. This is a weight associated with a particle (the E is not
>> divided, only the deposited E).
>>
>> Sincerely,
>> David
>>
>>
>> On Thu, May 2, 2013 at 4:11 PM, 刘斌信件 <golder_time at 163.com> wrote:
>>
>>> hi,
>>>   I  do not know the relation between "setTotalNumberOfPrimaries" of
>>> simulation  and  MU prescription dose in the external radiotherapy . How
>>> should  I set the number of the photon or events in simulation that the
>>> absorbed depth dose in phantom will arrive at a expected value. In addition
>>> , in Selective bremsstrahlung splitting (SBS) technology, the final state
>>> of the process is generated N times and the weight of each secondary is
>>> 1/N. Does it divide the energy of photon ( original produced by the
>>> bremsstrahlung)  into N pieces of energy ,and then get  single photon with
>>> original  energy of 1/N in  the same direction ?
>>>  Thank you for attention?
>>> yours sincerely,
>>> Bin
>>> _______________________________________________
>>> Gate-users mailing list
>>> Gate-users at lists.opengatecollaboration.org
>>> http://lists.opengatecollaboration.org/mailman/listinfo/gate-users
>>>
>>
>>
>>
>> --
>> David Sarrut, Phd
>> Chargé de recherche CNRS
>> CREATIS, UMR CNRS 5220, Inserm U 1044
>> Centre de lutte contre le cancer Léon Bérard
>> 28 rue Laënnec, 69373 Lyon cedex 08
>> Tel : 04 78 78 51 51 / 06 74 72 05 42
>> http://www.creatis.insa-lyon.fr/~dsarrut
>> _________________________________
>>  "2 + 2 = 5,  for extremely large values of 2"
>> _________________________________
>>
>>
>
>
> --
> David Sarrut, Phd
> Chargé de recherche CNRS
> CREATIS, UMR CNRS 5220, Inserm U 1044
> Centre de lutte contre le cancer Léon Bérard
> 28 rue Laënnec, 69373 Lyon cedex 08
> Tel : 04 78 78 51 51 / 06 74 72 05 42
> http://www.creatis.insa-lyon.fr/~dsarrut
> _________________________________
>  "2 + 2 = 5,  for extremely large values of 2"
> _________________________________
>
>

-- 
David Sarrut, Phd
Chargé de recherche CNRS
CREATIS, UMR CNRS 5220, Inserm U 1044
Centre de lutte contre le cancer Léon Bérard
28 rue Laënnec, 69373 Lyon cedex 08
Tel : 04 78 78 51 51 / 06 74 72 05 42
http://www.creatis.insa-lyon.fr/~dsarrut
_________________________________
 "2 + 2 = 5,  for extremely large values of 2"
_________________________________
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