RE: [fluka-discuss]: modulator wheel in proton radiotherapy

From: Vasilis Vlachoudis <Vasilis.Vlachoudis_at_cern.ch>
Date: Fri, 20 Jun 2014 10:07:54 +0000

Hi Mohammad,

I presume that the speed of rotation of your disc is very low compared to the propagation of the particles.

In this case you should modify the geometry (the bodies of the disc) for every starting particle.
You have to create a custom source.f routine (enabled with the SOURCE card)
and inside the
        IF (LFIRST) THEN
              CALL NM2BDY('AAA ',IAAA,IERR)
...
        END IF
block call the NM2BDY routine to convert the names to indexes of the bodies you want to modify.
e.g. Imagine I am cutting my rotating disc with a tilted plane named 'AAA' located at (0,0,0)
defined as PLA (not XYP, ...)
(be carefull on the spaces after the name it has to be exactly 8 characters.

Also in the header of the source.f you have to save the index with
        SAVE IAAA
and to declare the array of the WHATs
       DIMENSION WHAT(18)

before pushing the particle in the stack you can randomly select lets say a rotation for this plane
        PHI = FLRNDM(XXX)*TWOPIP
       WHAT(1) = COS(PHI)
       WHAT(2) = SIN(PHI)
       WHAT(3) = ZERZER
       WHAT(4) = ZERZER
       WHAT(5) = ZERZER
       WHAT(6) = ZERZER
       CALL RSTBDY(IAAA, 15, WHAT, 6)

Hope that helps
Vasilis

________________________________________
From: rafiqphy_at_gmail.com [rafiqphy_at_gmail.com] on behalf of Mohammad Islam [rafiqul.islam_at_okstate.edu]
Sent: 18 June 2014 04:19
To: Vasilis Vlachoudis
Cc: fluka-discuss_at_fluka.org
Subject: Re: [fluka-discuss]: modulator wheel in proton radiotherapy

Dear Vasilis,

Thank you very much for you help.
I am currently working as per your suggestion. One quick question:
where would I get CALL NM2BDY('name....', ID, IERR) and CALL
RSTBDY(ID, BODYTYPE, WHAT, NWHAT) routines. And where to use them. Any
example would be a great help. Thanks.

Rafiq

On Mon, Jun 16, 2014 at 1:51 AM, Vasilis Vlachoudis
<Vasilis.Vlachoudis_at_cern.ch> wrote:
> Hi Mohamad,
>
> it is possible to introduce a rotating wheel in your simulations. It will be treated as a moving body.
> You will have to modify its parameters (on the bodies that they describe it) during run time, most
> preferable with in a custom source routine. For every new particle you change the location of the wheel.
>
> However (even recommended) If you feel uncomfortable with user routines, then the easiest and safest
> way would be to make multiple simulations with various geometries. You can use
> #define VAR value
> to define variables and make a "dynamic" geometry. Using the flair ability to make muliple
> runs by tweaking the variables value you simulate several setups. Check the "loop" function.
>
> If you wish to modify a bodies parameter you need the following routines:
>
> * To get the body id (very slow, save the return value, to avoid multiple calls)
> CALL NM2BDY('name....', ID, IERR)
>
> * To reset the body parameters
> CALL RSTBDY(ID, BODYTYPE, WHAT, NWHAT)
>
> Body types:
> ARB 1
> SPH 2
> RCC 3
> REC 4
> TRC 5
> ELL 6
> BOX 7
> WED 8
> RPP 9
> ZCC 10
> ZEC 11
> XYP 12
> XZP 13
> YZP 14
> PLA 15
> XCC 16
> XEC 17
> YCC 18
> YEC 19
> QUA 20
> END 21
>
> Vasilis
>
> ________________________________________
> From: owner-fluka-discuss_at_mi.infn.it [owner-fluka-discuss_at_mi.infn.it] on behalf of Mohammad Islam [rafiqul.islam_at_okstate.edu]
> Sent: 15 June 2014 07:01
> To: fluka-discuss_at_fluka.org
> Subject: [fluka-discuss]: modulator wheel in proton radiotherapy
>
> Dear fluka users,
>
> I have a question:
> In proton radiotherapy, a range modulator wheel is usually used to
> produce the desired spread out Bragg peak (SOBP). Roughly, the range
> modulator wheel rotates when the beam is on and produces the SOBP. My
> question is can I introduce a rotating wheel in the input file, i.e
> the beam will pass through a rotating wheel of particular speed. Is it
> possible to do in FLUKA? I would appreciate any suggestion.
>
> I want to mention that the effect of the modulation wheel can be
> produced in some other ways without physically introducing the
> modulator wheel. But I am interested if a rotating wheel can be
> directly placed in the input.
>
> Thanks
> Rafiq
>
Received on Fri Jun 20 2014 - 13:54:26 CEST

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