IMRT or VMAT simulations

Flair
1

Dear Experts,

I have .dcm, RP.dcm, RD.dcm and RS.dcm files and that can be imported in the flair.

Now, can I simulate photon-based IMRT (Intensity Modulated Radiotherapy) or VMAT (Volumetric Arc Therapy) plan in FLUKA using these files ?

Additionally I have the following general queries for the situation when we import the RP.dcm file:

  1. I hope it will take the following information from RP.dcm file: beamlets (through SpotBeam) and gantry angles.

  2. Should I put BEAMPOS card in this case ?

  3. If IMRT is done using 6 MV photon, I hope I need to compile the photon spectrum and open 10 cm x 10 cm field size through source.f card ?

  4. I am not supposed to make the geometry of accelerator head or collimator or MLCs. That will be taken care by the imported RP.dcm file. Am I correct ?

Any example file or any documents related to this will be helpful for me.

Any reply will be helpful for me. Thanking you in advance.

2

Hi @ArghyaC

The dicom filenames are not part of the standard, so I presume with the filenames you refer to

  • RP.dcm RTPLAN modality
  • RD.dcm RTDOSE
  • RS.dcm RTSTRUCT
  1. flair will convert the RTPLAN to multiple SPOTBEAM, SPOTPOS cards with the proper energy position and direction. If you need a custom energy spread you need to define a beam model in the RTPlan page of flair.
  2. BEAMPOS would be irrelevant, however you need to put a BEAM card to define the max energy of the problem
  3. The rectangular profile can be defined with the SPOTPOS.
    Please verify in flair if the automatically created SPOTPOS contain a rectangular profile and not a Guassian.
    If you need a custom energy spectrum per spot, this is not possible through the SPOTBEAM/POS cards you would need a custom source.f routine.
  4. You would need to make the geometry of the accelerator head, collimator, MLC manually. As far as I am aware this information is not stored in a standard way inside the dicom files. Therefore flair has no way of creating them automatically.
3

Thank you very much for your reply.

What I understood from the reply that, MLC created irregular field size will not be taken care by the SPOTBEAM/SPOTPOS card.

So, it will be difficult to simulate photon based IMRT or VMAT plan where MLC movement and all are very important factor.

Am I correct. Kindly correct me if my understanding is wrong.

4

Yes, flair will correctly create the SPOTBEAM/POS cards as they are defined in the RTPLAN but not the MLC (multi-leaf collimator).
You will need to model it manually.