% IMPORTANT: The following is UTF-8 encoded.  This means that in the presence
% of non-ASCII characters, it will not work with BibTeX 0.99 or older.
% Instead, you should use an up-to-date BibTeX implementation like “bibtex8” or
% “biber”.

@ARTICLE{Marot:278407,
      author       = {M. Marot$^*$ and F. Jäger$^*$ and K.-S. Greilich$^*$ and
                      C. P. Karger$^*$ and O. Jaekel$^*$ and L. N. Burigo$^*$},
      title        = {{M}onte {C}arlo simulation for proton dosimetry in magnetic
                      fields: {F}ano test and magnetic field correction factors
                      k{B}for {F}armer-type ionization chambers.},
      journal      = {Physics in medicine and biology},
      volume       = {68},
      issn         = {0031-9155},
      address      = {Bristol},
      publisher    = {IOP Publ.},
      reportid     = {DKFZ-2023-01641},
      pages        = {175037},
      year         = {2023},
      note         = {#EA:E040#LA:E040# / Phys. Med. Biol. 68 (2023) 175037},
      abstract     = {In this contribution we present a special Fano test for
                      charged particles in presence of magnetic fields in the MC
                      code TOPAS, as well as the determination of magnetic field
                      correction factors kBfor Farmer-type ionization chambers
                      using proton $beams.\
\
Approach:$ Customized C++
                      extensions for TOPAS were implemented to model the special
                      Fano tests in presence of magnetic fields for electrons and
                      protons. The Geant4-specific transport
                      parameters,DRoverRandfinalRange, were investigated to
                      optimize passing rate and computation time. The kBwas
                      determined for the Farmer-type PTW 30013 ionization chamber,
                      and 5 custom built ionization chambers with same geometry
                      but varying inner radius, testing magnetic flux density
                      ranging from 0 to 1.0 T and two proton beam energies of
                      157.43 and 221.05 $MeV.\
\
Main$ results: Using the
                      investigated parameters, TOPAS passed the Fano test within
                      $0.39±0.15\%$ and $0.82±0.42\%,$ respectively for
                      electrons and protons. The chamber response (kBMQ) gives a
                      maximum at different magnetic flux densities depending of
                      the chamber size, 1.0043 at 1.0 T for the smallest chamber
                      and 1.0051 at 0.2 T for the largest chamber. The local dose
                      difference cBremained ≤ $0.1\%$ for both tested energies.
                      The magnetic field correction factor kB, for the chamber PTW
                      30013, varied from 0.9946 to 1.0036 for both tested
                      $energy.\
\
Significance:$ The developed extension
                      for the special Fano test in TOPAS MC code with the adjusted
                      transport parameters, can accurately transport electron and
                      proton particles in magnetic field. This makes TOPAS a
                      valuable tool for the determination of kB. The ionization
                      chambers we tested showed that kBremains small $(<0.7\%).$
                      To the best of our knowledge, this is the first calculations
                      of kBfor proton beams. This work represents a significant
                      step forward in the development of MRgPT and protocols for
                      proton dosimetry in presence of magnetic $field.\&#xD.$},
      keywords     = {MR-guided proton therapy (Other) / TOPAS (Other) /
                      dosimetry (Other) / magnetic field (Other) / magnetic field
                      correction factor (Other)},
      cin          = {E040},
      ddc          = {530},
      cid          = {I:(DE-He78)E040-20160331},
      pnm          = {315 - Bildgebung und Radioonkologie (POF4-315)},
      pid          = {G:(DE-HGF)POF4-315},
      typ          = {PUB:(DE-HGF)16},
      pubmed       = {pmid:37567226},
      doi          = {10.1088/1361-6560/acefa1},
      url          = {https://inrepo02.dkfz.de/record/278407},
}