% 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{Hfel:169693,
      author       = {S. Höfel and M. K. Fix and M. Drescher and F. Zwicker$^*$},
      title        = {{S}uitability of superficial electron paramagnetic
                      resonance dosimetry for in vivo measurement and verification
                      of cumulative total doses during {IMRT}: {A} proof of
                      principle.},
      journal      = {Zeitschrift für medizinische Physik},
      volume       = {31},
      number       = {4},
      issn         = {0939-3889},
      address      = {Amsterdam},
      publisher    = {Elsevier, Urban $\&$ Fischer},
      reportid     = {DKFZ-2021-01500},
      pages        = {365-377},
      year         = {2021},
      note         = {#LA:E055# / Volume 31, Issue 4, November 2021, Pages
                      365-377},
      abstract     = {The present study investigates superficial in vivo
                      dosimetry (IVD) by means of a previously proposed electron
                      paramagnetic resonance (EPR) dosimetry system aiming at
                      measuring and verifying total doses delivered by complex
                      radiotherapy treatments. In view of novel regulatory
                      requirements in Germany, differences between measured and
                      planned total doses to the EPR dosimeters are analyzed and
                      compared to reporting thresholds for significant
                      occurrences.EPR dosimeters, each consisting of one lithium
                      formate monohydrate (LFM) and one polycrystalline l-alanine
                      (ALA) pellet, were attached to the surface of an
                      anthropomorphic head phantom. Three head and neck treatments
                      with total target doses ranging from 30 to 64Gy were fully
                      delivered to the phantom by helical tomotherapy. During each
                      treatment, eight EPR dosimeters were placed at distinct
                      spots: (i) within or next to the planning target volume
                      (PTV), (ii) near to organs at risk including the parotids
                      and the lenses, (iii) at the thyroid lying out-of-field. EPR
                      read out was always performed after all fractions were
                      delivered. EPR results were compared to thermoluminescence
                      dosimeter (TLD) measurements and to the planned total doses
                      derived from the treatment planning system (TPS). Planned
                      total doses to the EPR dosimeters ranged from about 2 to
                      64Gy.By taking uncertainties into account, the measured and
                      planned doses were in good agreement. Exceptions occurred
                      mainly at the thyroid (out-of-field) and lenses (extreme
                      sparing). The maximum total dose difference between EPR
                      results and corresponding planned doses was 1.3Gy occurring
                      at the lenses. Remarkably, each LFM and ALA pellet placed
                      within or next to the PTV provided dose values that were
                      within $±4\%$ of the planned dose. Dose deviations from
                      planned dose values were comparable for EPR and TLD
                      measurements.The results of this proof of principle study
                      suggests that superficial EPR-IVD is applicable in a wide
                      dose range and in various irradiation conditions - being a
                      valuable tool for monitoring cumulative total doses
                      delivered by complex IMRT treatments. EPR-IVD in combination
                      with helical tomotherapy is suitable to reliably detect
                      local dose deviations at superficial dosimeter spots in the
                      order of current national reporting thresholds for
                      significant occurrences (i.e. $10\%/4Gy).$},
      keywords     = {Alanine (Other) / EPR dosimetry (Other) / In vivo (Other) /
                      Intensity modulated radiotherapy (Other) / Lithium formate
                      (Other) / Tomotherapy (Other)},
      cin          = {E055},
      ddc          = {610},
      cid          = {I:(DE-He78)E055-20160331},
      pnm          = {315 - Bildgebung und Radioonkologie (POF4-315)},
      pid          = {G:(DE-HGF)POF4-315},
      typ          = {PUB:(DE-HGF)16},
      pubmed       = {pmid:34210537},
      doi          = {10.1016/j.zemedi.2021.03.006},
      url          = {https://inrepo02.dkfz.de/record/169693},
}