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@ARTICLE{Hfel:177253,
      author       = {S. Höfel and M. Gandalini and M. K. Fix and M. Drescher
                      and F. Zwicker$^*$},
      title        = {{P}rospective superficial {EPR} in-vivo dosimetry study
                      during hypofractionated radiotherapy of breast cancer
                      patients treated with helical tomotherapy.},
      journal      = {Radiation oncology},
      volume       = {16},
      number       = {1},
      issn         = {1748-717X},
      address      = {London},
      publisher    = {BioMed Central},
      reportid     = {DKFZ-2021-02387},
      pages        = {209},
      year         = {2021},
      note         = {#LA:E055#},
      abstract     = {In-vivo dosimetry (IVD) is a patient specific measure of
                      quality control and safety during radiotherapy. With regard
                      to current reporting thresholds for significant occurrences
                      in radiotherapy defined by German regulatory authorities,
                      the present study examines the clinical feasibility of
                      superficial electron paramagnetic resonance (EPR) IVD of
                      cumulative total doses applied to breast cancer patients
                      treated with helical intensity-modulated radiotherapy
                      (tomotherapy).In total, 10 female patients with left- or
                      right-sided breast cancer were enrolled in this prospective
                      IVD study. Each patient received a hypofractionated whole
                      breast irradiation. A total median dose of 42.4 Gy in 16
                      fractions (5 fractions per week) was prescribed to the
                      planning target volume. The treatments were completely
                      delivered using helical tomotherapy and daily image guidance
                      via megavoltage CT (MVCT). For each patient, three EPR
                      dosimeters were prepared and placed at distinct locations on
                      the patient's skin during the delivery of all fractions. Two
                      dosimeters were placed next to the ipsilateral and
                      contralateral mammilla and one dosimeter was placed
                      ventrally to the thyroid (out-of-primary-beam). The total
                      doses delivered to the dosimeters were readout after all
                      fractions had been administered. The measured total dose
                      values were compared to the planned dose values derived from
                      the treatment planning system (TPS). Daily positional
                      variations (displacement vectors) of the ipsilateral
                      mammilla and of the respective dosimeter were analyzed with
                      respect to the planned positions using the daily registered
                      MVCT image.Averaged over all patients, the mean absolute
                      dose differences between measured and planned total dose
                      values (± standard deviation (SD)) were: 0.49 ± 0.85 Gy
                      for the ipsilateral dosimeter, 0.17 ± 0.49 Gy for the
                      contralateral dosimeter and -0.12 ± 0.30 Gy for the
                      thyroid dosimeter. The mean lengths of the ipsilateral
                      displacement vectors (± SD) averaged over all patients and
                      fractions were: 10 ± 7 mm for the dosimeter and 8 ± 4 mm
                      for the mammilla.Superficial EPR IVD is suitable as
                      additional safeguard for dose delivery during helical
                      tomotherapy of breast cancer. Despite positional
                      uncertainties in clinical routine, the observed dose
                      deviations at the ipsilateral breast were on average small
                      compared to national reporting thresholds for total dose
                      deviations (i.e. $10\%/4 Gy).$ EPR IVD may allow for the
                      detection of critical dose errors during whole breast
                      irradiations.},
      keywords     = {Alanine (Other) / Breast cancer (Other) / EPR dosimetry
                      (Other) / Hypofractionated (Other) / IMRT (Other) / In vivo
                      (Other) / Lithium formate (Other) / Radiotherapy (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:34717680},
      doi          = {10.1186/s13014-021-01938-8},
      url          = {https://inrepo02.dkfz.de/record/177253},
}