Überwachung von Veränderungen der Hautdosis während der bildgesteuerten helikalen Tomotherapie bei Patienten mit Kopf-Hals-Tumoren

Translated title of the contribution: Monitoring skin dose changes during image-guided helical tomotherapy for head and neck cancer patients

Martina Mori, Italo Dell’Oca, Marco Branchini, Silvia Foti, Sara Broggi, Lucia Perna, Giovanni Mauro Cattaneo, Riccardo Calandrino, Nadia Gisella Di Muzio, Claudio Fiorino

Research output: Contribution to journalArticlepeer-review

Abstract

Purpose: An increase of skin dose during head and neck cancer (HNC) radiotherapy is potentially dangerous. Aim of this study was to quantify skin dose variation and to assess the need of planning adaptation (ART) to counteract it. Methods: Planning CTs of 32 patients treated with helical tomotherapy (HT) according to a Simultaneous Integrated Boost (SIB) technique delivering 54/66 Gy in 30 fractions were deformably co-registered to MVCTs taken at fractions 15 and 30; in addition, the first fraction was also considered. The delivered dose-of-the-day was calculated on the corresponding deformed images. Superficial body layers (SL) were considered as a surrogate for skin, considering a layer thickness of 2 mm. Variations of SL DVH (∆SL) during therapy were quantified, focusing on ∆SL95% (i.e., 62.7 Gy). Results: Small changes (within ± 1 cc for ∆SL95%) were seen in 15/32 patients. Only 2 patients experienced ∆SL95% > 1 cc in at least one of the two monitored fractions. Negative ∆SL95% > 1 cc (up to 17 cc) were much more common (15/32 patients). The trend of skin dose changes was mostly detected at the first fraction. Negative changes were correlated with the presence of any overlap between PTV and SL at planning and were explained in terms of how the planning system optimizes the PTV dose coverage near the skin. Acute toxicity was associated with planning DVH and this association was not improved if considering DVHs referring to fractions 15/30. Conclusion: About half of the patients treated with SIB with HT for HNC experienced a skin-sparing effect during therapy; only 6% experienced an increase. Our findings do not support skin-sparing ART, while suggesting the introduction of improved skin-sparing planning techniques.

Translated title of the contributionMonitoring skin dose changes during image-guided helical tomotherapy for head and neck cancer patients
Original languageGerman
Pages (from-to)243-251
Number of pages9
JournalStrahlentherapie und Onkologie
Volume196
Issue number3
DOIs
Publication statusPublished - Mar 1 2020

Keywords

  • Adaptive radiotherapy
  • Head and neck cancer
  • Radiotherapy planning
  • Skin toxicity
  • Tomotherapy

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging
  • Oncology

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