Commissioning of the 4-D treatment delivery system for organ motion management in synchrotron-based scanning ion beams

Mario Ciocca*, Alfredo Mirandola, Silvia Molinelli, Stefania Russo, Edoardo Mastella, Alessandro Vai, Andrea Mairani, Giuseppe Magro, Andrea Pella, Marco Donetti, Francesca Valvo, Piero Fossati, Guido Baroni

*Corresponding author for this work

Research output: Journal article (peer-reviewed)Journal article

36 Citations (Scopus)


Purpose The aim of this work was the commissioning of delivery procedures for the treatment of moving targets in scanning pencil beam hadrontherapy. Methods EBT3 films fixed to the Anzai Respiratory Phantom were exposed to carbon ion scanned homogeneous fields (E = 332 MeV/u). To evaluate the interplay effect, field size and flatness for 3 different scenarios were compared to static condition: gated irradiation or repainting alone and combination of both. Respiratory signal was provided by Anzai pressure sensor or optical tracking system (OTS). End-exhale phase and 1 s gating window were chosen (2.5 mm residual motion). Dose measurements were performed using a PinPoint ionization chamber inserted into the Brainlab ET Gating Phantom. A sub-set of tests was also performed using proton beams. Results The combination of gating technique and repainting (N = 5) showed excellent results (6.1% vs 4.3% flatness, identical field size and dose deviation within 1.3%). Treatment delivery time was acceptable. Dose homogeneity for gated irradiation alone was poor. Both Anzai sensor and OTS appeared suitable for providing respiratory signal. Comparisons between protons and carbon ions showed that larger beam spot sizes represent more favorable condition for minimizing motion effect. Conclusion Results of measurements performed on different phantoms showed that the combination of gating and layered repainting is suitable to treat moving targets using scanning ion beams. Abdominal compression using thermoplastic masks, together with multi-field planning approach and multi-fractionation, have also been assessed as additional strategies to mitigate the effect of patient respiration in the clinical practice.

Original languageEnglish
Pages (from-to)1667-1671
Number of pages5
JournalPhysica Medica
Issue number12
Publication statusPublished - 01 Dec 2016
Externally publishedYes


  • Ion beam radiotherapy
  • Motion mitigation
  • Pencil beam scanning
  • Respiratory gating

ASJC Scopus subject areas

  • Biophysics
  • Radiology, Nuclear Medicine and Imaging
  • General Physics and Astronomy


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