Dosimetry for Scanned Pencil Beam Proton Therapy

Pencil beam scanning is a relatively new proton therapy delivery technique, in which narrow pencil beams are magnetically scanned across the target volume. In combination with energy changes, individually weighted pencil beams/Bragg peaks (PB/BP) can be delivered anywhere  within the target to create highly conformal proton plans.

International codes of practice for reference dosimetry and recommendations for measurement of beam characteristics in proton therapy exists (TRS-398, ICRU 78). However, they are mainly focused on passive scattering delivery technology and they do not address specific issues of pencil beam scanning. The aim of the subcommittee is to develop uniform guidelines for the absolute and relative dosimetry of the pencil beam scanning modality with continuous and pulsed proton beams, focusing on the new proton therapy facilities that are currently being developed in the Netherlands and Belgium. The guidelines will be based on current literature as well as clinical experience of the participating members of this subcommittee.

The first meeting of this committee was 5 September 2016.

Topics to be covered

  • Reference dosimetry
  • Single pencil beam specific characteristics
  • Time and space dependent dosimetry
  • Neutron contamination
  • Characteristics of dosimetry equipment

Members of this NCS subcommittee

  • Marco Schippers (PSI/UMCG, advisor)
  • Marc-Jan van Goethem (UMCG, chair)
  • Stephan Both (UMCG)
  • Frank Verhaegen (MAASTRO)
  • Enrica Seravalli (UMCU)
  • Steven Habraken (HPTC/ErasmusMC)
  • Paul van Beers (HPTC)
  • Gloria Vilches Freixas  (MAASTRO, secretary)
  • Petra Trnkova (HPTC/ErasmusMC)
  • Hugo Palmans (Medaustron, Austria and National Physical Laboratory, UK)
  • Jacco  de Pooter (VSL, representative NCS board)