Small field dosimetry

In 2017, the IAEA published the Code of Practice (CoP) on Dosimetry of Small Photon Fields in Radiotherapy (TRS-483). This document introduced a harmonized approach for small field dosimetry, based on the evidence and methodologies available at the time. Since its release, TRS-483 has served as an important reference in several NCS reports addressing small field dosimetry. However, TRS-483 is a comprehensive and technical document. It is also extensive and at times complex to implement in clinical practice. Moreover, new data sets have emerged since its publication, and further insights into key concepts, such as the equivalent square field, have been described in recent scientific literature.

The aim of the NCS Small Field Dosimetry Subcommittee is to provide a concise and practical summary of small field dosimetry, tailored to clinical practice in the Netherlands and Belgium. This report will serve as a user-friendly reference for medical physicists, assistants, research physicists and researchers, while remaining aligned with the core principles of TRS-483.

Efforts will be made to ensure that the scope of this subcommittee does not overlap with that of the NCS subcommittee on Quality Control for Linear Accelerators.

The subcommittee had its first meeting on 15 May 2025.

 Topics to be covered

  • Physics of small photon fields
  • Beam delivery systems
  • Detectors
  • Phantoms
  • Measurement methodology
  • Clinical QA work flow

 

Members of this NCS subcommittee

  • Kelvin Ng Wei Siang  (Erasmus MC/HollandPTC, chair)
  • Simon Woodings (UMCU, secretary)
  • Jacco de Pooter (VSL, representative of the NCS board)
  • Geert Pittomvils (UZ Gent, representative of the NCS board)
  • Jeroen van de Kamer (NKI-AVL)
  • Thomas Foppen (UMCU)
  • Marian Dwarswaard (LUMC)
  • Anne Monseux (CHU)
  • Thierry Gevaert (UZ Brussel)
  • Antoine Delor (UCL)
  • Luca Pellegri (CHU)
  • Geert Pittomvils (UZ Gent)
  • Sven Meijer (Radboud UMC)
  • Ans Swinnen (Maastro)
  • Femke van der Sloot (Erasmus MC)
  • Sander Kamerbeek (ISALA)
  • Marlies Boussaer (UZ Brussel)