Proton beam therapy has advantages in comparison to conventional photon radiotherapy due to the physical properties of proton beams (e.g. sharp distal fall off, adjustable range and modulation). In proton therapy, there is the possibility of sparing healthy tissue close to the target volume. This is especially important when tumours are located next to critical organs and while treating cancer in paediatric patients. On the other hand, the interactions of protons with matter result in the production of secondary radiation, mostly neutrons and gamma radiation, which deposit their energy at a distance from the target. The aim of this study was to compare the response of different passive dosimetry systems in mixed radiation field induced by proton pencil beam inside anthropomorphic phantoms representing 5 and 10 years old children. Doses were measured in different organs with thermoluminescent (MTS-7, MTS-6 and MCP-N), radiophotoluminescent (GD-352 M and GD-302M), bubble and poly-allyl-diglycol carbonate (PADC) track detectors. Results show that RPL detectors are the less sensitive for neutrons than LiF TLDs and can be applied for in-phantom dosimetry of gamma component. Neutron doses determined using track detectors, bubble detectors and pairs of MTS-7/MTS-6 are consistent within the uncertainty range. This is the first study dealing with measurements on child anthropomorphic phantoms irradiated by a pencil scanning beam technique.

Belgium Nuclear Research Center Boeretang 200 Mol Belgium

Cyclotron Centre Bronowice Institute of Nuclear Physics PAN Radzikowskiego 152 Krakow Poland

Departament de Física Universitat Autònoma de Barcelona Bellaterra Spain

Helmholtz Zentrum München Institute of Radiation Protection Ingolstädter Landstraße 1 Neuherberg Germany

Nuclear Physics Institute of the CAS Department of Radiation Dosimetry Na Truhlárce 39 64 Praha Czech Republic

Radiology therapeutic Center Poland SP Z O O Centrum Radioterapii Amethyst w Krakowie Zlotej Jesieni 1 Krakow Poland

Ruder Boškovic Institute Bijenicka cesta 54 Zagreb Croatia

Technische Universität München Physik Department James Franck Str 1 Garching bei München Germany

University of Newcastle upon Tyne Tyne and Wear Newcastle upon Tyne UK

References provided by Crossref.org

Out-of-Field Doses Produced by a Proton Scanning Beam Inside Pediatric Anthropomorphic Phantoms and Their Comparison With Different Photon Modalities

Neutron Radiation Dose Measurements in a Scanning Proton Therapy Room: Can Parents Remain Near Their Children During Treatment?