RESUMO
Measurements described in this article were carried out with the aim of evaluating risks of the patient exposure to secondary neutrons during treatment at the Proton Therapy Centre Prague. The neutron spectral fluence was measured by means of the extended Bonner sphere spectrometer (EBS). The article presents secondary neutron spectral fluences obtained by the EBS with passive thermoluminescent detectors, i.e. pairs of 6LiF and 7LiF chips. Measurements were performed in two positions: the first one behind the Nylon 6 phantom, and the second one close to the range shifter to evaluate their contribution to the generation of neutrons. Both the Nylon 6 phantom and the range shifter were irradiated with a pencil beam of protons 4 mm in diameter and the energy of 200 MeV. The results are supplemented with the values of effective dose derived from neutron spectral fluences.
Assuntos
Nêutrons , Imagens de Fantasmas , Terapia com Prótons/efeitos adversos , Radiometria/instrumentação , Humanos , Terapia com Prótons/instrumentação , Terapia com Prótons/métodos , Doses de Radiação , Radiometria/métodosRESUMO
This article addresses practical issues as being faced in the process of testing, verification and calibration of passive and active personal neutron dosemeters. Namely, a limited choice of neutron sources and geometric limitations occurring when ISO water phantom is used. The requirements of international standards for personal neutron dosemeters and the possibilities to fulfil them are discussed briefly.