Inside an IBA proton therapy centre, secondary neutrons are produced due to nuclear interactions of the proton beam with matter mainly inside the cyclotron, the beam line, the treatment nozzle and the patient. Accurate measurements of the neutron ambient dose equivalent H*(10) in such a facility require the use of a detector that has a good sensitivity for neutrons ranging from thermal energies up to 230 MeV, such as for instance the WENDI-2 detector. WENDI-2 measurements have been performed at the Westdeutsches Protonentherapiezentrum Essen, at several positions around the cyclotron room and around a gantry treatment room operated in two different beam delivery modes: Pencil Beam Scanning and Double Scattering. These measurements are compared with Monte Carlo simulation results for the neutron H*(10) obtained with MCNPX 2.5.0 and GEANT4 9.6.
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http://dx.doi.org/10.1093/rpd/nct289 | DOI Listing |
Appl Radiat Isot
December 2024
Department of Neutron Physics, Research Centre Řež, Hlavní 130, 250 68, Řež, Czech Republic. Electronic address:
The neutron spectrum was measured at two locations in the spent fuel storage facility of the Temelín nuclear power plant. The measurement had two primary objectives: to map the neutron -γ field by quantifying the ambient dose equivalent H∗(10) and to identify methods that could improve the quality of the adjusted neutron spectrum using a Bonner Sphere Spectrometer (BSS). Three spectrometers were used: a BSS and two proton recoil spectrometers.
View Article and Find Full Text PDFRep Pract Oncol Radiother
March 2024
Department of Nuclear Medicine, Medical University of Warsaw, Warsaw, Poland.
Background: The purpose was to assess the impact of irradiation technique type and beam energy on the mixed radiation field around the medical linear accelerator (linac) in terms of radiation quality and related radiation protection quantities.
Materials And Methods: Seven radiotherapeutic plans with Alderson-Rando anthropomorphic phantom [different techniques: conventional three-dimensional conformal radiotherapy (3D-CRT), intensity-modulated radiotherapy (IMRT) and intensity modulated arc therapy (IMAT), different beams: 6 MV or 18 MV, and their arrangements) were prepared for the case of prostate malignancy. Recombination chambers REM-2 and GW2 were positioned on the treatment couch 100 cm from the beam axis at the height of the isocentre.
Radiat Prot Dosimetry
August 2024
This study examines the relationship between ambient dose H*, ambient dose equivalent H*(10), and effective dose E for external neutron irradiation over 163 operational spectra from different workplaces. The results show that H* provides a reasonable estimate with a controlled margin, even if overestimated, to assess E compared with H*(10), which can lead to a significant overestimation or underestimation of E depending on the neutron spectra. The results highlight the limitations of H*(10) and the superiority of H* in estimating E according to the requirements of the operational quantities, especially in environments with high-energy neutrons.
View Article and Find Full Text PDFAppl Radiat Isot
September 2024
State Key Laboratory of NBC Protection for Civilian, Beijing 102205, China. Electronic address:
Introduction: This laboratory plans to establish neutron reference radiation fields with three neutron sources to calibrate neutron-measuring devices. To perform calibration at multiple dose rates, neutron ambient dose equivalent rate H˙(10) needs to range 1 μSv/h to 10 mSv/h. The lower limit requires that the maximum available calibration distance should be at least 4.
View Article and Find Full Text PDFAppl Radiat Isot
June 2024
Department of Energy and Nuclear Engineering, Ontario Tech University, Oshawa, Ontario, Canada.
Bruce Power operates a first-of-its-kind isotope production system (IPS) that enables continuous production of Lu within Canada Deuterium Uranium (CANDU) commercial power reactors. Located on the reactivity mechanisms deck of Unit 7, just outside of reactor containment but in close proximity to the primary heat transport (PHT) pumps, this facility offers unique advantages for Lu production. However, employees working in this area encounter a radiation hazard which consists primarily of photoneutrons.
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