226Ra, 222Rn AND PERMEABILITY OF BELGIAN SOILS IN RELATION WITH INDOOR RADON RISK.

Knowing the concentration of 226Ra in soil and of 222Rn in soil gas is important for the analysis of indoor radon data and the prediction of radon-prone areas. Except for soil Rn in Ardenne, the data concerning these two radionuclides in Belgian soils are very scarce. In the context of Master theses and international courses, students made 92 measurements of 226Ra in soil samples, 105 of 222Rn in soil gas, and 74 of soil permeability, a significant addition to the existing similar data.

Neutron H*(10) inside a proton therapy facility: comparison between Monte Carlo simulations and WENDI-2 measurements.

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.

Uncertainty analysis in MCNP5 calculations for brachytherapy treatment.

The Monte Carlo (MC) method can be applied to simulate brachytherapy treatment planning. The MCNP5 code gives, together with results, a statistical uncertainty associated with them. However, the latter is not the only existing uncertainty related to the simulation and other uncertainties must be taken into account.

Dosimetric characterization of a brachytherapy applicator using MCNP5 modelisation and in-phantom measurements.

A gynaecological applicator consisting of a metallic intra-uterine tube with a plastic vaginal applicator and an HDR Ir-192 source have been simulated with MCNP5 (Monte Carlo code). A solid phantom has been designed to perform measurements around the applicator with radiochromic films. The isodose curves obtained are compared with curves calculated with the F4MESH tally of MCNP5 with a good agreement.

Indoor radon in the region of Brussels.

The indoor radon (222Rn) concentration has been measured by charcoal detectors in 278 buildings in the region of Brussels, Belgium. The correlation with the nature of the subsoil can be studied in detail thanks to the available geotechnical map. With a geometrical mean indoor radon concentration of 19 Bq m(-3), Brussels can be considered as generally unaffected by the radon problem.