title: A quality assessment of the effects of a hydrogenous filter on a p(66)Be(40) neutron beam.
abstract: Recent measurements in a p(62)Be(36) neutron therapy beam have shown that the quality of the in-phantom beam changes with depth. This variation can be ascribed to the presence of a relatively large low-energy neutron component emanating from the neutron source. As part of the pre-clinical calibration programme at a newly commissioned neutron therapy facility, radiobiological and microdosimetric observations were made to determine the magnitude of this effect on a p(66)Be(40) beam and to evaluate the hardening effect of a hydrogenous filter. The reported data identify a correlation between the two assays and quantify a linear relationship between y* and filter thicknesses less than or equal to 6 cm. Using the data obtained in the study, a filter thickness was selected to comply with clinical requirements. By employing lineal energy spectra, it is demonstrated that subtle changes in beam quality may be quantified in a reproducible manner without resorting to time-consuming radiobiological studies.
authors.affiliation: National Accelerator Centre, Faure, South Africa.
authors.forename: J P
authors.initials: JP
authors.lastname: Slabbert
authors.forename: P J
authors.initials: PJ
authors.lastname: Binns
authors.forename: H L
authors.initials: HL
authors.lastname: Jones
authors.forename: J H
authors.initials: JH
authors.lastname: Hough
mesh_terms: D000818:Animals; D002470:Cell Survival / Q000528:radiation effects; D006224:Cricetinae; D005214:Fast Neutrons / Q000627:therapeutic use*; D005347:Fibroblasts / Q000528:radiation effects; D008851:Micropore Filters; D009502:Neutrons; D011095:Polyethylenes; D011126:Polypropylenes; D011879:Radiotherapy Dosage
chemical_list: C016674:Plastipore; D011095:Polyethylenes; D011126:Polypropylenes