title: RBE variation between fast neutron beams as a function of energy. Intercomparison involving 7 neutrontherapy facilities.
abstract: In fast neutron therapy, the relative biological effectiveness (RBE) of a given beam varies to a large extent with the neutron energy spectrum. This spectrum depends primarily on the energy of the incident particles and on the nuclear reaction used for neutron production. However, it also depends on other factors which are specific to the local facility, eg, target, collimation system, etc. Therefore direct radiobiological intercomparisons are justified. The present paper reports the results of an intercomparison performed at seven neutrontherapy centres: Orléans, France (p(34)+Be), Riyadh, Saudi Arabia (p(26)+Be), Ghent, Belgium (d(14.5)+Be), Faure, South Africa (p(66)+Be), Detroit, USA (d(48)+Be), Nice, France (p(65)+Be) and Louvain-la-Neuve, Belgium (p(65)+Be). The selected radiobiological system was intestinal crypt regeneration in mice after single fraction irradiation. The observed RBE values (ref cobalt-60 gamma-rays) were 1.79 +/- 0.10, 1.84 +/- 0.07, 2.24 +/- 0.11, 1.55 +/- 0.04, 1.51 +/- 0.03, 1.50 +/- 0.04 and 1.52 +/- 0.04, respectively. When machine availability permitted, additional factors were studied: two vs one fraction (Ghent, Louvain-la-Neuve), dose rate (Detroit), influence of depth in phantom (Faure, Detroit, Nice, Louvain-la-Neuve). In addition, at Orléans and Ghent, RBEs were also determined for LD50 at 6 days after selective abdominal irradiation and were found to be equal to the RBEs for crypt regeneration. The radiobiological intercomparisons were always combined with direct dosimetric intercomparisons and, when possible in some centres, with microdosimetric investigations.
authors.affiliation: Cliniques Universitaires St-Luc, Catholic University of Louvain-la-Neuve, UCL, Brussels, Belgium.
authors.forename: J
authors.initials: J
authors.lastname: Gueulette
authors.forename: M
authors.initials: M
authors.lastname: Beauduin
authors.forename: V
authors.initials: V
authors.lastname: Grégoire
authors.forename: S
authors.initials: S
authors.lastname: Vynckier
authors.forename: B M
authors.initials: BM
authors.lastname: De Coster
authors.forename: M
authors.initials: M
authors.lastname: Octave-Prignot
authors.forename: A
authors.initials: A
authors.lastname: Wambersie
authors.forename: K
authors.initials: K
authors.lastname: Strijkmans
authors.forename: A
authors.initials: A
authors.lastname: De Schrijver
authors.forename: S
authors.initials: S
authors.lastname: El-Akkad
authors.forename: L
authors.initials: L
authors.lastname: Böhm
authors.forename: J P
authors.initials: JP
authors.lastname: Slabbert
authors.forename: D T
authors.initials: DT
authors.lastname: Jones
authors.forename: R
authors.initials: R
authors.lastname: Maughan
authors.forename: J
authors.initials: J
authors.lastname: Onoda
authors.forename: M
authors.initials: M
authors.lastname: Yudelev
authors.forename: A T
authors.initials: AT
authors.lastname: Porter
authors.forename: W E
authors.initials: WE
authors.lastname: Powers
authors.forename: R
authors.initials: R
authors.lastname: Sabattier
authors.forename: N
authors.initials: N
authors.lastname: Breteau
authors.forename: A
authors.initials: A
authors.lastname: Courdi
authors.forename: N
authors.initials: N
authors.lastname: Brassart
authors.forename: P
authors.initials: P
authors.lastname: Chauvel
mesh_terms: D000005:Abdomen / Q000528:radiation effects; D000818:Animals; D002470:Cell Survival / Q000528:radiation effects*; D017357:Cyclotrons; D004307:Dose-Response Relationship, Radiation; D005214:Fast Neutrons; D005260:Female; D005720:Gamma Rays; D007413:Intestinal Mucosa / Q000166:cytology / Q000528:radiation effects; D051379:Mice; D008815:Mice, Inbred Strains; D011522:Protons; D011882:Radiotherapy, High-Energy / Q000379:methods*; D012038:Regeneration / Q000528:radiation effects; D012062:Relative Biological Effectiveness
chemical_list: D011522:Protons