title: Nanodosimetry and RBE values in radiotherapy.
abstract: In a recent paper, the authors reported that the dose mean lineal energy, [Formula: see text] in a volume of about 10-15 nm is approximately proportional to the α-parameter in the linear-quadratic relation used in fractionated radiotherapy in both low- and high-LET beams. This was concluded after analyses of reported radiation weighting factors, WisoE (clinical RBE values), and [Formula: see text] values in a large range of volumes. Usually, microdosimetry measurements in the nanometer range are difficult; therefore, model calculations become necessary. In this paper, the authors discuss the calculation method. A combination of condensed history Monte Carlo and track structure techniques for calculation of mean lineal energy values turned out to be quite useful. Briefly, the method consists in weighting the relative dose fractions of the primary and secondary charged particles with their respective energy-dependent dose mean lineal energies. The latter were obtained using a large database of Monte Carlo track structure calculations.
authors.affiliation: Radiation Biophysics Group, Department of Oncology-Pathology, Karolinska Institutet, Stockholm SE-17176, Sweden Lennart.lindborg@ki.se.
authors.forename: Lennart
authors.initials: L
authors.lastname: Lindborg
authors.affiliation: RaySearch Laboratories, Sveavägen 25, Stockholm SE-11134, Sweden.
authors.forename: Martha
authors.initials: M
authors.lastname: Hultqvist
authors.affiliation: Medical Radiation Physics, Department of Medicine and Health Sciences (IMH), Faculty of Health Sciences, Linköping University, Linköping SE 581 85, Sweden Swedish Radiation Safety Authority, Stockholm SE 171 16, Sweden.
authors.forename: Å
authors.initials: Å
authors.lastname: Carlsson Tedgren
authors.affiliation: Radiation Biophysics Group, Department of Oncology-Pathology, Karolinska Institutet, Stockholm SE-17176, Sweden.
authors.forename: Hooshang
authors.initials: H
authors.lastname: Nikjoo
mesh_terms: D003198:Computer Simulation; D006801:Humans; D018499:Linear Energy Transfer / Q000528:radiation effects*; D008954:Models, Biological; D009010:Monte Carlo Method; D036103:Nanotechnology / Q000379:methods*; D009369:Neoplasms / Q000532:radiotherapy*; D010315:Particle Accelerators / Q000295:instrumentation*; D011874:Radiometry / Q000295:instrumentation* / Q000379:methods; D011879:Radiotherapy Dosage; D012062:Relative Biological Effectiveness