title: Recent advances of nanodosimetry.
abstract: The early damage to genes and cells due to ionizing radiation is initiated by the overlay of the track structure of charged particles and of the structure of radiosensitive sub-cellular volumes. As a result of this overlay, a specified number of ionizations (the ionization cluster size) is formed per primary particle. Therefore, one of the aims of nanodosimetry is to determine ionization cluster-size distributions in nanometric volumes of liquid water, as a substitute to sub-cellular structures. After a short description of the main aspects of cluster-size formation by charged particles, an overview of the advanced measuring techniques that use millimetric target volumes filled with a low-pressure gas to simulate nanometric target volumes at unit density is given. Afterwards, physical principles are discussed which are applicable to convert ionization cluster-size distributions measured in gases into those for liquid water. Finally, a tentative possibility is proposed of how to relate parameters derived from cluster-size distributions in liquid water to parameters derived from radiation-induced radiobiological experiments.
authors.affiliation: Physikalisch-Technische Bundesanstalt, Department Fundamentals of Dosimetry, Bundesallee 100, D-38116 Braunschweig, Germany. Bernd.Grosswendt@ptb.de
authors.forename: B
authors.initials: B
authors.lastname: Grosswendt
mesh_terms: D001822:Body Burden; D004784:Environmental Monitoring / Q000295:instrumentation / Q000379:methods; D006801:Humans; D036103:Nanotechnology / Q000295:instrumentation / Q000379:methods* / Q000639:trends*; D009502:Neutrons; D016273:Occupational Exposure / Q000032:analysis; D011785:Quality Assurance, Health Care / Q000379:methods; D011829:Radiation Dosage; D011835:Radiation Protection / Q000295:instrumentation* / Q000379:methods*; D011874:Radiometry / Q000295:instrumentation / Q000379:methods* / Q000639:trends*; D012062:Relative Biological Effectiveness; D015203:Reproducibility of Results; D018570:Risk Assessment / Q000379:methods / Q000639:trends; D012307:Risk Factors; D017751:Safety Management / Q000379:methods; D012680:Sensitivity and Specificity; D013673:Technology Assessment, Biomedical